[v2,2/3] drm: bridge: add support for lontium LT9611UXC bridge

Add support for Lontium LT9611UXC HDMI bridge. Lontium LT9611UXC is a
DSI to HDMI bridge which supports two DSI ports and I2S port as an input
and HDMI port as output. Despite name being similar to LT9611, these
devices are different enough to warrant separate driver.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

---
 drivers/gpu/drm/bridge/Kconfig             |  13 +
 drivers/gpu/drm/bridge/Makefile            |   1 +
 drivers/gpu/drm/bridge/lontium-lt9611uxc.c | 774 +++++++++++++++++++++
 3 files changed, 788 insertions(+)
 create mode 100644 drivers/gpu/drm/bridge/lontium-lt9611uxc.c

-- 
2.28.0

On 28/08/2020 22:58, Sam Ravnborg wrote:
> Hi Dmitry
> 
> On Fri, Aug 28, 2020 at 06:49:05PM +0300, Dmitry Baryshkov wrote:
>> Add support for Lontium LT9611UXC HDMI bridge. Lontium LT9611UXC is a
>> DSI to HDMI bridge which supports two DSI ports and I2S port as an input
>> and HDMI port as output. Despite name being similar to LT9611, these
>> devices are different enough to warrant separate driver.
>>
>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> 
> I have browsed the driver - most looks good but the way modes are
> handled looks fishy.
> 
> The code either relies on edid or modes returned by a panel-timings
> node. The panel-timings node seems to be used to override the edid info.
> We do not need this in any other bridge driver today - and thus it is
> questionaable if this driver needs it. If it is needed then please
> document the rationale behind it - in the source code.
> The binding does not exaplin anything about a panel-timings node.
> 
> If the panel-timins stuff is not needed, then remember to drop include
> files that are no logner used.

Fine with me, I'll drop panel-timings then. If there are issues with 
EDID handling, we can readd them back later.

> 
> And then there is mode_valid which uses a set of modes obtained from
> a static list which also looks strange.
> 
> The last part can also be found in lontium-lt9611.c but that does
> not make it correct.

The lt9611uxc firmware supports only a fixed set of modes. Thus 
lt9611uxc driver has to check if the mode is supported by the fw.
Unsupported modes would result in HDMI display not receiving valid signal.

> 
> Please see other bridge drivers.
> 
> The extra patch that makes connector creation optinal should be
> merged with the first patch - there is no gain to split it in two.

Ok, I'll squash it.

