Merge branch 'for-4.7/pwm-atomic' into for-next

7 files changed, 194 insertions, 109 deletions

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index e4de9156974d..dba3843c53b8 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -227,6 +227,19 @@ void *pwm_get_chip_data(struct pwm_device *pwm)
 }
 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
 
+static bool pwm_ops_check(const struct pwm_ops *ops)
+{
+        /* driver supports legacy, non-atomic operation */
+        if (ops->config && ops->enable && ops->disable)
+                return true;
+
+        /* driver supports atomic operation */
+        if (ops->apply)
+                return true;
+
+        return false;
+}
+
 /**
  * pwmchip_add_with_polarity() - register a new PWM chip
  * @chip: the PWM chip to add
@@ -245,8 +258,10 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip,
         unsigned int i;
         int ret;
 
-        if (!chip || !chip->dev || !chip->ops || !chip->ops->config ||
-            !chip->ops->enable || !chip->ops->disable || !chip->npwm)
+        if (!chip || !chip->dev || !chip->ops || !chip->npwm)
+                return -EINVAL;
+
+        if (!pwm_ops_check(chip->ops))
                 return -EINVAL;
 
         mutex_lock(&pwm_lock);
@@ -269,8 +284,10 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip,
                 pwm->chip = chip;
                 pwm->pwm = chip->base + i;
                 pwm->hwpwm = i;
-                pwm->polarity = polarity;
-                mutex_init(&pwm->lock);
+                pwm->state.polarity = polarity;
+
+                if (chip->ops->get_state)
+                        chip->ops->get_state(chip, pwm, &pwm->state);
 
                 radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
         }
@@ -430,107 +447,138 @@ void pwm_free(struct pwm_device *pwm)
 EXPORT_SYMBOL_GPL(pwm_free);
 
 /**
- * pwm_config() - change a PWM device configuration
+ * pwm_apply_state() - atomically apply a new state to a PWM device
  * @pwm: PWM device
- * @duty_ns: "on" time (in nanoseconds)
- * @period_ns: duration (in nanoseconds) of one cycle
- *
- * Returns: 0 on success or a negative error code on failure.
+ * @state: new state to apply. This can be adjusted by the PWM driver
+ *         if the requested config is not achievable, for example,
+ *         ->duty_cycle and ->period might be approximated.
  */
-int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
+int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
 {
         int err;
 
-        if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns)
+        if (!pwm)
                 return -EINVAL;
 
-        err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
-        if (err)
-                return err;
-
-        pwm->duty_cycle = duty_ns;
-        pwm->period = period_ns;
+        if (!memcmp(state, &pwm->state, sizeof(*state)))
+                return 0;
 
-        return 0;
-}
-EXPORT_SYMBOL_GPL(pwm_config);
+        if (pwm->chip->ops->apply) {
+                err = pwm->chip->ops->apply(pwm->chip, pwm, state);
+                if (err)
+                        return err;
 
-/**
- * pwm_set_polarity() - configure the polarity of a PWM signal
- * @pwm: PWM device
- * @polarity: new polarity of the PWM signal
- *
- * Note that the polarity cannot be configured while the PWM device is
- * enabled.
- *
- * Returns: 0 on success or a negative error code on failure.
- */
-int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
-{
-        int err;
+                pwm->state = *state;
+        } else {
+                /*
+                 * FIXME: restore the initial state in case of error.
+                 */
+                if (state->polarity != pwm->state.polarity) {
+                        if (!pwm->chip->ops->set_polarity)
+                                return -ENOTSUPP;
+
+                        /*
+                         * Changing the polarity of a running PWM is
+                         * only allowed when the PWM driver implements
+                         * ->apply().
+                         */
+                        if (pwm->state.enabled) {
+                                pwm->chip->ops->disable(pwm->chip, pwm);
+                                pwm->state.enabled = false;
+                        }
+
+                        err = pwm->chip->ops->set_polarity(pwm->chip, pwm,
+                                                           state->polarity);
+                        if (err)
+                                return err;
+
+                        pwm->state.polarity = state->polarity;
+                }
 
-        if (!pwm || !pwm->chip->ops)
-                return -EINVAL;
+                if (state->period != pwm->state.period ||
+                    state->duty_cycle != pwm->state.duty_cycle) {
+                        err = pwm->chip->ops->config(pwm->chip, pwm,
+                                                     state->duty_cycle,
+                                                     state->period);
+                        if (err)
+                                return err;
 
-        if (!pwm->chip->ops->set_polarity)
-                return -ENOSYS;
+                        pwm->state.duty_cycle = state->duty_cycle;
+                        pwm->state.period = state->period;
+                }
 
