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path: root/drivers/hwmon/pwm-fan.c
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Diffstat (limited to 'drivers/hwmon/pwm-fan.c')
-rw-r--r--drivers/hwmon/pwm-fan.c450
1 files changed, 326 insertions, 124 deletions
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index f12b9a28a232..37269db2de84 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -7,12 +7,14 @@
* Author: Kamil Debski <k.debski@samsung.com>
*/
+#include <linux/delay.h>
#include <linux/hwmon.h>
#include <linux/interrupt.h>
+#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mutex.h>
-#include <linux/of.h>
#include <linux/platform_device.h>
+#include <linux/property.h>
#include <linux/pwm.h>
#include <linux/regulator/consumer.h>
#include <linux/sysfs.h>
@@ -25,17 +27,29 @@ struct pwm_fan_tach {
int irq;
atomic_t pulses;
unsigned int rpm;
- u8 pulses_per_revolution;
+};
+
+enum pwm_fan_enable_mode {
+ pwm_off_reg_off,
+ pwm_disable_reg_enable,
+ pwm_enable_reg_enable,
+ pwm_disable_reg_disable,
};
struct pwm_fan_ctx {
+ struct device *dev;
+
struct mutex lock;
struct pwm_device *pwm;
struct pwm_state pwm_state;
struct regulator *reg_en;
+ enum pwm_fan_enable_mode enable_mode;
+ bool regulator_enabled;
+ bool enabled;
int tach_count;
struct pwm_fan_tach *tachs;
+ u32 *pulses_per_revolution;
ktime_t sample_start;
struct timer_list rpm_timer;
@@ -47,16 +61,10 @@ struct pwm_fan_ctx {
struct hwmon_chip_info info;
struct hwmon_channel_info fan_channel;
-};
-
-static const u32 pwm_fan_channel_config_pwm[] = {
- HWMON_PWM_INPUT,
- 0
-};
-static const struct hwmon_channel_info pwm_fan_channel_pwm = {
- .type = hwmon_pwm,
- .config = pwm_fan_channel_config_pwm,
+ u64 pwm_duty_cycle_from_stopped;
+ u32 pwm_usec_from_stopped;
+ u8 pwm_shutdown;
};
/* This handler assumes self resetting edge triggered interrupt. */
@@ -71,7 +79,7 @@ static irqreturn_t pulse_handler(int irq, void *dev_id)
static void sample_timer(struct timer_list *t)
{
- struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
+ struct pwm_fan_ctx *ctx = timer_container_of(ctx, t, rpm_timer);
unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start);
int i;
@@ -83,7 +91,7 @@ static void sample_timer(struct timer_list *t)
pulses = atomic_read(&tach->pulses);
atomic_sub(pulses, &tach->pulses);
tach->rpm = (unsigned int)(pulses * 1000 * 60) /
- (tach->pulses_per_revolution * delta);
+ (ctx->pulses_per_revolution[i] * delta);
}
ctx->sample_start = ktime_get();
@@ -92,25 +100,154 @@ static void sample_timer(struct timer_list *t)
mod_timer(&ctx->rpm_timer, jiffies + HZ);
}
-static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
+static void pwm_fan_enable_mode_2_state(int enable_mode,
+ struct pwm_state *state,
+ bool *enable_regulator)
+{
+ switch (enable_mode) {
+ case pwm_disable_reg_enable:
+ /* disable pwm, keep regulator enabled */
+ state->enabled = false;
+ *enable_regulator = true;
+ break;
+ case pwm_enable_reg_enable:
+ /* keep pwm and regulator enabled */
+ state->enabled = true;
+ *enable_regulator = true;
+ break;
+ case pwm_off_reg_off:
+ case pwm_disable_reg_disable:
+ /* disable pwm and regulator */
+ state->enabled = false;
+ *enable_regulator = false;
+ }
+}
+
+static int pwm_fan_switch_power(struct pwm_fan_ctx *ctx, bool on)
{
- unsigned long period;
int ret = 0;
+
+ if (!ctx->reg_en)
+ return ret;
+
+ if (!ctx->regulator_enabled && on) {
+ ret = regulator_enable(ctx->reg_en);
+ if (ret == 0)
+ ctx->regulator_enabled = true;
+ } else if (ctx->regulator_enabled && !on) {
+ ret = regulator_disable(ctx->reg_en);
+ if (ret == 0)
+ ctx->regulator_enabled = false;
+ }
+ return ret;
+}
+
+static int pwm_fan_power_on(struct pwm_fan_ctx *ctx)
+{
struct pwm_state *state = &ctx->pwm_state;
+ int ret;
- mutex_lock(&ctx->lock);
- if (ctx->pwm_value == pwm)
- goto exit_set_pwm_err;
+ if (ctx->enabled)
+ return 0;
+
+ ret = pwm_fan_switch_power(ctx, true);