> 
> There was also a few style issues, see comments in the following.
> 
> Looks forward to see a new revision.
> 
> 	Sam
> 
> 
> 
>> ---
>>   drivers/gpu/drm/bridge/Kconfig             |  13 +
>>   drivers/gpu/drm/bridge/Makefile            |   1 +
>>   drivers/gpu/drm/bridge/lontium-lt9611uxc.c | 774 +++++++++++++++++++++
>>   3 files changed, 788 insertions(+)
>>   create mode 100644 drivers/gpu/drm/bridge/lontium-lt9611uxc.c
>>
>> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
>> index 3e11af4e9f63..8343fb054652 100644
>> --- a/drivers/gpu/drm/bridge/Kconfig
>> +++ b/drivers/gpu/drm/bridge/Kconfig
>> @@ -61,6 +61,19 @@ config DRM_LONTIUM_LT9611
>>   	  HDMI signals
>>   	  Please say Y if you have such hardware.
>>   
>> +config DRM_LONTIUM_LT9611UXC
>> +	tristate "Lontium LT9611UXC DSI/HDMI bridge"
>> +	select SND_SOC_HDMI_CODEC if SND_SOC
>> +	depends on OF
>> +	select DRM_PANEL_BRIDGE
>> +	select DRM_KMS_HELPER
>> +	select REGMAP_I2C
>> +	help
>> +	  Driver for Lontium LT9611UXC DSI to HDMI bridge
>> +	  chip driver that converts dual DSI and I2S to
>> +	  HDMI signals
>> +	  Please say Y if you have such hardware.
>> +
>>   config DRM_LVDS_CODEC
>>   	tristate "Transparent LVDS encoders and decoders support"
>>   	depends on OF
>> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
>> index c589a6a7cbe1..306850a5899b 100644
>> --- a/drivers/gpu/drm/bridge/Makefile
>> +++ b/drivers/gpu/drm/bridge/Makefile
>> @@ -3,6 +3,7 @@ obj-$(CONFIG_DRM_CDNS_DSI) += cdns-dsi.o
>>   obj-$(CONFIG_DRM_CHRONTEL_CH7033) += chrontel-ch7033.o
>>   obj-$(CONFIG_DRM_DISPLAY_CONNECTOR) += display-connector.o
>>   obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o
>> +obj-$(CONFIG_DRM_LONTIUM_LT9611UXC) += lontium-lt9611uxc.o
>>   obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
>>   obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
>>   obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
>> diff --git a/drivers/gpu/drm/bridge/lontium-lt9611uxc.c b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
>> new file mode 100644
>> index 000000000000..77c5aa5c6ad7
>> --- /dev/null
>> +++ b/drivers/gpu/drm/bridge/lontium-lt9611uxc.c
>> @@ -0,0 +1,774 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2018, The Linux Foundation. All rights reserved.
>> + * Copyright (c) 2019-2020. Linaro Limited.
>> + */
>> +
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/module.h>
>> +#include <linux/mutex.h>
>> +#include <linux/of_graph.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.h>
>> +#include <linux/regulator/consumer.h>
>> +
>> +#include <sound/hdmi-codec.h>
>> +
>> +#include <video/display_timing.h>
>> +#include <video/of_display_timing.h>
>> +#include <video/videomode.h>
>> +
>> +#include <drm/drm_probe_helper.h>
