pwm: omap-dmtimer: Implement .apply callback
Implement .apply callback and drop the legacy callbacks(enable, disable, config, set_polarity). In .apply() check for the current hardware status before changing the PWM configuration. Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com> Tested-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Lokesh Vutla
Thierry Reding
Родитель
e793eef806
Коммит
6b28fb6f3c
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@ -26,6 +26,11 @@
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* can get updated as below based on the current timer counter:
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* - period for current cycle = current_period + new period
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* - duty_cycle for current period = current period + new duty_cycle.
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* - PWM OMAP DM timer cannot change the polarity when pwm is active. When
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* user requests a change in polarity when in active state:
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* - PWM is stopped abruptly(without completing the current cycle)
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* - Polarity is changed
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* - A fresh cycle is started.
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*/
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#include <linux/clk.h>
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@ -46,8 +51,18 @@
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#define DM_TIMER_LOAD_MIN 0xfffffffe
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#define DM_TIMER_MAX 0xffffffff
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/**
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* struct pwm_omap_dmtimer_chip - Structure representing a pwm chip
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* corresponding to omap dmtimer.
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* @chip: PWM chip structure representing PWM controller
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* @mutex: Mutex to protect pwm apply state
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* @dm_timer: Pointer to omap dm timer.
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* @pdata: Pointer to omap dm timer ops.
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* dm_timer_pdev: Pointer to omap dm timer platform device
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*/
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struct pwm_omap_dmtimer_chip {
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struct pwm_chip chip;
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/* Mutex to protect pwm apply state */
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struct mutex mutex;
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struct omap_dm_timer *dm_timer;
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const struct omap_dm_timer_ops *pdata;
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@ -60,11 +75,22 @@ to_pwm_omap_dmtimer_chip(struct pwm_chip *chip)
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return container_of(chip, struct pwm_omap_dmtimer_chip, chip);
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}
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/**
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* pwm_omap_dmtimer_get_clock_cycles() - Get clock cycles in a time frame
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* @clk_rate: pwm timer clock rate
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* @ns: time frame in nano seconds.
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*
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* Return number of clock cycles in a given period(ins ns).
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*/
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static u32 pwm_omap_dmtimer_get_clock_cycles(unsigned long clk_rate, int ns)
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{
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return DIV_ROUND_CLOSEST_ULL((u64)clk_rate * ns, NSEC_PER_SEC);
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}
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/**
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* pwm_omap_dmtimer_start() - Start the pwm omap dm timer in pwm mode
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* @omap: Pointer to pwm omap dm timer chip
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*/
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static void pwm_omap_dmtimer_start(struct pwm_omap_dmtimer_chip *omap)
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{
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/*
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@ -82,33 +108,46 @@ static void pwm_omap_dmtimer_start(struct pwm_omap_dmtimer_chip *omap)
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omap->pdata->start(omap->dm_timer);
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}
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static int pwm_omap_dmtimer_enable(struct pwm_chip *chip,
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struct pwm_device *pwm)
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/**
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* pwm_omap_dmtimer_is_enabled() - Detect if the pwm is enabled.
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* @omap: Pointer to pwm omap dm timer chip
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*
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* Return true if pwm is enabled else false.
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*/
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static bool pwm_omap_dmtimer_is_enabled(struct pwm_omap_dmtimer_chip *omap)
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{
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struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
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u32 status;
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mutex_lock(&omap->mutex);
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omap->pdata->set_pwm(omap->dm_timer,
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pwm_get_polarity(pwm) == PWM_POLARITY_INVERSED,
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true, OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE,
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true);
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status = omap->pdata->get_pwm_status(omap->dm_timer);
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pwm_omap_dmtimer_start(omap);
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mutex_unlock(&omap->mutex);
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return 0;
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return !!(status & OMAP_TIMER_CTRL_ST);
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}
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static void pwm_omap_dmtimer_disable(struct pwm_chip *chip,
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struct pwm_device *pwm)
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/**
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* pwm_omap_dmtimer_polarity() - Detect the polarity of pwm.
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* @omap: Pointer to pwm omap dm timer chip
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*
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* Return the polarity of pwm.
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*/
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static int pwm_omap_dmtimer_polarity(struct pwm_omap_dmtimer_chip *omap)
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{
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struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
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u32 status;
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mutex_lock(&omap->mutex);
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omap->pdata->stop(omap->dm_timer);
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mutex_unlock(&omap->mutex);
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status = omap->pdata->get_pwm_status(omap->dm_timer);
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return !!(status & OMAP_TIMER_CTRL_SCPWM);
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}
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/**
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* pwm_omap_dmtimer_config() - Update the configuration of pwm omap dm timer
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* @chip: Pointer to PWM controller
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* @pwm: Pointer to PWM channel
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* @duty_ns: New duty cycle in nano seconds
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* @period_ns: New period in nano seconds
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*
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* Return 0 if successfully changed the period/duty_cycle else appropriate
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* error.