-        mutex_lock(&pwm->lock);
+                if (state->enabled != pwm->state.enabled) {
+                        if (state->enabled) {
+                                err = pwm->chip->ops->enable(pwm->chip, pwm);
+                                if (err)
+                                        return err;
+                        } else {
+                                pwm->chip->ops->disable(pwm->chip, pwm);
+                        }
 
-        if (pwm_is_enabled(pwm)) {
-                err = -EBUSY;
-                goto unlock;
+                        pwm->state.enabled = state->enabled;
+                }
         }
 
-        err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
-        if (err)
-                goto unlock;
-
-        pwm->polarity = polarity;
-
-unlock:
-        mutex_unlock(&pwm->lock);
-        return err;
+        return 0;
 }
-EXPORT_SYMBOL_GPL(pwm_set_polarity);
+EXPORT_SYMBOL_GPL(pwm_apply_state);
 
 /**
- * pwm_enable() - start a PWM output toggling
+ * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
  * @pwm: PWM device
  *
- * Returns: 0 on success or a negative error code on failure.
+ * This function will adjust the PWM config to the PWM arguments provided
+ * by the DT or PWM lookup table. This is particularly useful to adapt
+ * the bootloader config to the Linux one.
  */
-int pwm_enable(struct pwm_device *pwm)
+int pwm_adjust_config(struct pwm_device *pwm)
 {
-        int err = 0;
+        struct pwm_state state;
+        struct pwm_args pargs;
 
-        if (!pwm)
-                return -EINVAL;
+        pwm_get_args(pwm, &pargs);
+        pwm_get_state(pwm, &state);
 
-        mutex_lock(&pwm->lock);
+        /*
+         * If the current period is zero it means that either the PWM driver
+         * does not support initial state retrieval or the PWM has not yet
+         * been configured.
+         *
+         * In either case, we setup the new period and polarity, and assign a
+         * duty cycle of 0.
+         */
+        if (!state.period) {
+                state.duty_cycle = 0;
+                state.period = pargs.period;
+                state.polarity = pargs.polarity;
 
-        if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
-                err = pwm->chip->ops->enable(pwm->chip, pwm);
-                if (err)
-                        clear_bit(PWMF_ENABLED, &pwm->flags);
+                return pwm_apply_state(pwm, &state);
         }
 
-        mutex_unlock(&pwm->lock);
+        /*
+         * Adjust the PWM duty cycle/period based on the period value provided
+         * in PWM args.
+         */
+        if (pargs.period != state.period) {
+                u64 dutycycle = (u64)state.duty_cycle * pargs.period;
 
-        return err;
-}
-EXPORT_SYMBOL_GPL(pwm_enable);
+                do_div(dutycycle, state.period);
+                state.duty_cycle = dutycycle;
+                state.period = pargs.period;
+        }
 
-/**
- * pwm_disable() - stop a PWM output toggling
- * @pwm: PWM device
- */
-void pwm_disable(struct pwm_device *pwm)
-{
-        if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
-                pwm->chip->ops->disable(pwm->chip, pwm);
+        /*
+         * If the polarity changed, we should also change the duty cycle.
+         */
+        if (pargs.polarity != state.polarity) {
+                state.polarity = pargs.polarity;
+                state.duty_cycle = state.period - state.duty_cycle;
+        }
+
+        return pwm_apply_state(pwm, &state);
 }
-EXPORT_SYMBOL_GPL(pwm_disable);
+EXPORT_SYMBOL_GPL(pwm_adjust_config);
 
 static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
 {
@@ -621,13 +669,6 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
 
         pwm->label = con_id;
 
-        /*
-         * FIXME: This should be removed once all PWM users properly make use
-         * of struct pwm_args to initialize the PWM device. As long as this is
-         * here, the PWM state and hardware state can get out of sync.
-         */
-        pwm_apply_args(pwm);
-
 put:
         of_node_put(args.np);
 
@@ -762,13 +803,6 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
         pwm->args.period = chosen->period;
         pwm->args.polarity = chosen->polarity;
 
-        /*
-         * FIXME: This should be removed once all PWM users properly make use
-         * of struct pwm_args to initialize the PWM device. As long as this is
-         * here, the PWM state and hardware state can get out of sync.
-         */
-        pwm_apply_args(pwm);
-
 out:
         mutex_unlock(&pwm_lookup_lock);
         return pwm;
@@ -915,15 +949,23 @@ static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
 
         for (i = 0; i < chip->npwm; i++) {
                 struct pwm_device *pwm = &chip->pwms[i];
+                struct pwm_state state;
+
+                pwm_get_state(pwm, &state);
 
                 seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
 
                 if (test_bit(PWMF_REQUESTED, &pwm->flags))
                         seq_puts(s, " requested");
 
-                if (pwm_is_enabled(pwm))
+                if (state.enabled)
                         seq_puts(s, " enabled");
 
