[PATCH v2 0/2] Add driver for ST stts751 thermal sensor

[PATCH v2 0/2] Add driver for ST stts751 thermal sensor

[Andrea Merello]

This series adds new driver for ST stts751 thermal sensor

Changes since v1:
- removed the "manual mode" logic; always use automatic mode
- changed the way 16-bit data is read from two 8-bit regs (now similar to lm90)
- code simplifications
- comment style fixes

Andrea Merello (2):
  DT: add binding documentation for STTS751
  hwmon: new driver for ST stts751 thermal sensor

 .../devicetree/bindings/hwmon/stts751.txt          |  19 +
 drivers/hwmon/Kconfig                              |  12 +-
 drivers/hwmon/Makefile                             |   2 +-
 drivers/hwmon/stts751.c                            | 805 +++++++++++++++++++++
 4 files changed, 836 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/hwmon/stts751.txt
 create mode 100644 drivers/hwmon/stts751.c

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: LABBE Corentin <clabbe.montjoie@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.com>


--
2.7.4

[PATCH v2 1/2] DT: add binding documentation for STTS751

[Andrea Merello]

Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
---
 Documentation/devicetree/bindings/hwmon/stts751.txt | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/stts751.txt

diff --git a/Documentation/devicetree/bindings/hwmon/stts751.txt b/Documentation/devicetree/bindings/hwmon/stts751.txt
new file mode 100644
index 0000000..277ad46
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/stts751.txt
@@ -0,0 +1,19 @@
+* STTS751 thermometer.
+
+Required node properties:
+- compatible: "stts751"
+- reg: I2C bus address of the device
+
+Optional properties:
+- has-therm: specifies that the "therm" pin is wired
+- has-event: specifies that the "event" pin is wired
+- smbus-timeout-disable: when set, the smbus timeout function will be disabled
+
+Example stts751 node:
+
+temp-sensor {
+	compatible = "stts751";
+	reg = <0x48>;
+	has-therm;
+	has-event;
+}
-- 
2.7.4

[PATCH v2 2/2] hwmon: new driver for ST stts751 thermal sensor

[Andrea Merello]

This patch adds a HWMON driver for ST Microelectronics STTS751
temperature sensors.

It does support temperature reading (of course), SMBUS alert
functionality and "therm" output.

Thanks-to: LABBE Corentin [for suggestions]
Thanks-to: Guenter Roeck [for suggestions/discussions]
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Cc: LABBE Corentin <clabbe.montjoie@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.com>
---
 drivers/hwmon/Kconfig   |  12 +-
 drivers/hwmon/Makefile  |   2 +-
 drivers/hwmon/stts751.c | 805 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 817 insertions(+), 2 deletions(-)
 create mode 100644 drivers/hwmon/stts751.c

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index eaf2f91..4e70b42 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1448,6 +1448,16 @@ config SENSORS_SCH5636
 	  This driver can also be built as a module.  If so, the module
 	  will be called sch5636.
 
+config SENSORS_STTS751
+	tristate "ST Microelectronics STTS751"
+	depends on I2C
+	help
+	  If you say yes here you get support for STTS751
+	  temperature sensor chips.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called stts751.
+
 config SENSORS_SMM665
 	tristate "Summit Microelectronics SMM665"
 	depends on I2C
@@ -1506,7 +1516,7 @@ config SENSORS_ADS7871
 
 config SENSORS_AMC6821
 	tristate "Texas Instruments AMC6821"
-	depends on I2C 
+	depends on I2C
 	help
 	  If you say yes here you get support for the Texas Instruments
 	  AMC6821 hardware monitoring chips.
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index fe87d28..1114130 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -147,6 +147,7 @@ obj-$(CONFIG_SENSORS_SMM665)	+= smm665.o
 obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
 obj-$(CONFIG_SENSORS_SMSC47M1)	+= smsc47m1.o
 obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
+obj-$(CONFIG_SENSORS_STTS751)	+= stts751.o
 obj-$(CONFIG_SENSORS_AMC6821)	+= amc6821.o
 obj-$(CONFIG_SENSORS_TC74)	+= tc74.o
 obj-$(CONFIG_SENSORS_THMC50)	+= thmc50.o
@@ -169,4 +170,3 @@ obj-$(CONFIG_SENSORS_WM8350)	+= wm8350-hwmon.o
 obj-$(CONFIG_PMBUS)		+= pmbus/
 
