diff options
Diffstat (limited to 'drivers/hwmon/pwm-fan.c')
| -rw-r--r-- | drivers/hwmon/pwm-fan.c | 450 |
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, }, }; 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