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

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This commit is contained in:
Thierry Reding 2016-05-17 14:57:58 +02:00
parent d2a3f20684 23e3523f5d
commit 18c588786c
22 changed files with 591 additions and 224 deletions
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30
Documentation/pwm.txt
View file

@ -42,9 +42,26 @@ variants of these functions, devm_pwm_get() and devm_pwm_put(), also exist.
After being requested, a PWM has to be configured using:
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);
To start/stop toggling the PWM output use pwm_enable()/pwm_disable().
This API controls both the PWM period/duty_cycle config and the
enable/disable state.
The pwm_config(), pwm_enable() and pwm_disable() functions are just wrappers
around pwm_apply_state() and should not be used if the user wants to change
several parameter at once. For example, if you see pwm_config() and
pwm_{enable,disable}() calls in the same function, this probably means you
should switch to pwm_apply_state().
The PWM user API also allows one to query the PWM state with pwm_get_state().
In addition to the PWM state, the PWM API also exposes PWM arguments, which
are the reference PWM config one should use on this PWM.
PWM arguments are usually platform-specific and allows the PWM user to only
care about dutycycle relatively to the full period (like, duty = 50% of the
period). struct pwm_args contains 2 fields (period and polarity) and should
be used to set the initial PWM config (usually done in the probe function
of the PWM user). PWM arguments are retrieved with pwm_get_args().
Using PWMs with the sysfs interface
-----------------------------------
@ -105,6 +122,15 @@ goes low for the remainder of the period. Conversely, a signal with inversed
polarity starts low for the duration of the duty cycle and goes high for the
remainder of the period.
Drivers are encouraged to implement ->apply() instead of the legacy
->enable(), ->disable() and ->config() methods. Doing that should provide
atomicity in the PWM config workflow, which is required when the PWM controls
a critical device (like a regulator).
The implementation of ->get_state() (a method used to retrieve initial PWM
state) is also encouraged for the same reason: letting the PWM user know
about the current PWM state would allow him to avoid glitches.
Locking
-------

6
arch/arm/mach-s3c24xx/mach-rx1950.c
View file

@ -496,6 +496,12 @@ static int rx1950_backlight_init(struct device *dev)
return PTR_ERR(lcd_pwm);
}
/*
* FIXME: pwm_apply_args() should be removed when switching to
* the atomic PWM API.
*/
pwm_apply_args(lcd_pwm);
rx1950_lcd_power(1);
rx1950_bl_power(1);

17
drivers/clk/clk-pwm.c
View file

@ -59,6 +59,7 @@ static int clk_pwm_probe(struct platform_device *pdev)
struct clk_init_data init;
struct clk_pwm *clk_pwm;
struct pwm_device *pwm;
struct pwm_args pargs;
const char *clk_name;
struct clk *clk;
int ret;
@ -71,22 +72,28 @@ static int clk_pwm_probe(struct platform_device *pdev)
if (IS_ERR(pwm))
return PTR_ERR(pwm);
if (!pwm->period) {
pwm_get_args(pwm, &pargs);
if (!pargs.period) {
dev_err(&pdev->dev, "invalid PWM period\n");
return -EINVAL;
}
if (of_property_read_u32(node, "clock-frequency", &clk_pwm->fixed_rate))
clk_pwm->fixed_rate = NSEC_PER_SEC / pwm->period;
clk_pwm->fixed_rate = NSEC_PER_SEC / pargs.period;
if (pwm->period != NSEC_PER_SEC / clk_pwm->fixed_rate &&
pwm->period != DIV_ROUND_UP(NSEC_PER_SEC, clk_pwm->fixed_rate)) {
if (pargs.period != NSEC_PER_SEC / clk_pwm->fixed_rate &&
pargs.period != DIV_ROUND_UP(NSEC_PER_SEC, clk_pwm->fixed_rate)) {
dev_err(&pdev->dev,
"clock-frequency does not match PWM period\n");
return -EINVAL;
}
ret = pwm_config(pwm, (pwm->period + 1) >> 1, pwm->period);
/*
* FIXME: pwm_apply_args() should be removed when switching to the
* atomic PWM API.
*/
pwm_apply_args(pwm);
ret = pwm_config(pwm, (pargs.period + 1) >> 1, pargs.period);
if (ret < 0)
return ret;

