thermal: max77620: Add thermal driver for reporting junction temp

Maxim Semiconductor Max77620 supports alarm interrupts when
its die temperature crosses 120C and 140C. These threshold
temperatures are not configurable.

Add thermal driver to register PMIC die temperature as thermal
zone sensor and capture the die temperature warning interrupts
to notifying the client.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

3 files changed, 176 insertions, 0 deletions

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 900d505ee5d5..38a304e922c4 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -195,6 +195,16 @@ config IMX_THERMAL
           cpufreq is used as the cooling device to throttle CPUs when the
           passive trip is crossed.
 
+config MAX77620_THERMAL
+        tristate "Temperature sensor driver for Maxim MAX77620 PMIC"
+        depends on MFD_MAX77620
+        depends on OF
+        help
+          Support for die junction temperature warning alarm for Maxim
+          Semiconductor PMIC MAX77620 device. Device generates two alarm
+          interrupts when PMIC die temperature cross the threshold of
+          120 degC and 140 degC.
+
 config QORIQ_THERMAL
         tristate "QorIQ Thermal Monitoring Unit"
         depends on THERMAL_OF
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index fdb4b3871254..7c1aca6d8b14 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_DB8500_THERMAL)	+= db8500_thermal.o
 obj-$(CONFIG_ARMADA_THERMAL)    += armada_thermal.o
 obj-$(CONFIG_TANGO_THERMAL)     += tango_thermal.o
 obj-$(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_INTEL_POWERCLAMP)  += intel_powerclamp.o
diff --git a/drivers/thermal/max77620_thermal.c b/drivers/thermal/max77620_thermal.c
new file mode 100644
index 000000000000..8d6162676f68
--- /dev/null
+++ b/drivers/thermal/max77620_thermal.c
@@ -0,0 +1,165 @@
+/*
+ * Junction temperature thermal driver for Maxim Max77620.
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Author: Laxman Dewangan <ldewangan@nvidia.com>
+ *         Mallikarjun Kasoju <mkasoju@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/max77620.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+
+#define MAX77620_NORMAL_OPERATING_TEMP  100000
+#define MAX77620_TJALARM1_TEMP          120000
+#define MAX77620_TJALARM2_TEMP          140000
+
+struct max77620_therm_info {
+        struct device                   *dev;
+        struct regmap                   *rmap;
+        struct thermal_zone_device      *tz_device;
+        int                             irq_tjalarm1;
+        int                             irq_tjalarm2;
+};
+
+/**
+ * max77620_thermal_read_temp: Read PMIC die temperatue.
+ * @data:       Device specific data.
+ * temp:        Temperature in millidegrees Celsius
+ *
+ * The actual temperature of PMIC die is not available from PMIC.
+ * PMIC only tells the status if it has crossed or not the threshold level
+ * of 120degC or 140degC.
+ * If threshold has not been crossed then assume die temperature as 100degC
+ * else 120degC or 140deG based on the PMIC die temp threshold status.
+ *
+ * Return 0 on success otherwise error number to show reason of failure.
+ */
+
+static int max77620_thermal_read_temp(void *data, int *temp)
+{
+        struct max77620_therm_info *mtherm = data;
+        unsigned int val;
+        int ret;
+
+        ret = regmap_read(mtherm->rmap, MAX77620_REG_STATLBT, &val);
+        if (ret < 0) {
+                dev_err(mtherm->dev, "Failed to read STATLBT: %d\n", ret);
+                return ret;
+        }
+
+        if (val & MAX77620_IRQ_TJALRM2_MASK)
+                *temp = MAX77620_TJALARM2_TEMP;
+        else if (val & MAX77620_IRQ_TJALRM1_MASK)
+                *temp = MAX77620_TJALARM1_TEMP;
+        else
+                *temp = MAX77620_NORMAL_OPERATING_TEMP;
+
+        return 0;
+}
+
+static const struct thermal_zone_of_device_ops max77620_thermal_ops = {
+        .get_temp = max77620_thermal_read_temp,
+};
+
+static irqreturn_t max77620_thermal_irq(int irq, void *data)
+{
+        struct max77620_therm_info *mtherm = data;
+
+        if (irq == mtherm->irq_tjalarm1)
+                dev_warn(mtherm->dev, "Junction Temp Alarm1(120C) occurred\n");
+        else if (irq == mtherm->irq_tjalarm2)
+                dev_crit(mtherm->dev, "Junction Temp Alarm2(140C) occurred\n");
+
+        thermal_zone_device_update(mtherm->tz_device);
+
+        return IRQ_HANDLED;
+}
+
+static int max77620_thermal_probe(struct platform_device *pdev)
+{
+        struct max77620_therm_info *mtherm;
+        int ret;
+
+        mtherm = devm_kzalloc(&pdev->dev, sizeof(*mtherm), GFP_KERNEL);
+        if (!mtherm)
+                return -ENOMEM;
+
+        mtherm->irq_tjalarm1 = platform_get_irq(pdev, 0);
+        mtherm->irq_tjalarm2 = platform_get_irq(pdev, 1);
+        if ((mtherm->irq_tjalarm1 < 0) || (mtherm->irq_tjalarm2 < 0)) {
+                dev_err(&pdev->dev, "Alarm irq number not available\n");
+                return -EINVAL;
+        }
+
+        pdev->dev.of_node = pdev->dev.parent->of_node;
+
+        mtherm->dev = &pdev->dev;
+        mtherm->rmap = dev_get_regmap(pdev->dev.parent, NULL);
+        if (!mtherm->rmap) {
+                dev_err(&pdev->dev, "Failed to get parent regmap\n");
+                return -ENODEV;
+        }
+
+        mtherm->tz_device = devm_thermal_zone_of_sensor_register(&pdev->dev, 0,
+                                mtherm, &max77620_thermal_ops);
+        if (IS_ERR(mtherm->tz_device)) {
+                ret = PTR_ERR(mtherm->tz_device);
+                dev_err(&pdev->dev, "Failed to register thermal zone: %d\n",
+                        ret);
+                return ret;
+        }
+
+        ret = devm_request_threaded_irq(&pdev->dev, mtherm->irq_tjalarm1, NULL,
+                                        max77620_thermal_irq,
+                                        IRQF_ONESHOT | IRQF_SHARED,
+                                        dev_name(&pdev->dev), mtherm);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "Failed to request irq1: %d\n", ret);
+                return ret;
+        }
+
+        ret = devm_request_threaded_irq(&pdev->dev, mtherm->irq_tjalarm2, NULL,
+                                        max77620_thermal_irq,
+                                        IRQF_ONESHOT | IRQF_SHARED,
+                                        dev_name(&pdev->dev), mtherm);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "Failed to request irq2: %d\n", ret);
+                return ret;
+        }
+
+        platform_set_drvdata(pdev, mtherm);
+
+        return 0;
+}
+
+static struct platform_device_id max77620_thermal_devtype[] = {
+        { .name = "max77620-thermal", },
+        {},
+};
+
+static struct platform_driver max77620_thermal_driver = {
+        .driver = {
+                .name = "max77620-thermal",
+        },
+        .probe = max77620_thermal_probe,
+        .id_table = max77620_thermal_devtype,
+};
+
+module_platform_driver(max77620_thermal_driver);
+
+MODULE_DESCRIPTION("Max77620 Junction temperature Thermal driver");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_AUTHOR("Mallikarjun Kasoju <mkasoju@nvidia.com>");
+MODULE_LICENSE("GPL v2");