Add support for the temperature alarm peripheral found inside
Qualcomm plug-and-play (QPNP) PMIC chips.  The temperature alarm
peripheral outputs a pulse on an interrupt line whenever the
thermal over temperature stage value changes.  Implement an ISR
to manage this interrupt.

Register a thermal zone device in sysfs with multiple trip points
corresponding to the physical threshold temperatures between over
temperature stages.  The temperature reported by this thermal
zone device should reflect the actual PMIC die temperature if an
ADC is present on the given PMIC.  If no ADC is present, then the
reported temperature should be estimated from the over
temperature stage value.

Send a notification to userspace via sysfs_notify() whenever the
over temperature stage value changes.

Cc: David Collins <redacted>
Signed-off-by: Ivan T. Ivanov <redacted>
---

Changes since v2:

- Fixed review comments from Kiran Padwal
- Files renamed from qpnp-* to qcom-spmi-* to be inline with
  other PMIC sub-function drivers like qcom-spmi-iadc and
  qcom-spmi-vadc.

v2: http://www.gossamer-threads.com/lists/linux/kernel/2017366

 .../bindings/thermal/qcom-spmi-temp-alarm.txt      |  26 ++
 drivers/thermal/Kconfig                            |  13 +
 drivers/thermal/Makefile                           |   1 +
 drivers/thermal/qcom-spmi-temp-alarm.c             | 517 
+++++++++++++++++++++
 4 files changed, 557 insertions(+)
 create mode 100644 
Documentation/devicetree/bindings/thermal/qcom-spmi-temp-alarm.txt
 create mode 100644 drivers/thermal/qcom-spmi-temp-alarm.c

diff --git 

a/Documentation/devicetree/bindings/thermal/qcom-spmi-temp-alarm.txt 
b/Documentation/devicetree/bindings/thermal/qcom-spmi-temp-alarm.txt
new file mode 100644
index 0000000..afa908c

--- /dev/null
+++ 

b/Documentation/devicetree/bindings/thermal/qcom-spmi-temp-alarm.txt

@@ -0,0 +1,26 @@
+Qualcomm QPNP PMIC Temperature Alarm
+
+QPNP temperature alarm peripherals are found inside of Qualcomm 

PMIC chips
+that utilize the Qualcomm SPMI implementation. These peripherals 
provide an
+interrupt signal and status register to identify high PMIC die 
temperature.
+
+Required properties:
+- compatible:      Should contain "qcom,spmi-temp-alarm".
+- reg:             Specifies the SPMI address and length of the 
controller's
+                   registers.
+- interrupts:      PMIC temperature alarm interrupt
+
+Optional properties:
+- io-channels:     Should contain IIO channel specifier for the ADC 
channel,
+                   which report chip die temperature.
+- io-channel-names: Should contain "thermal".
+
+Example:
+
+       thermal-alarm@2400 {
+       compatible = "qcom,spmi-temp-alarm";
+       reg = <0x2400 0x100>;
+       interrupts = <0 0x24 0 IRQ_TYPE_EDGE_RISING>;
+       io-channels = <&pm8941_vadc VADC_DIE_TEMP>;
+       io-channel-names = "thermal";
+       };

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 693208e..6adb661 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig

@@ -248,4 +248,17 @@ depends on ARCH_STI && OF
 source "drivers/thermal/st/Kconfig"
 endmenu

+config QCOM_SPMI_TEMP_ALARM
+       tristate "Qualcomm SPMI PMIC Temperature Alarm"
+       depends on OF && SPMI && IIO
+       select REGMAP_SPMI
+       help
+       This enables a thermal sysfs driver for Qualcomm 

plug-and-play (QPNP)
+       PMIC devices. It shows up in sysfs as a thermal zone with 
multiple
+       trip points. The temperature reported by the thermal zone 
reflects the
+       real time die temperature if an ADC is present or an 
estimate of the
+       temperature based upon the over temperature stage value. 
Enabling the
+       thermal zone device via the mode file results in shifting 
PMIC over
+       temperature shutdown control from hardware to software.
+
 endif

diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 31e232f..55f6c23 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile

@@ -33,3 +33,4 @@ obj-$(CONFIG_INTEL_SOC_DTS_THERMAL)   += 

intel_soc_dts_thermal.o
 obj-$(CONFIG_TI_SOC_THERMAL)   += ti-soc-thermal/
 obj-$(CONFIG_ACPI_INT3403_THERMAL)     += int3403_thermal.o
 obj-$(CONFIG_ST_THERMAL)       += st/
+obj-$(CONFIG_QCOM_SPMI_TEMP_ALARM)     += qcom-spmi-temp-alarm.o

diff --git a/drivers/thermal/qcom-spmi-temp-alarm.c 

b/drivers/thermal/qcom-spmi-temp-alarm.c
new file mode 100644
index 0000000..5ce0fef

