Date:   Mon, 28 Nov 2016 17:24:10 -0800
From:   Eduardo Valentin <edubezval@...il.com>
To:     Steve Twiss <stwiss.opensource@...semi.com>
Cc:     LINUX-KERNEL <linux-kernel@...r.kernel.org>,
        LINUX-PM <linux-pm@...r.kernel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        DEVICETREE <devicetree@...r.kernel.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Guenter Roeck <linux@...ck-us.net>,
        LINUX-INPUT <linux-input@...r.kernel.org>,
        LINUX-WATCHDOG <linux-watchdog@...r.kernel.org>,
        Lee Jones <lee.jones@...aro.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Support Opensource <support.opensource@...semi.com>,
        Wim Van Sebroeck <wim@...ana.be>
Subject: Re: [PATCH V2 09/10] thermal: da9062/61: Thermal junction
 temperature monitoring driver

Hello Steve,

On Wed, Oct 26, 2016 at 05:56:39PM +0100, Steve Twiss wrote:
> From: Steve Twiss <stwiss.opensource@...semi.com>
> 
> Add junction temperature monitoring supervisor device driver, compatible
> with the DA9062 and DA9061 PMICs.
> 
> If the PMIC's internal junction temperature rises above TEMP_WARN (125
> degC) an interrupt is issued. This TEMP_WARN level is defined as the
> THERMAL_TRIP_HOT trip-wire inside the device driver.
> 
> The thermal triggering mechanism is interrupt based and happens when the
> temperature rises above a given threshold level. The component cannot
> return an exact temperature, it only has knowledge if the temperature is
> above or below a given threshold value. A status bit must be polled to
> detect when the temperature falls below that threshold level again. A
> kernel work queue is configured to repeatedly poll and detect when the
> temperature falls below this trip-wire, between 1 and 10 second intervals
> (defaulting at 3 seconds).
> 
> This first level of temperature supervision is intended for non-invasive
> temperature control, where the necessary measures for cooling the system
> down are left to the host software.
> 
> Signed-off-by: Steve Twiss <stwiss.opensource@...semi.com>
> 
> ---
> This patch applies against linux-next and v4.8
> 
> v1 -> v2
>  - Patch renamed from [PATCH V1 05/10] to [PATCH V2 09/10] -- these
>    changes were made to fix checkpatch warnings caused by the patch
>    set dependency order
>  - List the header files in alphabetical order
>  - Remove "GPL v2" and replace with MODULE_LICENSE("GPL") to match the
>    copyright "GNU Public License v2 or later" option in the header
>    comment for this file. See the allowed identifiers in the file
>    include/linux/module.h +170
>  - Remove notify function "da9062_thermal_notify" function.
>  - MODULE_AUTHOR() macros removes Company Name and just gives Name in
>    accordance with include/linux/module.h +200
>  - Remove the compatible "dlg,da9061-thermal" option in the of_device_id
>    struct table. This patch now assumes the use of a DA9062 fallback
>    compatible string in the DTS when using the DA9061 thermal component
>    of the DA9061 device.
>  - Re-ordered some assignments earlier in the probe() for thermal->hw,
>    thermal->polling_period, thermal->mode, thermal->dev
>  - Added further information in the patch description to explain the use
>    of the device driver's built-in work-queue.
> 
> Regards,
> Steve Twiss, Dialog Semiconductor Ltd.
> 
> 
>  drivers/thermal/Kconfig          |  10 ++
>  drivers/thermal/Makefile         |   1 +
>  drivers/thermal/da9062-thermal.c | 289 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 300 insertions(+)
>  create mode 100644 drivers/thermal/da9062-thermal.c
> 
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 2d702ca..da58e54 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -272,6 +272,16 @@ config DB8500_CPUFREQ_COOLING
>  	  bound cpufreq cooling device turns active to set CPU frequency low to
>  	  cool down the CPU.
>  
> +config DA9062_THERMAL
> +	tristate "DA9062/DA9061 Dialog Semiconductor thermal driver"
> +	depends on MFD_DA9062
> +	depends on OF
> +	help
> +	  Enable this for the Dialog Semiconductor thermal sensor driver.
> +	  This will report PMIC junction over-temperature for one thermal trip
> +	  zone.
> +	  Compatible with the DA9062 and DA9061 PMICs.