 ccflags-$(CONFIG_HWMON_DEBUG_CHIP) := -DDEBUG
-
diff --git a/drivers/hwmon/stts751.c b/drivers/hwmon/stts751.c
new file mode 100644
index 0000000..8358e04
--- /dev/null
+++ b/drivers/hwmon/stts751.c
@@ -0,0 +1,805 @@
+/*
+ * STTS751 sensor driver
+ *
+ * Copyright (C) 2016 Istituto Italiano di Tecnologia - RBCS - EDL
+ * Robotics, Brain and Cognitive Sciences department
+ * Electronic Design Laboratory
+ *
+ * Written by Andrea Merello <andrea.merello@gmail.com>
+ *
+ * Based on  LM95241 driver and LM90 driver
+ *
+ * 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/bitops.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/util_macros.h>
+
+#define DEVNAME "stts751"
+
+static const unsigned short normal_i2c[] = {
+	0x48, 0x49, 0x38, 0x39,  /* STTS751-0 */
+	0x4A, 0x4B, 0x3A, 0x3B,  /* STTS751-1 */
+	I2C_CLIENT_END };
+
+#define STTS751_REG_TEMP_H	0x00
+#define STTS751_REG_STATUS	0x01
+#define STTS751_STATUS_TRIPL	BIT(5)
+#define STTS751_STATUS_TRIPH	BIT(6)
+#define STTS751_STATUS_BUSY	BIT(8)
+#define STTS751_REG_TEMP_L	0x02
+#define STTS751_REG_CONF	0x03
+#define STTS751_CONF_RES_MASK	0x0C
+#define STTS751_CONF_RES_SHIFT  2
+#define STTS751_CONF_EVENT_DIS  BIT(7)
+#define STTS751_CONF_STOP	BIT(6)
+#define STTS751_REG_RATE	0x04
+#define STTS751_REG_HLIM_H	0x05
+#define STTS751_REG_HLIM_L	0x06
+#define STTS751_REG_LLIM_H	0x07
+#define STTS751_REG_LLIM_L	0x08
+#define STTS751_REG_ONESHOT	0x0F
+#define STTS751_REG_TLIM	0x20
+#define STTS751_REG_HYST	0x21
+#define STTS751_REG_SMBUS_TO	0x22
+
+#define STTS751_REG_PROD_ID	0xFD
+#define STTS751_REG_MAN_ID	0xFE
+#define STTS751_REG_REV_ID	0xFF
+
+#define STTS751_0_PROD_ID	0x00
+#define STTS751_1_PROD_ID	0x01
+#define ST_MAN_ID		0x53
+
+/* stick with HW defaults */
+#define STTS751_THERM_DEFAULT	85000
+#define STTS751_HYST_DEFAULT	10000
+#define STTS751_EVENT_MAX_DEFAULT 85000
+#define STTS751_EVENT_MIN_DEFAULT 0
+
+#define STTS751_RACE_RETRY	5
+#define STTS751_CONV_TIMEOUT	100 /* mS */
+#define STTS751_CACHE_TIME	100 /* mS */
+
+/*
+ * Possible update intervals are (in mS):
+ * 16000, 8000, 4000, 2000, 1000, 500, 250, 125, 62.5, 31.25
+ * However we are not going to complicate things too much and we stick to the
+ * approx value in mS.
+ */
+static const int stts751_intervals[] = {
+	16000, 8000, 4000, 2000, 1000, 500, 250, 125, 63, 31
+};
+
+struct stts751_priv {
+	struct device *dev;
+	struct i2c_client *client;
+	struct mutex access_lock;
+	unsigned long interval;
+	int res;
+	bool gen_therm, gen_event;
+	int event_max, event_min;
+	int therm;
+	int hyst;
+	bool smbus_timeout;
+	int temp;
+	unsigned long last_update;
+	u8 config;
+	bool min_alert, max_alert;
+	bool data_valid;
+
+	/*
+	 * Temperature/interval is always present.
+	 * Depending by DT therm and event are dynamically added.
+	 * There are max 4 entries plus the guard
+	 */
+	const struct attribute_group *groups[5];
+};
+
+/*
+ * These functions converts temperature from HW format to integer format and
+ * vice-vers. They are (mostly) taken from lm90 driver. Unit is in mC.
+ */
+static int stts751_to_deg(s32 hw_val)
+{
+	return hw_val * 125 / 32;
+}
+
+static s16 stts751_to_hw(int val, s32 *hw_val)
+{
+	/* HW works in range -64C to +127C */
+	if ((val > 127000) || (val < -64000))
+		return -EINVAL;
+
+	if (val < 0)
+		*hw_val = (val - 62) / 125 * 32;
+	else
+		*hw_val = (val + 62) / 125 * 32;
+
+	return 0;
+}
+
+static int stts751_adjust_resolution(struct stts751_priv *priv)
