Re: [RESEND PATCH V5 7/8] thermal: da9062/61: Thermal junction temperature monitoring driver

---
This patch applies against linux-next and v4.9

v4 -> v5
 - Rebased from v4.8 to v4.9
 - Updates from comments by Eduardo Valentin
 - Replace vendor defined dlg,tjunc-temp-polling-period-ms with standard
   thermal core polling-delay-passive as part of the device tree
   initialisation
 - Change to the commit message content and device driver source code to
   include an explanation of the repeated uevent strategy for monitoring
   over-temperature
 - Rename warning threshold name from TEMP_WARN to T_WARN to match the
   latest datasheet naming convention
 - Added reviewed-by Lukasz Luba to commit message

v3 -> v4
 - Patch renamed from [PATCH V3 8/9] to [PATCH V4 7/8]
 - Reordering of cancel_delayed_work_sync() in remove function
 - dev_warn() message for out-of-range polling period requests
 - Explanatory comment for expected values defined for
   DEFAULT_POLLING_MS_PERIOD, MAX_POLLING_MS_PERIOD and
   MIN_POLLING_MS_PERIOD

v2 -> v3
 - Patch renamed from [PATCH V2 09/10] to [PATCH V3 8/9]
 - Addition of MODULE_DEVICE_TABLE macro to allow modinfo additions

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 | 314 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 325 insertions(+)
 create mode 100644 drivers/thermal/da9062-thermal.c

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index a13541b..400d15c 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig

@@ -292,6 +292,16 @@ 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 c92eb22..f7783b3 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile

@@ -40,6 +40,7 @@ obj-$(CONFIG_IMX_THERMAL)	+= imx_thermal.o
 obj-$(CONFIG_MAX77620_THERMAL)	+= max77620_thermal.o
 obj-$(CONFIG_QORIQ_THERMAL)	+= qoriq_thermal.o
 obj-$(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..52a095d
--- /dev/null
+++ b/drivers/thermal/da9062-thermal.c

@@ -0,0 +1,314 @@
+/*
+ * 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.
+ */
+
+/* When over-temperature is reached, an interrupt from the device will be
+ * triggered. Following this event the interrupt will be disabled and
+ * periodic transmission of uevents (HOT trip point) should define the
+ * first level of temperature supervision. It is expected that any final
+ * implementation of the thermal driver will include a .notify() function
+ * to implement these uevents to userspace.
+ *
+ * These uevents are intended to indicate non-invasive temperature control
+ * of the system, where the necessary measures for cooling are the
+ * responsibility of the host software. Once the temperature falls again,
+ * the IRQ is re-enabled so the start of a new over-temperature event can
+ * be detected without constant software monitoring.
+ */
+
+#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>
+

+/* Minimum, maximum and default polling millisecond periods are provided
+ * here as an example. It is expected that any final implementation to also
+ * include a modification of these settings to match the required
+ * application.
+ */
+#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;
+	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);
+			mutex_unlock(&thermal->lock);
+			thermal_zone_device_update(thermal->zone,
+						   THERMAL_EVENT_UNSPECIFIED);
+
+			schedule_delayed_work(&thermal->work,
+				msecs_to_jiffies(thermal->zone->passive_delay));
+			return;
+		} else {
+			mutex_lock(&thermal->lock);
+			thermal->temperature = DA9062_MILLI_CELSIUS(0);
+			mutex_unlock(&thermal->lock);
+			thermal_zone_device_update(thermal->zone,
+						   THERMAL_EVENT_UNSPECIFIED);
+		}
+	}