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pwm: lpc32xx: Remove handling of PWM channels 

[ Upstream commit 4aae44f658 ]

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: 3d2813fb17 ("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>
This commit is contained in:
Vladimir Zapolskiy 2023-07-17 17:52:57 +02:00 committed by Greg Kroah-Hartman
parent 6909e28cf3
commit a2d9d884e8
1 changed files with 8 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/pwm/pwm-lpc32xx.c
View File

@ -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) {