Steve,

On Thursday 06 October 2016 02:13 PM, Steve Twiss wrote:
From: Steve Twiss <stwiss.opensou...@diasemi.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. A kernel work queue
is configured to repeatedly poll this temperature 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. In this case, inside the thermal
notification function da9062_thermal_notify().

Signed-off-by: Steve Twiss <stwiss.opensou...@diasemi.com>

---
This patch applies against linux-next and v4.8

Regards,
Steve Twiss, Dialog Semiconductor Ltd.


 drivers/thermal/Kconfig          |  10 ++
 drivers/thermal/Makefile         |   1 +
 drivers/thermal/da9062-thermal.c | 313 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 324 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.
+
 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..feeabf6
--- /dev/null
+++ b/drivers/thermal/da9062-thermal.c
@@ -0,0 +1,313 @@
+/*
+ * 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/module.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/workqueue.h>
+#include <linux/regmap.h>
+#include <linux/thermal.h>
+#include <linux/of.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 staus 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);
+                       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);
+
+       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;

125C is pretty hot. Just a suggestion, do look at THERMAL_TRIP_CRITICAL.

+               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_notify(struct thermal_zone_device *z,
+                                int trip,
+                                enum thermal_trip_type type)
+{
+       struct da9062_thermal *thermal = z->devdata;
+
+       switch (type) {
+       case THERMAL_TRIP_HOT:
+               dev_warn(thermal->dev, "Reached HOT (125degC) temperature\n");

Any cooling action? What is done once you reach this high temperature?

+               break;
+       default:
+               break;
+       }
+
+       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,
+       .notify         = da9062_thermal_notify,
+};
+
+static const struct da9062_thermal_config da9062_config = {
+       .name = "da9062-thermal",
+};
+
+static const struct da9062_thermal_config da9061_config = {
+       .name = "da9061-thermal",
+};
+
+static const struct of_device_id da9062_compatible_reg_id_table[] = {
+       { .compatible = "dlg,da9062-thermal", .data = &da9062_config },
+       { .compatible = "dlg,da9061-thermal", .data = &da9061_config },

Two separate compatible values. Do you have anything different apart from the name? Why use 2 compatibles when there is absolutely no difference?

+       { },
+};
+
+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;
+
+       INIT_DELAYED_WORK(&thermal->work, da9062_thermal_poll_on);
+       mutex_init(&thermal->lock);

thermal_zone_device_register itself does
INIT_DELAYED_WORK(&(tz->poll_queue), thermal_zone_device_check);

refer: drivers/thermal/thermal_core.c

It does a periodic monitoring of the temperature as well. Do you really want to have an additional work for monitoring temperature in your driver also?

+
+       thermal->zone = thermal_zone_device_register(thermal->config->name,
+                                       1, 0, thermal,
+                                       &da9062_thermal_ops, NULL, 0,
+                                       0);
+       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);
+       if (ret) {
+               dev_err(&pdev->dev,
+                       "Failed to request thermal device IRQ.\n");
+               goto err_zone;
+       }
+
+       thermal->hw = chip;
+       thermal->polling_period = pp_tmp;
+       thermal->mode = THERMAL_DEVICE_ENABLED;
+       thermal->dev = &pdev->dev;
+
+       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, Dialog Semiconductor");
+MODULE_DESCRIPTION("Thermal TJUNC device driver for Dialog DA9062 and DA9061");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:da9062-thermal");

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