diff options
Diffstat (limited to 'drivers/hwmon/pwm-fan.c')
| -rw-r--r-- | drivers/hwmon/pwm-fan.c | 143 |
1 files changed, 104 insertions, 39 deletions
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c index 83a347ca35da..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> @@ -25,7 +27,6 @@ struct pwm_fan_tach { int irq; atomic_t pulses; unsigned int rpm; - u8 pulses_per_revolution; }; enum pwm_fan_enable_mode { @@ -48,6 +49,7 @@ struct pwm_fan_ctx { int tach_count; struct pwm_fan_tach *tachs; + u32 *pulses_per_revolution; ktime_t sample_start; struct timer_list rpm_timer; @@ -59,6 +61,10 @@ struct pwm_fan_ctx { struct hwmon_chip_info info; struct hwmon_channel_info fan_channel; + + u64 pwm_duty_cycle_from_stopped; + u32 pwm_usec_from_stopped; + u8 pwm_shutdown; }; /* This handler assumes self resetting edge triggered interrupt. */ @@ -73,7 +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; @@ -85,7 +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(); @@ -151,7 +157,7 @@ static int pwm_fan_power_on(struct pwm_fan_ctx *ctx) } state->enabled = true; - ret = pwm_apply_state(ctx->pwm, state); + ret = pwm_apply_might_sleep(ctx->pwm, state); if (ret) { dev_err(ctx->dev, "failed to enable PWM\n"); goto disable_regulator; @@ -166,7 +172,7 @@ disable_regulator: return ret; } -static int pwm_fan_power_off(struct pwm_fan_ctx *ctx) +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; @@ -179,9 +185,10 @@ static int pwm_fan_power_off(struct pwm_fan_ctx *ctx) state, &enable_regulator); - state->enabled = false; + if (force_disable) + state->enabled = false; state->duty_cycle = 0; - ret = pwm_apply_state(ctx->pwm, state); + ret = pwm_apply_might_sleep(ctx->pwm, state); if (ret) { dev_err(ctx->dev, "failed to disable PWM\n"); return ret; @@ -197,7 +204,9 @@ static int pwm_fan_power_off(struct pwm_fan_ctx *ctx) 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) { @@ -206,13 +215,24 @@ static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) return 0; period = state->period; - state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM); - ret = pwm_apply_state(ctx->pwm, state); + 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); + ret = pwm_fan_power_off(ctx, false); } if (!ret) ctx->pwm_value = pwm; @@ -278,7 +298,7 @@ static int pwm_fan_update_enable(struct pwm_fan_ctx *ctx, long val) state, &enable_regulator); - pwm_apply_state(ctx->pwm, state); + pwm_apply_might_sleep(ctx->pwm, state); pwm_fan_switch_power(ctx, enable_regulator); pwm_fan_update_state(ctx, 0); } @@ -421,16 +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; @@ -442,8 +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; @@ -466,10 +484,15 @@ static void pwm_fan_cleanup(void *__ctx) { struct pwm_fan_ctx *ctx = __ctx; - del_timer_sync(&ctx->rpm_timer); - /* Switch off everything */ - ctx->enable_mode = pwm_disable_reg_disable; - pwm_fan_power_off(ctx); + 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) @@ -480,6 +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; @@ -508,6 +533,14 @@ static int pwm_fan_probe(struct platform_device *pdev) pwm_init_state(ctx->pwm, &ctx->pwm_state); /* + * 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. @@ -519,11 +552,21 @@ static int pwm_fan_probe(struct platform_device *pdev) 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, MAX_PWM); + ret = set_pwm(ctx, initial_pwm); if (ret) { dev_err(dev, "Failed to configure PWM: %d\n", ret); return ret; @@ -554,6 +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, @@ -565,14 +622,13 @@ static int pwm_fan_probe(struct platform_device *pdev) 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", @@ -581,12 +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; } @@ -594,7 +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) { @@ -604,6 +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; @@ -614,10 +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, @@ -646,7 +711,7 @@ static int pwm_fan_suspend(struct device *dev) { struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); - return pwm_fan_power_off(ctx); + return pwm_fan_power_off(ctx, true); } static int pwm_fan_resume(struct device *dev) |