>> +#include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_bridge.h>
>> +#include <drm/drm_mipi_dsi.h>
>> +#include <drm/drm_print.h>
> Sort this block
> 
>> +
>> +#define EDID_BLOCK_SIZE	128
>> +#define EDID_NUM_BLOCKS	2
>> +
>> +struct lt9611uxc {
>> +	struct device *dev;
>> +	struct drm_bridge bridge;
>> +
>> +	struct regmap *regmap;
>> +	/* Protects all accesses to registers by stopping the on-chip MCU */
>> +	struct mutex ocm_lock;
>> +
>> +	struct device_node *dsi0_node;
>> +	struct device_node *dsi1_node;
>> +	struct mipi_dsi_device *dsi0;
>> +	struct mipi_dsi_device *dsi1;
>> +	struct platform_device *audio_pdev;
>> +
>> +	struct gpio_desc *reset_gpio;
>> +	struct gpio_desc *enable_gpio;
>> +
>> +	bool sleep;
>> +
>> +	struct regulator_bulk_data supplies[2];
>> +
>> +	struct i2c_client *client;
>> +
>> +	bool hpd_supported;
>> +	struct display_timings *timings;
>> +	u8 edid_buf[EDID_BLOCK_SIZE * EDID_NUM_BLOCKS];
>> +};
>> +
>> +#define LT9611_PAGE_CONTROL	0xff
>> +
>> +static const struct regmap_range_cfg lt9611uxc_ranges[] = {
>> +	{
>> +		.name = "register_range",
>> +		.range_min =  0,
>> +		.range_max = 0xd0ff,
>> +		.selector_reg = LT9611_PAGE_CONTROL,
>> +		.selector_mask = 0xff,
>> +		.selector_shift = 0,
>> +		.window_start = 0,
>> +		.window_len = 0x100,
>> +	},
>> +};
>> +
>> +static const struct regmap_config lt9611uxc_regmap_config = {
>> +	.reg_bits = 8,
>> +	.val_bits = 8,
>> +	.max_register = 0xffff,
>> +	.ranges = lt9611uxc_ranges,
>> +	.num_ranges = ARRAY_SIZE(lt9611uxc_ranges),
>> +};
>> +
>> +struct lt9611uxc_mode {
>> +	u16 hdisplay;
>> +	u16 vdisplay;
>> +	u8 vrefresh;
>> +	u8 lanes;
>> +	u8 intfs;
>> +};
>> +
>> +static struct lt9611uxc_mode lt9611uxc_modes[] = {
>> +	{ 3840, 2160, 60, 4, 2 }, /* 3840x2160 24bit 60Hz 4Lane 2ports */
>> +	{ 3840, 2160, 30, 4, 2 }, /* 3840x2160 24bit 30Hz 4Lane 2ports */
>> +	{ 1920, 1080, 60, 4, 1 }, /* 1080P 24bit 60Hz 4lane 1port */
>> +	{ 1920, 1080, 30, 3, 1 }, /* 1080P 24bit 30Hz 3lane 1port */
>> +	{ 1920, 1080, 24, 3, 1 },
>> +	{ 1024, 768, 60, 4, 1},
>> +	{ 800, 600, 60, 4, 1},
>> +	{ 720, 480, 60, 4, 1 },
>> +	{ 720, 576, 50, 2, 1 },
>> +	{ 640, 480, 60, 2, 1 },
>> +};
>> +
>> +static struct lt9611uxc *bridge_to_lt9611uxc(struct drm_bridge *bridge)
>> +{
>> +	return container_of(bridge, struct lt9611uxc, bridge);
>> +}
>> +
>> +static void lt9611uxc_lock(struct lt9611uxc *lt9611uxc)
>> +{
>> +	mutex_lock(&lt9611uxc->ocm_lock);
>> +	regmap_write(lt9611uxc->regmap, 0x80ee, 0x01);
>> +}
>> +
>> +static void lt9611uxc_unlock(struct lt9611uxc *lt9611uxc)
>> +{
>> +	regmap_write(lt9611uxc->regmap, 0x80ee, 0x00);
>> +	msleep(50);
>> +	mutex_unlock(&lt9611uxc->ocm_lock);
>> +}
> If you have the data sheet then please use symbolic names for registers.