6
drivers/gpu/drm/i915/intel_panel.c
View file

@ -1640,6 +1640,12 @@ static int pwm_setup_backlight(struct intel_connector *connector,
return -ENODEV;
}
/*
* FIXME: pwm_apply_args() should be removed when switching to
* the atomic PWM API.
*/
pwm_apply_args(panel->backlight.pwm);
retval = pwm_config(panel->backlight.pwm, CRC_PMIC_PWM_PERIOD_NS,
CRC_PMIC_PWM_PERIOD_NS);
if (retval < 0) {

26
drivers/hwmon/pwm-fan.c
View file

@ -40,15 +40,18 @@ struct pwm_fan_ctx {
static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
{
struct pwm_args pargs;
unsigned long duty;
int ret = 0;
pwm_get_args(ctx->pwm, &pargs);
mutex_lock(&ctx->lock);
if (ctx->pwm_value == pwm)
goto exit_set_pwm_err;
duty = DIV_ROUND_UP(pwm * (ctx->pwm->period - 1), MAX_PWM);
ret = pwm_config(ctx->pwm, duty, ctx->pwm->period);
duty = DIV_ROUND_UP(pwm * (pargs.period - 1), MAX_PWM);
ret = pwm_config(ctx->pwm, duty, pargs.period);
if (ret)
goto exit_set_pwm_err;
@ -215,6 +218,7 @@ static int pwm_fan_probe(struct platform_device *pdev)
{
struct thermal_cooling_device *cdev;
struct pwm_fan_ctx *ctx;
struct pwm_args pargs;
struct device *hwmon;
int duty_cycle;
int ret;
@ -233,11 +237,19 @@ static int pwm_fan_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, ctx);
/*
* FIXME: pwm_apply_args() should be removed when switching to the
* atomic PWM API.
*/
pwm_apply_args(ctx->pwm);
/* Set duty cycle to maximum allowed */
duty_cycle = ctx->pwm->period - 1;
pwm_get_args(ctx->pwm, &pargs);
duty_cycle = pargs.period - 1;
ctx->pwm_value = MAX_PWM;
ret = pwm_config(ctx->pwm, duty_cycle, ctx->pwm->period);
ret = pwm_config(ctx->pwm, duty_cycle, pargs.period);
if (ret) {
dev_err(&pdev->dev, "Failed to configure PWM\n");
return ret;
@ -303,14 +315,16 @@ static int pwm_fan_suspend(struct device *dev)
static int pwm_fan_resume(struct device *dev)
{
struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
struct pwm_args pargs;
unsigned long duty;
int ret;
if (ctx->pwm_value == 0)
return 0;
duty = DIV_ROUND_UP(ctx->pwm_value * (ctx->pwm->period - 1), MAX_PWM);
ret = pwm_config(ctx->pwm, duty, ctx->pwm->period);
pwm_get_args(ctx->pwm, &pargs);
duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
ret = pwm_config(ctx->pwm, duty, pargs.period);
if (ret)
return ret;
return pwm_enable(ctx->pwm);