--- /dev/null
+++ b/drivers/thermal/qcom-spmi-temp-alarm.c

@@ -0,0 +1,517 @@
+/*
+ * Copyright (c) 2011-2014, The Linux Foundation. All rights 

reserved.
+ *
+ * This program is free software; you can redistribute it and/or 
modify
+ * it under the terms of the GNU General Public License version 2 
and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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/delay.h>
+#include <linux/err.h>
+#include <linux/iio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/thermal.h>
+
+#define QPNP_TM_REG_TYPE       0x04
+#define QPNP_TM_REG_SUBTYPE    0x05
+#define QPNP_TM_REG_STATUS     0x08
+#define QPNP_TM_REG_SHUTDOWN_CTRL1     0x40
+#define QPNP_TM_REG_SHUTDOWN_CTRL2     0x42
+#define QPNP_TM_REG_ALARM_CTRL 0x46
+
+#define QPNP_TM_TYPE   0x09
+#define QPNP_TM_SUBTYPE        0x08
+
+#define STATUS_STAGE_MASK      0x03
+
+#define SHUTDOWN_CTRL1_OVERRIDE_STAGE3 0x80
+#define SHUTDOWN_CTRL1_OVERRIDE_STAGE2 0x40
+#define SHUTDOWN_CTRL1_THRESHOLD_MASK  0x03
+
+#define SHUTDOWN_CTRL2_CLEAR_STAGE3    0x80
+#define SHUTDOWN_CTRL2_CLEAR_STAGE2    0x40
+
+#define ALARM_CTRL_FORCE_ENABLE        0x80
+#define ALARM_CTRL_FOLLOW_HW_ENABLE    0x01
+
+/*
+ * Trip point values based on threshold control
+ * 0 = {105 C, 125 C, 145 C}
+ * 1 = {110 C, 130 C, 150 C}
+ * 2 = {115 C, 135 C, 155 C}
+ * 3 = {120 C, 140 C, 160 C}
+*/
+#define TEMP_STAGE_STEP        20000   /* Stage step: 20.000 C */
+#define TEMP_STAGE_HYSTERESIS  2000
+
+#define TEMP_THRESH_MIN        105000  /* Threshold Min: 105 C */
+#define TEMP_THRESH_STEP       5000    /* Threshold step: 5 C */
+
+#define THRESH_MIN     0
+#define THRESH_MAX     3
+
+/* Trip points from most critical to least critical */
+#define TRIP_STAGE3    0
+#define TRIP_STAGE2    1
+#define TRIP_STAGE1    2
+#define TRIP_NUM       3
+
+/* Delay between TEMP_STAT IRQ going high and status value changing 
in ms */
+#define READ_DELAY_MS  40
+
+/* Temperature in Milli Celsius reported during stage 0 if no ADC 
is present */
+#define DEFAULT_TEMP   37000
+
+struct qpnp_tm_chip {
+       struct delayed_workwork;
+       struct regmap*map;
+       struct device*dev;
+       struct thermal_zone_device*tz_dev;
+       enum thermal_device_modemode;
+       long    temp;
+       unsigned intthresh;
+       unsigned intstage;
+       unsigned intprev_stage;
+       unsigned intbase;
+       struct iio_channel*adc;
+};
+
+static int qpnp_tm_read(struct qpnp_tm_chip *chip, u16 addr, u8 
*data)
+{
+       unsigned int val;
+       int ret;
+
+       ret = regmap_read(chip->map, chip->base + addr, &val);
+       if (ret < 0)
+       return ret;
+
+       *data = val;
+       return 0;
+}
+
+static int qpnp_tm_write(struct qpnp_tm_chip *chip, u16 addr, u8 
data)
+{
+       return regmap_write(chip->map, chip->base + addr, data);
+}
+
+static int qpnp_tm_shutdown_override(struct qpnp_tm_chip *chip, 
bool enable)
+{
+       u8 reg;
+
+       reg = chip->thresh & SHUTDOWN_CTRL1_THRESHOLD_MASK;
+
+       if (enable) {
+       reg |= SHUTDOWN_CTRL1_OVERRIDE_STAGE2;
+       reg |= SHUTDOWN_CTRL1_OVERRIDE_STAGE3;
+       }
+
+       return qpnp_tm_write(chip, QPNP_TM_REG_SHUTDOWN_CTRL1, reg);
+}
+
+/*
+ * This function updates the internal temp value based on the
+ * current thermal stage and threshold as well as the previous stage
+ */
+static int qpnp_tm_update_temp_no_adc(struct qpnp_tm_chip *chip)
+{