Unfortunately datasheet names only bit fields.

> 
>> +
>> +static irqreturn_t lt9611uxc_irq_thread_handler(int irq, void *dev_id)
>> +{
>> +	struct lt9611uxc *lt9611uxc = dev_id;
>> +	unsigned int irq_status = 0;
>> +	unsigned int hpd_status = 0;
>> +
>> +	lt9611uxc_lock(lt9611uxc);
>> +
>> +	regmap_read(lt9611uxc->regmap, 0xb022, &irq_status);
>> +	if (irq_status) {
>> +		regmap_write(lt9611uxc->regmap, 0xb022, 0);
>> +		regmap_read(lt9611uxc->regmap, 0xb023, &hpd_status);
> hpd_status is read, but the read value is never used.

removed

>> +	}
>> +
>> +	lt9611uxc_unlock(lt9611uxc);
>> +
>> +	if (irq_status & 0x3 && lt9611uxc->bridge.dev)
>> +		drm_kms_helper_hotplug_event(lt9611uxc->bridge.dev);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static void lt9611uxc_reset(struct lt9611uxc *lt9611uxc)
>> +{
>> +	gpiod_set_value_cansleep(lt9611uxc->reset_gpio, 1);
>> +	msleep(20);
>> +
>> +	gpiod_set_value_cansleep(lt9611uxc->reset_gpio, 0);
>> +	msleep(20);
>> +
>> +	gpiod_set_value_cansleep(lt9611uxc->reset_gpio, 1);
>> +	msleep(180);
>> +
>> +	lt9611uxc->sleep = false;
>> +}
>> +
>> +static void lt9611uxc_assert_5v(struct lt9611uxc *lt9611uxc)
>> +{
>> +	if (!lt9611uxc->enable_gpio)
>> +		return;
>> +
>> +	gpiod_set_value_cansleep(lt9611uxc->enable_gpio, 1);
>> +	msleep(20);
>> +}
>> +
>> +static int lt9611uxc_regulator_init(struct lt9611uxc *lt9611uxc)
>> +{
>> +	int ret;
>> +
>> +	lt9611uxc->supplies[0].supply = "vdd";
>> +	lt9611uxc->supplies[1].supply = "vcc";
>> +
>> +	ret = devm_regulator_bulk_get(lt9611uxc->dev, 2, lt9611uxc->supplies);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	return regulator_set_load(lt9611uxc->supplies[0].consumer, 200000);
>> +}
>> +
>> +static int lt9611uxc_regulator_enable(struct lt9611uxc *lt9611uxc)
>> +{
>> +	int ret;
>> +
>> +	ret = regulator_enable(lt9611uxc->supplies[0].consumer);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	usleep_range(1000, 10000); /* 50000 according to dtsi */
>> +
>> +	ret = regulator_enable(lt9611uxc->supplies[1].consumer);
>> +	if (ret < 0) {
>> +		regulator_disable(lt9611uxc->supplies[0].consumer);
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static struct lt9611uxc_mode *lt9611uxc_find_mode(const struct drm_display_mode *mode)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(lt9611uxc_modes); i++) {
>> +		if (lt9611uxc_modes[i].hdisplay == mode->hdisplay &&
>> +		    lt9611uxc_modes[i].vdisplay == mode->vdisplay &&
>> +		    lt9611uxc_modes[i].vrefresh == drm_mode_vrefresh(mode)) {
>> +			return &lt9611uxc_modes[i];
>> +		}
>> +	}
>> +
>> +	return NULL;
>> +}
>> +
>> +static struct mipi_dsi_device *lt9611uxc_attach_dsi(struct lt9611uxc *lt9611uxc,
>> +						    struct device_node *dsi_node)
>> +{
>> +	const struct mipi_dsi_device_info info = { "lt9611uxc", 0, NULL };
>> +	struct mipi_dsi_device *dsi;
>> +	struct mipi_dsi_host *host;
>> +	int ret;
>> +
>> +	host = of_find_mipi_dsi_host_by_node(dsi_node);
>> +	if (!host) {
>> +		dev_err(lt9611uxc->dev, "failed to find dsi host\n");
>> +		return ERR_PTR(-EPROBE_DEFER);
>> +	}
>> +
>> +	dsi = mipi_dsi_device_register_full(host, &info);
>> +	if (IS_ERR(dsi)) {
>> +		dev_err(lt9611uxc->dev, "failed to create dsi device\n");
>> +		return dsi;
>> +	}
>> +
>> +	dsi->lanes = 4;
>> +	dsi->format = MIPI_DSI_FMT_RGB888;
>> +	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
>> +			  MIPI_DSI_MODE_VIDEO_HSE;
>> +
>> +	ret = mipi_dsi_attach(dsi);
>> +	if (ret < 0) {
>> +		dev_err(lt9611uxc->dev, "failed to attach dsi to host\n");
>> +		mipi_dsi_device_unregister(dsi);
>> +		return ERR_PTR(ret);
>> +	}
>> +
>> +	return dsi;
>> +}
>> +
>> +static void lt9611uxc_bridge_detach(struct drm_bridge *bridge)
>> +{
>> +	struct lt9611uxc *lt9611uxc = bridge_to_lt9611uxc(bridge);
>> +
>> +	if (lt9611uxc->dsi1) {
>> +		mipi_dsi_detach(lt9611uxc->dsi1);
>> +		mipi_dsi_device_unregister(lt9611uxc->dsi1);
>> +	}
>> +
>> +	mipi_dsi_detach(lt9611uxc->dsi0);
>> +	mipi_dsi_device_unregister(lt9611uxc->dsi0);
> Hmm, is detach is called twice then thi will fail as the poiters are not
> set back to NULL. But I think this is fine - so ignore. >
>> +}
>> +
>> +static int lt9611uxc_bridge_attach(struct drm_bridge *bridge,
