| Message ID | 20220129005429.754727-1-bjorn.andersson@linaro.org |
|---|---|
| State | Accepted |
| Commit | a8e53db46f19f67be6a26488aafb7d10c78e33bd |
| Headers | show |
| Series | [v11,1/2] dt-bindings: leds: Add Qualcomm Light Pulse Generator binding | expand |
On Tue, Feb 1, 2022 at 12:31 AM Bjorn Andersson <bjorn.andersson@linaro.org> wrote: > > The Light Pulse Generator (LPG) is a PWM-block found in a wide range of > PMICs from Qualcomm. These PMICs typically comes with 1-8 LPG instances, > with their output being routed to various other components, such as > current sinks or GPIOs. > > Each LPG instance can operate on fixed parameters or based on a shared > lookup-table, altering the duty cycle over time. This provides the means > for hardware assisted transitions of LED brightness. > > A typical use case for the fixed parameter mode is to drive a PWM > backlight control signal, the driver therefor allows each LPG instance > to be exposed to the kernel either through the LED framework or the PWM > framework. > > A typical use case for the LED configuration is to drive RGB LEDs in > smartphones etc, for which the driver support multiple channels to be supports > ganged up to a MULTICOLOR LED. In this configuration the pattern > generators will be synchronized, to allow for multi-color patterns. ... > +config LEDS_QCOM_LPG > + tristate "LED support for Qualcomm LPG" > + depends on OF || COMPILE_TEST > + depends on SPMI > + help > + This option enables support for the Light Pulse Generator found in a > + wide variety of Qualcomm PMICs. Module name? ... > +#include <linux/of.h> > +#include <linux/of_device.h> Wondering if these can be changed to mod_devicetable.h + property.,h. ... > + * @dev: struct device for LPG device Description without value and actually wrong. it's a pointer to, and not a struct device. ... > + /* Hardware does not behave when LO_IDX == HI_IDX */ Any clue /. elaboration why? ... > +static void lpg_lut_free(struct lpg *lpg, unsigned int lo_idx, unsigned int hi_idx) > +{ > + int len; > + > + if (lo_idx == hi_idx) > + return; > + > + len = hi_idx - lo_idx + 1; Perhaps swap above and add the similar comment: /* We never do a single item because ... */ len = if (len == 1) > + bitmap_clear(lpg->lut_bitmap, lo_idx, len); Who protects this bitmap from simultaneous access by different users? > +} ... > +static int lpg_calc_freq(struct lpg_channel *chan, uint64_t period) > +{ > + unsigned int clk, best_clk = 0; > + unsigned int div, best_div = 0; > + unsigned int m, best_m = 0; > + unsigned int error; > + unsigned int best_err = UINT_MAX; > + u64 best_period = 0; > + > + /* > + * The PWM period is determined by: > + * > + * resolution * pre_div * 2^M > + * period = -------------------------- > + * refclk > + * > + * With resolution fixed at 2^9 bits, pre_div = {1, 3, 5, 6} and > + * M = [0..7]. > + * > + * This allows for periods between 27uS and 384s, as the PWM framework > + * wants a period of equal or lower length than requested, reject > + * anything below 27uS. > + */ > + if (period <= (u64)NSEC_PER_SEC * LPG_RESOLUTION / 19200000) > + return -EINVAL; > + /* Limit period to largest possible value, to avoid overflows */ > + if (period > (u64)NSEC_PER_SEC * LPG_RESOLUTION * 6 * (1 << LPG_MAX_M) / 1024) > + period = (u64)NSEC_PER_SEC * LPG_RESOLUTION * 6 * (1 << LPG_MAX_M) / 2014; 2014?! And if it's incorrect, it seems like a good example to avoid repetition of the long equations. What about best_period = clamp_val(period, ...); if (best_period >= period) return -EINVAL; period = best_period; ? > + /* > + * Search for the pre_div, clk and M by solving the rewritten formula > + * for each clk and pre_div value: > + * > + * period * clk > + * M = log2 ------------------------------------- > + * NSEC_PER_SEC * pre_div * resolution > + */ > + for (clk = 0; clk < ARRAY_SIZE(lpg_clk_rates); clk++) { > + u64 nom = period * lpg_clk_rates[clk]; Can we spell fully nunerator, denominator? > + for (div = 0; div < ARRAY_SIZE(lpg_pre_divs); div++) { > + u64 denom = (u64)NSEC_PER_SEC * lpg_pre_divs[div] * (1 << 9); " * (1 " part is redundant, you may shift left by 9, but see below. > + u64 actual; > + u64 ratio; > + > + if (nom < denom) > + continue; > + > + ratio = div64_u64(nom, denom); Instead of shifting left by 9, you may optimize below to count that in the equations... > + m = ilog2(ratio); > + if (m > LPG_MAX_M) > + m = LPG_MAX_M; > + actual = DIV_ROUND_UP_ULL(denom * (1 << m), lpg_clk_rates[clk]); ...including this one. So, I see room for improvement in the calculations. > + error = period - actual; > + if (error < best_err) { > + best_err = error; > + > + best_div = div; > + best_m = m; > + best_clk = clk; > + best_period = actual; > + } > + } > + } > + > + chan->clk = best_clk; > + chan->pre_div = best_div; > + chan->pre_div_exp = best_m; > + chan->period = best_period; > + > + return 0; > +} ... > + val = div64_u64(duty * lpg_clk_rates[chan->clk], > + (u64)NSEC_PER_SEC * lpg_pre_divs[chan->pre_div] * (1 << chan->pre_div_exp)); For all code, just shift right directly, it makes code easier to read. ... > + regmap_bulk_write(lpg->map, chan->base + PWM_VALUE_REG, &val, sizeof(val)); In some cases the error is handled from regmap calls, in many it's not. Why? ... > + count = of_property_count_u32_elems(np, "qcom,dtest"); > + if (count == -EINVAL) { > + return 0; > + } else if (count < 0) { Redundant 'else' > + ret = count; Do it other way around, i.e. ret = ... ... count = ret; > + goto err_malformed; > + } else if (count != lpg->data->num_channels * 2) { Redundant 'else'. > + dev_err(lpg->dev, "qcom,dtest needs to be %d items\n", > + lpg->data->num_channels * 2); > + return -EINVAL; > + } ... > + /* Only support oneshot or indefinite loops, due to limited pattern space */ one shot > + if (repeat != -1 && repeat != 1) abs(repeat) != 1 ? > + return -EINVAL; ... > + /* LPG_RAMP_DURATION_REG is 9 bit */ > + if (pattern[0].delta_t >= 512) Then compare with bit value? BIT(9)? > + return -EINVAL; ... > + lpg_brightness_single_set(cdev, LED_FULL); Isn't LED_FULL deprecated? ... > + ret = of_property_read_u32(np, "reg", ®); > + if (ret || !reg || reg > lpg->num_channels) { > + dev_err(lpg->dev, "invalid \"reg\" of %pOFn\n", np); Confusing message for some of the error conditions. > + return -EINVAL; Shadowed error code. > + } ... > + ret = of_property_read_u32(np, "color", &color); > + if (ret < 0 && ret != -EINVAL) { Why the specific error code check? > + dev_err(lpg->dev, "failed to parse \"color\" of %pOF\n", np); > + return ret; > + } ... > + if (!of_property_read_string(np, "default-state", &state) && > + !strcmp(state, "on")) of_property_match_string()? ... > + bitmap_size = BITS_TO_BYTES(lpg->lut_size); > + lpg->lut_bitmap = devm_kzalloc(lpg->dev, bitmap_size, GFP_KERNEL); devm_bitmap_zalloc() > + if (!lpg->lut_bitmap) > + return -ENOMEM; ... > + dev_err(&pdev->dev, "parent regmap unavailable\n"); > + return -ENXIO; return dev_err_probe(...); ... > + .pwm_9bit_mask = 3 << 4, GENMASK() ... > + .pwm_9bit_mask = 3 << 4, Ditto. -- With Best Regards, Andy Shevchenko
