diff options
Diffstat (limited to 'drivers/pwm/pwm-atmel.c')
| -rw-r--r-- | drivers/pwm/pwm-atmel.c | 63 |
1 files changed, 46 insertions, 17 deletions
diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c index d3c22de9ee47..a947c9095d9d 100644 --- a/drivers/pwm/pwm-atmel.c +++ b/drivers/pwm/pwm-atmel.c @@ -8,9 +8,11 @@ */ #include <linux/clk.h> +#include <linux/delay.h> #include <linux/err.h> #include <linux/io.h> #include <linux/module.h> +#include <linux/mutex.h> #include <linux/of.h> #include <linux/of_device.h> #include <linux/platform_device.h> @@ -21,6 +23,7 @@ #define PWM_ENA 0x04 #define PWM_DIS 0x08 #define PWM_SR 0x0C +#define PWM_ISR 0x1C /* Bit field in SR */ #define PWM_SR_ALL_CH_ON 0x0F @@ -60,6 +63,9 @@ struct atmel_pwm_chip { struct clk *clk; void __iomem *base; + unsigned int updated_pwms; + struct mutex isr_lock; /* ISR is cleared when read, ensure only one thread does that */ + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm, unsigned long dty, unsigned long prd); }; @@ -144,6 +150,10 @@ static int atmel_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, val = (val & ~PWM_CMR_CPRE_MSK) | (pres & PWM_CMR_CPRE_MSK); atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); atmel_pwm->config(chip, pwm, dty, prd); + mutex_lock(&atmel_pwm->isr_lock); + atmel_pwm->updated_pwms |= atmel_pwm_readl(atmel_pwm, PWM_ISR); + atmel_pwm->updated_pwms &= ~(1 << pwm->hwpwm); + mutex_unlock(&atmel_pwm->isr_lock); clk_disable(atmel_pwm->clk); return ret; @@ -155,24 +165,25 @@ static void atmel_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm, struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); unsigned int val; - if (test_bit(PWMF_ENABLED, &pwm->flags)) { - /* - * If the PWM channel is enabled, using the update register, - * it needs to set bit 10 of CMR to 0 - */ - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CUPD, dty); - val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); - val &= ~PWM_CMR_UPD_CDTY; - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); - } else { - /* - * If the PWM channel is disabled, write value to duty and - * period registers directly. - */ - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CDTY, dty); - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CPRD, prd); - } + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CUPD, dty); + + val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); + val &= ~PWM_CMR_UPD_CDTY; + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); + + /* + * If the PWM channel is enabled, only update CDTY by using the update + * register, it needs to set bit 10 of CMR to 0 + */ + if (test_bit(PWMF_ENABLED, &pwm->flags)) + return; + /* + * If the PWM channel is disabled, write value to duty and period + * registers directly. + */ + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CDTY, dty); + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CPRD, prd); } static void atmel_pwm_config_v2(struct pwm_chip *chip, struct pwm_device *pwm, @@ -242,7 +253,22 @@ static int atmel_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); + unsigned long timeout = jiffies + 2 * HZ; + + /* + * Wait for at least a complete period to have passed before disabling a + * channel to be sure that CDTY has been updated + */ + mutex_lock(&atmel_pwm->isr_lock); + atmel_pwm->updated_pwms |= atmel_pwm_readl(atmel_pwm, PWM_ISR); + + while (!(atmel_pwm->updated_pwms & (1 << pwm->hwpwm)) && + time_before(jiffies, timeout)) { + usleep_range(10, 100); + atmel_pwm->updated_pwms |= atmel_pwm_readl(atmel_pwm, PWM_ISR); + } + mutex_unlock(&atmel_pwm->isr_lock); atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm); clk_disable(atmel_pwm->clk); @@ -357,6 +383,8 @@ static int atmel_pwm_probe(struct platform_device *pdev) atmel_pwm->chip.npwm = 4; atmel_pwm->chip.can_sleep = true; atmel_pwm->config = data->config; + atmel_pwm->updated_pwms = 0; + mutex_init(&atmel_pwm->isr_lock); ret = pwmchip_add(&atmel_pwm->chip); if (ret < 0) { @@ -378,6 +406,7 @@ static int atmel_pwm_remove(struct platform_device *pdev) struct atmel_pwm_chip *atmel_pwm = platform_get_drvdata(pdev); clk_unprepare(atmel_pwm->clk); + mutex_destroy(&atmel_pwm->isr_lock); return pwmchip_remove(&atmel_pwm->chip); } |