+       unsigned int stage;
+       int ret;
+       u8 reg = 0;
+
+       ret = qpnp_tm_read(chip, QPNP_TM_REG_STATUS, &reg);
+       if (ret < 0)
+       return ret;
+
+       stage = reg & STATUS_STAGE_MASK;
+
+       if (stage > chip->stage) {
+       /* increasing stage, use lower bound */
+       chip->temp = (stage - 1) * TEMP_STAGE_STEP +
+       chip->thresh * TEMP_THRESH_STEP +
+       TEMP_STAGE_HYSTERESIS + TEMP_THRESH_MIN;
+       } else if (stage < chip->stage) {
+       /* decreasing stage, use upper bound */
+       chip->temp = stage * TEMP_STAGE_STEP +
+       chip->thresh * TEMP_THRESH_STEP -
+       TEMP_STAGE_HYSTERESIS + TEMP_THRESH_MIN;
+       }
+
+       chip->stage = stage;
+
+       return 0;
+}
+
+static int qpnp_tz_get_temp(struct thermal_zone_device *thermal,
+       unsigned long *temp)
+{
+       struct qpnp_tm_chip *chip = thermal->devdata;
+       int ret, mili_celsius;
+
+       if (!temp)
+       return -EINVAL;
+
+       if (IS_ERR(chip->adc)) {
+       ret = qpnp_tm_update_temp_no_adc(chip);
+       if (ret < 0)
+       return ret;
+       } else {
+       ret = iio_read_channel_processed(chip->adc, &mili_celsius);
+       if (ret < 0)
+       return ret;
+
+       chip->temp = mili_celsius;
+       }
+
+       *temp = chip->temp < 0 ? 0 : chip->temp;
+
+       return 0;
+}
+
+static int qpnp_tz_get_mode(struct thermal_zone_device *thermal,
+       enum thermal_device_mode *mode)
+{
+       struct qpnp_tm_chip *chip = thermal->devdata;
+
+       if (!mode)
+       return -EINVAL;
+
+       *mode = chip->mode;
+
+       return 0;
+}
+
+static int qpnp_tz_set_mode(struct thermal_zone_device *thermal,
+       enum thermal_device_mode mode)
+{
+       struct qpnp_tm_chip *chip = thermal->devdata;
+       int ret;
+
+       if (mode == chip->mode)
+       return 0;
+
+       if (mode == THERMAL_DEVICE_ENABLED)
+       ret = qpnp_tm_shutdown_override(chip, true);
+       else
+       ret = qpnp_tm_shutdown_override(chip, false);
+
+       chip->mode = mode;
+
+       return ret;
+}
+
+static int qpnp_tz_get_trip_type(struct thermal_zone_device 
*thermal, int trip,
+       enum thermal_trip_type *type)
+{
+       if (trip < 0 || !type)
+       return -EINVAL;
+
+       switch (trip) {
+       case TRIP_STAGE3:
+       *type = THERMAL_TRIP_CRITICAL;
+       break;
+       case TRIP_STAGE2:
+       *type = THERMAL_TRIP_HOT;
+       break;
+       case TRIP_STAGE1:
+       *type = THERMAL_TRIP_HOT;
+       break;
+       default:
+       return -EINVAL;
+       }
+
+       return 0;
+}
+
+static int qpnp_tz_get_trip_temp(struct thermal_zone_device 
*thermal, int trip,
+       unsigned long *temp)
+{
+       struct qpnp_tm_chip *chip = thermal->devdata;
+       int thresh_temp;
+
+       if (trip < 0 || !temp)
+       return -EINVAL;
+
+       thresh_temp = chip->thresh * TEMP_THRESH_STEP + 
TEMP_THRESH_MIN;
+
+       switch (trip) {
+       case TRIP_STAGE3:
+       thresh_temp += 2 * TEMP_STAGE_STEP;
+       break;
+       case TRIP_STAGE2:
+       thresh_temp += TEMP_STAGE_STEP;
+       break;
+       case TRIP_STAGE1:
+       break;
+       default:
+       return -EINVAL;
+       }
+
+       *temp = thresh_temp;
+
+       return 0;
+}
+
+static int qpnp_tz_get_crit_temp(struct thermal_zone_device 
*thermal,
+       unsigned long *temp)
+{
+       struct qpnp_tm_chip *chip = thermal->devdata;
+
+       if (!temp)
+       return -EINVAL;