+{
+	u8 res;
+
+	switch (priv->interval) {
+	case 9:
+		/* 10 bits */
+		res = 0;
+		break;
+	case 8:
+		/* 11 bits */
+		res = 1;
+		break;
+	default:
+		/* 12 bits */
+		res = 3;
+		break;
+	}
+
+	if (priv->res == res)
+		return 0;
+
+	priv->config &= ~STTS751_CONF_RES_MASK;
+	priv->config |= res << STTS751_CONF_RES_SHIFT;
+
+	return i2c_smbus_write_byte_data(priv->client,
+				STTS751_REG_CONF, priv->config);
+}
+
+static int stts751_update_temp(struct stts751_priv *priv)
+{
+	s32 integer1, integer2, frac;
+	int ret = 0;
+
+	mutex_lock(&priv->access_lock);
+
+	/*
+	 * There is a trick here, like in the lm90 driver. We have to read two
+	 * registers to get the sensor temperature, but we have to beware a
+	 * conversion could occur between the readings. We could use the
+	 * one-shot conversion register, but we don't want to do this (disables
+	 * hardware monitoring). So the solution used here is to read the high
+	 * byte once, then the low byte, then the high byte again. If the new
+	 * high byte matches the old one, then we have a valid reading. Else we
+	 * have to read the low byte again, and now we believe we have a correct
+	 * reading.
+	 */
+	integer1 = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_H);
+	if (integer1 < 0) {
+		dev_dbg(&priv->client->dev,
+			"I2C read failed (temp H). ret: %x\n", ret);
+		ret = integer1;
+		goto exit;
+	}
+
+	frac = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_L);
+	if (frac < 0) {
+		dev_dbg(&priv->client->dev,
+			"I2C read failed (temp L). ret: %x\n", ret);
+		ret = frac;
+		goto exit;
+	}
+
+	integer2 = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_H);
+	if (integer2 < 0) {
+		dev_dbg(&priv->client->dev,
+			"I2C 2nd read failed (temp H). ret: %x\n", ret);
+		ret = integer2;
+		goto exit;
+	}
+
+	if (integer1 != integer2) {
+		frac = i2c_smbus_read_byte_data(priv->client,
+						STTS751_REG_TEMP_L);
+		if (frac < 0) {
+			dev_dbg(&priv->client->dev,
+				"I2C 2nd read failed (temp L). ret: %x\n", ret);
+			ret = frac;
+			goto exit;
+		}
+	}
+
+exit:
+	mutex_unlock(&priv->access_lock);
+	if (ret)
+		return ret;
+
+	priv->temp = stts751_to_deg((integer1 << 8) | frac);
+	return ret;
+}
+
+static int stts751_set_temp_reg(struct stts751_priv *priv, int temp,
+				bool is_frac, u8 hreg, u8 lreg)
+{
+	s32 hwval;
+	int ret;
+
+	if (stts751_to_hw(temp, &hwval))
+		return -EINVAL;
+
+	mutex_lock(&priv->access_lock);
+	ret = i2c_smbus_write_byte_data(priv->client, hreg, hwval >> 8);
+	if (ret)
+		goto exit;
+	if (is_frac)
+		ret = i2c_smbus_write_byte_data(priv->client,
+						lreg, hwval & 0xff);
+exit:
+	mutex_unlock(&priv->access_lock);
+
+	return ret;
+}
+
+static int stts751_update_alert(struct stts751_priv *priv)
+{
+	int ret;
+
+	/* not for us.. */
+	if (!priv->gen_event)
+		return 0;
+
+	ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_STATUS);
+
+	if (ret < 0)
+		return ret;
+
+	priv->max_alert = priv->max_alert || !!(ret & STTS751_STATUS_TRIPH);
+	priv->min_alert = priv->min_alert || !!(ret & STTS751_STATUS_TRIPL);
+
+	return 0;
+}
+
+static void stts751_alert(struct i2c_client *client,
+			enum i2c_alert_protocol type, unsigned int data)
+{
+	int ret;
+	struct stts751_priv *priv = i2c_get_clientdata(client);
+	bool prev_max = priv->max_alert;
+	bool prev_min = priv->min_alert;
+
+	if (type != I2C_PROTOCOL_SMBUS_ALERT)
+		return;
+
+	dev_dbg(&client->dev, "alert!");