Is there any hardware documentation available for this chip that can be
pointed out?

> +
>  config INTEL_POWERCLAMP
>  	tristate "Intel PowerClamp idle injection driver"
>  	depends on THERMAL
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 10b07c1..0a2b3f2 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -38,6 +38,7 @@ obj-$(CONFIG_ARMADA_THERMAL)	+= armada_thermal.o
>  obj-$(CONFIG_TANGO_THERMAL)	+= tango_thermal.o
>  obj-$(CONFIG_IMX_THERMAL)	+= imx_thermal.o
>  obj-$(CONFIG_DB8500_CPUFREQ_COOLING)	+= db8500_cpufreq_cooling.o
> +obj-$(CONFIG_DA9062_THERMAL)	+= da9062-thermal.o
>  obj-$(CONFIG_INTEL_POWERCLAMP)	+= intel_powerclamp.o
>  obj-$(CONFIG_X86_PKG_TEMP_THERMAL)	+= x86_pkg_temp_thermal.o
>  obj-$(CONFIG_INTEL_SOC_DTS_IOSF_CORE)	+= intel_soc_dts_iosf.o
> diff --git a/drivers/thermal/da9062-thermal.c b/drivers/thermal/da9062-thermal.c
> new file mode 100644
> index 0000000..e0d2b1b
> --- /dev/null
> +++ b/drivers/thermal/da9062-thermal.c
> @@ -0,0 +1,289 @@
> +/*
> + * Thermal device driver for DA9062 and DA9061
> + * Copyright (C) 2016  Dialog Semiconductor Ltd.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/errno.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/thermal.h>
> +#include <linux/workqueue.h>
> +
> +#include <linux/mfd/da9062/core.h>
> +#include <linux/mfd/da9062/registers.h>
> +
> +#define DA9062_DEFAULT_POLLING_MS_PERIOD	3000
> +#define DA9062_MAX_POLLING_MS_PERIOD		10000
> +#define DA9062_MIN_POLLING_MS_PERIOD		1000
> +
> +#define DA9062_MILLI_CELSIUS(t)			((t)*1000)
> +
> +struct da9062_thermal_config {
> +	const char *name;
> +};
> +
> +struct da9062_thermal {
> +	struct da9062 *hw;
> +	struct delayed_work work;
> +	struct thermal_zone_device *zone;
> +	enum thermal_device_mode mode;
> +	unsigned int polling_period;
> +	struct mutex lock;
> +	int temperature;
> +	int irq;
> +	const struct da9062_thermal_config *config;
> +	struct device *dev;
> +};
> +
> +static void da9062_thermal_poll_on(struct work_struct *work)
> +{
> +	struct da9062_thermal *thermal = container_of(work,
> +						struct da9062_thermal,
> +						work.work);
> +	unsigned int val;
> +	int ret;
> +
> +	/* clear E_TEMP */
> +	ret = regmap_write(thermal->hw->regmap,
> +				DA9062AA_EVENT_B,
> +				DA9062AA_E_TEMP_MASK);
> +	if (ret < 0) {
> +		dev_err(thermal->dev,
> +			"Cannot clear the TJUNC temperature status\n");
> +		goto err_enable_irq;
> +	}
> +
> +	/* Now read E_TEMP again: it is acting like a status bit.
> +	 * If over-temperature, then this status will be true.
> +	 * If not over-temperature, this status will be false.
> +	 */
> +	ret = regmap_read(thermal->hw->regmap,
> +			  DA9062AA_EVENT_B,
> +			  &val);
> +	if (ret < 0) {
> +		dev_err(thermal->dev,
> +			"Cannot check the TJUNC temperature status\n");
> +		goto err_enable_irq;
> +	} else {
> +		if (val & DA9062AA_E_TEMP_MASK) {
> +			mutex_lock(&thermal->lock);
> +			thermal->temperature = DA9062_MILLI_CELSIUS(125);

Does this mean that the chip temperature is above or equal to 125C, is
this really a safe temperature to keep it running?

