| Message ID | 20241106021559.175105-2-marex@denx.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2,1/2] dt-bindings: hwmon: pwm-fan: Document start from stopped state properties | expand |
On 11/5/24 18:14, Marek Vasut wrote: > Delta AFC0612DB-F00 fan has to be set to at least 30% PWM duty cycle > to spin up from a stopped state, and can be afterward throttled down to > lower PWM duty cycle. Introduce support for operating such fans which > need to start at higher PWM duty cycle first and can slow down next. > > Introduce two new DT properties, "fan-stop-to-start-percent" and > "fan-stop-to-start-us". The former describes the minimum percent > of fan RPM at which it will surely spin up from stopped state. This > value can be found in the fan datasheet and can be converted to PWM > duty cycle easily. The "fan-stop-to-start-us" describes the minimum > time in microseconds for which the fan has to be set to stopped state > start RPM for the fan to surely spin up. > > Adjust the PWM setting code such that if the PWM duty cycle is below > the minimum duty cycle needed by the fan to spin up from stopped state, > then first set the PWM duty cycle to the minimum duty cycle needed > by the fan to spin up from stopped state, then wait the time necessary > for the fan to spin up from stopped state, and finally set the PWM duty > cycle to the one desired by user. > > Signed-off-by: Marek Vasut <marex@denx.de> > --- > Cc: Conor Dooley <conor+dt@kernel.org> > Cc: Guenter Roeck <linux@roeck-us.net> > Cc: Jean Delvare <jdelvare@suse.com> > Cc: Krzysztof Kozlowski <krzk+dt@kernel.org> > Cc: Rob Herring <robh@kernel.org> > Cc: devicetree@vger.kernel.org > Cc: linux-hwmon@vger.kernel.org > --- > V2: - Rename fan-dead-stop-start-percent to fan-stop-to-start-percent > - Rename fan-dead-stop-start-usec to fan-stop-to-start-us > - Rename variables containing dead_stop to contain stopped > --- > drivers/hwmon/pwm-fan.c | 33 ++++++++++++++++++++++++++++++++- > 1 file changed, 32 insertions(+), 1 deletion(-) > > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c > index c434db4656e7d..27f449b65f285 100644 > --- a/drivers/hwmon/pwm-fan.c > +++ b/drivers/hwmon/pwm-fan.c > @@ -7,6 +7,7 @@ > * Author: Kamil Debski <k.debski@samsung.com> > */ > > +#include <linux/delay.h> > #include <linux/hwmon.h> > #include <linux/interrupt.h> > #include <linux/mod_devicetable.h> > @@ -60,6 +61,9 @@ 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; > }; > > /* This handler assumes self resetting edge triggered interrupt. */ > @@ -199,7 +203,9 @@ static int pwm_fan_power_off(struct pwm_fan_ctx *ctx, bool force_disable) > 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) { > @@ -208,11 +214,22 @@ 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); > + 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); > } > @@ -480,6 +497,7 @@ static int pwm_fan_probe(struct platform_device *pdev) > struct device *hwmon; > int ret; > const struct hwmon_channel_info **channels; > + u32 pwm_min_from_stopped = 0; > u32 *fan_channel_config; > int channel_count = 1; /* We always have a PWM channel. */ > int i; > @@ -620,6 +638,19 @@ static int pwm_fan_probe(struct platform_device *pdev) > channels[1] = &ctx->fan_channel; > } > > + ret = of_property_read_u32(dev->of_node, "fan-stop-to-start-percent", > + &pwm_min_from_stopped); > + if (!ret && pwm_min_from_stopped) { > + ctx->pwm_duty_cycle_from_stopped = > + DIV_ROUND_UP(pwm_min_from_stopped * > + (ctx->pwm_state.period - 1), > + 100); Since "period" is u64, this results in the "ERROR: modpost: "__aeabi_uldivmod" [drivers/hwmon/pwm-fan.ko] undefined!" error as reported by 0-day. Or at least I think that is the problem. I'd suggest to try building the driver on a 32-bit system to be sure. Guenter > + } > + ret = of_property_read_u32(dev->of_node, "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; >
On 11/6/24 5:26 AM, Guenter Roeck wrote: [...] >> @@ -480,6 +497,7 @@ static int pwm_fan_probe(struct platform_device >> *pdev) >> struct device *hwmon; >> int ret; >> const struct hwmon_channel_info **channels; >> + u32 pwm_min_from_stopped = 0; >> u32 *fan_channel_config; >> int channel_count = 1; /* We always have a PWM channel. */ >> int i; >> @@ -620,6 +638,19 @@ static int pwm_fan_probe(struct platform_device >> *pdev) >> channels[1] = &ctx->fan_channel; >> } >> + ret = of_property_read_u32(dev->of_node, "fan-stop-to-start- >> percent", >> + &pwm_min_from_stopped); >> + if (!ret && pwm_min_from_stopped) { >> + ctx->pwm_duty_cycle_from_stopped = >> + DIV_ROUND_UP(pwm_min_from_stopped * >> + (ctx->pwm_state.period - 1), >> + 100); > > Since "period" is u64, this results in the "ERROR: modpost: > "__aeabi_uldivmod" > [drivers/hwmon/pwm-fan.ko] undefined!" error as reported by 0-day. Or at > least > I think that is the problem. I'd suggest to try building the driver on a > 32-bit > system to be sure. Ah, right, fixed in V3. Thanks !