+ if (ret < 0) {
+ dev_err(ctx->dev, "failed to enable power supply\n");
+ return ret;
+ }
+
+ state->enabled = true;
+ ret = pwm_apply_might_sleep(ctx->pwm, state);
+ if (ret) {
+ dev_err(ctx->dev, "failed to enable PWM\n");
+ goto disable_regulator;
+ }
+
+ ctx->enabled = true;
+
+ return 0;
+
+disable_regulator:
+ pwm_fan_switch_power(ctx, false);
+ return ret;
+}
+
+static int pwm_fan_power_off(struct pwm_fan_ctx *ctx, bool force_disable)
+{
+ struct pwm_state *state = &ctx->pwm_state;
+ bool enable_regulator = false;
+ int ret;
+
+ if (!ctx->enabled)
+ return 0;
+
+ pwm_fan_enable_mode_2_state(ctx->enable_mode,
+ state,
+ &enable_regulator);
+
+ if (force_disable)
+ state->enabled = false;
+ state->duty_cycle = 0;
+ ret = pwm_apply_might_sleep(ctx->pwm, state);
+ if (ret) {
+ dev_err(ctx->dev, "failed to disable PWM\n");
+ return ret;
+ }
+
+ pwm_fan_switch_power(ctx, enable_regulator);
- period = state->period;
- state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
- state->enabled = pwm ? true : false;
+ ctx->enabled = false;
- ret = pwm_apply_state(ctx->pwm, state);
+ return 0;
+}
+
+static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
+{
+ struct pwm_state *state = &ctx->pwm_state;
+ unsigned long final_pwm = pwm;
+ unsigned long period;
+ bool update = false;
+ int ret = 0;
+
+ if (pwm > 0) {
+ if (ctx->enable_mode == pwm_off_reg_off)
+ /* pwm-fan hard disabled */
+ return 0;
+
+ period = state->period;
+ update = state->duty_cycle < ctx->pwm_duty_cycle_from_stopped;
+ if (update)
+ state->duty_cycle = ctx->pwm_duty_cycle_from_stopped;
+ else
+ state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
+ ret = pwm_apply_might_sleep(ctx->pwm, state);
+ if (ret)
+ return ret;
+ ret = pwm_fan_power_on(ctx);
+ if (!ret && update) {
+ pwm = final_pwm;
+ state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
+ usleep_range(ctx->pwm_usec_from_stopped,
+ ctx->pwm_usec_from_stopped * 2);
+ ret = pwm_apply_might_sleep(ctx->pwm, state);
+ }
+ } else {
+ ret = pwm_fan_power_off(ctx, false);
+ }
if (!ret)
ctx->pwm_value = pwm;
-exit_set_pwm_err:
+
+ return ret;
+}
+
+static int set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
+{
+ int ret;
+
+ mutex_lock(&ctx->lock);
+ ret = __set_pwm(ctx, pwm);
mutex_unlock(&ctx->lock);
+
return ret;
}
@@ -125,20 +262,79 @@ static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
ctx->pwm_fan_state = i;
}
+static int pwm_fan_update_enable(struct pwm_fan_ctx *ctx, long val)
+{
+ int ret = 0;
+ int old_val;
+
+ mutex_lock(&ctx->lock);
+
+ if (ctx->enable_mode == val)
+ goto out;
+
+ old_val = ctx->enable_mode;
+ ctx->enable_mode = val;
+
+ if (val == 0) {
+ /* Disable pwm-fan unconditionally */
+ if (ctx->enabled)
+ ret = __set_pwm(ctx, 0);
+ else
+ ret = pwm_fan_switch_power(ctx, false);
+ if (ret)
+ ctx->enable_mode = old_val;
+ pwm_fan_update_state(ctx, 0);
+ } else {
+ /*
+ * Change PWM and/or regulator state if currently disabled
+ * Nothing to do if currently enabled
+ */
+ if (!ctx->enabled) {
+ struct pwm_state *state = &ctx->pwm_state;
+ bool enable_regulator = false;
+
+ state->duty_cycle = 0;
+ pwm_fan_enable_mode_2_state(val,
+ state,
+ &enable_regulator);
+
+ pwm_apply_might_sleep(ctx->pwm, state);
+ pwm_fan_switch_power(ctx, enable_regulator);
+ pwm_fan_update_state(ctx, 0);
+ }
+ }
+out:
+ mutex_unlock(&ctx->lock);
+
+ return ret;
+}
+
static int pwm_fan_write(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long val)
{
struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
int ret;
- if (val < 0 || val > MAX_PWM)
- return -EINVAL;
+ switch (attr) {
+ case hwmon_pwm_input:
+ if (val < 0 || val > MAX_PWM)
+ return -EINVAL;
+ ret = set_pwm(ctx, val);
+ if (ret)
+ return ret;
+ pwm_fan_update_state(ctx, val);
+ break;
+ case hwmon_pwm_enable:
+ if (val < 0 || val > 3)
+ ret = -EINVAL;
+ else
+ ret = pwm_fan_update_enable(ctx, val);
- ret = __set_pwm(ctx, val);
- if (ret)
return ret;