17
drivers/input/misc/max77693-haptic.c
View file

@ -70,10 +70,13 @@ struct max77693_haptic {
static int max77693_haptic_set_duty_cycle(struct max77693_haptic *haptic)
{
int delta = (haptic->pwm_dev->period + haptic->pwm_duty) / 2;
struct pwm_args pargs;
int delta;
int error;
error = pwm_config(haptic->pwm_dev, delta, haptic->pwm_dev->period);
pwm_get_args(haptic->pwm_dev, &pargs);
delta = (pargs.period + haptic->pwm_duty) / 2;
error = pwm_config(haptic->pwm_dev, delta, pargs.period);
if (error) {
dev_err(haptic->dev, "failed to configure pwm: %d\n", error);
return error;
@ -234,6 +237,7 @@ static int max77693_haptic_play_effect(struct input_dev *dev, void *data,
struct ff_effect *effect)
{
struct max77693_haptic *haptic = input_get_drvdata(dev);
struct pwm_args pargs;
u64 period_mag_multi;
haptic->magnitude = effect->u.rumble.strong_magnitude;
@ -245,7 +249,8 @@ static int max77693_haptic_play_effect(struct input_dev *dev, void *data,
* The formula to convert magnitude to pwm_duty as follows:
* - pwm_duty = (magnitude * pwm_period) / MAX_MAGNITUDE(0xFFFF)
*/
period_mag_multi = (u64)haptic->pwm_dev->period * haptic->magnitude;
pwm_get_args(haptic->pwm_dev, &pargs);
period_mag_multi = (u64)pargs.period * haptic->magnitude;
haptic->pwm_duty = (unsigned int)(period_mag_multi >>
MAX_MAGNITUDE_SHIFT);
@ -329,6 +334,12 @@ static int max77693_haptic_probe(struct platform_device *pdev)
return PTR_ERR(haptic->pwm_dev);
}
/*
* FIXME: pwm_apply_args() should be removed when switching to the
* atomic PWM API.
*/
pwm_apply_args(haptic->pwm_dev);
haptic->motor_reg = devm_regulator_get(&pdev->dev, "haptic");
if (IS_ERR(haptic->motor_reg)) {
dev_err(&pdev->dev, "failed to get regulator\n");

6
drivers/input/misc/max8997_haptic.c
View file

@ -304,6 +304,12 @@ static int max8997_haptic_probe(struct platform_device *pdev)
error);
goto err_free_mem;
}
/*
* FIXME: pwm_apply_args() should be removed when switching to
* the atomic PWM API.
*/
pwm_apply_args(chip->pwm);
break;
default:

6
drivers/input/misc/pwm-beeper.c
View file

@ -87,6 +87,12 @@ static int pwm_beeper_probe(struct platform_device *pdev)
goto err_free;
}
/*
* FIXME: pwm_apply_args() should be removed when switching to
* the atomic PWM API.
*/
pwm_apply_args(beeper->pwm);
beeper->input = input_allocate_device();
if (!beeper->input) {
dev_err(&pdev->dev, "Failed to allocate input device\n");

11
drivers/leds/leds-pwm.c
View file

@ -91,6 +91,7 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
struct led_pwm *led, struct device_node *child)
{
struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
struct pwm_args pargs;
int ret;
led_data->active_low = led->active_low;
@ -117,7 +118,15 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
else
led_data->cdev.brightness_set_blocking = led_pwm_set_blocking;
led_data->period = pwm_get_period(led_data->pwm);
/*
* FIXME: pwm_apply_args() should be removed when switching to the
* atomic PWM API.
*/
pwm_apply_args(led_data->pwm);
pwm_get_args(led_data->pwm, &pargs);
led_data->period = pargs.period;
if (!led_data->period && (led->pwm_period_ns > 0))
led_data->period = led->pwm_period_ns;