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c index c434db4656e7d..27f449b65f285 100644 --- a/drivers/hwmon/pwm-fan.c +++ b/drivers/hwmon/pwm-fan.c @@ -7,6 +7,7 @@ * Author: Kamil Debski <k.debski@samsung.com> */ +#include <linux/delay.h> #include <linux/hwmon.h> #include <linux/interrupt.h> #include <linux/mod_devicetable.h> @@ -60,6 +61,9 @@ 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; }; /* This handler assumes self resetting edge triggered interrupt. */ @@ -199,7 +203,9 @@ static int pwm_fan_power_off(struct pwm_fan_ctx *ctx, bool force_disable) 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) { @@ -208,11 +214,22 @@ 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); + 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); } @@ -480,6 +497,7 @@ static int pwm_fan_probe(struct platform_device *pdev) struct device *hwmon; int ret; const struct hwmon_channel_info **channels; + u32 pwm_min_from_stopped = 0; u32 *fan_channel_config; int channel_count = 1; /* We always have a PWM channel. */ int i; @@ -620,6 +638,19 @@ static int pwm_fan_probe(struct platform_device *pdev) channels[1] = &ctx->fan_channel; } + ret = of_property_read_u32(dev->of_node, "fan-stop-to-start-percent", + &pwm_min_from_stopped); + if (!ret && pwm_min_from_stopped) { + ctx->pwm_duty_cycle_from_stopped = + DIV_ROUND_UP(pwm_min_from_stopped * + (ctx->pwm_state.period - 1), + 100); + } + ret = of_property_read_u32(dev->of_node, "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;
Delta AFC0612DB-F00 fan has to be set to at least 30% PWM duty cycle to spin up from a stopped state, and can be afterward throttled down to lower PWM duty cycle. Introduce support for operating such fans which need to start at higher PWM duty cycle first and can slow down next. Introduce two new DT properties, "fan-stop-to-start-percent" and "fan-stop-to-start-us". The former describes the minimum percent of fan RPM at which it will surely spin up from stopped state. This value can be found in the fan datasheet and can be converted to PWM duty cycle easily. The "fan-stop-to-start-us" describes the minimum time in microseconds for which the fan has to be set to stopped state start RPM for the fan to surely spin up. Adjust the PWM setting code such that if the PWM duty cycle is below the minimum duty cycle needed by the fan to spin up from stopped state, then first set the PWM duty cycle to the minimum duty cycle needed by the fan to spin up from stopped state, then wait the time necessary for the fan to spin up from stopped state, and finally set the PWM duty cycle to the one desired by user. Signed-off-by: Marek Vasut <marex@denx.de> --- Cc: Conor Dooley <conor+dt@kernel.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jean Delvare <jdelvare@suse.com> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org> Cc: Rob Herring <robh@kernel.org> Cc: devicetree@vger.kernel.org Cc: linux-hwmon@vger.kernel.org --- V2: - Rename fan-dead-stop-start-percent to fan-stop-to-start-percent - Rename fan-dead-stop-start-usec to fan-stop-to-start-us - Rename variables containing dead_stop to contain stopped --- drivers/hwmon/pwm-fan.c | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-)