+
+	mutex_lock(&priv->access_lock);
+	ret = stts751_update_alert(priv);
+	if (ret < 0) {
+		/* default to worst case */
+		priv->max_alert = true;
+		priv->min_alert = true;
+
+		if (!(prev_max && prev_min)) {
+			dev_warn(&priv->client->dev,
+				"Alert received, but can't communicate to the device. Something bad happening? Triggering all alarms!");
+		}
+	}
+
+	if (!prev_max && priv->max_alert) {
+		dev_notice(&client->dev, "got alert for HIGH temperature");
+
+		/* unblock alert poll */
+		sysfs_notify(&priv->dev->kobj, NULL, "temp1_event_max_alert");
+		kobject_uevent(&priv->dev->kobj, KOBJ_CHANGE);
+	}
+
+	if (!prev_min && priv->min_alert) {
+		dev_notice(&client->dev, "got alert for LOW temperature");
+
+		/* unblock alert poll */
+		sysfs_notify(&priv->dev->kobj, NULL, "temp1_event_min_alert");
+		kobject_uevent(&priv->dev->kobj, KOBJ_CHANGE);
+	}
+	mutex_unlock(&priv->access_lock);
+}
+
+static ssize_t show_max_alert(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->max_alert);
+}
+
+static ssize_t set_max_alert(struct device *dev, struct device_attribute *attr,
+		       const char *buf, size_t count)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	mutex_lock(&priv->access_lock);
+	priv->max_alert = false;
+	mutex_unlock(&priv->access_lock);
+
+	return count;
+}
+
+static ssize_t show_min_alert(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->min_alert);
+}
+
+static ssize_t set_min_alert(struct device *dev, struct device_attribute *attr,
+		       const char *buf, size_t count)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	mutex_lock(&priv->access_lock);
+	priv->min_alert = false;
+	mutex_unlock(&priv->access_lock);
+
+	return count;
+}
+
+static ssize_t show_input(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	int ret;
+	int cache_time = STTS751_CACHE_TIME * HZ / 1000;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	/*
+	 * Adjust the cache time wrt the sample rate. We do 4X in order to get
+	 * a new measure in no more than 1/4 of the sample time (that seemed
+	 * reasonable to me).
+	 */
+	cache_time = stts751_intervals[priv->interval] / 4 * HZ / 1000;
+
+	if (time_after(jiffies,	priv->last_update + cache_time) ||
+		!priv->data_valid) {
+		ret = stts751_update_temp(priv);
+		if (ret)
+			return ret;
+		priv->last_update = jiffies;
+		priv->data_valid = true;
+	}
+
+	return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->temp);
+}
+
+static ssize_t show_therm(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->therm);
+}
+
+
+static ssize_t set_therm(struct device *dev, struct device_attribute *attr,
+		       const char *buf, size_t count)
+{
+	int ret;
+	long temp;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	if (kstrtol(buf, 10, &temp) < 0)
+		return -EINVAL;
+
+	ret = stts751_set_temp_reg(priv, temp, false, STTS751_REG_TLIM, 0);
+	if (ret)
+		return ret;
+
+	dev_dbg(dev, "setting therm %ld", temp);
+
+	priv->therm = temp;
+	return count;
+}
+
+static ssize_t show_hyst(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->hyst);
+}
+
+
+static ssize_t set_hyst(struct device *dev, struct device_attribute *attr,
+		       const char *buf, size_t count)
+{
+	int ret;
+	long temp;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	if (kstrtol(buf, 10, &temp) < 0)
+		return -EINVAL;
+
+	ret = stts751_set_temp_reg(priv, temp, false, STTS751_REG_HYST, 0);
+	if (ret)
+		return ret;
+