244
drivers/pwm/core.c
View file

@ -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)
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;
return 0;
}
EXPORT_SYMBOL_GPL(pwm_config);
/**
* 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;
if (!pwm || !pwm->chip->ops)
return -EINVAL;
if (!pwm->chip->ops->set_polarity)
return -ENOSYS;
mutex_lock(&pwm->lock);
if (pwm_is_enabled(pwm)) {
err = -EBUSY;
goto unlock;
}
err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
if (err)
goto unlock;
pwm->polarity = polarity;
unlock:
mutex_unlock(&pwm->lock);
return err;
}
EXPORT_SYMBOL_GPL(pwm_set_polarity);
/**
* pwm_enable() - start a PWM output toggling
* @pwm: PWM device
*
* Returns: 0 on success or a negative error code on failure.
*/
int pwm_enable(struct pwm_device *pwm)
{
int err = 0;
if (!pwm)
return -EINVAL;
mutex_lock(&pwm->lock);
if (!memcmp(state, &pwm->state, sizeof(*state)))
return 0;
if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
err = pwm->chip->ops->enable(pwm->chip, pwm);
if (pwm->chip->ops->apply) {
err = pwm->chip->ops->apply(pwm->chip, pwm, state);
if (err)
clear_bit(PWMF_ENABLED, &pwm->flags);
return 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 (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;
pwm->state.duty_cycle = state->duty_cycle;
pwm->state.period = state->period;
}
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);
}
pwm->state.enabled = state->enabled;
}
}
mutex_unlock(&pwm->lock);
return err;
return 0;
}
EXPORT_SYMBOL_GPL(pwm_enable);
EXPORT_SYMBOL_GPL(pwm_apply_state);
/**
* pwm_disable() - stop a PWM output toggling
* pwm_adjust_config() - adjust the current PWM config to the PWM arguments
* @pwm: PWM device
*
* 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.
*/
void pwm_disable(struct pwm_device *pwm)
int pwm_adjust_config(struct pwm_device *pwm)
{
if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
pwm->chip->ops->disable(pwm->chip, pwm);
struct pwm_state state;
struct pwm_args pargs;
pwm_get_args(pwm, &pargs);
pwm_get_state(pwm, &state);
/*
* 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;
return pwm_apply_state(pwm, &state);
}
/*
* 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;
do_div(dutycycle, state.period);
state.duty_cycle = dutycycle;
state.period = pargs.period;
}
/*
* 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");
}
}

2
drivers/pwm/pwm-crc.c
View file

@ -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 */

2
drivers/pwm/pwm-lpc18xx-sct.c
View file

@ -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;

2
drivers/pwm/pwm-omap-dmtimer.c
View file

@ -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);

2
drivers/pwm/pwm-rcar.c
View file

@ -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);

3
drivers/pwm/pwm-sun4i.c
View file

@ -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;

70
drivers/pwm/sysfs.c
View file

@ -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;
return sprintf(buf, "%u\n", pwm_get_duty_cycle(pwm));
pwm_get_state(pwm, &state);
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;
return sprintf(buf, "%d\n", pwm_is_enabled(pwm));
pwm_get_state(pwm, &state);
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;
switch (pwm_get_polarity(pwm)) {
pwm_get_state(pwm, &state);
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;

9
drivers/video/backlight/lm3630a_bl.c
View file

@ -162,7 +162,7 @@ static int lm3630a_intr_config(struct lm3630a_chip *pchip)
static void lm3630a_pwm_ctrl(struct lm3630a_chip *pchip, int br, int br_max)
{
unsigned int period = pwm_get_period(pchip->pwmd);
unsigned int period = pchip->pdata->pwm_period;
unsigned int duty = br * period / br_max;
pwm_config(pchip->pwmd, duty, period);
@ -424,8 +424,13 @@ static int lm3630a_probe(struct i2c_client *client,
dev_err(&client->dev, "fail : get pwm device\n");
return PTR_ERR(pchip->pwmd);
}
/*
* FIXME: pwm_apply_args() should be removed when switching to
* the atomic PWM API.
*/
pwm_apply_args(pchip->pwmd);
}
pchip->pwmd->period = pdata->pwm_period;
/* interrupt enable : irq 0 is not allowed */
pchip->irq = client->irq;

6
drivers/video/backlight/lp855x_bl.c
View file

@ -246,6 +246,12 @@ static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
return;
lp->pwm = pwm;
/*
* FIXME: pwm_apply_args() should be removed when switching to
* the atomic PWM API.
*/
pwm_apply_args(pwm);
}
pwm_config(lp->pwm, duty, period);

6
drivers/video/backlight/lp8788_bl.c
View file

@ -145,6 +145,12 @@ static void lp8788_pwm_ctrl(struct lp8788_bl *bl, int br, int max_br)
}
bl->pwm = pwm;
/*
* FIXME: pwm_apply_args() should be removed when switching to
* the atomic PWM API.
*/
pwm_apply_args(pwm);
}
pwm_config(bl->pwm, duty, period);