Hello, did you consider my earlier feedback "It would also be good if the PWM code could live in drivers/pwm"? (https://lore.kernel.org/r/20210505051958.e5lvwfxuo2skdu2q@pengutronix.de) At least splitting in two patches would be good IMHO. On Fri, Jan 28, 2022 at 04:54:29PM -0800, Bjorn Andersson wrote: > The Light Pulse Generator (LPG) is a PWM-block found in a wide range of > PMICs from Qualcomm. These PMICs typically comes with 1-8 LPG instances, > with their output being routed to various other components, such as > current sinks or GPIOs. > > Each LPG instance can operate on fixed parameters or based on a shared > lookup-table, altering the duty cycle over time. This provides the means > for hardware assisted transitions of LED brightness. > > A typical use case for the fixed parameter mode is to drive a PWM > backlight control signal, the driver therefor allows each LPG instance > to be exposed to the kernel either through the LED framework or the PWM > framework. > > A typical use case for the LED configuration is to drive RGB LEDs in > smartphones etc, for which the driver support multiple channels to be > ganged up to a MULTICOLOR LED. In this configuration the pattern > generators will be synchronized, to allow for multi-color patterns. > > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> > --- > > Changes since v10: > - Check for and reject pattern.delta_t greater than 9 bits > - Write all 9 bits of LPG_RAMP_DURATION_REG > > drivers/leds/Kconfig | 3 + > drivers/leds/Makefile | 3 + > drivers/leds/rgb/Kconfig | 13 + > drivers/leds/rgb/Makefile | 3 + > drivers/leds/rgb/leds-qcom-lpg.c | 1306 ++++++++++++++++++++++++++++++ > 5 files changed, 1328 insertions(+) > create mode 100644 drivers/leds/rgb/Kconfig > create mode 100644 drivers/leds/rgb/Makefile > create mode 100644 drivers/leds/rgb/leds-qcom-lpg.c > > diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig > index 6090e647daee..a49979f41eee 100644 > --- a/drivers/leds/Kconfig > +++ b/drivers/leds/Kconfig > @@ -869,6 +869,9 @@ source "drivers/leds/blink/Kconfig" > comment "Flash and Torch LED drivers" > source "drivers/leds/flash/Kconfig" > > +comment "RGB LED drivers" > +source "drivers/leds/rgb/Kconfig" > + > comment "LED Triggers" > source "drivers/leds/trigger/Kconfig" > > diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile > index e58ecb36360f..4fd2f92cd198 100644 > --- a/drivers/leds/Makefile > +++ b/drivers/leds/Makefile > @@ -99,6 +99,9 @@ obj-$(CONFIG_LEDS_USER) += uleds.o > # Flash and Torch LED Drivers > obj-$(CONFIG_LEDS_CLASS_FLASH) += flash/ > > +# RGB LED Drivers > +obj-$(CONFIG_LEDS_CLASS_MULTICOLOR) += rgb/ > + > # LED Triggers > obj-$(CONFIG_LEDS_TRIGGERS) += trigger/ > > diff --git a/drivers/leds/rgb/Kconfig b/drivers/leds/rgb/Kconfig > new file mode 100644 > index 000000000000..20be3e11fe4a > --- /dev/null > +++ b/drivers/leds/rgb/Kconfig > @@ -0,0 +1,13 @@ > +# SPDX-License-Identifier: GPL-2.0 > + > +if LEDS_CLASS_MULTICOLOR > + > +config LEDS_QCOM_LPG > + tristate "LED support for Qualcomm LPG" > + depends on OF > + depends on SPMI > + help > + This option enables support for the Light Pulse Generator found in a > + wide variety of Qualcomm PMICs. > + > +endif # LEDS_CLASS_MULTICOLOR > diff --git a/drivers/leds/rgb/Makefile b/drivers/leds/rgb/Makefile > new file mode 100644 > index 000000000000..83114f44c4ea > --- /dev/null > +++ b/drivers/leds/rgb/Makefile > @@ -0,0 +1,3 @@ > +# SPDX-License-Identifier: GPL-2.0 > + > +obj-$(CONFIG_LEDS_QCOM_LPG) += leds-qcom-lpg.o > diff --git a/drivers/leds/rgb/leds-qcom-lpg.c b/drivers/leds/rgb/leds-qcom-lpg.c > new file mode 100644 > index 000000000000..06d5fca1d4b5 > --- /dev/null > +++ b/drivers/leds/rgb/leds-qcom-lpg.c > @@ -0,0 +1,1306 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (c) 2017-2022 Linaro Ltd > + * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved. > + */ > +#include <linux/bits.h> > +#include <linux/led-class-multicolor.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > +#include <linux/pwm.h> > +#include <linux/regmap.h> > +#include <linux/slab.h> > + > +#define LPG_PATTERN_CONFIG_REG 0x40 > +#define LPG_SIZE_CLK_REG 0x41 > +#define LPG_PREDIV_CLK_REG 0x42 > +#define PWM_TYPE_CONFIG_REG 0x43 > +#define PWM_VALUE_REG 0x44 > +#define PWM_ENABLE_CONTROL_REG 0x46 > +#define PWM_SYNC_REG 0x47 > +#define LPG_RAMP_DURATION_REG 0x50 > +#define LPG_HI_PAUSE_REG 0x52 > +#define LPG_LO_PAUSE_REG 0x54 > +#define LPG_HI_IDX_REG 0x56 > +#define LPG_LO_IDX_REG 0x57 > +#define PWM_SEC_ACCESS_REG 0xd0 > +#define PWM_DTEST_REG(x) (0xe2 + (x) - 1) > + > +#define TRI_LED_SRC_SEL 0x45 > +#define TRI_LED_EN_CTL 0x46 > +#define TRI_LED_ATC_CTL 0x47 > + > +#define LPG_LUT_REG(x) (0x40 + (x) * 2) > +#define RAMP_CONTROL_REG 0xc8 > + > +#define LPG_RESOLUTION 512 > +#define LPG_MAX_M 7 > + > +struct lpg_channel; > +struct lpg_data; > + > +/** > + * struct lpg - LPG device context > + * @dev: struct device for LPG device > + * @map: regmap for register access > + * @pwm: PWM-chip object, if operating in PWM mode > + * @data: reference to version specific data > + * @lut_base: base address of the LUT block (optional) > + * @lut_size: number of entries in the LUT block > + * @lut_bitmap: allocation bitmap for LUT entries > + * @triled_base: base address of the TRILED block (optional) > + * @triled_src: