Thread (8 messages) 8 messages, 1 author, 2026-03-30
STALE121d REVIEWED: 1 (0M)

[PATCH v3 3/7] pwm: tegra: Modify read/write accessors for multi-register channel

From: Mikko Perttunen <mperttunen@nvidia.com>
Date: 2026-03-30 08:54:08
Also in: linux-pwm, linux-tegra, lkml
Subsystem: pwm subsystem, tegra pwm driver, the rest · Maintainers: Uwe Kleine-König, Thierry Reding, Linus Torvalds

On Tegra264, each PWM instance has two registers (per channel, of which
there is one). Update the pwm_readl/pwm_writel helper functions to
take channel (as struct pwm_device *) and offset separately.

Reviewed-by: Thierry Reding <redacted>
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
---
 drivers/pwm/pwm-tegra.c | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)
diff --git a/drivers/pwm/pwm-tegra.c b/drivers/pwm/pwm-tegra.c
index 759b98b97b6e..cf54f75d92a5 100644
--- a/drivers/pwm/pwm-tegra.c
+++ b/drivers/pwm/pwm-tegra.c
@@ -57,6 +57,8 @@
 #define PWM_SCALE_WIDTH	13
 #define PWM_SCALE_SHIFT	0
 
+#define PWM_CSR_0	0
+
 struct tegra_pwm_soc {
 	unsigned int num_channels;
 };
@@ -78,14 +80,18 @@ static inline struct tegra_pwm_chip *to_tegra_pwm_chip(struct pwm_chip *chip)
 	return pwmchip_get_drvdata(chip);
 }
 
-static inline u32 pwm_readl(struct tegra_pwm_chip *pc, unsigned int offset)
+static inline u32 pwm_readl(struct pwm_device *dev, unsigned int offset)
 {
-	return readl(pc->regs + (offset << 4));
+	struct tegra_pwm_chip *chip = to_tegra_pwm_chip(dev->chip);
+
+	return readl(chip->regs + (dev->hwpwm * 16) + offset);
 }
 
-static inline void pwm_writel(struct tegra_pwm_chip *pc, unsigned int offset, u32 value)
+static inline void pwm_writel(struct pwm_device *dev, unsigned int offset, u32 value)
 {
-	writel(value, pc->regs + (offset << 4));
+	struct tegra_pwm_chip *chip = to_tegra_pwm_chip(dev->chip);
+
+	writel(value, chip->regs + (dev->hwpwm * 16) + offset);
 }
 
 static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -194,7 +200,7 @@ static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	} else
 		val |= PWM_ENABLE;
 
-	pwm_writel(pc, pwm->hwpwm, val);
+	pwm_writel(pwm, PWM_CSR_0, val);
 
 	/*
 	 * If the PWM is not enabled, turn the clock off again to save power.
@@ -207,7 +213,6 @@ static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 
 static int tegra_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
-	struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
 	int rc = 0;
 	u32 val;
 
@@ -215,21 +220,20 @@ static int tegra_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 	if (rc)
 		return rc;
 
-	val = pwm_readl(pc, pwm->hwpwm);
+	val = pwm_readl(pwm, PWM_CSR_0);
 	val |= PWM_ENABLE;
-	pwm_writel(pc, pwm->hwpwm, val);
+	pwm_writel(pwm, PWM_CSR_0, val);
 
 	return 0;
 }
 
 static void tegra_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
-	struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
 	u32 val;
 
-	val = pwm_readl(pc, pwm->hwpwm);
+	val = pwm_readl(pwm, PWM_CSR_0);
 	val &= ~PWM_ENABLE;
-	pwm_writel(pc, pwm->hwpwm, val);
+	pwm_writel(pwm, PWM_CSR_0, val);
 
 	pm_runtime_put_sync(pwmchip_parent(chip));
 }
-- 
2.53.0
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