14
drivers/video/backlight/pwm_bl.c
View file

@ -201,6 +201,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
struct device_node *node = pdev->dev.of_node;
struct pwm_bl_data *pb;
int initial_blank = FB_BLANK_UNBLANK;
struct pwm_args pargs;
int ret;
if (!data) {
@ -306,17 +307,22 @@ static int pwm_backlight_probe(struct platform_device *pdev)
dev_dbg(&pdev->dev, "got pwm for backlight\n");
/*
* FIXME: pwm_apply_args() should be removed when switching to
* the atomic PWM API.
*/
pwm_apply_args(pb->pwm);
/*
* The DT case will set the pwm_period_ns field to 0 and store the
* period, parsed from the DT, in the PWM device. For the non-DT case,
* set the period from platform data if it has not already been set
* via the PWM lookup table.
*/
pb->period = pwm_get_period(pb->pwm);
if (!pb->period && (data->pwm_period_ns > 0)) {
pwm_get_args(pb->pwm, &pargs);
pb->period = pargs.period;
if (!pb->period && (data->pwm_period_ns > 0))
pb->period = data->pwm_period_ns;
pwm_set_period(pb->pwm, data->pwm_period_ns);
}
pb->lth_brightness = data->lth_brightness * (pb->period / pb->scale);

11
drivers/video/fbdev/ssd1307fb.c
View file

@ -286,6 +286,7 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
{
int ret;
u32 precharge, dclk, com_invdir, compins;
struct pwm_args pargs;
if (par->device_info->need_pwm) {
par->pwm = pwm_get(&par->client->dev, NULL);
@ -294,7 +295,15 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
return PTR_ERR(par->pwm);
}
par->pwm_period = pwm_get_period(par->pwm);
/*
* FIXME: pwm_apply_args() should be removed when switching to
* the atomic PWM API.
*/
pwm_apply_args(par->pwm);
pwm_get_args(par->pwm, &pargs);
par->pwm_period = pargs.period;
/* Enable the PWM */
pwm_config(par->pwm, par->pwm_period / 2, par->pwm_period);
pwm_enable(par->pwm);