power-source for the TRILED > + * @triled_has_atc_ctl: true if there is TRI_LED_ATC_CTL register > + * @triled_has_src_sel: true if there is TRI_LED_SRC_SEL register > + * @channels: list of PWM channels > + * @num_channels: number of @channels > + */ > +struct lpg { > + struct device *dev; > + struct regmap *map; > + > + struct pwm_chip pwm; > + > + const struct lpg_data *data; > + > + u32 lut_base; > + u32 lut_size; > + unsigned long *lut_bitmap; > + > + u32 triled_base; > + u32 triled_src; > + bool triled_has_atc_ctl; > + bool triled_has_src_sel; > + > + struct lpg_channel *channels; > + unsigned int num_channels; > +}; > + > +/** > + * struct lpg_channel - per channel data > + * @lpg: reference to parent lpg > + * @base: base address of the PWM channel > + * @triled_mask: mask in TRILED to enable this channel > + * @lut_mask: mask in LUT to start pattern generator for this channel > + * @in_use: channel is exposed to LED framework > + * @color: color of the LED attached to this channel > + * @dtest_line: DTEST line for output, or 0 if disabled > + * @dtest_value: DTEST line configuration > + * @pwm_value: duty (in microseconds) of the generated pulses, overridden by LUT > + * @enabled: output enabled? > + * @period: period (in nanoseconds) of the generated pulses > + * @clk: base frequency of the clock generator > + * @pre_div: divider of @clk > + * @pre_div_exp: exponential divider of @clk > + * @ramp_enabled: duty cycle is driven by iterating over lookup table > + * @ramp_ping_pong: reverse through pattern, rather than wrapping to start > + * @ramp_oneshot: perform only a single pass over the pattern > + * @ramp_reverse: iterate over pattern backwards > + * @ramp_tick_ms: length (in milliseconds) of one step in the pattern > + * @ramp_lo_pause_ms: pause (in milliseconds) before iterating over pattern > + * @ramp_hi_pause_ms: pause (in milliseconds) after iterating over pattern > + * @pattern_lo_idx: start index of associated pattern > + * @pattern_hi_idx: last index of associated pattern > + */ > +struct lpg_channel { > + struct lpg *lpg; > + > + u32 base; > + unsigned int triled_mask; > + unsigned int lut_mask; > + > + bool in_use; > + > + int color; > + > + u32 dtest_line; > + u32 dtest_value; > + > + u16 pwm_value; > + bool enabled; > + > + u64 period; > + unsigned int clk; > + unsigned int pre_div; > + unsigned int pre_div_exp; > + > + bool ramp_enabled; > + bool ramp_ping_pong; > + bool ramp_oneshot; > + bool ramp_reverse; > + unsigned short ramp_tick_ms; > + unsigned long ramp_lo_pause_ms; > + unsigned long ramp_hi_pause_ms; > + > + unsigned int pattern_lo_idx; > + unsigned int pattern_hi_idx; > +}; > + > +/** > + * struct lpg_led - logical LED object > + * @lpg: lpg context reference > + * @cdev: LED class device > + * @mcdev: Multicolor LED class device > + * @num_channels: number of @channels > + * @channels: list of channels associated with the LED > + */ > +struct lpg_led { > + struct lpg *lpg; > + > + struct led_classdev cdev; > + struct led_classdev_mc mcdev; > + > + unsigned int num_channels; > + struct lpg_channel *channels[]; > +}; > + > +/** > + * struct lpg_channel_data - per channel initialization data > + * @base: base address for PWM channel registers > + * @triled_mask: bitmask for controlling this channel in TRILED > + */ > +struct lpg_channel_data { > + unsigned int base; > + u8 triled_mask; > +}; > + > +/** > + * struct lpg_data - initialization data > + * @lut_base: base address of LUT block > + * @lut_size: number of entries in LUT > + * @triled_base: base address of TRILED > + * @triled_has_atc_ctl: true if there is TRI_LED_ATC_CTL register > + * @triled_has_src_sel: true if there is TRI_LED_SRC_SEL register > + * @pwm_9bit_mask: bitmask for switching from 6bit to 9bit pwm > + * @num_channels: number of channels in LPG > + * @channels: list of channel initialization data > + */ > +struct lpg_data { > + unsigned int lut_base; > + unsigned int lut_size; > + unsigned int triled_base; > + bool triled_has_atc_ctl; > + bool triled_has_src_sel; > + unsigned int pwm_9bit_mask; > + int num_channels; > + const struct lpg_channel_data *channels; > +}; > + > +static int triled_set(struct lpg *lpg, unsigned int mask, unsigned int enable) > +{ > + /* Skip if we don't have a triled block */ > + if (!lpg->triled_base) > + return 0; > + > + return regmap_update_bits(lpg->map, lpg->triled_base + TRI_LED_EN_CTL, > + mask, enable); > +} > + > +static int lpg_lut_store(struct lpg *lpg, struct led_pattern *pattern, > + size_t len, unsigned int *lo_idx, unsigned int *hi_idx) > +{ > + unsigned int idx; > + u16 val; > + int i; > + > + /* Hardware does not behave when LO_IDX == HI_IDX */ > + if (len == 1) > + return -EINVAL; > + > + idx = bitmap_find_next_zero_area(lpg->lut_bitmap, lpg->lut_size, > + 0, len, 0); > + if (idx >= lpg->lut_size) > + return -ENOMEM; > + > + for (i = 0; i < len; i++) { > + val = pattern[i].brightness; > + > + regmap_bulk_write(lpg->map, lpg->lut_base + LPG_LUT_REG(idx + i), > + &val, sizeof(val)); > + } > + > + bitmap_set(lpg->lut_bitmap, idx, len); > + > + *lo_idx = idx; > + *hi_idx = idx + len - 1; > + > + return 0; > +} > + > +static void lpg_lut_free(struct lpg *lpg, unsigned int lo_idx, unsigned int hi_idx) > +{ > + int len; > + > + if (lo_idx == hi_idx) > + return; > + > + len = hi_idx - lo_idx + 1; > + bitmap_clear(lpg->lut_bitmap, lo_idx, len); > +} > + > +static int lpg_lut_sync(struct lpg *lpg, unsigned int mask) > +{ > + return regmap_write(lpg->map, lpg->lut_base + RAMP_CONTROL_REG, mask); > +} > + > +static const unsigned int lpg_clk_rates[] = {1024, 32768, 19200000}; > +static const unsigned int lpg_pre_divs[] = {1, 3, 5, 6}; > + > +static int lpg_calc_freq(struct lpg_channel *chan, uint64_t period) > +{ > + unsigned int clk, best_clk = 0; > + unsigned int div, best_div = 0; > + unsigned int m, best_m = 0; > + unsigned int error; > + unsigned int best_err = UINT_MAX; > + u64 best_period = 0; > + > + /* > + * The PWM period is determined by: > + * > + * resolution * pre_div * 2^M > + * period = -------------------------- > + * refclk > + * > + * With resolution fixed at 2^9 bits, pre_div = {1, 3, 5, 6} and > + * M = [0..7]. > + * > + * This allows for periods