+ default:
+ return -EOPNOTSUPP;
+ }
- pwm_fan_update_state(ctx, val);
return 0;
}
@@ -149,9 +345,15 @@ static int pwm_fan_read(struct device *dev, enum hwmon_sensor_types type,
switch (type) {
case hwmon_pwm:
- *val = ctx->pwm_value;
- return 0;
-
+ switch (attr) {
+ case hwmon_pwm_input:
+ *val = ctx->pwm_value;
+ return 0;
+ case hwmon_pwm_enable:
+ *val = ctx->enable_mode;
+ return 0;
+ }
+ return -EOPNOTSUPP;
case hwmon_fan:
*val = ctx->tachs[channel].rpm;
return 0;
@@ -222,7 +424,7 @@ pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
if (state == ctx->pwm_fan_state)
return 0;
- ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
+ ret = set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
if (ret) {
dev_err(&cdev->device, "Cannot set pwm!\n");
return ret;
@@ -239,16 +441,14 @@ static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
.set_cur_state = pwm_fan_set_cur_state,
};
-static int pwm_fan_of_get_cooling_data(struct device *dev,
- struct pwm_fan_ctx *ctx)
+static int pwm_fan_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx)
{
- struct device_node *np = dev->of_node;
int num, i, ret;
- if (!of_find_property(np, "cooling-levels", NULL))
+ if (!device_property_present(dev, "cooling-levels"))
return 0;
- ret = of_property_count_u32_elems(np, "cooling-levels");
+ ret = device_property_count_u32(dev, "cooling-levels");
if (ret <= 0) {
dev_err(dev, "Wrong data!\n");
return ret ? : -EINVAL;
@@ -260,8 +460,8 @@ static int pwm_fan_of_get_cooling_data(struct device *dev,
if (!ctx->pwm_fan_cooling_levels)
return -ENOMEM;
- ret = of_property_read_u32_array(np, "cooling-levels",
- ctx->pwm_fan_cooling_levels, num);
+ ret = device_property_read_u32_array(dev, "cooling-levels",
+ ctx->pwm_fan_cooling_levels, num);
if (ret) {
dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
return ret;
@@ -280,18 +480,19 @@ static int pwm_fan_of_get_cooling_data(struct device *dev,
return 0;
}
-static void pwm_fan_regulator_disable(void *data)
-{
- regulator_disable(data);
-}
-
-static void pwm_fan_pwm_disable(void *__ctx)
+static void pwm_fan_cleanup(void *__ctx)
{
struct pwm_fan_ctx *ctx = __ctx;
- ctx->pwm_state.enabled = false;
- pwm_apply_state(ctx->pwm, &ctx->pwm_state);
- del_timer_sync(&ctx->rpm_timer);
+ timer_delete_sync(&ctx->rpm_timer);
+ if (ctx->pwm_shutdown) {
+ ctx->enable_mode = pwm_enable_reg_enable;
+ __set_pwm(ctx, ctx->pwm_shutdown);
+ } else {
+ /* Switch off everything */
+ ctx->enable_mode = pwm_disable_reg_disable;
+ pwm_fan_power_off(ctx, true);
+ }
}
static int pwm_fan_probe(struct platform_device *pdev)
@@ -302,6 +503,8 @@ static int pwm_fan_probe(struct platform_device *pdev)
struct device *hwmon;
int ret;
const struct hwmon_channel_info **channels;
+ u32 initial_pwm, pwm_min_from_stopped = 0;
+ u32 pwm_shutdown_percent = 0;
u32 *fan_channel_config;
int channel_count = 1; /* We always have a PWM channel. */
int i;
@@ -312,7 +515,8 @@ static int pwm_fan_probe(struct platform_device *pdev)
mutex_init(&ctx->lock);
- ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL);
+ ctx->dev = &pdev->dev;
+ ctx->pwm = devm_pwm_get(dev, NULL);
if (IS_ERR(ctx->pwm))
return dev_err_probe(dev, PTR_ERR(ctx->pwm), "Could not get PWM\n");
@@ -324,22 +528,20 @@ static int pwm_fan_probe(struct platform_device *pdev)
return PTR_ERR(ctx->reg_en);
ctx->reg_en = NULL;
- } else {
- ret = regulator_enable(ctx->reg_en);
- if (ret) {
- dev_err(dev, "Failed to enable fan supply: %d\n", ret);
- return ret;
- }
- ret = devm_add_action_or_reset(dev, pwm_fan_regulator_disable,
- ctx->reg_en);
- if (ret)
- return ret;
}
pwm_init_state(ctx->pwm, &ctx->pwm_state);
/*
- * __set_pwm assumes that MAX_PWM * (period - 1) fits into an unsigned
+ * PWM fans are controlled solely by the duty cycle of the PWM signal,
+ * they do not care about the exact timing. Thus set usage_power to true
+ * to allow less flexible hardware to work as a PWM source for fan
+ * control.