319
include/linux/pwm.h
View file

@ -5,59 +5,7 @@
#include <linux/mutex.h>
#include <linux/of.h>
struct pwm_device;
struct seq_file;
#if IS_ENABLED(CONFIG_PWM)
/*
* pwm_request - request a PWM device
*/
struct pwm_device *pwm_request(int pwm_id, const char *label);
/*
* pwm_free - free a PWM device
*/
void pwm_free(struct pwm_device *pwm);
/*
* pwm_config - change a PWM device configuration
*/
int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns);
/*
* pwm_enable - start a PWM output toggling
*/
int pwm_enable(struct pwm_device *pwm);
/*
* pwm_disable - stop a PWM output toggling
*/
void pwm_disable(struct pwm_device *pwm);
#else
static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
{
return ERR_PTR(-ENODEV);
}
static inline void pwm_free(struct pwm_device *pwm)
{
}
static inline int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
return -EINVAL;
}
static inline int pwm_enable(struct pwm_device *pwm)
{
return -EINVAL;
}
static inline void pwm_disable(struct pwm_device *pwm)
{
}
#endif
struct pwm_chip;
/**
@ -94,8 +42,21 @@ struct pwm_args {
enum {
PWMF_REQUESTED = 1 << 0,
PWMF_ENABLED = 1 << 1,
PWMF_EXPORTED = 1 << 2,
PWMF_EXPORTED = 1 << 1,
};
/*
* struct pwm_state - state of a PWM channel
* @period: PWM period (in nanoseconds)
* @duty_cycle: PWM duty cycle (in nanoseconds)
* @polarity: PWM polarity
* @enabled: PWM enabled status
*/
struct pwm_state {
unsigned int period;
unsigned int duty_cycle;
enum pwm_polarity polarity;
bool enabled;
};
/**
@ -106,11 +67,8 @@ enum {
* @pwm: global index of the PWM device
* @chip: PWM chip providing this PWM device
* @chip_data: chip-private data associated with the PWM device
* @lock: used to serialize accesses to the PWM device where necessary
* @period: period of the PWM signal (in nanoseconds)
* @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
* @polarity: polarity of the PWM signal
* @args: PWM arguments
* @state: curent PWM channel state
*/
struct pwm_device {
const char *label;
@ -119,50 +77,68 @@ struct pwm_device {
unsigned int pwm;
struct pwm_chip *chip;
void *chip_data;
struct mutex lock;
unsigned int period;
unsigned int duty_cycle;
enum pwm_polarity polarity;
struct pwm_args args;
struct pwm_state state;
};
/**
* pwm_get_state() - retrieve the current PWM state
* @pwm: PWM device
* @state: state to fill with the current PWM state
*/
static inline void pwm_get_state(const struct pwm_device *pwm,
struct pwm_state *state)
{
*state = pwm->state;
}
static inline bool pwm_is_enabled(const struct pwm_device *pwm)
{
return test_bit(PWMF_ENABLED, &pwm->flags);
struct pwm_state state;
pwm_get_state(pwm, &state);
return state.enabled;
}
static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period)
{
if (pwm)
pwm->period = period;
pwm->state.period = period;
}
static inline unsigned int pwm_get_period(const struct pwm_device *pwm)
{
return pwm ? pwm->period : 0;
struct pwm_state state;
pwm_get_state(pwm, &state);
return state.period;
}
static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty)
{
if (pwm)
pwm->duty_cycle = duty;
pwm->state.duty_cycle = duty;
}
static inline unsigned int pwm_get_duty_cycle(const struct pwm_device *pwm)
{
return pwm ? pwm->duty_cycle : 0;
}
struct pwm_state state;
/*
* pwm_set_polarity - configure the polarity of a PWM signal
*/
int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity);
pwm_get_state(pwm, &state);
return state.duty_cycle;
}
static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm)
{
return pwm ? pwm->polarity : PWM_POLARITY_NORMAL;
struct pwm_state state;
pwm_get_state(pwm, &state);
return state.polarity;
}
static inline void pwm_get_args(const struct pwm_device *pwm,
@ -171,12 +147,6 @@ static inline void pwm_get_args(const struct pwm_device *pwm,
*args = pwm->args;
}
static inline void pwm_apply_args(struct pwm_device *pwm)
{
pwm_set_period(pwm, pwm->args.period);
pwm_set_polarity(pwm, pwm->args.polarity);
}
/**
* struct pwm_ops - PWM controller operations
* @request: optional hook for requesting a PWM
@ -185,6 +155,13 @@ static inline void pwm_apply_args(struct pwm_device *pwm)
* @set_polarity: configure the polarity of this PWM
* @enable: enable PWM output toggling
* @disable: disable PWM output toggling
* @apply: atomically apply a new PWM config. The state argument
* should be adjusted with the real hardware config (if the
* approximate the period or duty_cycle value, state should
* reflect it)
* @get_state: get the current PWM state. This function is only
* called once per PWM device when the PWM chip is
* registered.
* @dbg_show: optional routine to show contents in debugfs
* @owner: helps prevent removal of modules exporting active PWMs
