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Commit 422470a8 authored by Tony Prisk's avatar Tony Prisk Committed by Thierry Reding
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pwm: vt8500: Ensure PWM clock is enabled during pwm_config 



This patch corrects a bug reported by Peter Vasil.

When all PWMs are disabled, PWM module may be disabled during
calls to pwm_config. This patch enables/disables the clock in
pwm_config to ensure the module is active before register read/
writes.

Signed-off-by: default avatarTony Prisk <linux@prisktech.co.nz>
Tested-by: default avatarPeter Vasil <petervasil@gmail.com>
Signed-off-by: default avatarThierry Reding <thierry.reding@avionic-design.de>
parent 2f9569f7

drivers/pwm/pwm-vt8500.c

+12 −2
Original line number Diff line number Diff line
@@ -62,6 +62,13 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 
	struct vt8500_chip *vt8500 = to_vt8500_chip(chip);

	unsigned long long c;

	unsigned long period_cycles, prescale, pv, dc;

	int err;



	err = clk_enable(vt8500->clk);

	if (err < 0) {

		dev_err(chip->dev, "failed to enable clock\n");

		return err;

	}



	c = clk_get_rate(vt8500->clk);

	c = c * period_ns;
@@ -75,8 +82,10 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 
	if (pv > 4095)

		pv = 4095;



	if (prescale > 1023)

	if (prescale > 1023) {

		clk_disable(vt8500->clk);

		return -EINVAL;

	}



	c = (unsigned long long)pv * duty_ns;

	do_div(c, period_ns);
@@ -91,6 +100,7 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 
	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 3));

	writel(dc, vt8500->base + 0xc + (pwm->hwpwm << 4));



	clk_disable(vt8500->clk);

	return 0;

}
@@ -103,7 +113,7 @@ static int vt8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 
	if (err < 0) {

		dev_err(chip->dev, "failed to enable clock\n");

		return err;

	};

	}



	pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 0));

	writel(5, vt8500->base + (pwm->hwpwm << 4));