+                seq_printf(s, " period: %u ns", state.period);
+                seq_printf(s, " duty: %u ns", state.duty_cycle);
+                seq_printf(s, " polarity: %s",
+                           state.polarity ? "inverse" : "normal");
+
                 seq_puts(s, "\n");
         }
 }
diff --git a/drivers/pwm/pwm-crc.c b/drivers/pwm/pwm-crc.c
index 7101c7020bf4..bd0ebd04856a 100644
--- a/drivers/pwm/pwm-crc.c
+++ b/drivers/pwm/pwm-crc.c
@@ -75,7 +75,7 @@ static int crc_pwm_config(struct pwm_chip *c, struct pwm_device *pwm,
                 return -EINVAL;
         }
 
-        if (pwm->period != period_ns) {
+        if (pwm_get_period(pwm) != period_ns) {
                 int clk_div;
 
                 /* changing the clk divisor, need to disable fisrt */
diff --git a/drivers/pwm/pwm-lpc18xx-sct.c b/drivers/pwm/pwm-lpc18xx-sct.c
index 9861fed4e67d..19dc64cab2f0 100644
--- a/drivers/pwm/pwm-lpc18xx-sct.c
+++ b/drivers/pwm/pwm-lpc18xx-sct.c
@@ -249,7 +249,7 @@ static int lpc18xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
                            LPC18XX_PWM_EVSTATEMSK(lpc18xx_data->duty_event),
                            LPC18XX_PWM_EVSTATEMSK_ALL);
 
-        if (pwm->polarity == PWM_POLARITY_NORMAL) {
+        if (pwm_get_polarity(pwm) == PWM_POLARITY_NORMAL) {
                 set_event = lpc18xx_pwm->period_event;
                 clear_event = lpc18xx_data->duty_event;
                 res_action = LPC18XX_PWM_RES_SET;
diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c
index b7e6ecba7d5c..3e95090cd7cf 100644
--- a/drivers/pwm/pwm-omap-dmtimer.c
+++ b/drivers/pwm/pwm-omap-dmtimer.c
@@ -192,7 +192,7 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
                 load_value, load_value, match_value, match_value);
 
         omap->pdata->set_pwm(omap->dm_timer,
-                              pwm->polarity == PWM_POLARITY_INVERSED,
+                              pwm_get_polarity(pwm) == PWM_POLARITY_INVERSED,
                               true,
                               PWM_OMAP_DMTIMER_TRIGGER_OVERFLOW_AND_COMPARE);
 
diff --git a/drivers/pwm/pwm-rcar.c b/drivers/pwm/pwm-rcar.c
index 7b8ac0678137..1c85ecc9e7ac 100644
--- a/drivers/pwm/pwm-rcar.c
+++ b/drivers/pwm/pwm-rcar.c
@@ -157,7 +157,7 @@ static int rcar_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
                 return div;
 
         /* Let the core driver set pwm->period if disabled and duty_ns == 0 */
-        if (!test_bit(PWMF_ENABLED, &pwm->flags) && !duty_ns)
+        if (!pwm_is_enabled(pwm) && !duty_ns)
                 return 0;
 
         rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);
diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 67af9f62361f..03a99a53c39e 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -354,7 +354,8 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
         val = sun4i_pwm_readl(pwm, PWM_CTRL_REG);
         for (i = 0; i < pwm->chip.npwm; i++)
                 if (!(val & BIT_CH(PWM_ACT_STATE, i)))
-                        pwm->chip.pwms[i].polarity = PWM_POLARITY_INVERSED;
+                        pwm_set_polarity(&pwm->chip.pwms[i],
+                                         PWM_POLARITY_INVERSED);
         clk_disable_unprepare(pwm->clk);
 
         return 0;
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index 9c90886f4123..d98599249a05 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -26,6 +26,7 @@
 struct pwm_export {
         struct device child;
         struct pwm_device *pwm;
+        struct mutex lock;
 };
 
 static struct pwm_export *child_to_pwm_export(struct device *child)
@@ -45,15 +46,20 @@ static ssize_t period_show(struct device *child,
                            char *buf)
 {
         const struct pwm_device *pwm = child_to_pwm_device(child);
+        struct pwm_state state;
 
-        return sprintf(buf, "%u\n", pwm_get_period(pwm));
+        pwm_get_state(pwm, &state);
+
+        return sprintf(buf, "%u\n", state.period);
 }
 
 static ssize_t period_store(struct device *child,
                             struct device_attribute *attr,
                             const char *buf, size_t size)
 {
-        struct pwm_device *pwm = child_to_pwm_device(child);
+        struct pwm_export *export = child_to_pwm_export(child);
+        struct pwm_device *pwm = export->pwm;
+        struct pwm_state state;
         unsigned int val;
         int ret;
 