between 27uS and 384s, as the PWM framework > + * wants a period of equal or lower length than requested, reject > + * anything below 27uS. > + */ > + if (period <= (u64)NSEC_PER_SEC * LPG_RESOLUTION / 19200000) u64 divisions must not be done by / in the kernel. Also I wonder if the following would be more correct (though with the same semantic): if (period < DIV64_U64_ROUND_UP((u64)NSEC_PER_SEC * LPG_RESOLUTION, 19200000)) > + return -EINVAL; > + > + /* Limit period to largest possible value, to avoid overflows */ > + if (period > (u64)NSEC_PER_SEC * LPG_RESOLUTION * 6 * (1 << LPG_MAX_M) / 1024) > + period = (u64)NSEC_PER_SEC * LPG_RESOLUTION * 6 * (1 << LPG_MAX_M) / 2014; > + > + /* > + * Search for the pre_div, clk and M by solving the rewritten formula > + * for each clk and pre_div value: > + * > + * period * clk > + * M = log2 ------------------------------------- > + * NSEC_PER_SEC * pre_div * resolution > + */ > + for (clk = 0; clk < ARRAY_SIZE(lpg_clk_rates); clk++) { > + u64 nom = period * lpg_clk_rates[clk]; > + > + for (div = 0; div < ARRAY_SIZE(lpg_pre_divs); div++) { > + u64 denom = (u64)NSEC_PER_SEC * lpg_pre_divs[div] * (1 << 9); > + u64 actual; > + u64 ratio; > + > + if (nom < denom) > + continue; > + > + ratio = div64_u64(nom, denom); > + m = ilog2(ratio); > + if (m > LPG_MAX_M) > + m = LPG_MAX_M; > + > + actual = DIV_ROUND_UP_ULL(denom * (1 << m), lpg_clk_rates[clk]); > + > + error = period - actual; This looks good, though I didn't revalidate the calculation (e.g. to convince myself that error is always >= 0) > + if (error < best_err) { > + best_err = error; > + > + best_div = div; > + best_m = m; > + best_clk = clk; > + best_period = actual; > + } > + } > + } > + > + chan->clk = best_clk; > + chan->pre_div = best_div; > + chan->pre_div_exp = best_m; > + chan->period = best_period; > + > + return 0; > +} > + > +static void lpg_calc_duty(struct lpg_channel *chan, uint64_t duty) > +{ > + unsigned int max = LPG_RESOLUTION - 1; > + unsigned int val; > + > + val = div64_u64(duty * lpg_clk_rates[chan->clk], > + (u64)NSEC_PER_SEC * lpg_pre_divs[chan->pre_div] * (1 << chan->pre_div_exp)); > + > + chan->pwm_value = min(val, max); > +} > + > +static void lpg_apply_freq(struct lpg_channel *chan) > +{ > + unsigned long val; > + struct lpg *lpg = chan->lpg; > + > + if (!chan->enabled) > + return; > + > + /* Clock register values are off-by-one from lpg_clk_table */ > + val = chan->clk + 1; > + > + /* Enable 9bit resolution */ > + val |= lpg->data->pwm_9bit_mask; > + > + regmap_write(lpg->map, chan->base + LPG_SIZE_CLK_REG, val); > + > + val = chan->pre_div << 5 | chan->pre_div_exp; > + regmap_write(lpg->map, chan->base + LPG_PREDIV_CLK_REG, val); > +} > + > +#define LPG_ENABLE_GLITCH_REMOVAL BIT(5) > + > +static void lpg_enable_glitch(struct lpg_channel *chan) > +{ > + struct lpg *lpg = chan->lpg; > + > + regmap_update_bits(lpg->map, chan->base + PWM_TYPE_CONFIG_REG, > + LPG_ENABLE_GLITCH_REMOVAL, 0); > +} > + > +static void lpg_disable_glitch(struct lpg_channel *chan) > +{ > + struct lpg *lpg = chan->lpg; > + > + regmap_update_bits(lpg->map, chan->base + PWM_TYPE_CONFIG_REG, > + LPG_ENABLE_GLITCH_REMOVAL, > + LPG_ENABLE_GLITCH_REMOVAL); > +} > + > +static void lpg_apply_pwm_value(struct lpg_channel *chan) > +{ > + struct lpg *lpg = chan->lpg; > + u16 val = chan->pwm_value; > + > + if (!chan->enabled) > + return; > + > + regmap_bulk_write(lpg->map, chan->base + PWM_VALUE_REG, &val, sizeof(val)); > +} > + > +#define LPG_PATTERN_CONFIG_LO_TO_HI BIT(4) > +#define LPG_PATTERN_CONFIG_REPEAT BIT(3) > +#define LPG_PATTERN_CONFIG_TOGGLE BIT(2) > +#define LPG_PATTERN_CONFIG_PAUSE_HI BIT(1) > +#define LPG_PATTERN_CONFIG_PAUSE_LO BIT(0) > + > +static void lpg_apply_lut_control(struct lpg_channel *chan) > +{ > + struct lpg *lpg = chan->lpg; > + unsigned int hi_pause; > + unsigned int lo_pause; > + unsigned int conf = 0; > + unsigned int lo_idx = chan->pattern_lo_idx; > + unsigned int hi_idx = chan->pattern_hi_idx; > + u16 step = chan->ramp_tick_ms; > + > + if (!chan->ramp_enabled || chan->pattern_lo_idx == chan->pattern_hi_idx) > + return; > + > + hi_pause = DIV_ROUND_UP(chan->ramp_hi_pause_ms, step); > + lo_pause = DIV_ROUND_UP(chan->ramp_lo_pause_ms, step); > + > + if (!chan->ramp_reverse) > + conf |= LPG_PATTERN_CONFIG_LO_TO_HI; > + if (!chan->ramp_oneshot) > + conf |= LPG_PATTERN_CONFIG_REPEAT; > + if (chan->ramp_ping_pong) > + conf |= LPG_PATTERN_CONFIG_TOGGLE; > + if (chan->ramp_hi_pause_ms) > + conf |= LPG_PATTERN_CONFIG_PAUSE_HI; > + if (chan->ramp_lo_pause_ms) > + conf |= LPG_PATTERN_CONFIG_PAUSE_LO; > + > + regmap_write(lpg->map, chan->base + LPG_PATTERN_CONFIG_REG, conf); > + regmap_write(lpg->map, chan->base + LPG_HI_IDX_REG, hi_idx); > + regmap_write(lpg->map, chan->base + LPG_LO_IDX_REG, lo_idx); > + > + regmap_bulk_write(lpg->map, chan->base + LPG_RAMP_DURATION_REG, &step, sizeof(step)); > + regmap_write(lpg->map, chan->base + LPG_HI_PAUSE_REG, hi_pause); > + regmap_write(lpg->map, chan->base + LPG_LO_PAUSE_REG, lo_pause); > +} > + > +#define LPG_ENABLE_CONTROL_OUTPUT BIT(7) > +#define LPG_ENABLE_CONTROL_BUFFER_TRISTATE BIT(5) > +#define LPG_ENABLE_CONTROL_SRC_PWM BIT(2) > +#define LPG_ENABLE_CONTROL_RAMP_GEN BIT(1) > + > +static void lpg_apply_control(struct lpg_channel *chan) > +{ > + unsigned int ctrl; > + struct lpg *lpg = chan->lpg; > + > + ctrl = LPG_ENABLE_CONTROL_BUFFER_TRISTATE; > + > + if (chan->enabled) > + ctrl |= LPG_ENABLE_CONTROL_OUTPUT; > + > + if (chan->pattern_lo_idx != chan->pattern_hi_idx) > + ctrl |= LPG_ENABLE_CONTROL_RAMP_GEN; > + else > + ctrl |= LPG_ENABLE_CONTROL_SRC_PWM; > + > + regmap_write(lpg->map, chan->base + PWM_ENABLE_CONTROL_REG, ctrl); > + > + /* > + * Due to LPG hardware bug, in the PWM mode, having enabled PWM, > + * We have to write PWM values one more time. > + */ > + if (chan->enabled) > + lpg_apply_pwm_value(chan); > +} > + > +#define LPG_SYNC_PWM BIT(0) > + > +static void lpg_apply_sync(struct lpg_channel *chan) > +{ > + struct lpg *lpg = chan->lpg; > + > + regmap_write(lpg->map, chan->base + PWM_SYNC_REG, LPG_SYNC_PWM); > +} > + > +static int lpg_parse_dtest(struct lpg *lpg) > +{ > + struct lpg_channel *chan; > + struct device_node *np = lpg->dev->of_node; > + int