From a2f68c7e312f94c8f78740449a88e8d7308ab18d Mon Sep 17 00:00:00 2001 From: Guiting Shen Date: Sun, 16 Jul 2023 10:06:52 +0800 Subject: pwm: atmel: Enable clk when pwm already enabled in bootloader 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 Reviewed-by: Claudiu Beznea Signed-off-by: Thierry Reding --- drivers/pwm/pwm-atmel.c | 47 +++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 45 insertions(+), 2 deletions(-) (limited to 'drivers/pwm') diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c index 4b243c0e8490..03c7810416b8 100644 --- a/drivers/pwm/pwm-atmel.c +++ b/drivers/pwm/pwm-atmel.c @@ -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; -- cgit v1.2.3