>> +				   enum drm_bridge_attach_flags flags)
>> +{
>> +	struct lt9611uxc *lt9611uxc = bridge_to_lt9611uxc(bridge);
>> +	int ret;
>> +
>> +	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
>> +		dev_err(lt9611uxc->dev, "This bridge driver does not support providing connector!");
>> +		return -EINVAL;
>> +	}
>> +
>> +	/* Attach primary DSI */
>> +	lt9611uxc->dsi0 = lt9611uxc_attach_dsi(lt9611uxc, lt9611uxc->dsi0_node);
>> +	if (IS_ERR(lt9611uxc->dsi0))
>> +		return PTR_ERR(lt9611uxc->dsi0);
>> +
>> +	/* Attach secondary DSI, if specified */
>> +	if (lt9611uxc->dsi1_node) {
>> +		lt9611uxc->dsi1 = lt9611uxc_attach_dsi(lt9611uxc, lt9611uxc->dsi1_node);
>> +		if (IS_ERR(lt9611uxc->dsi1)) {
>> +			ret = PTR_ERR(lt9611uxc->dsi1);
>> +			goto err_unregister_dsi0;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +
>> +err_unregister_dsi0:
>> +	mipi_dsi_detach(lt9611uxc->dsi0);
>> +	mipi_dsi_device_unregister(lt9611uxc->dsi0);
>> +
>> +	return ret;
>> +}
>> +
>> +static enum drm_mode_status
>> +lt9611uxc_bridge_mode_valid(struct drm_bridge *bridge,
>> +			    const struct drm_display_info *info,
>> +			    const struct drm_display_mode *mode)
>> +{
>> +	struct lt9611uxc_mode *lt9611uxc_mode;
>> +
>> +	lt9611uxc_mode = lt9611uxc_find_mode(mode);
>> +
>> +	return lt9611uxc_mode ? MODE_OK : MODE_BAD;
>> +}
>> +
>> +static void lt9611uxc_bridge_post_disable(struct drm_bridge *bridge)
>> +{
>> +	struct lt9611uxc *lt9611uxc = bridge_to_lt9611uxc(bridge);
>> +
>> +	lt9611uxc_lock(lt9611uxc);
>> +	regmap_update_bits(lt9611uxc->regmap, 0xb024, 0x1, 0x1);
>> +	lt9611uxc->sleep = true;
>> +	lt9611uxc_unlock(lt9611uxc);
>> +}
>> +
>> +static void lt9611uxc_video_setup(struct lt9611uxc *lt9611uxc,
>> +				  const struct drm_display_mode *mode)
>> +{
>> +	u32 h_total, hactive, hsync_len, hfront_porch;
>> +	u32 v_total, vactive, vsync_len, vfront_porch;
>> +
>> +	h_total = mode->htotal;
>> +	v_total = mode->vtotal;
>> +
>> +	hactive = mode->hdisplay;
>> +	hsync_len = mode->hsync_end - mode->hsync_start;
>> +	hfront_porch = mode->hsync_start - mode->hdisplay;
>> +
>> +	vactive = mode->vdisplay;
>> +	vsync_len = mode->vsync_end - mode->vsync_start;
>> +	vfront_porch = mode->vsync_start - mode->vdisplay;
>> +
>> +	regmap_write(lt9611uxc->regmap, 0xd00d, (u8)(v_total / 256));
>> +	regmap_write(lt9611uxc->regmap, 0xd00e, (u8)(v_total % 256));
>> +
>> +	regmap_write(lt9611uxc->regmap, 0xd00f, (u8)(vactive / 256));
>> +	regmap_write(lt9611uxc->regmap, 0xd010, (u8)(vactive % 256));
>> +
>> +	regmap_write(lt9611uxc->regmap, 0xd011, (u8)(h_total / 256));
>> +	regmap_write(lt9611uxc->regmap, 0xd012, (u8)(h_total % 256));
>> +
>> +	regmap_write(lt9611uxc->regmap, 0xd013, (u8)(hactive / 256));
>> +	regmap_write(lt9611uxc->regmap, 0xd014, (u8)(hactive % 256));
>> +
>> +	regmap_write(lt9611uxc->regmap, 0xd015, (u8)(vsync_len % 256));
>> +
>> +	regmap_update_bits(lt9611uxc->regmap, 0xd016, 0xf, (u8)(hsync_len / 256));
>> +	regmap_write(lt9611uxc->regmap, 0xd017, (u8)(hsync_len % 256));
>> +
>> +	regmap_update_bits(lt9611uxc->regmap, 0xd018, 0xf, (u8)(vfront_porch / 256));
>> +	regmap_write(lt9611uxc->regmap, 0xd019, (u8)(vfront_porch % 256));
>> +
>> +	regmap_update_bits(lt9611uxc->regmap, 0xd01a, 0xf, (u8)(hfront_porch / 256));
>> +	regmap_write(lt9611uxc->regmap, 0xd01b, (u8)(hfront_porch % 256));
>> +}
>> +
>> +static void lt9611uxc_bridge_mode_set(struct drm_bridge *bridge,
>> +				      const struct drm_display_mode *mode,
>> +				      const struct drm_display_mode *adj_mode)
>> +{
>> +	struct lt9611uxc *lt9611uxc = bridge_to_lt9611uxc(bridge);
>> +
>> +	if (lt9611uxc->sleep)
>> +		lt9611uxc_reset(lt9611uxc);
>> +
>> +	lt9611uxc_lock(lt9611uxc);
>> +	lt9611uxc_video_setup(lt9611uxc, mode);
>> +	lt9611uxc_unlock(lt9611uxc);
>> +}
>> +
>> +static enum drm_connector_status lt9611uxc_bridge_detect(struct drm_bridge *bridge)
>> +{
>> +	struct lt9611uxc *lt9611uxc = bridge_to_lt9611uxc(bridge);
>> +	unsigned int reg_val = 0;
>> +	int ret;
>> +	int connected = 1;
>> +
>> +	if (lt9611uxc->hpd_supported) {
>> +		lt9611uxc_lock(lt9611uxc);
>> +		ret = regmap_read(lt9611uxc->regmap, 0xb023, &reg_val);
> Would it be better to save this value in the irq function?
> We read the same register here.