count; > + int ret; > + int i; > + > + count = of_property_count_u32_elems(np, "qcom,dtest"); > + if (count == -EINVAL) { > + return 0; > + } else if (count < 0) { > + ret = count; > + goto err_malformed; > + } else if (count != lpg->data->num_channels * 2) { > + dev_err(lpg->dev, "qcom,dtest needs to be %d items\n", > + lpg->data->num_channels * 2); > + return -EINVAL; > + } > + > + for (i = 0; i < lpg->data->num_channels; i++) { > + chan = &lpg->channels[i]; > + > + ret = of_property_read_u32_index(np, "qcom,dtest", i * 2, > + &chan->dtest_line); > + if (ret) > + goto err_malformed; > + > + ret = of_property_read_u32_index(np, "qcom,dtest", i * 2 + 1, > + &chan->dtest_value); > + if (ret) > + goto err_malformed; > + } > + > + return 0; > + > +err_malformed: > + dev_err(lpg->dev, "malformed qcom,dtest\n"); > + return ret; > +} > + > +static void lpg_apply_dtest(struct lpg_channel *chan) > +{ > + struct lpg *lpg = chan->lpg; > + > + if (!chan->dtest_line) > + return; > + > + regmap_write(lpg->map, chan->base + PWM_SEC_ACCESS_REG, 0xa5); > + regmap_write(lpg->map, chan->base + PWM_DTEST_REG(chan->dtest_line), > + chan->dtest_value); > +} > + > +static void lpg_apply(struct lpg_channel *chan) > +{ > + lpg_disable_glitch(chan); > + lpg_apply_freq(chan); > + lpg_apply_pwm_value(chan); > + lpg_apply_control(chan); > + lpg_apply_sync(chan); > + lpg_apply_lut_control(chan); > + lpg_enable_glitch(chan); > +} > + > +static void lpg_brightness_set(struct lpg_led *led, struct led_classdev *cdev, > + struct mc_subled *subleds) > +{ > + enum led_brightness brightness; > + struct lpg_channel *chan; > + unsigned int triled_enabled = 0; > + unsigned int triled_mask = 0; > + unsigned int lut_mask = 0; > + unsigned int duty; > + struct lpg *lpg = led->lpg; > + int i; > + > + for (i = 0; i < led->num_channels; i++) { > + chan = led->channels[i]; > + brightness = subleds[i].brightness; > + > + if (brightness == LED_OFF) { > + chan->enabled = false; > + chan->ramp_enabled = false; > + } else if (chan->pattern_lo_idx != chan->pattern_hi_idx) { > + lpg_calc_freq(chan, NSEC_PER_MSEC); > + > + chan->enabled = true; > + chan->ramp_enabled = true; > + > + lut_mask |= chan->lut_mask; > + triled_enabled |= chan->triled_mask; > + } else { > + lpg_calc_freq(chan, NSEC_PER_MSEC); > + > + duty = div_u64(brightness * chan->period, cdev->max_brightness); > + lpg_calc_duty(chan, duty); > + chan->enabled = true; > + chan->ramp_enabled = false; > + > + triled_enabled |= chan->triled_mask; > + } > + > + triled_mask |= chan->triled_mask; > + > + lpg_apply(chan); > + } > + > + /* Toggle triled lines */ > + if (triled_mask) > + triled_set(lpg, triled_mask, triled_enabled); > + > + /* Trigger start of ramp generator(s) */ > + if (lut_mask) > + lpg_lut_sync(lpg, lut_mask); > +} > + > +static void lpg_brightness_single_set(struct led_classdev *cdev, > + enum led_brightness value) > +{ > + struct lpg_led *led = container_of(cdev, struct lpg_led, cdev); > + struct mc_subled info; > + > + info.brightness = value; > + lpg_brightness_set(led, cdev, &info); > +} > + > +static void lpg_brightness_mc_set(struct led_classdev *cdev, > + enum led_brightness value) > +{ > + struct led_classdev_mc *mc = lcdev_to_mccdev(cdev); > + struct lpg_led *led = container_of(mc, struct lpg_led, mcdev); > + > + led_mc_calc_color_components(mc, value); > + lpg_brightness_set(led, cdev, mc->subled_info); > +} > + > +static int lpg_blink_set(struct lpg_led *led, > + unsigned long *delay_on, unsigned long *delay_off) > +{ > + struct lpg_channel *chan; > + unsigned int period; > + unsigned int triled_mask = 0; > + struct lpg *lpg = led->lpg; > + u64 duty; > + int i; > + > + if (!*delay_on && !*delay_off) { > + *delay_on = 500; > + *delay_off = 500; > + } > + > + duty = *delay_on * NSEC_PER_MSEC; > + period = (*delay_on + *delay_off) * NSEC_PER_MSEC; > + > + for (i = 0; i < led->num_channels; i++) { > + chan = led->channels[i]; > + > + lpg_calc_freq(chan, period); > + lpg_calc_duty(chan, duty); > + > + chan->enabled = true; > + chan->ramp_enabled = false; > + > + triled_mask |= chan->triled_mask; > + > + lpg_apply(chan); > + } > + > + /* Enable triled lines */ > + triled_set(lpg, triled_mask, triled_mask); > + > + chan = led->channels[0]; > + duty = div_u64(chan->pwm_value * chan->period, LPG_RESOLUTION); > + *delay_on = div_u64(duty, NSEC_PER_MSEC); > + *delay_off = div_u64(chan->period - duty, NSEC_PER_MSEC); > + > + return 0; > +} > + > +static int lpg_blink_single_set(struct led_classdev *cdev, > + unsigned long *delay_on, unsigned long *delay_off) > +{ > + struct lpg_led *led = container_of(cdev, struct lpg_led, cdev); > + > + return lpg_blink_set(led, delay_on, delay_off); > +} > + > +static int lpg_blink_mc_set(struct led_classdev *cdev, > + unsigned long *delay_on, unsigned long *delay_off) > +{ > + struct led_classdev_mc *mc = lcdev_to_mccdev(cdev); > + struct lpg_led *led = container_of(mc, struct lpg_led, mcdev); > + > + return lpg_blink_set(led, delay_on, delay_off); > +} > + > +static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *pattern, > + u32 len, int repeat) > +{ > + struct lpg_channel *chan; > + struct lpg *lpg = led->lpg; > + unsigned int hi_pause; > + unsigned int lo_pause; > + unsigned int lo_idx; > + unsigned int hi_idx; > + bool ping_pong = true; > + int brightness_a; > + int brightness_b; > + int ret; > + int i; > + > + /* Only support oneshot or indefinite loops, due to limited pattern space */ > + if (repeat != -1 && repeat != 1) > + return -EINVAL; > + > + /* LPG_RAMP_DURATION_REG is 9 bit */ > + if (pattern[0].delta_t >= 512) > + return -EINVAL; > + > + /* > + * The LPG plays patterns with at a fixed pace, a "low pause" can be > + * performed before the pattern and a "high pause" after. In order to > + * save space the pattern can be played in "ping pong" mode, in which > + * the pattern is first played forward, then "high pause" is applied, > + * then the pattern is played backwards and finally the "low pause" is > + * applied. > + * > + * The delta_t of the first entry is used to determine the pace of the > + * pattern. > + * > + * If the specified pattern is a palindrome the ping pong mode is > + * enabled. In this scenario the delta_t of the last entry determines > + * the "low pause" time and the delta_t of the middle entry (i.e. the > + * last in the programmed pattern) determines the "high pause". If the > + * pattern consists of an odd number of values, no "high pause" is > + * used. > + * > + * When ping pong mode is not selected, the delta_t of the last entry > + * is used as "high pause". No "low pause" is used. > + * > + * delta_t of any other members of the pattern is ignored. > + */ > + > + /* Detect palindromes and use "ping pong" to reduce LUT usage */ > + for (i = 0; i < len / 2; i++) { > + brightness_a = pattern[i].brightness; > + brightness_b = pattern[len - i - 1].brightness; > + > + if (brightness_a != brightness_b) { > + ping_pong = false; > + break; > + } > + } > + > + if (ping_pong) { > + if (len % 2) > + hi_pause = 0; > + else > + hi_pause = pattern[(len + 1) / 2].delta_t; > + lo_pause = pattern[len - 1].delta_t; > + > + len = (len + 1) / 2; > + } else { > + hi_pause = pattern[len - 1].delta_t; > + lo_pause = 0; > + } > + > + ret = lpg_lut_store(lpg, pattern, len, &lo_idx, &hi_idx); > + if (ret < 0) > + return ret; > + > + for (i = 0; i < led->num_channels; i++) { > + chan = led->channels[i]; > + > + chan->ramp_tick_ms = pattern[0].delta_t; > + chan->ramp_ping_pong = ping_pong; > + chan->ramp_oneshot = repeat != -1; > + > + chan->ramp_lo_pause_ms = lo_pause; > + chan->ramp_hi_pause_ms = hi_pause; > + > + chan->pattern_lo_idx = lo_idx; > + chan->pattern_hi_idx = hi_idx; > + } > + > + return 0; > +} > + > +static int lpg_pattern_single_set(struct led_classdev *cdev, > + struct led_pattern *pattern, u32 len, > + int repeat) > +{ > + struct lpg_led *led = container_of(cdev, struct lpg_led, cdev); > + int ret; > + > + ret = lpg_pattern_set(led, pattern, len, repeat); > + if (ret < 0) > + return ret; > + > + lpg_brightness_single_set(cdev, LED_FULL); > + > + return 0; > +} > + > +static int lpg_pattern_mc_set(struct led_classdev *cdev, > + struct led_pattern *pattern, u32 len, > + int repeat) > +{ > + struct led_classdev_mc *mc = lcdev_to_mccdev(cdev); > + struct lpg_led *led = container_of(mc, struct lpg_led, mcdev); > + int ret; > + > + ret = lpg_pattern_set(led, pattern, len, repeat); > + if (ret < 0) > + return ret; > + > + led_mc_calc_color_components(mc, LED_FULL); > + lpg_brightness_set(led, cdev, mc->subled_info); > + > + return 0; > +} > + > +static int lpg_pattern_clear(struct lpg_led *led) > +{ > + struct lpg_channel *chan; > + struct lpg *lpg = led->lpg; > + int i; > + > + chan = led->channels[0]; > + lpg_lut_free(lpg, chan->pattern_lo_idx, chan->pattern_hi_idx); > + > + for (i = 0; i < led->num_channels; i++) { > + chan = led->channels[i]; > + chan->pattern_lo_idx = 0; > + chan->pattern_hi_idx = 0; > + } > + > + return 0; > +} > + > +static int lpg_pattern_single_clear(struct led_classdev *cdev) > +{ > + struct lpg_led *led = container_of(cdev, struct lpg_led, cdev); > + > + return lpg_pattern_clear(led); > +} > + > +static int lpg_pattern_mc_clear(struct led_classdev *cdev) > +{ > + struct led_classdev_mc *mc = lcdev_to_mccdev(cdev); > + struct lpg_led *led = container_of(mc, struct lpg_led, mcdev); > + > + return lpg_pattern_clear(led); > +} > + > +static int lpg_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) > +{ > + struct lpg *lpg = container_of(chip, struct lpg, pwm); > + struct lpg_channel *chan = &lpg->channels[pwm->hwpwm]; > + > + return chan->in_use ? -EBUSY : 0; > +} > + > +/* > + * Limitations: > + * - Updating both duty and period is not done atomically, so the output signal > + * will momentarily be a mix of the settings. Is the PWM well-behaved? (i.e. does it emit the inactive level when disabled?) Does it complete a period before switching to the new setting? Did you test with PWM_DEBUG enabled? > + */ > +static int lpg_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, > + const struct pwm_state *state) > +{ > + struct lpg *lpg = container_of(chip, struct lpg, pwm); > + struct lpg_channel *chan = &lpg->channels[pwm->hwpwm]; > + int ret; > + > + if (state->polarity != PWM_POLARITY_NORMAL) > + return -EINVAL; > + > + ret = lpg_calc_freq(chan, state->period); > + if (ret < 0) > + return ret; > + > + lpg_calc_duty(chan, state->duty_cycle); > + chan->enabled = state->enabled; > + > + lpg_apply(chan); > + > + triled_set(lpg, chan->triled_mask, chan->enabled ? chan->triled_mask : 0); > + > + return 0; Would it make sense to skip the calculation if state->enabled is false? > +} > + > +static void lpg_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, > + struct pwm_state *state) > +{ > + struct lpg *lpg = container_of(chip, struct lpg, pwm); > + struct lpg_channel *chan = &lpg->channels[pwm->hwpwm]; > + u64 duty = DIV_ROUND_UP_ULL(chan->pwm_value * chan->period, LPG_RESOLUTION - 1); > + > + state->period = chan->period; > + state->duty_cycle = duty; > + state->polarity = PWM_POLARITY_NORMAL; > + state->enabled = chan->enabled; This doesn't work if .get_state() is called before .apply() was called, does it? > +} > + > +static const struct pwm_ops lpg_pwm_ops = { > + .request = lpg_pwm_request, > + .apply = lpg_pwm_apply, > + .get_state = lpg_pwm_get_state, > + .owner = THIS_MODULE, > +}; > + > +static int lpg_add_pwm(struct lpg *lpg) > +{ > + int ret; > + > + lpg->pwm.base = -1; I already asked in May to drop this ... > + lpg->pwm.dev = lpg->dev; > + lpg->pwm.npwm = lpg->num_channels; > + lpg->pwm.ops = &lpg_pwm_ops; > + Best regards Uwe