+ */
+ ctx->pwm_state.usage_power = true;
+
+ /*
+ * set_pwm assumes that MAX_PWM * (period - 1) fits into an unsigned
* long. Check this here to prevent the fan running at a too low
* frequency.
*/
@@ -348,14 +550,29 @@ static int pwm_fan_probe(struct platform_device *pdev)
return -EINVAL;
}
- /* Set duty cycle to maximum allowed and enable PWM output */
- ret = __set_pwm(ctx, MAX_PWM);
+ ctx->enable_mode = pwm_disable_reg_enable;
+
+ ret = pwm_fan_get_cooling_data(dev, ctx);
+ if (ret)
+ return ret;
+
+ /* use maximum cooling level if provided */
+ if (ctx->pwm_fan_cooling_levels)
+ initial_pwm = ctx->pwm_fan_cooling_levels[ctx->pwm_fan_max_state];
+ else
+ initial_pwm = MAX_PWM;
+
+ /*
+ * Set duty cycle to maximum allowed and enable PWM output as well as
+ * the regulator. In case of error nothing is changed
+ */
+ ret = set_pwm(ctx, initial_pwm);
if (ret) {
dev_err(dev, "Failed to configure PWM: %d\n", ret);
return ret;
}
timer_setup(&ctx->rpm_timer, sample_timer, 0);
- ret = devm_add_action_or_reset(dev, pwm_fan_pwm_disable, ctx);
+ ret = devm_add_action_or_reset(dev, pwm_fan_cleanup, ctx);
if (ret)
return ret;
@@ -380,6 +597,20 @@ static int pwm_fan_probe(struct platform_device *pdev)
if (!fan_channel_config)
return -ENOMEM;
ctx->fan_channel.config = fan_channel_config;
+
+ ctx->pulses_per_revolution = devm_kmalloc_array(dev,
+ ctx->tach_count,
+ sizeof(*ctx->pulses_per_revolution),
+ GFP_KERNEL);
+ if (!ctx->pulses_per_revolution)
+ return -ENOMEM;
+
+ /* Setup default pulses per revolution */
+ for (i = 0; i < ctx->tach_count; i++)
+ ctx->pulses_per_revolution[i] = 2;
+
+ device_property_read_u32_array(dev, "pulses-per-revolution",
+ ctx->pulses_per_revolution, ctx->tach_count);
}
channels = devm_kcalloc(dev, channel_count + 1,
@@ -387,18 +618,17 @@ static int pwm_fan_probe(struct platform_device *pdev)
if (!channels)
return -ENOMEM;
- channels[0] = &pwm_fan_channel_pwm;
+ channels[0] = HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_ENABLE);
for (i = 0; i < ctx->tach_count; i++) {
struct pwm_fan_tach *tach = &ctx->tachs[i];
- u32 ppr = 2;
tach->irq = platform_get_irq(pdev, i);
if (tach->irq == -EPROBE_DEFER)
return tach->irq;
if (tach->irq > 0) {
- ret = devm_request_irq(dev, tach->irq, pulse_handler, 0,
- pdev->name, tach);
+ ret = devm_request_irq(dev, tach->irq, pulse_handler,
+ IRQF_NO_THREAD, pdev->name, tach);
if (ret) {
dev_err(dev,
"Failed to request interrupt: %d\n",
@@ -407,12 +637,7 @@ static int pwm_fan_probe(struct platform_device *pdev)
}
}
- of_property_read_u32_index(dev->of_node,
- "pulses-per-revolution",
- i,
- &ppr);
- tach->pulses_per_revolution = ppr;
- if (!tach->pulses_per_revolution) {
+ if (!ctx->pulses_per_revolution[i]) {
dev_err(dev, "pulses-per-revolution can't be zero.\n");
return -EINVAL;
}
@@ -420,7 +645,7 @@ static int pwm_fan_probe(struct platform_device *pdev)
fan_channel_config[i] = HWMON_F_INPUT;
dev_dbg(dev, "tach%d: irq=%d, pulses_per_revolution=%d\n",
- i, tach->irq, tach->pulses_per_revolution);
