linux-kernel - [PATCH v2 5/9] pwm: stm32: add support for stm32mp25

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Message-ID: <20241220095927.1122782-6-fabrice.gasnier@foss.st.com>
Date: Fri, 20 Dec 2024 10:59:23 +0100
From: Fabrice Gasnier <fabrice.gasnier@...s.st.com>
To: <lee@...nel.org>, <robh@...nel.org>, <krzk+dt@...nel.org>,
        <conor+dt@...nel.org>, <alexandre.torgue@...s.st.com>,
        <wbg@...nel.org>, <jic23@...nel.org>, <ukleinek@...nel.org>
CC: <catalin.marinas@....com>, <will@...nel.org>, <devicetree@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-iio@...r.kernel.org>, <linux-pwm@...r.kernel.org>,
        <olivier.moysan@...s.st.com>
Subject: [PATCH v2 5/9] pwm: stm32: add support for stm32mp25

Add support for STM32MP25 SoC. Use newly introduced compatible to handle
new features along with registers and bits diversity.
The MFD part of the driver fills in ipidr, so it is used to check the
hardware configuration register, when available to gather the number
of PWM channels and complementary outputs.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@...s.st.com>
---
Changes in v2:
Address Uwe review comments:
- Make MAX_PWM_OUTPUT definition less generic: STM32_PWM_MAX_OUTPUT
- No need to initialize 'npwm'
- refactor code, for *num_enabled to use same code path
---
 drivers/pwm/pwm-stm32.c | 42 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 35 insertions(+), 7 deletions(-)

diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
index 17e591f61efb..b9aadc473280 100644
--- a/drivers/pwm/pwm-stm32.c
+++ b/drivers/pwm/pwm-stm32.c
@@ -19,6 +19,7 @@
 #define CCMR_CHANNEL_SHIFT 8
 #define CCMR_CHANNEL_MASK  0xFF
 #define MAX_BREAKINPUT 2
+#define STM32_MAX_PWM_OUTPUT 4
 
 struct stm32_breakinput {
 	u32 index;
@@ -775,10 +776,19 @@ static int stm32_pwm_probe_breakinputs(struct stm32_pwm *priv,
 	return stm32_pwm_apply_breakinputs(priv);
 }
 
-static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
+static void stm32_pwm_detect_complementary(struct stm32_pwm *priv, struct stm32_timers *ddata)
 {
 	u32 ccer;
 
+	if (ddata->ipidr) {
+		u32 val;
+
+		/* Simply read from HWCFGR the number of complementary outputs (MP25). */
+		regmap_read(priv->regmap, TIM_HWCFGR1, &val);
+		priv->have_complementary_output = !!FIELD_GET(TIM_HWCFGR1_NB_OF_DT, val);
+		return;
+	}
+
 	/*
 	 * If complementary bit doesn't exist writing 1 will have no
 	 * effect so we can detect it.
@@ -790,22 +800,39 @@ static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
 	priv->have_complementary_output = (ccer != 0);
 }
 
-static unsigned int stm32_pwm_detect_channels(struct regmap *regmap,
+static unsigned int stm32_pwm_detect_channels(struct stm32_timers *ddata,
 					      unsigned int *num_enabled)
 {
+	struct regmap *regmap = ddata->regmap;
 	u32 ccer, ccer_backup;
 
+	regmap_read(regmap, TIM_CCER, &ccer_backup);
+	*num_enabled = hweight32(ccer_backup & TIM_CCER_CCXE);
+
+	if (ddata->ipidr) {
+		u32 hwcfgr;
+		unsigned int npwm;
+
+		/* Deduce from HWCFGR the number of outputs (MP25). */
+		regmap_read(regmap, TIM_HWCFGR1, &hwcfgr);
+
+		/*
+		 * Timers may have more capture/compare channels than the
+		 * actual number of PWM channel outputs (e.g. TIM_CH[1..4]).
+		 */
+		npwm = FIELD_GET(TIM_HWCFGR1_NB_OF_CC, hwcfgr);
+
+		return npwm < STM32_MAX_PWM_OUTPUT ? npwm : STM32_MAX_PWM_OUTPUT;
+	}
+
 	/*
 	 * If channels enable bits don't exist writing 1 will have no
 	 * effect so we can detect and count them.
 	 */
-	regmap_read(regmap, TIM_CCER, &ccer_backup);
 	regmap_set_bits(regmap, TIM_CCER, TIM_CCER_CCXE);
 	regmap_read(regmap, TIM_CCER, &ccer);
 	regmap_write(regmap, TIM_CCER, ccer_backup);
 
-	*num_enabled = hweight32(ccer_backup & TIM_CCER_CCXE);
-
 	return hweight32(ccer & TIM_CCER_CCXE);
 }
 
@@ -820,7 +847,7 @@ static int stm32_pwm_probe(struct platform_device *pdev)
 	unsigned int i;
 	int ret;
 
-	npwm = stm32_pwm_detect_channels(ddata->regmap, &num_enabled);
+	npwm = stm32_pwm_detect_channels(ddata, &num_enabled);
 
 	chip = devm_pwmchip_alloc(dev, npwm, sizeof(*priv));
 	if (IS_ERR(chip))
@@ -841,7 +868,7 @@ static int stm32_pwm_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, ret,
 				     "Failed to configure breakinputs\n");
 
-	stm32_pwm_detect_complementary(priv);
+	stm32_pwm_detect_complementary(priv, ddata);
 
 	ret = devm_clk_rate_exclusive_get(dev, priv->clk);
 	if (ret)
@@ -911,6 +938,7 @@ static DEFINE_SIMPLE_DEV_PM_OPS(stm32_pwm_pm_ops, stm32_pwm_suspend, stm32_pwm_r
 
 static const struct of_device_id stm32_pwm_of_match[] = {
 	{ .compatible = "st,stm32-pwm",	},
+	{ .compatible = "st,stm32mp25-pwm", },
 	{ /* end node */ },
 };
 MODULE_DEVICE_TABLE(of, stm32_pwm_of_match);
-- 
2.25.1