> +			mutex_unlock(&thermal->lock);
> +			thermal_zone_device_update(thermal->zone);
> +
> +			schedule_delayed_work(&thermal->work,
> +				msecs_to_jiffies(thermal->polling_period));
> +			return;
> +		} else {
> +			mutex_lock(&thermal->lock);
> +			thermal->temperature = DA9062_MILLI_CELSIUS(0);
> +			mutex_unlock(&thermal->lock);
> +			thermal_zone_device_update(thermal->zone);
> +		}
> +	}
> +
> +err_enable_irq:
> +	enable_irq(thermal->irq);
> +}
> +
> +static irqreturn_t da9062_thermal_irq_handler(int irq, void *data)
> +{
> +	struct da9062_thermal *thermal = data;
> +
> +	disable_irq_nosync(thermal->irq);
> +	schedule_delayed_work(&thermal->work, 0);

Can you please elaborate a little on why you have an one shot threaded IRQ
handler that is only disabling the IRQ then, scheduling a work with delay of 0?

To my understanding, this is exactly what you get when you run your
threaded IRQ handler, when you configure it as one shot.

Have you tried simply handling the same work done in your workqueue
handler in your threaded IRQ? That should simplify your code and get the
same result you are expecting.

If you are not getting the IRQ disabled on the threaded IRQ when
configured as one shot, something else seams to be broken.

> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int da9062_thermal_get_mode(struct thermal_zone_device *z,
> +				   enum thermal_device_mode *mode)
> +{
> +	struct da9062_thermal *thermal = z->devdata;
> +	*mode = thermal->mode;
> +	return 0;
> +}
> +
> +static int da9062_thermal_get_trip_type(struct thermal_zone_device *z,
> +				int trip,
> +				enum thermal_trip_type *type)
> +{
> +	struct da9062_thermal *thermal = z->devdata;
> +
> +	switch (trip) {
> +	case 0:
> +		*type = THERMAL_TRIP_HOT;
> +		break;
> +	default:
> +		dev_err(thermal->dev,
> +			"Driver does not support more than 1 trip-wire\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int da9062_thermal_get_trip_temp(struct thermal_zone_device *z,
> +					int trip,
> +					int *temp)
> +{
> +	struct da9062_thermal *thermal = z->devdata;
> +
> +	switch (trip) {
> +	case 0:
> +		*temp = DA9062_MILLI_CELSIUS(125);
> +		break;
> +	default:
> +		dev_err(thermal->dev,
> +			"Driver does not support more than 1 trip-wire\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int da9062_thermal_get_temp(struct thermal_zone_device *z,
> +				   int *temp)
> +{
> +	struct da9062_thermal *thermal = z->devdata;
> +
> +	mutex_lock(&thermal->lock);
> +	*temp = thermal->temperature;
> +	mutex_unlock(&thermal->lock);
> +
> +	return 0;
> +}
> +
> +static struct thermal_zone_device_ops da9062_thermal_ops = {
> +	.get_temp	= da9062_thermal_get_temp,
> +	.get_mode	= da9062_thermal_get_mode,
> +	.get_trip_type	= da9062_thermal_get_trip_type,
> +	.get_trip_temp	= da9062_thermal_get_trip_temp,
> +};
> +
> +static const struct da9062_thermal_config da9062_config = {
> +	.name = "da9062-thermal",
> +};
> +
> +static const struct of_device_id da9062_compatible_reg_id_table[] = {
> +	{ .compatible = "dlg,da9062-thermal", .data = &da9062_config },
> +	{ },
> +};
> +
> +static int da9062_thermal_probe(struct platform_device *pdev)
> +{
> +	struct da9062 *chip = dev_get_drvdata(pdev->dev.parent);
> +	struct da9062_thermal *thermal;
> +	unsigned int pp_tmp = DA9062_DEFAULT_POLLING_MS_PERIOD;
> +	const struct of_device_id *match;
> +	int ret = 0;
> +
> +	match = of_match_node(da9062_compatible_reg_id_table,
> +			      pdev->dev.of_node);
> +	if (!match)
> +		return -ENXIO;
> +
> +	if (pdev->dev.of_node) {
> +		if (!of_property_read_u32(pdev->dev.of_node,
> +					"dlg,tjunc-temp-polling-period-ms",
> +					&pp_tmp)) {
> +			if (pp_tmp < DA9062_MIN_POLLING_MS_PERIOD ||
> +				pp_tmp > DA9062_MAX_POLLING_MS_PERIOD)
> +				pp_tmp = DA9062_DEFAULT_POLLING_MS_PERIOD;
> +		}
> +
> +		dev_dbg(&pdev->dev,
> +			 "TJUNC temp polling period set at %d ms\n",
> +			 pp_tmp);
> +	}
> +
> +	thermal = devm_kzalloc(&pdev->dev, sizeof(struct da9062_thermal),
> +			     GFP_KERNEL);
> +	if (!thermal) {
> +		ret = -ENOMEM;
> +		goto err;
> +	}
> +
> +	thermal->config = match->data;
> +	thermal->hw = chip;
> +	thermal->polling_period = pp_tmp;
> +	thermal->mode = THERMAL_DEVICE_ENABLED;
> +	thermal->dev = &pdev->dev;
> +
> +	INIT_DELAYED_WORK(&thermal->work, da9062_thermal_poll_on);
> +	mutex_init(&thermal->lock);
> +
> +	thermal->zone = thermal_zone_device_register(thermal->config->name,
> +					1, 0, thermal,
> +					&da9062_thermal_ops, NULL, 0,
> +					0);

