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pwm: rockchip: Enable clock before calling clk_get_rate() 

The documentation for clk_get_rate() in include/linux/clk.h states the
function's result is valid only for a clock source that has been
enabled. However, the Rockchip PWM driver uses this function in two places
to query the rate of a clock without first ensuring it is enabled.

Fix this by modifying rockchip_pwm_get_state() and rockchip_pwm_apply() so
they enable a device's PWM clock before querying its rate (in the latter
case, the querying is actually done in rockchip_pwm_config()) and disable
the clock again before returning.

Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Simon South <simon@simonsouth.net>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
master
Simon South 2021-01-19 11:12:09 -05:00 committed by Thierry Reding
parent d21ba5d621
commit 11be938ae0
1 changed files with 10 additions and 0 deletions
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10
drivers/pwm/pwm-rockchip.c
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@ -72,6 +72,10 @@ static void rockchip_pwm_get_state(struct pwm_chip *chip,
if (ret)
return;
ret = clk_enable(pc->clk);
if (ret)
return;
clk_rate = clk_get_rate(pc->clk);
tmp = readl_relaxed(pc->base + pc->data->regs.period);
@ -90,6 +94,7 @@ static void rockchip_pwm_get_state(struct pwm_chip *chip,
else
state->polarity = PWM_POLARITY_NORMAL;
clk_disable(pc->clk);
clk_disable(pc->pclk);
}
@ -189,6 +194,10 @@ static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
if (ret)
return ret;
ret = clk_enable(pc->clk);
if (ret)
return ret;
pwm_get_state(pwm, &curstate);
enabled = curstate.enabled;
@ -208,6 +217,7 @@ static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
}
out:
clk_disable(pc->clk);
clk_disable(pc->pclk);
return ret;