+	dev_dbg(dev, "setting hyst %ld", temp);
+
+	priv->hyst = temp;
+	return count;
+}
+
+static ssize_t show_max(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->event_max);
+}
+
+static ssize_t set_max(struct device *dev, struct device_attribute *attr,
+		       const char *buf, size_t count)
+{
+	int ret;
+	long temp;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	if (kstrtol(buf, 10, &temp) < 0)
+		return -EINVAL;
+
+	ret = stts751_set_temp_reg(priv, temp, true,
+				STTS751_REG_HLIM_H, STTS751_REG_HLIM_L);
+	if (ret)
+		return ret;
+
+	dev_dbg(dev, "setting event max %ld", temp);
+	priv->event_max = temp;
+	return count;
+}
+
+static ssize_t show_min(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE - 1, "%d\n", priv->event_min);
+}
+
+
+static ssize_t set_min(struct device *dev, struct device_attribute *attr,
+		       const char *buf, size_t count)
+{
+	int ret;
+	long temp;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	if (kstrtol(buf, 10, &temp) < 0)
+		return -EINVAL;
+
+	ret = stts751_set_temp_reg(priv, temp, true,
+				STTS751_REG_LLIM_H, STTS751_REG_LLIM_L);
+	if (ret)
+		return ret;
+
+	dev_dbg(dev, "setting event min %ld", temp);
+
+	priv->event_min = temp;
+	return count;
+}
+
+static ssize_t show_interval(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE - 1, "%d\n",
+			stts751_intervals[priv->interval]);
+}
+
+static ssize_t set_interval(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	unsigned long val;
+	int idx;
+	int ret = 0;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	if (kstrtoul(buf, 10, &val) < 0)
+		return -EINVAL;
+
+	idx = find_closest_descending(val, stts751_intervals,
+				ARRAY_SIZE(stts751_intervals));
+
+	dev_dbg(dev, "setting interval. req:%lu, idx: %d, val: %d", val, idx,
+		stts751_intervals[idx]);
+
+	if (priv->interval == idx)
+		return count;
+
+	mutex_lock(&priv->access_lock);
+
+	/* speed up, lower the resolution, then modify convrate */
+	if (priv->interval < idx) {
+		priv->interval = idx;
+		ret = stts751_adjust_resolution(priv);
+		if (ret)
+			goto exit;
+	}
+
+	ret = i2c_smbus_write_byte_data(priv->client, STTS751_REG_RATE, idx);
+	if (ret)
+		goto exit;
+
+	/* slow down, modify convrate, then raise resolution */
+	if (priv->interval != idx) {
+		priv->interval = idx;
+		ret = stts751_adjust_resolution(priv);
+		if (ret)
+			goto exit;
+
+	}
+exit:
+	mutex_unlock(&priv->access_lock);
+
+	return count;
+}
+
+static int stts751_detect(struct i2c_client *new_client,
+			  struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = new_client->adapter;
+	const char *name;
+	int mfg_id, prod_id, rev_id;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	mfg_id = i2c_smbus_read_byte_data(new_client, ST_MAN_ID);
+	if (mfg_id != ST_MAN_ID)
+		return -ENODEV;
+
+	prod_id = i2c_smbus_read_byte_data(new_client, STTS751_REG_PROD_ID);
+
+	switch (prod_id) {
+	case STTS751_0_PROD_ID:
+		name = "STTS751-0";
+		break;
+	case STTS751_1_PROD_ID:
+		name = "STTS751-1";
+		break;
+	default:
+		return -ENODEV;
+	}
+	dev_info(&new_client->dev, "Chip %s detected!", name);
+
+	rev_id = i2c_smbus_read_byte_data(new_client, STTS751_REG_REV_ID);
+
+	if (rev_id != 0x1) {
+		dev_notice(&new_client->dev,
+			"Chip revision 0x%x is untested\nPlease report whether it works to andrea.merello@gmail.com",
+			rev_id);
+	}
+
+	strlcpy(info->type, name, I2C_NAME_SIZE);
+	return 0;
+}
+
+static int stts751_init_chip(struct stts751_priv *priv)
