From 01b2d4536f0215c6d97d77e157afee04300ffc90 Mon Sep 17 00:00:00 2001 From: "Philip, Avinash" Date: Thu, 6 Sep 2012 10:44:25 +0530 Subject: [PATCH] pwm: pwm-tiehrpwm: Fix conflicting channel period setting EHRPWM hardware supports 2 independent PWM channels. However the device uses only one register to handle period setting for both channels. So both channels should be configured for same period (in nsec). Fix the same by returning error for conflicting period values. However, allow 1. Configuration of period settings if not conflicting with other channels 2. Re-configuring of period settings if no other channels being configured Signed-off-by: Philip, Avinash Signed-off-by: Thierry Reding --- drivers/pwm/pwm-tiehrpwm.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/drivers/pwm/pwm-tiehrpwm.c b/drivers/pwm/pwm-tiehrpwm.c index c3756d1be194..b1996bcd5b78 100644 --- a/drivers/pwm/pwm-tiehrpwm.c +++ b/drivers/pwm/pwm-tiehrpwm.c @@ -104,6 +104,7 @@ struct ehrpwm_pwm_chip { struct pwm_chip chip; unsigned int clk_rate; void __iomem *mmio_base; + unsigned long period_cycles[NUM_PWM_CHANNEL]; }; static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip) @@ -210,6 +211,7 @@ static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, unsigned long long c; unsigned long period_cycles, duty_cycles; unsigned short ps_divval, tb_divval; + int i; if (period_ns < 0 || duty_ns < 0 || period_ns > NSEC_PER_SEC) return -ERANGE; @@ -229,6 +231,28 @@ static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, duty_cycles = (unsigned long)c; } + /* + * Period values should be same for multiple PWM channels as IP uses + * same period register for multiple channels. + */ + for (i = 0; i < NUM_PWM_CHANNEL; i++) { + if (pc->period_cycles[i] && + (pc->period_cycles[i] != period_cycles)) { + /* + * Allow channel to reconfigure period if no other + * channels being configured. + */ + if (i == pwm->hwpwm) + continue; + + dev_err(chip->dev, "Period value conflicts with channel %d\n", + i); + return -EINVAL; + } + } + + 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, &tb_divval)) { @@ -320,10 +344,15 @@ static void ehrpwm_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) static void ehrpwm_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) { + struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip); + if (test_bit(PWMF_ENABLED, &pwm->flags)) { dev_warn(chip->dev, "Removing PWM device without disabling\n"); pm_runtime_put_sync(chip->dev); } + + /* set period value to zero on free */ + pc->period_cycles[pwm->hwpwm] = 0; } static const struct pwm_ops ehrpwm_pwm_ops = { -- 2.30.2