i've removed from the IRQ function in the end. The register can be 
updated between IRQ function and detect callback.

> 
>> +		lt9611uxc_unlock(lt9611uxc);
>> +
>> +		if (ret)
>> +			dev_err(lt9611uxc->dev, "failed to read hpd status: %d\n", ret);
> So if failed to read status it is considered connected. Hmm..

To be on a safe side.

> 
>> +		else
>> +			connected  = reg_val & BIT(1);
>> +	}
>> +
>> +	return connected ?  connector_status_connected :
>> +				connector_status_disconnected;
>> +}
>> +
>> +static int lt9611uxc_bridge_get_modes(struct drm_bridge *bridge,
>> +				      struct drm_connector *connector)
>> +{
>> +	struct lt9611uxc *lt9611uxc = bridge_to_lt9611uxc(bridge);
>> +	struct display_timings *timings = lt9611uxc->timings;
>> +	int i;
>> +
>> +	for (i = 0; i < timings->num_timings; i++) {
>> +		struct drm_display_mode *mode = drm_mode_create(bridge->dev);
>> +		struct videomode vm;
>> +
>> +		if (videomode_from_timings(timings, &vm, i))
>> +			break;
>> +
>> +		drm_display_mode_from_videomode(&vm, mode);
>> +
>> +		mode->type = DRM_MODE_TYPE_DRIVER;
>> +
>> +		if (timings->native_mode == i)
>> +			mode->type |= DRM_MODE_TYPE_PREFERRED;
>> +
>> +		drm_mode_set_name(mode);
>> +		drm_mode_probed_add(connector, mode);
>> +	}
>> +
>> +	return i;
>> +}
>> +
>> +static int lt9611uxc_read_edid(struct lt9611uxc *lt9611uxc)
>> +{
>> +	int ret = 0;
>> +	int i;
>> +
>> +	/* memset to clear old buffer, if any */
>> +	memset(lt9611uxc->edid_buf, 0, sizeof(lt9611uxc->edid_buf));
>> +
>> +	lt9611uxc_lock(lt9611uxc);
>> +
>> +	regmap_write(lt9611uxc->regmap, 0xb00b, 0x10);
>> +
>> +#define EDID_SEG 16
>> +	for (i = 0; i < 2 * EDID_BLOCK_SIZE; i += EDID_SEG) {
>> +		regmap_write(lt9611uxc->regmap, 0xb00a, i);
>> +		ret = regmap_noinc_read(lt9611uxc->regmap, 0xb0b0,
>> +					&lt9611uxc->edid_buf[i], EDID_SEG);
>> +		if (ret < 0)
>> +			break;
>> +	}
>> +
>> +	lt9611uxc_unlock(lt9611uxc);
>> +	return ret;
>> +}
>> +
>> +static int lt9611uxc_get_edid_block(void *data, u8 *buf, unsigned int block, size_t len)
>> +{
>> +	struct lt9611uxc *lt9611uxc = data;
>> +	int ret;
>> +
>> +	if (len > EDID_BLOCK_SIZE)
>> +		return -EINVAL;
>> +
>> +	if (block >= EDID_NUM_BLOCKS)
>> +		return -EINVAL;
>> +
>> +	if (block == 0) {
>> +		ret = lt9611uxc_read_edid(lt9611uxc);
>> +		if (ret) {
>> +			dev_err(lt9611uxc->dev, "edid read failed\n");
>> +			return ret;
>> +		}
>> +	}
>> +
>> +	memcpy(buf, lt9611uxc->edid_buf + block * EDID_BLOCK_SIZE, len);
>> +	return 0;
>> +};
>> +
>> +static struct edid *lt9611uxc_bridge_get_edid(struct drm_bridge *bridge,
>> +					      struct drm_connector *connector)
>> +{
>> +	struct lt9611uxc *lt9611uxc = bridge_to_lt9611uxc(bridge);
>> +
>> +	return drm_do_get_edid(connector, lt9611uxc_get_edid_block, lt9611uxc);
>> +}
>> +
>> +static const struct drm_bridge_funcs lt9611uxc_bridge_funcs = {
>> +	.attach = lt9611uxc_bridge_attach,
>> +	.detach = lt9611uxc_bridge_detach,
>> +	.mode_valid = lt9611uxc_bridge_mode_valid,
>> +	.post_disable = lt9611uxc_bridge_post_disable,
>> +	.mode_set = lt9611uxc_bridge_mode_set,
>> +	.detect = lt9611uxc_bridge_detect,
>> +	.get_modes = lt9611uxc_bridge_get_modes,
>> +	.get_edid = lt9611uxc_bridge_get_edid,
>> +};
>> +
>> +static int lt9611uxc_parse_dt(struct device *dev,
>> +			      struct lt9611uxc *lt9611uxc)
