Date:   Thu, 5 Dec 2019 11:50:26 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Pascal Paillet <p.paillet@...com>, rui.zhang@...el.com,
        edubezval@...il.com, amit.kucheria@...durent.com,
        mcoquelin.stm32@...il.com, alexandre.torgue@...com,
        david.hernandezsanchez@...com, horms+renesas@...ge.net.au,
        wsa+renesas@...g-engineering.com, linux-pm@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/5] thermal: stm32: handle multiple trip points



Hi Pascal,

On 04/11/2019 14:30, Pascal Paillet wrote:
> Let the thermal framework handle the trip points instead
> of custom code inside the driver. This leads to remove a lot
> of code and simplifies the driver.
> Implement set_trips callback to set the low and high thresholds,
> modify irq enable and disable to handle those thresholds.

there are a lot of changes in this patch, please split it into smaller
pieces with a good description.

Thanks


> Signed-off-by: Pascal Paillet <p.paillet@...com>
> ---
>  drivers/thermal/st/stm_thermal.c | 283 +++++++++++--------------------
>  1 file changed, 95 insertions(+), 188 deletions(-)
> 
> diff --git a/drivers/thermal/st/stm_thermal.c b/drivers/thermal/st/stm_thermal.c
> index 7577242dadb4..cb72252f2800 100644
> --- a/drivers/thermal/st/stm_thermal.c
> +++ b/drivers/thermal/st/stm_thermal.c
> @@ -51,10 +51,17 @@
>  /* DTS_DR register mask definitions */
>  #define TS1_MFREQ_MASK		GENMASK(15, 0)
>  
> +/* DTS_ITENR register mask definitions */
> +#define ITENR_MASK		(GENMASK(2, 0) | GENMASK(6, 4))
> +
> +/* DTS_ICIFR register mask definitions */
> +#define ICIFR_MASK		(GENMASK(2, 0) | GENMASK(6, 4))
> +
>  /* Less significant bit position definitions */
>  #define TS1_T0_POS		16
>  #define TS1_SMP_TIME_POS	16
>  #define TS1_HITTHD_POS		16
> +#define TS1_LITTHD_POS		0
>  #define HSREF_CLK_DIV_POS	24
>  
>  /* DTS_CFGR1 bit definitions */
> @@ -91,32 +98,28 @@ struct stm_thermal_sensor {
>  	struct thermal_zone_device *th_dev;
>  	enum thermal_device_mode mode;
>  	struct clk *clk;
> -	int high_temp;
> -	int low_temp;
> -	int temp_critical;
> -	int temp_passive;
>  	unsigned int low_temp_enabled;
> -	int num_trips;
> +	unsigned int high_temp_enabled;
>  	int irq;
>  	void __iomem *base;
>  	int t0, fmt0, ramp_coeff;
>  };
>  
> +static int stm_enable_irq(struct stm_thermal_sensor *sensor);
> +

Move the function instead of adding a declaration.