+{
+	int ret;
+
+	priv->config = STTS751_CONF_EVENT_DIS | STTS751_CONF_STOP;
+	ret = i2c_smbus_write_byte_data(priv->client, STTS751_REG_CONF,
+					priv->config);
+	if (ret)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(priv->client, STTS751_REG_RATE,
+					priv->interval);
+	if (ret)
+		return ret;
+
+	/* invalid, to force update */
+	priv->res = -1;
+	ret = stts751_adjust_resolution(priv);
+	if (ret)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(priv->client,
+					STTS751_REG_SMBUS_TO,
+					priv->smbus_timeout ? 0x80 : 0);
+	if (ret)
+		return ret;
+
+
+	if (priv->gen_event) {
+		ret = stts751_set_temp_reg(priv, priv->event_max, true,
+					STTS751_REG_HLIM_H, STTS751_REG_HLIM_L);
+		if (ret)
+			return ret;
+
+		ret = stts751_set_temp_reg(priv, priv->event_min, true,
+					STTS751_REG_LLIM_H, STTS751_REG_LLIM_L);
+		if (ret)
+			return ret;
+		priv->config &= ~STTS751_CONF_EVENT_DIS;
+	}
+
+	if (priv->gen_therm) {
+		ret = stts751_set_temp_reg(priv, priv->therm, false,
+					STTS751_REG_TLIM, 0);
+		if (ret)
+			return ret;
+
+		ret = stts751_set_temp_reg(priv, priv->hyst, false,
+					STTS751_REG_HYST, 0);
+		if (ret)
+			return ret;
+	}
+
+	priv->config &= ~STTS751_CONF_STOP;
+	ret = i2c_smbus_write_byte_data(priv->client,
+					STTS751_REG_CONF, priv->config);
+
+	return ret;
+}
+
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_event_min, S_IWUSR | S_IRUGO,
+			show_min, set_min, 0);
+static SENSOR_DEVICE_ATTR(temp1_event_max, S_IWUSR | S_IRUGO,
+			show_max, set_max, 0);
+static SENSOR_DEVICE_ATTR(temp1_event_min_alert, S_IWUSR | S_IRUGO,
+			show_min_alert, set_min_alert, 0);
+static SENSOR_DEVICE_ATTR(temp1_event_max_alert, S_IWUSR | S_IRUGO,
+			show_max_alert, set_max_alert, 0);
+static SENSOR_DEVICE_ATTR(temp1_therm, S_IWUSR | S_IRUGO, show_therm,
+			set_therm, 0);
+static SENSOR_DEVICE_ATTR(temp1_therm_hyst, S_IWUSR | S_IRUGO, show_hyst,
+			set_hyst, 0);
+static SENSOR_DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO,
+			show_interval, set_interval, 0);
+
+/* always present */
+static struct attribute *stts751_temp_attrs[] = {
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	NULL
+};
+
+static struct attribute_group stts751_temp_group = {
+	.attrs = stts751_temp_attrs,
+};
+
+/* present when therm pin or event pin are connected */
+static struct attribute *stts751_interval_attrs[] = {
+	&sensor_dev_attr_update_interval.dev_attr.attr,
+	NULL
+};
+
+static struct attribute_group stts751_interval_group = {
+	.attrs = stts751_interval_attrs,
+};
+
+/* present when event pin is connected */
+static struct attribute *stts751_event_attrs[] = {
+	&sensor_dev_attr_temp1_event_min.dev_attr.attr,
+	&sensor_dev_attr_temp1_event_max.dev_attr.attr,
+	&sensor_dev_attr_temp1_event_min_alert.dev_attr.attr,
+	&sensor_dev_attr_temp1_event_max_alert.dev_attr.attr,
+	NULL
+};
+
+static struct attribute_group stts751_event_group = {
+	.attrs = stts751_event_attrs,
+};
+
+/* present when therm pin is connected */
+static struct attribute *stts751_therm_attrs[] = {
+	&sensor_dev_attr_temp1_therm.dev_attr.attr,
+	&sensor_dev_attr_temp1_therm_hyst.dev_attr.attr,
+	NULL
+};
+
+static struct attribute_group stts751_therm_group = {
+	.attrs = stts751_therm_attrs,
+};
+
+static int stts751_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct stts751_priv *priv;
+	int ret;
+	int groups_idx = 0;