>> +{
>> +	lt9611uxc->timings = of_get_display_timings(dev->of_node);
>> +	if (!lt9611uxc->timings)
>> +		dev_info(dev, "no display timings provided\n");
>> +
>> +	lt9611uxc->dsi0_node = of_graph_get_remote_node(dev->of_node, 0, -1);
>> +	if (!lt9611uxc->dsi0_node) {
>> +		dev_err(lt9611uxc->dev, "failed to get remote node for primary dsi\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	lt9611uxc->dsi1_node = of_graph_get_remote_node(dev->of_node, 1, -1);
>> +
>> +	return 0;
>> +}
>> +
>> +static int lt9611uxc_gpio_init(struct lt9611uxc *lt9611uxc)
>> +{
>> +	struct device *dev = lt9611uxc->dev;
>> +
>> +	lt9611uxc->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
>> +	if (IS_ERR(lt9611uxc->reset_gpio)) {
>> +		dev_err(dev, "failed to acquire reset gpio\n");
>> +		return PTR_ERR(lt9611uxc->reset_gpio);
>> +	}
>> +
>> +	lt9611uxc->enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);
>> +	if (IS_ERR(lt9611uxc->enable_gpio)) {
>> +		dev_err(dev, "failed to acquire enable gpio\n");
>> +		return PTR_ERR(lt9611uxc->enable_gpio);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int lt9611uxc_read_device_rev(struct lt9611uxc *lt9611uxc)
>> +{
>> +	unsigned int rev0, rev1, rev2;
>> +	int ret;
>> +
>> +	lt9611uxc_lock(lt9611uxc);
>> +
>> +	ret = regmap_read(lt9611uxc->regmap, 0x8100, &rev0);
>> +	ret |= regmap_read(lt9611uxc->regmap, 0x8101, &rev1);
>> +	ret |= regmap_read(lt9611uxc->regmap, 0x8102, &rev2);
>> +	if (ret)
>> +		dev_err(lt9611uxc->dev, "failed to read revision: %d\n", ret);
>> +	else
>> +		dev_info(lt9611uxc->dev, "LT9611 revision: 0x%02x.%02x.%02x\n", rev0, rev1, rev2);
>> +
>> +	lt9611uxc_unlock(lt9611uxc);
>> +
>> +	return ret;
>> +}
>> +
>> +static int lt9611uxc_read_version(struct lt9611uxc *lt9611uxc)
>> +{
>> +	unsigned int rev;
>> +	int ret;
>> +
>> +	lt9611uxc_lock(lt9611uxc);
>> +
>> +	ret = regmap_read(lt9611uxc->regmap, 0xb021, &rev);
>> +	if (ret)
>> +		dev_err(lt9611uxc->dev, "failed to read revision: %d\n", ret);
>> +	else
>> +		dev_info(lt9611uxc->dev, "LT9611 version: 0x%02x\n", rev);
>> +
>> +	lt9611uxc_unlock(lt9611uxc);
>> +
>> +	return ret < 0 ? ret : rev;
>> +}
>> +
>> +static int lt9611uxc_hdmi_hw_params(struct device *dev, void *data,
>> +				    struct hdmi_codec_daifmt *fmt,
>> +				    struct hdmi_codec_params *hparms)
>> +{
>> +	/*
>> +	 * LT9611UXC will automatically detect rate and sample size, so no need
>> +	 * to setup anything here.
>> +	 */
>> +	return 0;
>> +}
>> +
>> +static void lt9611uxc_audio_shutdown(struct device *dev, void *data)
>> +{
>> +}
>> +
>> +static int lt9611uxc_hdmi_i2s_get_dai_id(struct snd_soc_component *component,
>> +					 struct device_node *endpoint)
>> +{
>> +	struct of_endpoint of_ep;
>> +	int ret;
>> +
>> +	ret = of_graph_parse_endpoint(endpoint, &of_ep);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	/*
>> +	 * HDMI sound should be located as reg = <2>
>> +	 * Then, it is sound port 0
>> +	 */
>> +	if (of_ep.port == 2)
>> +		return 0;
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static const struct hdmi_codec_ops lt9611uxc_codec_ops = {
>> +	.hw_params	= lt9611uxc_hdmi_hw_params,
>> +	.audio_shutdown = lt9611uxc_audio_shutdown,
>> +	.get_dai_id	= lt9611uxc_hdmi_i2s_get_dai_id,
>> +};
> Is an audio_startup() operation missing here?