On Wed 02 Feb 06:56 PST 2022, Andy Shevchenko wrote: > On Tue, Feb 1, 2022 at 12:31 AM Bjorn Andersson > <bjorn.andersson@linaro.org> wrote: > > > > The Light Pulse Generator (LPG) is a PWM-block found in a wide range of > > PMICs from Qualcomm. These PMICs typically comes with 1-8 LPG instances, > > with their output being routed to various other components, such as > > current sinks or GPIOs. > > > > Each LPG instance can operate on fixed parameters or based on a shared > > lookup-table, altering the duty cycle over time. This provides the means > > for hardware assisted transitions of LED brightness. > > > > A typical use case for the fixed parameter mode is to drive a PWM > > backlight control signal, the driver therefor allows each LPG instance > > to be exposed to the kernel either through the LED framework or the PWM > > framework. > > > > A typical use case for the LED configuration is to drive RGB LEDs in > > smartphones etc, for which the driver support multiple channels to be > > supports > > > ganged up to a MULTICOLOR LED. In this configuration the pattern > > generators will be synchronized, to allow for multi-color patterns. > > ... > > > +config LEDS_QCOM_LPG > > + tristate "LED support for Qualcomm LPG" > > > + depends on OF > > || COMPILE_TEST > > > + depends on SPMI > > + help > > + This option enables support for the Light Pulse Generator found in a > > + wide variety of Qualcomm PMICs. > > Module name? > > ... > > > +#include <linux/of.h> > > +#include <linux/of_device.h> > > Wondering if these can be changed to mod_devicetable.h + property.,h. > > ... > > > + * @dev: struct device for LPG device > > Description without value and actually wrong. it's a pointer to, and > not a struct device. > > ... > > > + /* Hardware does not behave when LO_IDX == HI_IDX */ > > Any clue /. elaboration why? > As the two indices are inclusive I was expecting to just get a single-value pattern (i.e. static configuration), but instead it just keeps looping through the entire pattern memory. > ... > > > +static void lpg_lut_free(struct lpg *lpg, unsigned int lo_idx, unsigned int hi_idx) > > +{ > > + int len; > > + > > + if (lo_idx == hi_idx) > > + return; > > + > > + len = hi_idx - lo_idx + 1; > > Perhaps swap above and add the similar comment: > Sounds reasonable. > /* We never do a single item because ... */ > len = > if (len == 1) > > > + bitmap_clear(lpg->lut_bitmap, lo_idx, len); > > Who protects this bitmap from simultaneous access by different users? > It's protected per LED, but apparently not cross LEDs. Will fix. > > +} > > ... > > > +static int lpg_calc_freq(struct lpg_channel *chan, uint64_t period) > > +{ > > + unsigned int clk, best_clk = 0; > > + unsigned int div, best_div = 0; > > + unsigned int m, best_m = 0; > > + unsigned int error; > > + unsigned int best_err = UINT_MAX; > > + u64 best_period = 0; > > + > > + /* > > + * The PWM period is determined by: > > + * > > + * resolution * pre_div * 2^M > > + * period = -------------------------- > > + * refclk > > + * > > + * With resolution fixed at 2^9 bits, pre_div = {1, 3, 5, 6} and > > + * M = [0..7]. > > + * > > + * This allows for periods between 27uS and 384s, as the PWM framework > > + * wants a period of equal or lower length than requested, reject > > + * anything below 27uS. > > + */ > > > + if (period <= (u64)NSEC_PER_SEC * LPG_RESOLUTION / 19200000) > > + return -EINVAL; > > > + /* Limit period to largest possible value, to avoid overflows */ > > + if (period > (u64)NSEC_PER_SEC * LPG_RESOLUTION * 6 * (1 << LPG_MAX_M) / 1024) > > + period = (u64)NSEC_PER_SEC * LPG_RESOLUTION * 6 * (1 << LPG_MAX_M) / 2014; > > 2014?! > I thought I fixed that... > And if it's incorrect, it seems like a good example to avoid > repetition of the long equations. > > What about > > best_period = clamp_val(period, ...); > if (best_period >= period) > return -EINVAL; > > period = best_period; > > ? Sounds reasonable. > > > + /* > > + * Search for the pre_div, clk and M by solving the rewritten formula > > + * for each clk and pre_div value: > > + * > > + * period * clk > > + * M = log2 ------------------------------------- > > + * NSEC_PER_SEC * pre_div * resolution > > + */ > > + for (clk = 0; clk < ARRAY_SIZE(lpg_clk_rates); clk++) { > > + u64 nom = period * lpg_clk_rates[clk]; > > Can we spell fully nunerator, denominator? > Sure. > > + for (div = 0; div < ARRAY_SIZE(lpg_pre_divs); div++) { > > + u64 denom = (u64)NSEC_PER_SEC * lpg_pre_divs[div] * (1 << 9); > > " * (1 " part is redundant, you may shift left by 9, but see below. > I could, but as written now it matches the formula as written in the comment above. With (1 << 9) being the resolution part. That said, I think I introduced the LPG_RESOLUTION constant after writing this, would be reasonable to reuse that here. > > + u64 actual; > > + u64 ratio; > > + > > + if (nom < denom) > > + continue; > > + > > + ratio = div64_u64(nom, denom); > > Instead of shifting left by 9, you may optimize below to count that in > the equations... > > > + m = ilog2(ratio); > > + if (m > LPG_MAX_M) > > + m = LPG_MAX_M; > > > + actual = DIV_ROUND_UP_ULL(denom * (1 << m), lpg_clk_rates[clk]); > > ...including this one. > > So, I see room for improvement in the calculations. > So you're saying that I should remove the resolution from the denominator and then just subtract 9 from M? I presume it improves things by replacing one bitshift with a subtraction, but afaict it wouldn't improve the readability of the code. > > + error = period - actual; > > + if (error < best_err) { > > + best_err = error; > > + > > + best_div = div; > > + best_m = m; > > + best_clk = clk; > > + best_period = actual; > > + } > > + } > > + } > > + > > + chan->clk = best_clk; > > + chan->pre_div = best_div; > > + chan->pre_div_exp = best_m; > > + chan->period = best_period; > > + > > + return 0; > > +} > > ... > > > + val = div64_u64(duty * lpg_clk_rates[chan->clk], > > + (u64)NSEC_PER_SEC * lpg_pre_divs[chan->pre_div] * (1 << chan->pre_div_exp)); > > For all code, just shift right directly, it makes code easier to read. > Code might be easier to read, but as written now it matches the formula described above. You're right that we should get the same result if I replace the multiplication from the denominator to be a shift in the numerator, but at least for me that require me to think 1-2 extra steps when reading this to convince myself that below is the same as the formula described in the comments: val = div64_u64((duty * lpg_clk_rates[chan->clk]) >> chan->pre_div_exp, (u64)NSEC_PER_SEC * lpg_pre_divs[chan->pre_div]); > ... > > > + regmap_bulk_write(lpg->map, chan->base + PWM_VALUE_REG, &val, sizeof(val)); > > In some cases the error is handled from regmap calls, in many it's not. Why? > The brightness_set() in struct led_classdev is a void function, so I have to throw away the very unlikely error at some point... > ... > > > + count = of_property_count_u32_elems(np, "qcom,dtest"); > > + if (count == -EINVAL) { > > + return 0; > > > + } else if (count < 0) { > > Redundant 'else' > > > + ret = count; > > Do it other way around, i.e. > > ret = ... > ... > count = ret; > > > + goto err_malformed; > > + } else if (count != lpg->data->num_channels * 2) { > > Redundant 'else'. > So you're saying that this form is preferable? if (a) { return 0; } if (b) { goto err_malformed: } if (c) { return -EINVAL; } The else has absolutely no meaning to the compiler, but it immediately tells me as a human that we will enter only one of these branches. > > + dev_err(lpg->dev, "qcom,dtest needs to be %d items\n", > > + lpg->data->num_channels * 2); > > + return -EINVAL; > > + } > > ... > > > + /* Only support oneshot or indefinite loops, due to limited pattern space */ > > one shot > > > + if (repeat != -1 && repeat != 1) > > abs(repeat) != 1 ? > While equivalent, I'm not checking to see if the absolute value of repeat is 1, I'm checking that repeat is either -1 and 1. Again, same outcome but different meaning to a human reading the code. > > + return -EINVAL; > > ... > > > + /* LPG_RAMP_DURATION_REG is 9 bit */ > > + if (pattern[0].delta_t >= 512) > > Then compare with bit value? BIT(9)? > > > + return -EINVAL; > > ... > > > + lpg_brightness_single_set(cdev, LED_FULL); > > Isn't LED_FULL deprecated? > I had missed that the LED framework now supports variable max_brightness. Will update accordingly throughout the driver. > ... > > > + ret = of_property_read_u32(np, "reg", ®); > > + if (ret || !reg || reg > lpg->num_channels) { > > > + dev_err(lpg->dev, "invalid \"reg\" of %pOFn\n", np); > > Confusing message for some of the error conditions. > > > + return -EINVAL; > > Shadowed error code. > > > + } > > ... > > > + ret = of_property_read_u32(np, "color", &color); > > + if (ret < 0 && ret != -EINVAL) { > > Why the specific error code check? > Because color is an optional property, so -EINVAL would imply that we didn't find the property and color was left untouched. > > + dev_err(lpg->dev, "failed to parse \"color\" of %pOF\n", np); > > + return ret; > > + } > > ... > > > + if (!of_property_read_string(np, "default-state", &state) && > > + !strcmp(state, "on")) > > of_property_match_string()? > Neat. Regards, Bjorn > ... > > > + bitmap_size = BITS_TO_BYTES(lpg->lut_size); > > + lpg->lut_bitmap = devm_kzalloc(lpg->dev, bitmap_size, GFP_KERNEL); > > devm_bitmap_zalloc() > > > + if (!lpg->lut_bitmap) > > + return -ENOMEM; > > ... > > > + dev_err(&pdev->dev, "parent regmap unavailable\n"); > > + return -ENXIO; > > return dev_err_probe(...); > > ... > > > + .pwm_9bit_mask = 3 << 4, > > GENMASK() > > ... > > > + .pwm_9bit_mask = 3 << 4, > > Ditto. > > -- > With Best Regards, > Andy Shevchenko
diff --git a/Documentation/devicetree/bindings/leds/leds-qcom-lpg.yaml b/Documentation/devicetree/bindings/leds/leds-qcom-lpg.yaml new file mode 100644 index 000000000000..336bd8e10efd --- /dev/null +++ b/Documentation/devicetree/bindings/leds/leds-qcom-lpg.yaml @@ -0,0 +1,173 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/leds/leds-qcom-lpg.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Qualcomm Light Pulse Generator + +maintainers: + - Bjorn Andersson <bjorn.andersson@linaro.org> + +description: > + The Qualcomm Light Pulse Generator consists of three different hardware blocks; + a ramp generator with lookup table, the light pulse generator and a three + channel current sink. These blocks are found in a wide range of Qualcomm PMICs. + +properties: + compatible: + enum: + - qcom,pm8150b-lpg + - qcom,pm8150l-lpg + - qcom,pm8916-pwm + - qcom,pm8941-lpg + - qcom,pm8994-lpg + - qcom,pmc8180c-lpg + - qcom,pmi8994-lpg + - qcom,pmi8998-lpg + + "#pwm-cells": + const: 2 + + "#address-cells": + const: 1 + + "#size-cells": + const: 0 + + qcom,power-source: + $ref: /schemas/types.yaml#/definitions/uint32 + description: + power-source used to drive the output, as defined in the datasheet. + Should be specified if the TRILED block is present + enum: [0, 1, 3] + + qcom,dtest: + $ref: /schemas/types.yaml#/definitions/uint32-matrix + description: > + A list of integer pairs, where each pair represent the dtest line the + particular channel should be connected to and the flags denoting how the + value should be outputed, as defined in the datasheet. The number of + pairs should be the same as the number of channels. + items: + items: + - description: dtest line to attach + - description: flags for the attachment + + multi-led: + type: object + $ref: leds-class-multicolor.yaml# + properties: + "#address-cells": + const: 1 + + "#size-cells": + const: 0 + + patternProperties: + "^led@[0-9a-f]$": + type: object + $ref: common.yaml# + +patternProperties: + "^led@[0-9a-f]$": + type: object + $ref: common.yaml# + + properties: + reg: true + + required: + - reg + +required: + - compatible + +additionalProperties: false + +examples: + - | + #include <dt-bindings/leds/common.h> + + led-controller { + compatible = "qcom,pmi8994-lpg"; + + #address-cells = <1>; + #size-cells = <0>; + + qcom,power-source = <1>; + + qcom,dtest = <0 0>, + <0 0>, + <0 0>, + <4 1>; + + led@1 { + reg = <1>; + color = <LED_COLOR_ID_GREEN>; + function = LED_FUNCTION_INDICATOR; + function-enumerator = <1>; + }; + + led@2 { + reg = <2>; + color = <LED_COLOR_ID_GREEN>; + function = LED_FUNCTION_INDICATOR; + function-enumerator = <0>; + default-state = "on"; + }; + + led@3 { + reg = <3>; + color = <LED_COLOR_ID_GREEN>; + function = LED_FUNCTION_INDICATOR; + function-enumerator = <2>; + }; + + led@4 { + reg = <4>; + color = <LED_COLOR_ID_GREEN>; + function = LED_FUNCTION_INDICATOR; + function-enumerator = <3>; + }; + }; + - | + #include <dt-bindings/leds/common.h> + + led-controller { + compatible = "qcom,pmi8994-lpg"; + + #address-cells = <1>; + #size-cells = <0>; + + qcom,power-source = <1>; + + multi-led { + color = <LED_COLOR_ID_RGB>; + function = LED_FUNCTION_STATUS; + + #address-cells = <1>; + #size-cells = <0>; + + led@1 { + reg = <1>; + color = <LED_COLOR_ID_RED>; + }; + + led@2 { + reg = <2>; + color = <LED_COLOR_ID_GREEN>; + }; + + led@3 { + reg = <3>; + color = <LED_COLOR_ID_BLUE>; + }; + }; + }; + - | + pwm-controller { + compatible = "qcom,pm8916-pwm"; + #pwm-cells = <2>; + }; +...