+
+       *temp = chip->thresh * TEMP_THRESH_STEP + TEMP_THRESH_MIN +
+       2 * TEMP_STAGE_STEP;
+
+       return 0;
+}
+
+static irqreturn_t qpnp_tm_isr(int irq, void *data)
+{
+       struct qpnp_tm_chip *chip = data;
+
+       schedule_delayed_work(&chip->work, 
msecs_to_jiffies(READ_DELAY_MS) + 1);
+
+       return IRQ_HANDLED;
+}
+
+static void qpnp_tm_work(struct work_struct *work)
+{
+       struct delayed_work *dwork;
+       struct qpnp_tm_chip *chip;
+       int ret, mili_celsius;
+       u8 reg;
+
+       dwork = container_of(work, struct delayed_work, work);
+       chip = container_of(dwork, struct qpnp_tm_chip, work);
+
+       if (IS_ERR(chip->adc)) {
+       ret = qpnp_tm_update_temp_no_adc(chip);
+       if (ret < 0)
+       return;
+       } else {
+       ret = qpnp_tm_read(chip, QPNP_TM_REG_STATUS, &reg);
+       if (ret < 0)
+       return;
+
+       chip->stage = reg & STATUS_STAGE_MASK;
+
+       ret = iio_read_channel_processed(chip->adc, &mili_celsius);
+       if (ret < 0)
+       return;
+
+       chip->temp = mili_celsius;
+       }
+
+       if (chip->stage != chip->prev_stage) {
+       chip->prev_stage = chip->stage;
+
+       dev_warn(chip->dev, "Thermal alarm stage %u, threshold %u, 
temp %ld mC\n",
+       chip->stage, chip->thresh, chip->temp);
+
+       thermal_zone_device_update(chip->tz_dev);
+
+       /* Notify user space */
+       sysfs_notify(&chip->tz_dev->device.kobj, NULL, "type");
+       }
+}
+
+/*
+ * This function initializes the internal temp value based on only 
the
+ * current thermal stage and threshold. Setup threshold control and
+ * disable shutdown override.
+ */
+static int qpnp_tm_init(struct qpnp_tm_chip *chip)
+{
+       int ret;
+       u8 reg;
+
+       chip->thresh = THRESH_MIN;
+       chip->temp = DEFAULT_TEMP;
+
+       ret = qpnp_tm_read(chip, QPNP_TM_REG_STATUS, &reg);
+       if (ret < 0)
+       return ret;
+
+       chip->stage = reg & STATUS_STAGE_MASK;
+
+       if (chip->stage)
+       chip->temp = chip->thresh * TEMP_THRESH_STEP +
+       (chip->stage - 1) * TEMP_STAGE_STEP +
+       TEMP_THRESH_MIN;
+
+       /*
+       * Set threshold and disable software override of stage 2 and 
3
+       * shutdowns.
+       */
+       reg = chip->thresh & SHUTDOWN_CTRL1_THRESHOLD_MASK;
+       ret = qpnp_tm_write(chip, QPNP_TM_REG_SHUTDOWN_CTRL1, reg);
+       if (ret < 0)
+       return ret;
+
+       /* Enable the thermal alarm PMIC module in always-on mode. */
+       reg = ALARM_CTRL_FORCE_ENABLE;
+       ret = qpnp_tm_write(chip, QPNP_TM_REG_ALARM_CTRL, reg);
+
+       return ret;
+}
+
+static struct thermal_zone_device_ops qpnp_tz_ops = {
+       .get_temp= qpnp_tz_get_temp,
+       .get_mode= qpnp_tz_get_mode,
+       .set_mode= qpnp_tz_set_mode,
+       .get_trip_type= qpnp_tz_get_trip_type,
+       .get_trip_temp= qpnp_tz_get_trip_temp,
+       .get_crit_temp= qpnp_tz_get_crit_temp,
+};
+
+static int qpnp_tm_probe(struct platform_device *pdev)
+{
+       struct qpnp_tm_chip *chip;
+       struct device_node *node;
+       u8 type, subtype;
+       int ret, irq, res[2];
+
+       node = pdev->dev.of_node;
+
+       chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+       if (!chip)
+       return -ENOMEM;
+
+       dev_set_drvdata(&pdev->dev, chip);
+
+       chip->dev = &pdev->dev;
+       INIT_DELAYED_WORK(&chip->work, qpnp_tm_work);
+
+       chip->map = dev_get_regmap(chip->dev->parent, NULL);