@@ -61,7 +67,11 @@ static ssize_t period_store(struct device *child,
         if (ret)
                 return ret;
 
-        ret = pwm_config(pwm, pwm_get_duty_cycle(pwm), val);
+        mutex_lock(&export->lock);
+        pwm_get_state(pwm, &state);
+        state.period = val;
+        ret = pwm_apply_state(pwm, &state);
+        mutex_unlock(&export->lock);
 
         return ret ? : size;
 }
@@ -71,15 +81,20 @@ static ssize_t duty_cycle_show(struct device *child,
                                char *buf)
 {
         const struct pwm_device *pwm = child_to_pwm_device(child);
+        struct pwm_state state;
+
+        pwm_get_state(pwm, &state);
 
-        return sprintf(buf, "%u\n", pwm_get_duty_cycle(pwm));
+        return sprintf(buf, "%u\n", state.duty_cycle);
 }
 
 static ssize_t duty_cycle_store(struct device *child,
                                 struct device_attribute *attr,
                                 const char *buf, size_t size)
 {
-        struct pwm_device *pwm = child_to_pwm_device(child);
+        struct pwm_export *export = child_to_pwm_export(child);
+        struct pwm_device *pwm = export->pwm;
+        struct pwm_state state;
         unsigned int val;
         int ret;
 
@@ -87,7 +102,11 @@ static ssize_t duty_cycle_store(struct device *child,
         if (ret)
                 return ret;
 
-        ret = pwm_config(pwm, val, pwm_get_period(pwm));
+        mutex_lock(&export->lock);
+        pwm_get_state(pwm, &state);
+        state.duty_cycle = val;
+        ret = pwm_apply_state(pwm, &state);
+        mutex_unlock(&export->lock);
 
         return ret ? : size;
 }
@@ -97,33 +116,46 @@ static ssize_t enable_show(struct device *child,
                            char *buf)
 {
         const struct pwm_device *pwm = child_to_pwm_device(child);
+        struct pwm_state state;
+
+        pwm_get_state(pwm, &state);
 
-        return sprintf(buf, "%d\n", pwm_is_enabled(pwm));
+        return sprintf(buf, "%d\n", state.enabled);
 }
 
 static ssize_t enable_store(struct device *child,
                             struct device_attribute *attr,
                             const char *buf, size_t size)
 {
-        struct pwm_device *pwm = child_to_pwm_device(child);
+        struct pwm_export *export = child_to_pwm_export(child);
+        struct pwm_device *pwm = export->pwm;
+        struct pwm_state state;
         int val, ret;
 
         ret = kstrtoint(buf, 0, &val);
         if (ret)
                 return ret;
 
+        mutex_lock(&export->lock);
+
+        pwm_get_state(pwm, &state);
+
         switch (val) {
         case 0:
-                pwm_disable(pwm);
+                state.enabled = false;
                 break;
         case 1:
-                ret = pwm_enable(pwm);
+                state.enabled = true;
                 break;
         default:
                 ret = -EINVAL;
-                break;
+                goto unlock;
         }
 
+        pwm_apply_state(pwm, &state);
+
+unlock:
+        mutex_unlock(&export->lock);
         return ret ? : size;
 }
 
@@ -133,8 +165,11 @@ static ssize_t polarity_show(struct device *child,
 {
         const struct pwm_device *pwm = child_to_pwm_device(child);
         const char *polarity = "unknown";
+        struct pwm_state state;
+
+        pwm_get_state(pwm, &state);
 
-        switch (pwm_get_polarity(pwm)) {
+        switch (state.polarity) {
         case PWM_POLARITY_NORMAL:
                 polarity = "normal";
                 break;
@@ -151,8 +186,10 @@ static ssize_t polarity_store(struct device *child,
                               struct device_attribute *attr,
                               const char *buf, size_t size)
 {
-        struct pwm_device *pwm = child_to_pwm_device(child);
+        struct pwm_export *export = child_to_pwm_export(child);
+        struct pwm_device *pwm = export->pwm;
         enum pwm_polarity polarity;
+        struct pwm_state state;
         int ret;
 
         if (sysfs_streq(buf, "normal"))
@@ -162,7 +199,11 @@ static ssize_t polarity_store(struct device *child,
         else
                 return -EINVAL;
 
-        ret = pwm_set_polarity(pwm, polarity);
+        mutex_lock(&export->lock);
+        pwm_get_state(pwm, &state);
+        state.polarity = polarity;
+        ret = pwm_apply_state(pwm, &state);
+        mutex_unlock(&export->lock);
 
         return ret ? : size;
 }
@@ -203,6 +244,7 @@ static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
         }
 
         export->pwm = pwm;
+        mutex_init(&export->lock);
 
         export->child.release = pwm_export_release;
         export->child.parent = parent;