Did you try using of-thermal?

So you would avoid having specific DT properties for something that
there is already a defined property?

> +	if (IS_ERR(thermal->zone)) {
> +		dev_err(&pdev->dev, "Cannot register thermal zone device\n");
> +		ret = PTR_ERR(thermal->zone);
> +		goto err;
> +	}
> +
> +	ret = platform_get_irq_byname(pdev, "THERMAL");
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "Failed to get platform IRQ.\n");
> +		goto err_zone;
> +	}
> +	thermal->irq = ret;
> +
> +	ret = request_threaded_irq(thermal->irq, NULL,
> +				   da9062_thermal_irq_handler,
> +				   IRQF_TRIGGER_LOW | IRQF_ONESHOT,
> +				   "THERMAL", thermal);

How about using the devm_ version?

> +	if (ret) {
> +		dev_err(&pdev->dev,
> +			"Failed to request thermal device IRQ.\n");
> +		goto err_zone;
> +	}
> +
> +	platform_set_drvdata(pdev, thermal);
> +	return 0;
> +
> +err_zone:
> +	thermal_zone_device_unregister(thermal->zone);
> +err:
> +	return ret;
> +}
> +
> +static int da9062_thermal_remove(struct platform_device *pdev)
> +{
> +	struct	da9062_thermal *thermal = platform_get_drvdata(pdev);
> +
> +	free_irq(thermal->irq, thermal);
> +	thermal_zone_device_unregister(thermal->zone);
> +	cancel_delayed_work_sync(&thermal->work);
> +	return 0;
> +}
> +
> +static struct platform_driver da9062_thermal_driver = {
> +	.probe	= da9062_thermal_probe,
> +	.remove	= da9062_thermal_remove,
> +	.driver	= {
> +		.name	= "da9062-thermal",
> +		.of_match_table = da9062_compatible_reg_id_table,
> +	},
> +};
> +
> +module_platform_driver(da9062_thermal_driver);
> +
> +MODULE_AUTHOR("Steve Twiss");
> +MODULE_DESCRIPTION("Thermal TJUNC device driver for Dialog DA9062 and DA9061");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:da9062-thermal");
> -- 
> end-of-patch for PATCH V2
> 

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