>  static irqreturn_t stm_thermal_alarm_irq_thread(int irq, void *sdata)
>  {
> -	u32 value;
>  	struct stm_thermal_sensor *sensor = sdata;
>  
> -	/* read IT reason in SR and clear flags */
> -	value = readl_relaxed(sensor->base + DTS_SR_OFFSET);
> +	dev_dbg(sensor->dev, "sr:%d\n",
> +		readl_relaxed(sensor->base + DTS_SR_OFFSET));
>  
> -	if ((value & LOW_THRESHOLD) == LOW_THRESHOLD)
> -		writel_relaxed(LOW_THRESHOLD, sensor->base + DTS_ICIFR_OFFSET);
> +	thermal_zone_device_update(sensor->th_dev, THERMAL_EVENT_UNSPECIFIED);
>  
> -	if ((value & HIGH_THRESHOLD) == HIGH_THRESHOLD)
> -		writel_relaxed(HIGH_THRESHOLD, sensor->base + DTS_ICIFR_OFFSET);
> +	stm_enable_irq(sensor);
>  
> -	thermal_zone_device_update(sensor->th_dev, THERMAL_EVENT_UNSPECIFIED);
> +	/* Acknoledge all DTS irqs */
> +	writel_relaxed(ICIFR_MASK, sensor->base + DTS_ICIFR_OFFSET);
>  
>  	return IRQ_HANDLED;
>  }
> @@ -149,6 +152,8 @@ static int stm_sensor_power_on(struct stm_thermal_sensor *sensor)
>  	writel_relaxed(value, sensor->base +
>  		       DTS_CFGR1_OFFSET);
>  
> +	sensor->mode = THERMAL_DEVICE_ENABLED;
> +
>  	return 0;
>  }
>  
> @@ -156,6 +161,8 @@ static int stm_sensor_power_off(struct stm_thermal_sensor *sensor)
>  {
>  	u32 value;
>  
> +	sensor->mode = THERMAL_DEVICE_DISABLED;
> +
>  	/* Stop measuring */
>  	value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
>  	value &= ~TS1_START;
> @@ -277,50 +284,15 @@ static int stm_thermal_calculate_threshold(struct stm_thermal_sensor *sensor,
>  	return 0;
>  }
>  
> -static int stm_thermal_set_threshold(struct stm_thermal_sensor *sensor)
> -{
> -	u32 value, th;
> -	int ret;
> -
> -	value = readl_relaxed(sensor->base + DTS_ITR1_OFFSET);
> -
> -	/* Erase threshold content */
> -	value &= ~(TS1_LITTHD_MASK | TS1_HITTHD_MASK);
> -
> -	/* Retrieve the sample threshold number th for a given temperature */
> -	ret = stm_thermal_calculate_threshold(sensor, sensor->high_temp, &th);
> -	if (ret)
> -		return ret;
> -
> -	value |= th & TS1_LITTHD_MASK;
> -
> -	if (sensor->low_temp_enabled) {
> -		/* Retrieve the sample threshold */
> -		ret = stm_thermal_calculate_threshold(sensor, sensor->low_temp,
> -						      &th);
> -		if (ret)
> -			return ret;
> -
> -		value |= (TS1_HITTHD_MASK  & (th << TS1_HITTHD_POS));
> -	}
> -
> -	/* Write value on the Low interrupt threshold */
> -	writel_relaxed(value, sensor->base + DTS_ITR1_OFFSET);
> -
> -	return 0;
> -}
> -
>  /* Disable temperature interrupt */
>  static int stm_disable_irq(struct stm_thermal_sensor *sensor)
>  {
>  	u32 value;
>  
> -	/* Disable IT generation for low and high thresholds */
> +	/* Disable IT generation */
>  	value = readl_relaxed(sensor->base + DTS_ITENR_OFFSET);
> -	writel_relaxed(value & ~(LOW_THRESHOLD | HIGH_THRESHOLD),
> -		       sensor->base + DTS_ITENR_OFFSET);
> -
> -	dev_dbg(sensor->dev, "%s: IT disabled on sensor side", __func__);
> +	value &= ~ITENR_MASK;
> +	writel_relaxed(value, sensor->base + DTS_ITENR_OFFSET);
>  
>  	return 0;
>  }
> @@ -330,62 +302,67 @@ static int stm_enable_irq(struct stm_thermal_sensor *sensor)