No, it is not. Audio is started automatically and it is optional.

> 
>> +
>> +static int lt9611uxc_audio_init(struct device *dev, struct lt9611uxc *lt9611uxc)
>> +{
>> +	struct hdmi_codec_pdata codec_data = {
>> +		.ops = &lt9611uxc_codec_ops,
>> +		.max_i2s_channels = 2,
>> +		.i2s = 1,
>> +		.data = lt9611uxc,
>> +	};
>> +
>> +	lt9611uxc->audio_pdev =
>> +		platform_device_register_data(dev, HDMI_CODEC_DRV_NAME,
>> +					      PLATFORM_DEVID_AUTO,
>> +					      &codec_data, sizeof(codec_data));
>> +
>> +	return PTR_ERR_OR_ZERO(lt9611uxc->audio_pdev);
>> +}
>> +
>> +static void lt9611uxc_audio_exit(struct lt9611uxc *lt9611uxc)
>> +{
>> +	if (lt9611uxc->audio_pdev) {
>> +		platform_device_unregister(lt9611uxc->audio_pdev);
>> +		lt9611uxc->audio_pdev = NULL;
>> +	}
>> +}
>> +
>> +static int lt9611uxc_probe(struct i2c_client *client,
>> +			   const struct i2c_device_id *id)
>> +{
>> +	struct lt9611uxc *lt9611uxc;
>> +	struct device *dev = &client->dev;
>> +	int ret;
>> +
>> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
>> +		dev_err(dev, "device doesn't support I2C\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	lt9611uxc = devm_kzalloc(dev, sizeof(*lt9611uxc), GFP_KERNEL);
>> +	if (!lt9611uxc)
>> +		return -ENOMEM;
>> +
>> +	lt9611uxc->dev = &client->dev;
>> +	lt9611uxc->client = client;
>> +	mutex_init(&lt9611uxc->ocm_lock);
>> +
>> +	lt9611uxc->regmap = devm_regmap_init_i2c(client, &lt9611uxc_regmap_config);
>> +	if (IS_ERR(lt9611uxc->regmap)) {
>> +		dev_err(lt9611uxc->dev, "regmap i2c init failed\n");
>> +		return PTR_ERR(lt9611uxc->regmap);
>> +	}
>> +
>> +	ret = lt9611uxc_parse_dt(&client->dev, lt9611uxc);
>> +	if (ret) {
>> +		dev_err(dev, "failed to parse device tree\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = lt9611uxc_gpio_init(lt9611uxc);
>> +	if (ret < 0)
>> +		goto err_of_put;
>> +
>> +	ret = lt9611uxc_regulator_init(lt9611uxc);
>> +	if (ret < 0)
>> +		goto err_of_put;
>> +
>> +	lt9611uxc_assert_5v(lt9611uxc);
>> +
>> +	ret = lt9611uxc_regulator_enable(lt9611uxc);
>> +	if (ret)
>> +		goto err_of_put;
>> +
>> +	lt9611uxc_reset(lt9611uxc);
>> +
>> +	ret = lt9611uxc_read_device_rev(lt9611uxc);
>> +	if (ret) {
>> +		dev_err(dev, "failed to read chip rev\n");
>> +		goto err_disable_regulators;
>> +	}
>> +
>> +	ret = lt9611uxc_read_version(lt9611uxc);
>> +	if (ret < 0) {
>> +		dev_err(dev, "failed to read FW version\n");
>> +		goto err_disable_regulators;
>> +	} else if (ret == 0) {
>> +		dev_err(dev, "FW version 0, FW update not supported\n");
>> +		ret = -EOPNOTSUPP;
>> +		goto err_disable_regulators;
>> +	} else if (ret < 0x40) {
>> +		dev_info(dev, "FW version 0x%x, HPD not supported\n", ret);
>> +	} else {
>> +		lt9611uxc->hpd_supported = true;
>> +	}
>> +
>> +	ret = devm_request_threaded_irq(dev, client->irq, NULL,
>> +					lt9611uxc_irq_thread_handler,
>> +					IRQF_ONESHOT, "lt9611uxc", lt9611uxc);
>> +	if (ret) {
>> +		dev_err(dev, "failed to request irq\n");
>> +		goto err_disable_regulators;
>> +	}
>> +
>> +	i2c_set_clientdata(client, lt9611uxc);
>> +
>> +	lt9611uxc->bridge.funcs = &lt9611uxc_bridge_funcs;
>> +	lt9611uxc->bridge.of_node = client->dev.of_node;
>> +	lt9611uxc->bridge.ops = DRM_BRIDGE_OP_DETECT;
>> +	if (lt9611uxc->timings)
>> +		lt9611uxc->bridge.ops |= DRM_BRIDGE_OP_MODES;
>> +	else
>> +		lt9611uxc->bridge.ops |= DRM_BRIDGE_OP_EDID;
>> +	if (lt9611uxc->hpd_supported)
>> +		lt9611uxc->bridge.ops |= DRM_BRIDGE_OP_HPD;
>> +	lt9611uxc->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
>> +
>> +	drm_bridge_add(&lt9611uxc->bridge);
>> +
>> +	return lt9611uxc_audio_init(dev, lt9611uxc);
>> +
>> +err_disable_regulators:
>> +	regulator_bulk_disable(ARRAY_SIZE(lt9611uxc->supplies), lt9611uxc->supplies);
>> +
>> +err_of_put:
>> +	of_node_put(lt9611uxc->dsi1_node);
>> +	of_node_put(lt9611uxc->dsi0_node);
>> +
>> +	return ret;
>> +}
>> +
>> +static int lt9611uxc_remove(struct i2c_client *client)
>> +{
>> +	struct lt9611uxc *lt9611uxc = i2c_get_clientdata(client);
>> +
>> +	disable_irq(client->irq);
>> +	lt9611uxc_audio_exit(lt9611uxc);
>> +	drm_bridge_remove(&lt9611uxc->bridge);
>> +
>> +	mutex_destroy(&lt9611uxc->ocm_lock);
>> +
>> +	regulator_bulk_disable(ARRAY_SIZE(lt9611uxc->supplies), lt9611uxc->supplies);
>> +
>> +	of_node_put(lt9611uxc->dsi1_node);
>> +	of_node_put(lt9611uxc->dsi0_node);
>> +
>> +	return 0;
>> +}
>> +
>> +static struct i2c_device_id lt9611uxc_id[] = {
>> +	{ "lontium,lt9611uxc", 0 },
>> +	{}
>> +};
>> +
>> +static const struct of_device_id lt9611uxc_match_table[] = {
>> +	{ .compatible = "lontium,lt9611uxc" },
>> +	{ }
> 	{ /* sentinel */ },
>> +};
>> +MODULE_DEVICE_TABLE(of, lt9611uxc_match_table);
>> +
>> +static struct i2c_driver lt9611uxc_driver = {
>> +	.driver = {
>> +		.name = "lt9611uxc",
>> +		.of_match_table = lt9611uxc_match_table,
>> +	},
>> +	.probe = lt9611uxc_probe,
>> +	.remove = lt9611uxc_remove,
>> +	.id_table = lt9611uxc_id,
>> +};
>> +module_i2c_driver(lt9611uxc_driver);
>> +
>> +MODULE_LICENSE("GPL v2");
>> -- 
>> 2.28.0