+       if (!chip->map)
+       return -ENXIO;
+
+       ret = of_property_read_u32_array(node, "reg", res, 2);
+       if (ret < 0)
+       return ret;
+
+       chip->base = res[0];
+
+       ret = qpnp_tm_read(chip, QPNP_TM_REG_TYPE, &type);
+       if (ret < 0) {
+       dev_err(&pdev->dev, "could not read type\n");
+       return ret;
+       }
+
+       ret = qpnp_tm_read(chip, QPNP_TM_REG_SUBTYPE, &subtype);
+       if (ret < 0) {
+       dev_err(&pdev->dev, "could not read subtype\n");
+       return ret;
+       }
+
+       if (type != QPNP_TM_TYPE || subtype != QPNP_TM_SUBTYPE) {
+       dev_err(&pdev->dev, "invalid type 0x%02x or subtype 
0x%02x\n",
+       type, subtype);
+       return -ENODEV;
+       }
+
+       irq = platform_get_irq(pdev, 0);
+       if (irq < 0)
+       return irq;
+
+       chip->adc = iio_channel_get(chip->dev, "thermal");
+       if (PTR_ERR(chip->adc) == -EPROBE_DEFER)
+       return PTR_ERR(chip->adc);
+
+       ret = qpnp_tm_init(chip);
+       if (ret < 0) {
+       dev_err(&pdev->dev, "init failed\n");
+       return ret;
+       }
+
+       /* Start in HW control. Switch to SW control when user 
changes mode. */
+       chip->mode = THERMAL_DEVICE_DISABLED;
+
+       chip->tz_dev = thermal_zone_device_register(node->name, 
TRIP_NUM, 0,
+       chip, &qpnp_tz_ops, NULL,
+       0, 0);
+       if (IS_ERR(chip->tz_dev)) {
+       dev_err(&pdev->dev, "TZ registration failed\n");
+       return PTR_ERR(chip->tz_dev);
+       }
+
+       ret = devm_request_irq(chip->dev, irq, qpnp_tm_isr, 0, 
node->name,
+       chip);
+       if (ret < 0)
+       thermal_zone_device_unregister(chip->tz_dev);
+
+       return ret;
+}
+
+static int qpnp_tm_remove(struct platform_device *pdev)
+{
+       struct qpnp_tm_chip *chip = dev_get_drvdata(&pdev->dev);
+
+       cancel_delayed_work_sync(&chip->work);
+       thermal_zone_device_unregister(chip->tz_dev);
+       qpnp_tm_shutdown_override(chip, false);
+
+       return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int qpnp_tm_suspend(struct device *dev)
+{
+       struct qpnp_tm_chip *chip = dev_get_drvdata(dev);
+
+       /* Clear override bits in suspend to allow hardware control 
*/
+       qpnp_tm_shutdown_override(chip, false);
+
+       return 0;
+}
+
+static int qpnp_tm_resume(struct device *dev)
+{
+       struct qpnp_tm_chip *chip = dev_get_drvdata(dev);
+
+       /* Override hardware actions so software can control */
+       if (chip->mode == THERMAL_DEVICE_ENABLED)
+       qpnp_tm_shutdown_override(chip, true);
+
+       return 0;
+}
+
+static const struct dev_pm_ops qpnp_tm_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(qpnp_tm_suspend, qpnp_tm_resume)
+};
+
+#define QPNP_TM_PM_OPS (&qpnp_tm_pm_ops)
+#else
+#define QPNP_TM_PM_OPS NULL
+#endif
+
+static const struct of_device_id qpnp_tm_match_table[] = {
+       { .compatible = "qcom,spmi-temp-alarm" },
+       { }
+};
+MODULE_DEVICE_TABLE(of, qpnp_tm_match_table);
+
+static struct platform_driver qpnp_tm_driver = {
+       .driver = {
+       .name = "spmi-temp-alarm",
+       .of_match_table = qpnp_tm_match_table,
+       .pm = QPNP_TM_PM_OPS,
+       },
+       .probe  = qpnp_tm_probe,
+       .remove = qpnp_tm_remove,
+};
+module_platform_driver(qpnp_tm_driver);
+
+MODULE_ALIAS("platform:spmi-temp-alarm");
+MODULE_DESCRIPTION("QPNP PMIC Temperature Alarm driver");
+MODULE_LICENSE("GPL v2");