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Commit 04301da4 authored by Vladimir Zapolskiy's avatar Vladimir Zapolskiy Committed by Greg Kroah-Hartman
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pwm: lpc32xx: Remove handling of PWM channels 



[ 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: default avatarDan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: default avatarVladimir Zapolskiy <vz@mleia.com>
Signed-off-by: default avatarUwe 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: default avatarThierry Reding <thierry.reding@gmail.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 565f7bb0

drivers/pwm/pwm-lpc32xx.c

+8 −8
Original line number Diff line number Diff line
@@ -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) {