[PATCH 5.10 340/406] pwm: lpc32xx: Remove handling of PWM channels

Greg Kroah-Hartman
2023-09-17T19:41:15Z

From: Vladimir Zapolskiy <vz@mleia.com>

[ Upstream commit 4aae44f65827f0213a7361cf9c32cfe06114473f ]

Because LPC32xx PWM controllers have only a single output which is
registered as the only PWM device/channel per controller, it is known in
advance that pwm->hwpwm value is always 0. On basis of this fact
simplify the code by removing operations with pwm->hwpwm, there is no
controls which require channel number as input.

Even though I wasn't aware at the time when I forward ported that patch,
this fixes a null pointer dereference as lpc32xx->chip.pwms is NULL
before devm_pwmchip_add() is called.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Fixes: 3d2813fb17e5 ("pwm: lpc32xx: Don't modify HW state in .probe() after the PWM chip was registered")
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pwm/pwm-lpc32xx.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/pwm/pwm-lpc32xx.c b/drivers/pwm/pwm-lpc32xx.c
index 522f862eca526..504a8f506195a 100644
--- a/drivers/pwm/pwm-lpc32xx.c
+++ b/drivers/pwm/pwm-lpc32xx.c
@@ -51,10 +51,10 @@ static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
if (duty_cycles > 255)
duty_cycles = 255;

- val = readl(lpc32xx->base + (pwm->hwpwm << 2));
+ val = readl(lpc32xx->base);
val &= ~0xFFFF;
val |= (period_cycles << 8) | duty_cycles;
- writel(val, lpc32xx->base + (pwm->hwpwm << 2));
+ writel(val, lpc32xx->base);

return 0;
}
@@ -69,9 +69,9 @@ static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
if (ret)
return ret;

- val = readl(lpc32xx->base + (pwm->hwpwm << 2));
+ val = readl(lpc32xx->base);
val |= PWM_ENABLE;
- writel(val, lpc32xx->base + (pwm->hwpwm << 2));
+ writel(val, lpc32xx->base);

return 0;
}
@@ -81,9 +81,9 @@ static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
u32 val;

- val = readl(lpc32xx->base + (pwm->hwpwm << 2));
+ val = readl(lpc32xx->base);
val &= ~PWM_ENABLE;
- writel(val, lpc32xx->base + (pwm->hwpwm << 2));
+ writel(val, lpc32xx->base);

clk_disable_unprepare(lpc32xx->clk);
}
@@ -121,9 +121,9 @@ static int lpc32xx_pwm_probe(struct platform_device *pdev)
lpc32xx->chip.base = -1;

/* If PWM is disabled, configure the output to the default value */
- val = readl(lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2));
+ val = readl(lpc32xx->base);
val &= ~PWM_PIN_LEVEL;
- writel(val, lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2));
+ writel(val, lpc32xx->base);

ret = pwmchip_add(&lpc32xx->chip);
if (ret < 0) {
--
2.40.1