>  {
>  	u32 value;
>  
> -	/*
> -	 * Code below enables High temperature threshold using a low threshold
> -	 * sampling value
> -	 */
> -
> -	/* Make sure LOW_THRESHOLD IT is clear before enabling */
> -	writel_relaxed(LOW_THRESHOLD, sensor->base + DTS_ICIFR_OFFSET);
> +	dev_dbg(sensor->dev, "low:%d high:%d\n", sensor->low_temp_enabled,
> +		sensor->high_temp_enabled);
>  
> -	/* Enable IT generation for low threshold */
> +	/* Disable IT generation for low and high thresholds */
>  	value = readl_relaxed(sensor->base + DTS_ITENR_OFFSET);
> -	value |= LOW_THRESHOLD;
> -
> -	/* Enable the low temperature threshold if needed */
> -	if (sensor->low_temp_enabled) {
> -		/* Make sure HIGH_THRESHOLD IT is clear before enabling */
> -		writel_relaxed(HIGH_THRESHOLD, sensor->base + DTS_ICIFR_OFFSET);
> +	value &= ~(LOW_THRESHOLD | HIGH_THRESHOLD);
>  
> -		/* Enable IT generation for high threshold */
> +	if (sensor->low_temp_enabled)
>  		value |= HIGH_THRESHOLD;
> -	}
>  
> -	/* Enable thresholds */
> -	writel_relaxed(value, sensor->base + DTS_ITENR_OFFSET);
> +	if (sensor->high_temp_enabled)
> +		value |= LOW_THRESHOLD;
>  
> -	dev_dbg(sensor->dev, "%s: IT enabled on sensor side", __func__);
> +	/* Enable interrupts */
> +	writel_relaxed(value, sensor->base + DTS_ITENR_OFFSET);
>  
>  	return 0;
>  }
>  
> -static int stm_thermal_update_threshold(struct stm_thermal_sensor *sensor)
> +static int stm_thermal_set_trips(void *data, int low, int high)
>  {
> +	struct stm_thermal_sensor *sensor = data;
> +	u32 itr1, th;
>  	int ret;
>  
> -	sensor->mode = THERMAL_DEVICE_DISABLED;
> +	dev_dbg(sensor->dev, "set trips %d <--> %d\n", low, high);
>  
> -	ret = stm_sensor_power_off(sensor);
> -	if (ret)
> -		return ret;
> +	/* Erase threshold content */
> +	itr1 = readl_relaxed(sensor->base + DTS_ITR1_OFFSET);
> +	itr1 &= ~(TS1_LITTHD_MASK | TS1_HITTHD_MASK);
>  
> -	ret = stm_disable_irq(sensor);
> -	if (ret)
> -		return ret;
> +	/*
> +	 * Disable low-temp if "low" is too small. As per thermal framework
> +	 * API, we use -INT_MAX rather than INT_MIN.
> +	 */
>  
> -	ret = stm_thermal_set_threshold(sensor);
> -	if (ret)
> -		return ret;
> +	if (low > -INT_MAX) {
> +		sensor->low_temp_enabled = 1;
> +		ret = stm_thermal_calculate_threshold(sensor, low, &th);
> +		if (ret)
> +			return ret;
>  
> -	ret = stm_enable_irq(sensor);
> -	if (ret)
> -		return ret;
> +		itr1 |= (TS1_HITTHD_MASK  & (th << TS1_HITTHD_POS));
> +	} else {
> +		sensor->low_temp_enabled = 0;
> +	}
>  
> -	ret = stm_sensor_power_on(sensor);
> -	if (ret)
> -		return ret;
> +	/* Disable high-temp if "high" is too big. */
> +	if (high < INT_MAX) {
> +		sensor->high_temp_enabled = 1;
> +		ret = stm_thermal_calculate_threshold(sensor, high, &th);
> +		if (ret)
> +			return ret;
>  
> -	sensor->mode = THERMAL_DEVICE_ENABLED;
> +		itr1 |= (TS1_LITTHD_MASK  & (th << TS1_LITTHD_POS));
> +	} else {
> +		sensor->high_temp_enabled = 0;
> +	}
> +
> +	/* Write new threshod values*/
> +	writel_relaxed(itr1, sensor->base + DTS_ITR1_OFFSET);
>  
>  	return 0;
>  }