+ i, tach->irq, ctx->pulses_per_revolution[i]);
}
if (ctx->tach_count > 0) {
@@ -430,6 +655,24 @@ static int pwm_fan_probe(struct platform_device *pdev)
channels[1] = &ctx->fan_channel;
}
+ ret = device_property_read_u32(dev, "fan-shutdown-percent",
+ &pwm_shutdown_percent);
+ if (!ret && pwm_shutdown_percent)
+ ctx->pwm_shutdown = (clamp(pwm_shutdown_percent, 0, 100) * 255) / 100;
+
+ ret = device_property_read_u32(dev, "fan-stop-to-start-percent",
+ &pwm_min_from_stopped);
+ if (!ret && pwm_min_from_stopped) {
+ ctx->pwm_duty_cycle_from_stopped =
+ DIV_ROUND_UP_ULL(pwm_min_from_stopped *
+ (ctx->pwm_state.period - 1),
+ 100);
+ }
+ ret = device_property_read_u32(dev, "fan-stop-to-start-us",
+ &ctx->pwm_usec_from_stopped);
+ if (ret)
+ ctx->pwm_usec_from_stopped = 250000;
+
ctx->info.ops = &pwm_fan_hwmon_ops;
ctx->info.info = channels;
@@ -440,10 +683,6 @@ static int pwm_fan_probe(struct platform_device *pdev)
return PTR_ERR(hwmon);
}
- ret = pwm_fan_of_get_cooling_data(dev, ctx);
- if (ret)
- return ret;
-
ctx->pwm_fan_state = ctx->pwm_fan_max_state;
if (IS_ENABLED(CONFIG_THERMAL)) {
cdev = devm_thermal_of_cooling_device_register(dev,
@@ -461,65 +700,28 @@ static int pwm_fan_probe(struct platform_device *pdev)
return 0;
}
-static int pwm_fan_disable(struct device *dev)
-{
- struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
- int ret;
-
- if (ctx->pwm_value) {
- /* keep ctx->pwm_state unmodified for pwm_fan_resume() */
- struct pwm_state state = ctx->pwm_state;
-
- state.duty_cycle = 0;
- state.enabled = false;
- ret = pwm_apply_state(ctx->pwm, &state);
- if (ret < 0)
- return ret;
- }
-
- if (ctx->reg_en) {
- ret = regulator_disable(ctx->reg_en);
- if (ret) {
- dev_err(dev, "Failed to disable fan supply: %d\n", ret);
- return ret;
- }
- }
-
- return 0;
-}
-
static void pwm_fan_shutdown(struct platform_device *pdev)
{
- pwm_fan_disable(&pdev->dev);
+ struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
+
+ pwm_fan_cleanup(ctx);
}
-#ifdef CONFIG_PM_SLEEP
static int pwm_fan_suspend(struct device *dev)
{
- return pwm_fan_disable(dev);
+ struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+
+ return pwm_fan_power_off(ctx, true);
}
static int pwm_fan_resume(struct device *dev)
{
struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
- int ret;
-
- if (ctx->reg_en) {
- ret = regulator_enable(ctx->reg_en);
- if (ret) {
- dev_err(dev, "Failed to enable fan supply: %d\n", ret);
- return ret;
- }
- }
-
- if (ctx->pwm_value == 0)
- return 0;
- return pwm_apply_state(ctx->pwm, &ctx->pwm_state);
+ return set_pwm(ctx, ctx->pwm_value);
}
-#endif
-static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
+static DEFINE_SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
static const struct of_device_id of_pwm_fan_match[] = {
{ .compatible = "pwm-fan", },
@@ -532,7 +734,7 @@ static struct platform_driver pwm_fan_driver = {
.shutdown = pwm_fan_shutdown,
.driver = {
.name = "pwm-fan",
- .pm = &pwm_fan_pm,
+ .pm = pm_sleep_ptr(&pwm_fan_pm),
.of_match_table = of_pwm_fan_match,
},
};