5.4-stable review patch. If anyone has any objections, please let me know.
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From: Uwe Kleine-König u.kleine-koenig@baylibre.com
[ Upstream commit 00f83f0e07e44e2f1fb94b223e77ab7b18ee2d7d ]
The function set_prescale_div() is responsible for calculating the clock divisor settings such that the input clock rate is divided down such that the required period length is at most 0x10000 clock ticks. If period_cycles is an integer multiple of 0x10000, the divisor period_cycles / 0x10000 is good enough. So round up in the calculation of the required divisor and compare it using >= instead of >.
Fixes: 19891b20e7c2 ("pwm: pwm-tiehrpwm: PWM driver support for EHRPWM") Signed-off-by: Uwe Kleine-König u.kleine-koenig@baylibre.com Link: https://lore.kernel.org/r/85488616d7bfcd9c32717651d0be7e330e761b9c.175492768... Signed-off-by: Uwe Kleine-König ukleinek@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pwm/pwm-tiehrpwm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/pwm/pwm-tiehrpwm.c b/drivers/pwm/pwm-tiehrpwm.c index 7b4c770ce9d67..7414daef81a35 100644 --- a/drivers/pwm/pwm-tiehrpwm.c +++ b/drivers/pwm/pwm-tiehrpwm.c @@ -167,7 +167,7 @@ static int set_prescale_div(unsigned long rqst_prescaler, u16 *prescale_div,
*prescale_div = (1 << clkdiv) * (hspclkdiv ? (hspclkdiv * 2) : 1); - if (*prescale_div > rqst_prescaler) { + if (*prescale_div >= rqst_prescaler) { *tb_clk_div = (clkdiv << TBCTL_CLKDIV_SHIFT) | (hspclkdiv << TBCTL_HSPCLKDIV_SHIFT); return 0; @@ -266,7 +266,7 @@ static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, pc->period_cycles[pwm->hwpwm] = period_cycles;
/* Configure clock prescaler to support Low frequency PWM wave */ - if (set_prescale_div(period_cycles/PERIOD_MAX, &ps_divval, + if (set_prescale_div(DIV_ROUND_UP(period_cycles, PERIOD_MAX), &ps_divval, &tb_divval)) { dev_err(chip->dev, "Unsupported values\n"); return -EINVAL;