+	struct device_node *np = client->dev.of_node;
+
+	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->client = client;
+	i2c_set_clientdata(client, priv);
+	mutex_init(&priv->access_lock);
+
+	/* default to 2 samples per second */
+	priv->interval = 5;
+	/* default to timeout enable, as per chip default */
+	priv->smbus_timeout = true;
+	priv->last_update = 0;
+	priv->data_valid = false;
+	priv->max_alert = false;
+	priv->min_alert = false;
+	priv->gen_therm = false;
+	priv->gen_event = false;
+	priv->therm = STTS751_THERM_DEFAULT;
+	priv->hyst = STTS751_HYST_DEFAULT;
+	priv->event_max = STTS751_EVENT_MAX_DEFAULT;
+	priv->event_min = STTS751_EVENT_MIN_DEFAULT;
+
+	if (np) {
+		priv->gen_therm = of_property_read_bool(np, "has-therm");
+		priv->gen_event = of_property_read_bool(np, "has-event");
+		priv->smbus_timeout = !of_property_read_bool(np,
+						"smbus-timeout-disable");
+	} else {
+		dev_notice(&client->dev, "No DT data. Event/therm disabled\n");
+	}
+
+	dev_dbg(&client->dev, "gen_event: %s, gen_therm: %s",
+		priv->gen_event ? "YES" : "NO",
+		priv->gen_therm ? "YES" : "NO");
+
+	priv->groups[groups_idx++] = &stts751_temp_group;
+	priv->groups[groups_idx++] = &stts751_interval_group;
+
+	if (priv->gen_therm)
+		priv->groups[groups_idx++] = &stts751_therm_group;
+
+	if (priv->gen_event)
+		priv->groups[groups_idx++] = &stts751_event_group;
+
+	priv->groups[groups_idx] = NULL;
+
+	ret = stts751_init_chip(priv);
+	if (ret)
+		return ret;
+
+	priv->dev = devm_hwmon_device_register_with_groups(&client->dev,
+							client->name, priv,
+							priv->groups);
+	return PTR_ERR_OR_ZERO(priv->dev);
+}
+
+static const struct i2c_device_id stts751_id[] = {
+	{ "stts751", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, stts751_id);
+
+static struct i2c_driver stts751_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.driver = {
+		.name	= DEVNAME,
+	},
+	.probe		= stts751_probe,
+	.id_table	= stts751_id,
+	.detect		= stts751_detect,
+	.alert		= stts751_alert,
+	.address_list	= normal_i2c,
+};
+
+module_i2c_driver(stts751_driver);
+
+MODULE_AUTHOR("Andrea Merello <andrea.merello@gmail.com>");
+MODULE_DESCRIPTION("STTS751 sensor driver");
+MODULE_LICENSE("GPL");
-- 
2.7.4

Re: [PATCH v2 1/2] DT: add binding documentation for STTS751

[Guenter Roeck]

On Tue, Sep 27, 2016 at 02:07:26PM +0200, Andrea Merello wrote:
> Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> ---
>  Documentation/devicetree/bindings/hwmon/stts751.txt | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/hwmon/stts751.txt
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/stts751.txt b/Documentation/devicetree/bindings/hwmon/stts751.txt
> new file mode 100644
> index 0000000..277ad46
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/stts751.txt
> @@ -0,0 +1,19 @@
> +* STTS751 thermometer.
> +
> +Required node properties:
> +- compatible: "stts751"
> +- reg: I2C bus address of the device
> +
> +Optional properties:
> +- has-therm: specifies that the "therm" pin is wired
> +- has-event: specifies that the "event" pin is wired

As mentioned in the code patch, I don't think those properties are actually
needed.

Guenter

> +- smbus-timeout-disable: when set, the smbus timeout function will be disabled
> +
> +Example stts751 node:
> +
> +temp-sensor {
> +	compatible = "stts751";
> +	reg = <0x48>;
> +	has-therm;
> +	has-event;
> +}
> -- 
> 2.7.4
> 
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