From c436e3e9c265a1f012008ef5da6fd28863f8025c Mon Sep 17 00:00:00 2001 From: Devi Priya Date: Mon, 6 Apr 2026 22:24:39 +0200 Subject: [PATCH] pwm: Driver for qualcomm ipq6018 pwm block MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 IPQ5018 and IPQ6010 based hardware. Co-developed-by: Baruch Siach Signed-off-by: Baruch Siach Signed-off-by: Devi Priya Reviewed-by: Bjorn Andersson Signed-off-by: George Moussalem Link: https://patch.msgid.link/20260406-ipq-pwm-v21-2-6ed1e868e4c2@outlook.com [ukleinek: Fixed a few nitpicks as agreed on the mailing list] Signed-off-by: Uwe Kleine-König --- drivers/pwm/Kconfig | 12 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-ipq.c | 263 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 276 insertions(+) create mode 100644 drivers/pwm/pwm-ipq.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 6f3147518376..e8886a9b64d9 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -347,6 +347,18 @@ 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 0dc0d2b69025..5630a521a7cf 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -29,6 +29,7 @@ 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..592c26fcc9e6 --- /dev/null +++ b/drivers/pwm/pwm-ipq.c @@ -0,0 +1,263 @@ +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 +/* + * Copyright (c) 2016-2017, 2020 The Linux Foundation. All rights reserved. + * + * Limitations: + * - The PWM controller has no publicly available datasheet. + * - Each of the four channels is programmed via two 32-bit registers + * (REG0 and REG1 at 8-byte stride). + * - Period and duty-cycle reconfiguration is fully atomic: new divider, + * pre-divider, and high-duration values are latched by setting the + * UPDATE bit (bit 30 in REG1). The hardware applies the new settings + * at the beginning of the next period without disabling the output, + * so the currently running period is always completed. + * - On disable (clearing the ENABLE bit 31 in REG1), the hardware + * finishes the current period before stopping the output. The pin + * is then driven to the inactive (low) level. + * - Upon disabling, the hardware resets the pre-divider (PRE_DIV) and divider + * fields (PWM_DIV) in REG0 and REG1 to 0x0000 and 0x0001 respectively. + * - Only normal polarity is supported. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* The frequency range supported is 1 Hz to 100 Mhz (clock rate) */ +#define IPQ_PWM_MAX_PERIOD_NS ((u64)NSEC_PER_SEC) +#define IPQ_PWM_MIN_PERIOD_NS 10 + +/* + * 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 trigger the change and is unset automatically + * 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) + +/* + * The max value specified for each field is based on the number of bits + * in the pwm control register for that field (16-bit) + */ +#define IPQ_PWM_MAX_DIV FIELD_MAX(IPQ_PWM_REG0_PWM_DIV) + +struct ipq_pwm_chip { + void __iomem *mem; + unsigned long clk_rate; +}; + +static struct ipq_pwm_chip *ipq_pwm_from_chip(struct pwm_chip *chip) +{ + return pwmchip_get_drvdata(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 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; + u64 period_ns, duty_ns; + unsigned long val = 0; + unsigned long hi_dur; + + if (!state->enabled) { + /* clear IPQ_PWM_REG1_ENABLE */ + ipq_pwm_reg_write(pwm, IPQ_PWM_REG1, IPQ_PWM_REG1_UPDATE); + return 0; + } + + if (state->polarity != PWM_POLARITY_NORMAL) + return -EINVAL; + + /* + * Check the upper