*/
@ -197,6 +174,10 @@ struct pwm_ops {
enum pwm_polarity polarity);
int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm);
void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm);
int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state);
void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state);
#ifdef CONFIG_DEBUG_FS
void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s);
#endif
@ -232,6 +213,115 @@ struct pwm_chip {
};
#if IS_ENABLED(CONFIG_PWM)
/* PWM user APIs */
struct pwm_device *pwm_request(int pwm_id, const char *label);
void pwm_free(struct pwm_device *pwm);
int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state);
int pwm_adjust_config(struct pwm_device *pwm);
/**
* pwm_config() - change a PWM device configuration
* @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.
*/
static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
int period_ns)
{
struct pwm_state state;
if (!pwm)
return -EINVAL;
pwm_get_state(pwm, &state);
if (state.duty_cycle == duty_ns && state.period == period_ns)
return 0;
state.duty_cycle = duty_ns;
state.period = period_ns;
return pwm_apply_state(pwm, &state);
}
/**
* 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.
*/
static inline int pwm_set_polarity(struct pwm_device *pwm,
enum pwm_polarity polarity)
{
struct pwm_state state;
if (!pwm)
return -EINVAL;
pwm_get_state(pwm, &state);
if (state.polarity == polarity)
return 0;
/*
* Changing the polarity of a running PWM without adjusting the
* dutycycle/period value is a bit risky (can introduce glitches).
* Return -EBUSY in this case.
* Note that this is allowed when using pwm_apply_state() because
* the user specifies all the parameters.
*/
if (state.enabled)
return -EBUSY;
state.polarity = polarity;
return pwm_apply_state(pwm, &state);
}
/**
* pwm_enable() - start a PWM output toggling
* @pwm: PWM device
*
* Returns: 0 on success or a negative error code on failure.
*/
static inline int pwm_enable(struct pwm_device *pwm)
{
struct pwm_state state;
if (!pwm)
return -EINVAL;
pwm_get_state(pwm, &state);
if (state.enabled)
return 0;
state.enabled = true;
return pwm_apply_state(pwm, &state);
}
/**
* pwm_disable() - stop a PWM output toggling
* @pwm: PWM device
*/
static inline void pwm_disable(struct pwm_device *pwm)
{
struct pwm_state state;
if (!pwm)
return;
pwm_get_state(pwm, &state);
if (!state.enabled)
return;
state.enabled = false;
pwm_apply_state(pwm, &state);
}
/* PWM provider APIs */
int pwm_set_chip_data(struct pwm_device *pwm, void *data);
void *pwm_get_chip_data(struct pwm_device *pwm);
@ -257,6 +347,47 @@ void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
bool pwm_can_sleep(struct pwm_device *pwm);
#else
static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
{
return ERR_PTR(-ENODEV);
}
static inline void pwm_free(struct pwm_device *pwm)
{
}
static inline int pwm_apply_state(struct pwm_device *pwm,
const struct pwm_state *state)
{
return -ENOTSUPP;
}
static inline int pwm_adjust_config(struct pwm_device *pwm)
{
return -ENOTSUPP;
}
static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
int period_ns)
{
return -EINVAL;
}
static inline int pwm_set_polarity(struct pwm_device *pwm,
enum pwm_polarity polarity)
{
return -ENOTSUPP;
}
static inline int pwm_enable(struct pwm_device *pwm)
{
return -EINVAL;
}
static inline void pwm_disable(struct pwm_device *pwm)
{
}
static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data)
{
return -EINVAL;
@ -328,6 +459,34 @@ static inline bool pwm_can_sleep(struct pwm_device *pwm)
}
#endif
static inline void pwm_apply_args(struct pwm_device *pwm)
{
/*
* PWM users calling pwm_apply_args() expect to have a fresh config
* where the polarity and period are set according to pwm_args info.
* The problem is, polarity can only be changed when the PWM is
* disabled.
*
* PWM drivers supporting hardware readout may declare the PWM device
* as enabled, and prevent polarity setting, which changes from the
* existing behavior, where all PWM devices are declared as disabled
* at startup (even if they are actually enabled), thus authorizing
* polarity setting.
*
* Instead of setting ->enabled to false, we call pwm_disable()
* before pwm_set_polarity() to ensure that everything is configured
* as expected, and the PWM is really disabled when the user request
* it.
*
* Note that PWM users requiring a smooth handover between the
* bootloader and the kernel (like critical regulators controlled by
* PWM devices) will have to switch to the atomic API and avoid calling
* pwm_apply_args().
*/
pwm_disable(pwm);
pwm_set_polarity(pwm, pwm->args.polarity);
}
struct pwm_lookup {
struct list_head list;
const char *provider;