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pwm: atmel: Enable clk when pwm already enabled in bootloader

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The driver would never call clk_enable() if the PWM channel was already
enabled in bootloader which lead to dump the warning message "the PWM
clock already disabled" when turning off the PWM channel.

Add atmel_pwm_enable_clk_if_on() in probe function to enable clock if
the PWM channel was already enabled in bootloader.

Signed-off-by: Guiting Shen <aarongt.shen@gmail.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Guiting Shen 2023-07-16 10:06:52 +08:00 committed by Thierry Reding
parent 0a41b0c5d9
commit a2f68c7e31
1 changed files with 45 additions and 2 deletions
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47
drivers/pwm/pwm-atmel.c
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@ -35,7 +35,7 @@
#define PWM_SR 0x0C
#define PWM_ISR 0x1C
/* Bit field in SR */
#define PWM_SR_ALL_CH_ON 0x0F
#define PWM_SR_ALL_CH_MASK 0x0F
/* The following register is PWM channel related registers */
#define PWM_CH_REG_OFFSET 0x200
@ -463,6 +463,42 @@ static const struct of_device_id atmel_pwm_dt_ids[] = {
};
MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids);
static int atmel_pwm_enable_clk_if_on(struct atmel_pwm_chip *atmel_pwm, bool on)
{
unsigned int i, cnt = 0;
unsigned long sr;
int ret = 0;
sr = atmel_pwm_readl(atmel_pwm, PWM_SR) & PWM_SR_ALL_CH_MASK;
if (!sr)
return 0;
cnt = bitmap_weight(&sr, atmel_pwm->chip.npwm);
if (!on)
goto disable_clk;
for (i = 0; i < cnt; i++) {
ret = clk_enable(atmel_pwm->clk);
if (ret) {
dev_err(atmel_pwm->chip.dev,
"failed to enable clock for pwm %pe\n",
ERR_PTR(ret));
cnt = i;
goto disable_clk;
}
}
return 0;
disable_clk:
while (cnt--)
clk_disable(atmel_pwm->clk);
return ret;
}
static int atmel_pwm_probe(struct platform_device *pdev)
{
struct atmel_pwm_chip *atmel_pwm;
@ -495,16 +531,23 @@ static int atmel_pwm_probe(struct platform_device *pdev)
atmel_pwm->chip.ops = &atmel_pwm_ops;
atmel_pwm->chip.npwm = 4;
ret = atmel_pwm_enable_clk_if_on(atmel_pwm, true);
if (ret < 0)
goto unprepare_clk;
ret = pwmchip_add(&atmel_pwm->chip);
if (ret < 0) {
dev_err(&pdev->dev, "failed to add PWM chip %d\n", ret);
goto unprepare_clk;
goto disable_clk;
}
platform_set_drvdata(pdev, atmel_pwm);
return ret;
disable_clk:
atmel_pwm_enable_clk_if_on(atmel_pwm, false);
unprepare_clk:
clk_unprepare(atmel_pwm->clk);
return ret;