> @@ -429,32 +406,6 @@ static int stm_thermal_get_temp(void *data, int *temp)
>  	*temp = mcelsius(sensor->t0 + ((freqM - sensor->fmt0) /
>  			 sensor->ramp_coeff));
>  
> -	dev_dbg(sensor->dev, "%s: temperature = %d millicelsius",
> -		__func__, *temp);
> -
> -	/* Update thresholds */
> -	if (sensor->num_trips > 1) {
> -		/* Update alarm threshold value to next higher trip point */
> -		if (sensor->high_temp == sensor->temp_passive &&
> -		    celsius(*temp) >= sensor->temp_passive) {
> -			sensor->high_temp = sensor->temp_critical;
> -			sensor->low_temp = sensor->temp_passive;
> -			sensor->low_temp_enabled = true;
> -			ret = stm_thermal_update_threshold(sensor);
> -			if (ret)
> -				return ret;
> -		}
> -
> -		if (sensor->high_temp == sensor->temp_critical &&
> -		    celsius(*temp) < sensor->temp_passive) {
> -			sensor->high_temp = sensor->temp_passive;
> -			sensor->low_temp_enabled = false;
> -			ret = stm_thermal_update_threshold(sensor);
> -			if (ret)
> -				return ret;
> -		}
> -	}
> -
>  	return 0;
>  }
>  
> @@ -491,6 +442,8 @@ static int stm_thermal_sensor_off(struct stm_thermal_sensor *sensor)
>  {
>  	int ret;
>  
> +	stm_disable_irq(sensor);
> +
>  	ret = stm_sensor_power_off(sensor);
>  	if (ret)
>  		return ret;
> @@ -503,7 +456,6 @@ static int stm_thermal_sensor_off(struct stm_thermal_sensor *sensor)
>  static int stm_thermal_prepare(struct stm_thermal_sensor *sensor)
>  {
>  	int ret;
> -	struct device *dev = sensor->dev;
>  
>  	ret = clk_prepare_enable(sensor->clk);
>  	if (ret)
> @@ -517,26 +469,8 @@ static int stm_thermal_prepare(struct stm_thermal_sensor *sensor)
>  	if (ret)
>  		goto thermal_unprepare;
>  
> -	/* Set threshold(s) for IRQ */
> -	ret = stm_thermal_set_threshold(sensor);
> -	if (ret)
> -		goto thermal_unprepare;
> -
> -	ret = stm_enable_irq(sensor);
> -	if (ret)
> -		goto thermal_unprepare;
> -
> -	ret = stm_sensor_power_on(sensor);
> -	if (ret) {
> -		dev_err(dev, "%s: failed to power on sensor\n", __func__);
> -		goto irq_disable;
> -	}
> -
>  	return 0;
>  
> -irq_disable:
> -	stm_disable_irq(sensor);
> -
>  thermal_unprepare:
>  	clk_disable_unprepare(sensor->clk);
>  
> @@ -553,8 +487,6 @@ static int stm_thermal_suspend(struct device *dev)
>  	if (ret)
>  		return ret;
>  
> -	sensor->mode = THERMAL_DEVICE_DISABLED;
> -
>  	return 0;
>  }
>  
> @@ -567,7 +499,12 @@ static int stm_thermal_resume(struct device *dev)
>  	if (ret)
>  		return ret;
>  
> -	sensor->mode = THERMAL_DEVICE_ENABLED;
> +	ret = stm_sensor_power_on(sensor);
> +	if (ret)
> +		return ret;
> +
> +	thermal_zone_device_update(sensor->th_dev, THERMAL_EVENT_UNSPECIFIED);
> +	stm_enable_irq(sensor);
>  
>  	return 0;
>  }
> @@ -577,6 +514,7 @@ SIMPLE_DEV_PM_OPS(stm_thermal_pm_ops, stm_thermal_suspend, stm_thermal_resume);
>  
>  static const struct thermal_zone_of_device_ops stm_tz_ops = {
>  	.get_temp	= stm_thermal_get_temp,
> +	.set_trips	= stm_thermal_set_trips,
>  };
>  
>  static const struct of_device_id stm_thermal_of_match[] = {
> @@ -589,9 +527,8 @@ static int stm_thermal_probe(struct platform_device *pdev)