and lower bounds for the period as per + * hardware limits + */ + if (state->period < IPQ_PWM_MIN_PERIOD_NS) + return -ERANGE; + period_ns = min(state->period, IPQ_PWM_MAX_PERIOD_NS); + duty_ns = min(state->duty_cycle, period_ns); + + /* + * Pick the maximal value for PWM_DIV that still allows a + * 100% relative duty cycle. This allows a fine grained + * selection of duty cycles. + */ + pwm_div = IPQ_PWM_MAX_DIV - 1; + + /* + * although mul_u64_u64_div_u64 returns a u64, in practice it + * won't overflow due to above constraints. Take the max period + * of 10^9 (NSEC_PER_SEC) and the pwm_div + 1 (IPQ_PWM_MAX_DIV) + * 10^9 * 10^8 + * ------------- => which fits well into a 32-bit unsigned int. + * 10^9 * 65,535 + */ + pre_div = mul_u64_u64_div_u64(period_ns, ipq_chip->clk_rate, + (u64)NSEC_PER_SEC * (pwm_div + 1)); + + if (!pre_div) + return -ERANGE; + + pre_div -= 1; + + if (pre_div > IPQ_PWM_MAX_DIV) + pre_div = IPQ_PWM_MAX_DIV; + + /* pwm duty = HI_DUR * (PRE_DIV + 1) / clk_rate */ + hi_dur = mul_u64_u64_div_u64(duty_ns, ipq_chip->clk_rate, + (u64)NSEC_PER_SEC * (pre_div + 1)); + + 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 | IPQ_PWM_REG1_ENABLE; + ipq_pwm_reg_write(pwm, IPQ_PWM_REG1, val); + + return 0; +} + +static int 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 int pre_div, pwm_div, hi_dur; + u64 effective_div, hi_div; + u32 reg0, reg1; + + reg1 = ipq_pwm_reg_read(pwm, IPQ_PWM_REG1); + state->enabled = reg1 & IPQ_PWM_REG1_ENABLE; + + if (!state->enabled) + return 0; + + reg0 = ipq_pwm_reg_read(pwm, IPQ_PWM_REG0); + + state->polarity = PWM_POLARITY_NORMAL; + + 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); + + effective_div = (u64)(pwm_div + 1) * (pre_div + 1); + + /* + * effective_div <= 0x100000000, so the multiplication doesn't overflow. + */ + state->period = DIV64_U64_ROUND_UP(effective_div * NSEC_PER_SEC, + ipq_chip->clk_rate); + + hi_div = hi_dur * (pre_div + 1); + state->duty_cycle = DIV64_U64_ROUND_UP(hi_div * NSEC_PER_SEC, + ipq_chip->clk_rate); + + /* + * ensure a valid config is passed back to PWM core in case duty_cycle + * is > period (>100%) + */ + state->duty_cycle = min(state->duty_cycle, state->period); + + return 0; +} + +static const struct pwm_ops ipq_pwm_ops = { + .apply = ipq_pwm_apply, + .get_state = ipq_pwm_get_state, +}; + +static int ipq_pwm_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct ipq_pwm_chip *pwm; + struct pwm_chip *chip; + struct clk *clk; + int ret; + + chip = devm_pwmchip_alloc(dev, 4, sizeof(*pwm)); + if (IS_ERR(chip)) + return PTR_ERR(chip); + pwm = ipq_pwm_from_chip(chip); + + pwm->mem = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(pwm->mem)) + return dev_err_probe(dev, PTR_ERR(pwm->mem), + "Failed to acquire resource\n"); + + clk = devm_clk_get_enabled(dev, NULL); + if (IS_ERR(clk)) + return dev_err_probe(dev, PTR_ERR(clk), + "Failed to get clock\n"); + + ret = devm_clk_rate_exclusive_get(dev, clk); + if (ret) + return dev_err_probe(dev, ret, "Failed to lock clock rate\n"); + + pwm->clk_rate = clk_get_rate(clk); + if (!pwm->clk_rate) + return dev_err_probe(dev, -EINVAL, "Failed due to clock rate being zero\n"); + + chip->ops = &ipq_pwm_ops; + + ret = devm_pwmchip_add(dev, chip); + if (ret < 0) + return dev_err_probe(dev, ret, "Failed to add pwm chip\n"); + + 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, +}; + +module_platform_driver(ipq_pwm_driver); + +MODULE_LICENSE("GPL");