From patchwork Mon Feb 7 09:30:43 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Baruch Siach X-Patchwork-Id: 540589 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7390EC433FE for ; Mon, 7 Feb 2022 09:55:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237862AbiBGJyH (ORCPT ); Mon, 7 Feb 2022 04:54:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352881AbiBGJin (ORCPT ); Mon, 7 Feb 2022 04:38:43 -0500 X-Greylist: delayed 459 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 07 Feb 2022 01:38:41 PST Received: from mx.tkos.co.il (guitar.tcltek.co.il [84.110.109.230]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0CE32C043189; Mon, 7 Feb 2022 01:38:40 -0800 (PST) Received: from tarshish.tkos.co.il (unknown [10.0.8.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx.tkos.co.il (Postfix) with ESMTPS id BA55B440846; Mon, 7 Feb 2022 11:30:36 +0200 (IST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tkos.co.il; s=default; t=1644226237; bh=yltlW2MOkdXLFix08jxzuS/XdtDFj/ZvZb24rkwNFKk=; h=From:To:Cc:Subject:Date:From; b=CWiNuJ5Qkc03iptNCAeyPbKeugKPr8bA01lUvsrQYArVACukHdmKoOLTBfSzJIZrb fsT+K5bqeVQfZTZlmodkMRDqc2EZ75EJT+b7Jr894+2agEpohORutpUFm1NBjqPsB2 HUb8Y4HfspBzxvZPIpPug0Flnlbeq/Pyb8o+tnE6nHSw1KK+8GsBERt8fW4Wg6NjSf WClx8aKgHfKSo+K4CUme/STuoEJkRtU2DZK169N0bczLLVYBisf8X4CLx9TA5OznJz y+s8K3hMaXcI1DcA2te+saIt9slVXNrYF86KaMuSUPLmu+0yUtghuvFjWIhr9j1KSP 7+870EkArAeGg== From: Baruch Siach To: Thierry Reding , =?utf-8?q?Uwe_Kleine-K=C3=B6n?= =?utf-8?q?ig?= , Andy Gross , Bjorn Andersson Cc: Baruch Siach , Balaji Prakash J , Rob Herring , Robert Marko , Kathiravan T , linux-pwm@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/3] pwm: driver for qualcomm ipq6018 pwm block Date: Mon, 7 Feb 2022 11:30:43 +0200 Message-Id: <17dd231f496d09ed8502bdd505eaa77bb6637e4b.1644226245.git.baruch@tkos.co.il> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org From: Baruch Siach Driver for the PWM block in Qualcomm IPQ6018 line of SoCs. Based on driver from downstream Codeaurora kernel tree. Removed support for older (V1) variants because I have no access to that hardware. Tested on IPQ6010 based hardware. Signed-off-by: Baruch Siach --- v11: Address comment from Uwe Kleine-König: Drop redundant registers field comments Fix period limit check in .apply Clarify the comment explaining skip of pre_div > pwm_div values Add explicit check for clock rate within limit Add comment explaining the selection of initial pre_div Use pwm_div division with remainder instead of separate diff calculation Round up duty_cycle calculation in .get_state v10: Restore round up in pwm_div calculation; otherwise diff is always <= 0, so only bingo match works Don't overwrite min_diff on every loop iteration v9: Address comment from Uwe Kleine-König: Use period_ns*rate in dividers calculation for better accuracy Round down pre_div and pwm_div Add a comment explaining why pwm_div can't underflow Add a comment explaining why pre_div > pwm_div end the search loop Drop 'CFG_' from register macros Rename to_ipq_pwm_chip() to ipq_pwm_from_chip() Change bare 'unsigned' to 'unsigned int' Clarify the comment on separate REG1 write for enable/disable Round up the period value in .get_state Use direct readl/writel so no need to check for regmap errors v7: Change 'offset' to 'reg' for the tcsr offset (Rob) Drop clock name; there is only one clock (Bjorn) Simplify probe failure code path (Bjorn) v6: Address Uwe Kleine-König review comments: Drop IPQ_PWM_MAX_DEVICES Rely on assigned-clock-rates; drop IPQ_PWM_CLK_SRC_FREQ Simplify register offset calculation Calculate duty cycle more precisely Refuse to set inverted polarity Drop redundant IPQ_PWM_REG1_ENABLE bit clear Remove x1000 factor in pwm_div calculation, use rate directly, and round up Choose initial pre_div such that pwm_div < IPQ_PWM_MAX_DIV Ensure pre_div <= pwm_div Rename close_ to best_ Explain in comment why effective_div doesn't overflow Limit pwm_div to IPQ_PWM_MAX_DIV - 1 to allow 100% duty cycle Disable clock only after pwmchip_remove() const pwm_ops Other changes: Add missing linux/bitfield.h header include (kernel test robot) Adjust code for PWM device node under TCSR (Rob Herring) v5: Use &tcsr_q6 syscon to access registers (Bjorn Andersson) Address Uwe Kleine-König review comments: Implement .get_state() Add IPQ_PWM_ prefix to local macros Use GENMASK/BIT/FIELD_PREP for register fields access Make type of config_div_and_duty() parameters consistent Derive IPQ_PWM_MIN_PERIOD_NS from IPQ_PWM_CLK_SRC_FREQ Integrate enable/disable into config_div_and_duty() to save register read, and reduce frequency glitch on update Use min() instead of min_t() Fix comment format Use dev_err_probe() to indicate probe step failure Add missing clk_disable_unprepare() in .remove Don't set .owner v4: Use div64_u64() to fix link for 32-bit targets ((kernel test robot , Uwe Kleine-König) v3: s/qcom,pwm-ipq6018/qcom,ipq6018-pwm/ (Rob Herring) Fix integer overflow on 32-bit targets (kernel test robot ) v2: Address Uwe Kleine-König review comments: Fix period calculation when out of range Don't set period larger than requested Remove PWM disable on configuration change Implement .apply instead of non-atomic .config/.enable/.disable Don't modify PWM on .request/.free Check pwm_div underflow Fix various code and comment formatting issues Other changes: Use u64 divisor safe division Remove now empty .request/.free --- drivers/pwm/Kconfig | 12 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-ipq.c | 281 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 294 insertions(+) create mode 100644 drivers/pwm/pwm-ipq.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 21e3b05a5153..e39718137ecd 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -260,6 +260,18 @@ config PWM_INTEL_LGM To compile this driver as a module, choose M here: the module will be called pwm-intel-lgm. +config PWM_IPQ + tristate "IPQ PWM support" + depends on ARCH_QCOM || COMPILE_TEST + depends on HAVE_CLK && HAS_IOMEM + help + Generic PWM framework driver for IPQ PWM block which supports + 4 pwm channels. Each of the these channels can be configured + independent of each other. + + To compile this driver as a module, choose M here: the module + will be called pwm-ipq. + config PWM_IQS620A tristate "Azoteq IQS620A PWM support" depends on MFD_IQS62X || COMPILE_TEST diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 708840b7fba8..7402feae4b36 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -22,6 +22,7 @@ obj-$(CONFIG_PWM_IMX1) += pwm-imx1.o obj-$(CONFIG_PWM_IMX27) += pwm-imx27.o obj-$(CONFIG_PWM_IMX_TPM) += pwm-imx-tpm.o obj-$(CONFIG_PWM_INTEL_LGM) += pwm-intel-lgm.o +obj-$(CONFIG_PWM_IPQ) += pwm-ipq.o obj-$(CONFIG_PWM_IQS620A) += pwm-iqs620a.o obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o obj-$(CONFIG_PWM_KEEMBAY) += pwm-keembay.o diff --git a/drivers/pwm/pwm-ipq.c b/drivers/pwm/pwm-ipq.c new file mode 100644 index 000000000000..994027290bcb --- /dev/null +++ b/drivers/pwm/pwm-ipq.c @@ -0,0 +1,281 @@ +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 +/* + * Copyright (c) 2016-2017, 2020 The Linux Foundation. All rights reserved. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* The frequency range supported is 1 Hz to clock rate */ +#define IPQ_PWM_MAX_PERIOD_NS ((u64)NSEC_PER_SEC) + +/* + * The max value specified for each field is based on the number of bits + * in the pwm control register for that field + */ +#define IPQ_PWM_MAX_DIV 0xFFFF + +/* + * Two 32-bit registers for each PWM: REG0, and REG1. + * Base offset for PWM #i is at 8 * #i. + */ +#define IPQ_PWM_REG0 0 +#define IPQ_PWM_REG0_PWM_DIV GENMASK(15, 0) +#define IPQ_PWM_REG0_HI_DURATION GENMASK(31, 16) + +#define IPQ_PWM_REG1 4 +#define IPQ_PWM_REG1_PRE_DIV GENMASK(15, 0) +/* + * Enable bit is set to enable output toggling in pwm device. + * Update bit is set to reflect the changed divider and high duration + * values in register. + */ +#define IPQ_PWM_REG1_UPDATE BIT(30) +#define IPQ_PWM_REG1_ENABLE BIT(31) + + +struct ipq_pwm_chip { + struct pwm_chip chip; + struct clk *clk; + void __iomem *mem; +}; + +static struct ipq_pwm_chip *ipq_pwm_from_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct ipq_pwm_chip, chip); +} + +static unsigned int ipq_pwm_reg_read(struct pwm_device *pwm, unsigned int reg) +{ + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(pwm->chip); + unsigned int off = 8 * pwm->hwpwm + reg; + + return readl(ipq_chip->mem + off); +} + +static void ipq_pwm_reg_write(struct pwm_device *pwm, unsigned int reg, + unsigned int val) +{ + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(pwm->chip); + unsigned int off = 8 * pwm->hwpwm + reg; + + writel(val, ipq_chip->mem + off); +} + +static void config_div_and_duty(struct pwm_device *pwm, unsigned int pre_div, + unsigned int pwm_div, unsigned long rate, u64 duty_ns, + bool enable) +{ + unsigned long hi_dur; + unsigned long val = 0; + + /* + * high duration = pwm duty * (pwm div + 1) + * pwm duty = duty_ns / period_ns + */ + hi_dur = div64_u64(duty_ns * rate, (pre_div + 1) * NSEC_PER_SEC); + + val = FIELD_PREP(IPQ_PWM_REG0_HI_DURATION, hi_dur) | + FIELD_PREP(IPQ_PWM_REG0_PWM_DIV, pwm_div); + ipq_pwm_reg_write(pwm, IPQ_PWM_REG0, val); + + val = FIELD_PREP(IPQ_PWM_REG1_PRE_DIV, pre_div); + ipq_pwm_reg_write(pwm, IPQ_PWM_REG1, val); + + /* PWM enable toggle needs a separate write to REG1 */ + val |= IPQ_PWM_REG1_UPDATE; + if (enable) + val |= IPQ_PWM_REG1_ENABLE; + ipq_pwm_reg_write(pwm, IPQ_PWM_REG1, val); +} + +static int ipq_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(chip); + unsigned int pre_div, pwm_div, best_pre_div, best_pwm_div; + unsigned long rate = clk_get_rate(ipq_chip->clk); + u64 period_ns, duty_ns, period_rate; + u64 min_diff; + + if (state->polarity != PWM_POLARITY_NORMAL) + return -EINVAL; + + if (state->period < DIV64_U64_ROUND_UP(NSEC_PER_SEC, rate)) + return -ERANGE; + + period_ns = min(state->period, IPQ_PWM_MAX_PERIOD_NS); + duty_ns = min(state->duty_cycle, period_ns); + + /* + * period_ns is 1G or less. As long as rate is less than 16 GHz, + * period_rate does not overflow. Make that explicit. + */ + if (rate > 16ULL * GIGA) + return -EINVAL; + period_rate = period_ns * rate; + best_pre_div = IPQ_PWM_MAX_DIV; + best_pwm_div = IPQ_PWM_MAX_DIV; + /* + * We don't need to consider pre_div values smaller than + * + * period_rate + * pre_div_min := ------------------------------------ + * NSEC_PER_SEC * (IPQ_PWM_MAX_DIV + 1) + * + * because pre_div = pre_div_min results in a better + * approximation. + */ + pre_div = div64_u64(period_rate, + (u64)NSEC_PER_SEC * (IPQ_PWM_MAX_DIV + 1)); + min_diff = period_rate; + + for (; pre_div <= IPQ_PWM_MAX_DIV; pre_div++) { + u64 remainder; + + pwm_div = div64_u64_rem(period_rate, + (u64)NSEC_PER_SEC * (pre_div + 1), &remainder); + /* pwm_div is unsigned; the check below catches underflow */ + pwm_div--; + + /* + * Swapping values for pre_div and pwm_div produces the same + * period length. So we can skip all settings with pre_div > + * pwm_div which results in bigger constraints for selecting + * the duty_cycle than with the two values swapped. + */ + if (pre_div > pwm_div) + break; + + /* + * Make sure we can do 100% duty cycle where + * hi_dur == pwm_div + 1 + */ + if (pwm_div > IPQ_PWM_MAX_DIV - 1) + continue; + + if (remainder < min_diff) { + best_pre_div = pre_div; + best_pwm_div = pwm_div; + min_diff = remainder; + + if (min_diff == 0) /* bingo */ + break; + } + } + + /* config divider values for the closest possible frequency */ + config_div_and_duty(pwm, best_pre_div, best_pwm_div, + rate, duty_ns, state->enabled); + + return 0; +} + +static void ipq_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(chip); + unsigned long rate = clk_get_rate(ipq_chip->clk); + unsigned int pre_div, pwm_div, hi_dur; + u64 effective_div, hi_div; + u32 reg0, reg1; + + reg0 = ipq_pwm_reg_read(pwm, IPQ_PWM_REG0); + reg1 = ipq_pwm_reg_read(pwm, IPQ_PWM_REG1); + + state->polarity = PWM_POLARITY_NORMAL; + state->enabled = reg1 & IPQ_PWM_REG1_ENABLE; + + pwm_div = FIELD_GET(IPQ_PWM_REG0_PWM_DIV, reg0); + hi_dur = FIELD_GET(IPQ_PWM_REG0_HI_DURATION, reg0); + pre_div = FIELD_GET(IPQ_PWM_REG1_PRE_DIV, reg1); + + /* No overflow here, both pre_div and pwm_div <= 0xffff */ + effective_div = (u64)(pre_div + 1) * (pwm_div + 1); + state->period = DIV64_U64_ROUND_UP(effective_div * NSEC_PER_SEC, rate); + + hi_div = hi_dur * (pre_div + 1); + state->duty_cycle = DIV64_U64_ROUND_UP(hi_div * NSEC_PER_SEC, rate); +} + +static const struct pwm_ops ipq_pwm_ops = { + .apply = ipq_pwm_apply, + .get_state = ipq_pwm_get_state, + .owner = THIS_MODULE, +}; + +static int ipq_pwm_probe(struct platform_device *pdev) +{ + struct ipq_pwm_chip *pwm; + struct device *dev = &pdev->dev; + int ret; + + pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL); + if (!pwm) + return -ENOMEM; + + platform_set_drvdata(pdev, pwm); + + pwm->mem = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(pwm->mem)) + return dev_err_probe(dev, PTR_ERR(pwm->mem), + "regs map failed"); + + pwm->clk = devm_clk_get(dev, NULL); + if (IS_ERR(pwm->clk)) + return dev_err_probe(dev, PTR_ERR(pwm->clk), + "failed to get clock"); + + ret = clk_prepare_enable(pwm->clk); + if (ret) + return dev_err_probe(dev, ret, "clock enable failed"); + + pwm->chip.dev = dev; + pwm->chip.ops = &ipq_pwm_ops; + pwm->chip.npwm = 4; + + ret = pwmchip_add(&pwm->chip); + if (ret < 0) { + dev_err_probe(dev, ret, "pwmchip_add() failed\n"); + clk_disable_unprepare(pwm->clk); + } + + return ret; +} + +static int ipq_pwm_remove(struct platform_device *pdev) +{ + struct ipq_pwm_chip *pwm = platform_get_drvdata(pdev); + + pwmchip_remove(&pwm->chip); + clk_disable_unprepare(pwm->clk); + + return 0; +} + +static const struct of_device_id pwm_ipq_dt_match[] = { + { .compatible = "qcom,ipq6018-pwm", }, + {} +}; +MODULE_DEVICE_TABLE(of, pwm_ipq_dt_match); + +static struct platform_driver ipq_pwm_driver = { + .driver = { + .name = "ipq-pwm", + .of_match_table = pwm_ipq_dt_match, + }, + .probe = ipq_pwm_probe, + .remove = ipq_pwm_remove, +}; + +module_platform_driver(ipq_pwm_driver); + +MODULE_LICENSE("Dual BSD/GPL");