[PATCH v4 3/7] pwm: tegra: Modify read/write accessors for multi-register channel

Mikko Perttunen
2026-03-31T02:12:44Z

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 <treding@nvidia.com>
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 8a330169d531..358c81cea05b 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