>  {
>  	struct stm_thermal_sensor *sensor;
>  	struct resource *res;
> -	const struct thermal_trip *trip;
>  	void __iomem *base;
> -	int ret, i;
> +	int ret;
>  
>  	if (!pdev->dev.of_node) {
>  		dev_err(&pdev->dev, "%s: device tree node not found\n",
> @@ -622,10 +559,23 @@ static int stm_thermal_probe(struct platform_device *pdev)
>  		return PTR_ERR(sensor->clk);
>  	}
>  
> -	/* Register IRQ into GIC */
> -	ret = stm_register_irq(sensor);
> -	if (ret)
> +	stm_disable_irq(sensor);
> +
> +	/* Clear irq flags */
> +	writel_relaxed(ICIFR_MASK, sensor->base + DTS_ICIFR_OFFSET);
> +
> +	/* Configure and enable HW sensor */
> +	ret = stm_thermal_prepare(sensor);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Error preprare sensor: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = stm_sensor_power_on(sensor);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Error power on sensor: %d\n", ret);
>  		return ret;
> +	}
>  
>  	sensor->th_dev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0,
>  							      sensor,
> @@ -638,53 +588,12 @@ static int stm_thermal_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	if (!sensor->th_dev->ops->get_crit_temp) {
> -		/* Critical point must be provided */
> -		ret = -EINVAL;
> -		goto err_tz;
> -	}
> -
> -	ret = sensor->th_dev->ops->get_crit_temp(sensor->th_dev,
> -			&sensor->temp_critical);
> -	if (ret) {
> -		dev_err(&pdev->dev,
> -			"Not able to read critical_temp: %d\n", ret);
> +	/* Register IRQ into GIC */
> +	ret = stm_register_irq(sensor);
> +	if (ret)
>  		goto err_tz;
> -	}
> -
> -	sensor->temp_critical = celsius(sensor->temp_critical);
> -
> -	/* Set thresholds for IRQ */
> -	sensor->high_temp = sensor->temp_critical;
> -
> -	trip = of_thermal_get_trip_points(sensor->th_dev);
> -	sensor->num_trips = of_thermal_get_ntrips(sensor->th_dev);
> -
> -	/* Find out passive temperature if it exists */
> -	for (i = (sensor->num_trips - 1); i >= 0;  i--) {
> -		if (trip[i].type == THERMAL_TRIP_PASSIVE) {
> -			sensor->temp_passive = celsius(trip[i].temperature);
> -			/* Update high temperature threshold */
> -			sensor->high_temp = sensor->temp_passive;
> -			}
> -	}
> -
> -	/*
> -	 * Ensure low_temp_enabled flag is disabled.
> -	 * By disabling low_temp_enabled, low threshold IT will not be
> -	 * configured neither enabled because it is not needed as high
> -	 * threshold is set on the lowest temperature trip point after
> -	 * probe.
> -	 */
> -	sensor->low_temp_enabled = false;
>  
> -	/* Configure and enable HW sensor */
> -	ret = stm_thermal_prepare(sensor);
> -	if (ret) {
> -		dev_err(&pdev->dev,
> -			"Not able to enable sensor: %d\n", ret);
> -		goto err_tz;
> -	}
> +	stm_enable_irq(sensor);
>  
>  	/*
>  	 * Thermal_zone doesn't enable hwmon as default,
> @@ -695,8 +604,6 @@ static int stm_thermal_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto err_tz;
>  
> -	sensor->mode = THERMAL_DEVICE_ENABLED;
> -
>  	dev_info(&pdev->dev, "%s: Driver initialized successfully\n",
>  		 __func__);
>  
> 


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