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*/
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static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
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struct pwm_device *pwm,
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int duty_ns, int period_ns)
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@ -116,30 +155,26 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
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struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
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u32 period_cycles, duty_cycles;
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u32 load_value, match_value;
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struct clk *fclk;
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unsigned long clk_rate;
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struct clk *fclk;
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dev_dbg(chip->dev, "requested duty cycle: %d ns, period: %d ns\n",
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duty_ns, period_ns);
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mutex_lock(&omap->mutex);
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if (duty_ns == pwm_get_duty_cycle(pwm) &&
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period_ns == pwm_get_period(pwm)) {
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/* No change - don't cause any transients. */
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mutex_unlock(&omap->mutex);
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period_ns == pwm_get_period(pwm))
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return 0;
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}
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fclk = omap->pdata->get_fclk(omap->dm_timer);
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if (!fclk) {
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dev_err(chip->dev, "invalid pmtimer fclk\n");
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goto err_einval;
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return -EINVAL;
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}
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clk_rate = clk_get_rate(fclk);
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if (!clk_rate) {
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dev_err(chip->dev, "invalid pmtimer fclk rate\n");
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goto err_einval;
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return -EINVAL;
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}
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dev_dbg(chip->dev, "clk rate: %luHz\n", clk_rate);
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@ -167,7 +202,7 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
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dev_info(chip->dev,
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"period %d ns too short for clock rate %lu Hz\n",
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period_ns, clk_rate);
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goto err_einval;
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return -EINVAL;
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}
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if (duty_cycles < 1) {
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@ -199,55 +234,97 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
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dev_dbg(chip->dev, "load value: %#08x (%d), match value: %#08x (%d)\n",
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load_value, load_value, match_value, match_value);
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mutex_unlock(&omap->mutex);
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return 0;
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err_einval:
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mutex_unlock(&omap->mutex);
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return -EINVAL;
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}
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static int pwm_omap_dmtimer_set_polarity(struct pwm_chip *chip,
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/**
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* pwm_omap_dmtimer_set_polarity() - Changes the polarity of the pwm dm timer.
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* @chip: Pointer to PWM controller
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* @pwm: Pointer to PWM channel
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* @polarity: New pwm polarity to be set
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*/
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static void pwm_omap_dmtimer_set_polarity(struct pwm_chip *chip,
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struct pwm_device *pwm,
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enum pwm_polarity polarity)
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{
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struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
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bool enabled;
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/* Disable the PWM before changing the polarity. */
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enabled = pwm_omap_dmtimer_is_enabled(omap);
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if (enabled)
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omap->pdata->stop(omap->dm_timer);
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/*
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* PWM core will not call set_polarity while PWM is enabled so it's
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* safe to reconfigure the timer here without stopping it first.
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*/
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mutex_lock(&omap->mutex);
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omap->pdata->set_pwm(omap->dm_timer,
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polarity == PWM_POLARITY_INVERSED,
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true, OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE,
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true);
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if (enabled)
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pwm_omap_dmtimer_start(omap);
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}
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/**
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* pwm_omap_dmtimer_apply() - Changes the state of the pwm omap dm timer.
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* @chip: Pointer to PWM controller
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* @pwm: Pointer to PWM channel
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* @state: New state to apply
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*
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* Return 0 if successfully changed the state else appropriate error.
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*/
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static int pwm_omap_dmtimer_apply(struct pwm_chip *chip,
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struct pwm_device *pwm,
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const struct pwm_state *state)
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{
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struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
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int ret = 0;
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mutex_lock(&omap->mutex);
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if (pwm_omap_dmtimer_is_enabled(omap) && !state->enabled) {
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omap->pdata->stop(omap->dm_timer);
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goto unlock_mutex;
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}
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if (pwm_omap_dmtimer_polarity(omap) != state->polarity)
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pwm_omap_dmtimer_set_polarity(chip, pwm, state->polarity);
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ret = pwm_omap_dmtimer_config(chip, pwm, state->duty_cycle,
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state->period);
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if (ret)
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goto unlock_mutex;
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if (!pwm_omap_dmtimer_is_enabled(omap) && state->enabled) {
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omap->pdata->set_pwm(omap->dm_timer,
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state->polarity == PWM_POLARITY_INVERSED,
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true,
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OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE,
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true);
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pwm_omap_dmtimer_start(omap);
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}
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unlock_mutex:
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mutex_unlock(&omap->mutex);
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return 0;
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return ret;
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}
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static const struct pwm_ops pwm_omap_dmtimer_ops = {
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.enable = pwm_omap_dmtimer_enable,
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.disable = pwm_omap_dmtimer_disable,
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.config = pwm_omap_dmtimer_config,
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.set_polarity = pwm_omap_dmtimer_set_polarity,
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.apply = pwm_omap_dmtimer_apply,
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.owner = THIS_MODULE,
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};
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static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
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{
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struct device_node *np = pdev->dev.of_node;
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struct device_node *timer;
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struct platform_device *timer_pdev;
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struct pwm_omap_dmtimer_chip *omap;
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struct dmtimer_platform_data *timer_pdata;
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const struct omap_dm_timer_ops *pdata;
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struct platform_device *timer_pdev;
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struct pwm_omap_dmtimer_chip *omap;
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struct omap_dm_timer *dm_timer;
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u32 v;
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struct device_node *timer;
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int ret = 0;
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u32 v;
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timer = of_parse_phandle(np, "ti,timers", 0);
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if (!timer)
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@ -280,6 +357,7 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
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!pdata->set_load ||
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!pdata->set_match ||
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!pdata->set_pwm ||
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!pdata->get_pwm_status ||
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!pdata->set_prescaler ||
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!pdata->write_counter) {
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dev_err(&pdev->dev, "Incomplete dmtimer pdata structure\n");
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