[PATCH 02/02] HWMON: HWMON driver for DA9052/53 PMIC v4

[Ashish Jangam]

The DA9052 PMIC provides an Analogue to Digital Converter with 10 bits
resolution and 10 channels.

This patch monitors the DA9052 PMIC's ADC channels mostly for battery
parameters like battery temperature, junction temperature, battery
current etc.

This patch is functionally tested on Samsung SMDKV6410

Signed-off-by: David Dajun Chen <dchen@xxxxxxxxxxx>
Signed-off-by: Ashish Jangam <ashish.jangam@xxxxxxxxxxxxxxx>
--- 
Changes since V3
- Add DIV_ROUND_CLOSEST() macro
Changes since v2
- Update documentation file
Changes since v1
- Update documentation file for url
- Modify the entry in Kconfig file
- Correct reporting of junction temperature
- Add conversion function for backup battery voltage
- Change labels for temperatures in the device attributes to follow
sensor index
---
 Documentation/hwmon/da9052   |   61 ++++++++
 drivers/hwmon/Kconfig        |   10 ++
 drivers/hwmon/Makefile       |    1 +
 drivers/hwmon/da9052-hwmon.c |  344 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 416 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/hwmon/da9052
 create mode 100644 drivers/hwmon/da9052-hwmon.c

diff --git a/Documentation/hwmon/da9052 b/Documentation/hwmon/da9052
new file mode 100644
index 0000000..ef89855
--- /dev/null
+++ b/Documentation/hwmon/da9052
@@ -0,0 +1,61 @@
+Supported chips:
+  * Dialog Semiconductors DA9052-BC and DA9053-AA/Bx PMICs
+    Prefix: 'da9052'
+    Datasheet: Datasheet is not publicly available.
+
+Authors: David Dajun Chen <dchen@xxxxxxxxxxx>
+
+Description
+-----------
+
+The DA9052/53 provides an Analogue to Digital Converter (ADC) with 10 bits
+resolution and track and hold circuitry combined with an analogue input
+multiplexer. The analogue input multiplexer will allow conversion of up to 10
+different inputs. The track and hold circuit ensures stable input voltages at
+the input of the ADC during the conversion.
+
+The ADC is used to measure the following inputs:
+Channel 0: VDDOUT - measurement of the system voltage
+Channel 1: ICH - internal battery charger current measurement
+Channel 2: TBAT - output from the battery NTC
+Channel 3: VBAT - measurement of the battery voltage
+Channel 4: ADC_IN4 - high impedance input (0 - 2.5V)
+Channel 5: ADC_IN5 - high impedance input (0 - 2.5V)
+Channel 6: ADC_IN6 - high impedance input (0 - 2.5V)
+Channel 7: XY - TSI interface to measure the X and Y voltage of the touch
+	   screen resistive potentiometers
+Channel 8: Internal Tjunc. - sense (internal temp. sensor)
+Channel 9: VBBAT - measurement of the backup battery voltage
+
+By using sysfs attributes we can measure the system voltage VDDOUT, the battery
+charging current ICH, battery temperature TBAT, battery junction temperature
+TJUNC, battery voltage VBAT and the back up battery voltage VBBAT.
+
+Voltage Monitoring
+------------------
+
+Voltages are sampled by a 10 bit ADC.
+
+The battery voltage is calculated as:
+	Milli volt = ((ADC value * 1000) / 512) + 2500
+
+The backup battery voltage is calculated as:
+	Milli volt = (ADC value * 2500) / 512;
+
+The voltages on ADC channels 4, 5 and 6 are calculated as:
+	Milli volt = (ADC value * 2500) / 1023
+
+Temperature Monitoring
+----------------------
+
+Temperatures are sampled by a 10 bit ADC.  Junction and battery temperatures
+are monitored by the ADC channels.
+
+The junction temperature is calculated:
+	Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8
+The junction temperature attribute is supported by the driver.
+
+The battery temperature is calculated:
+	Degree Celcius = 1 / (t1 + 1/298)- 273
+where t1 = (1/B)* ln(( ADCval * 2.5)/(R25*ITBAT*255))
+Default values of R25, B, ITBAT are 10e3, 3380 and 50e-6 respectively.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 12bc500..5549c5b 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -313,6 +313,16 @@ config SENSORS_DS1621
 	  This driver can also be built as a module.  If so, the module
 	  will be called ds1621.
 
+config SENSORS_DA9052_ADC
+	tristate "Dialog DA9052/DA9053 ADC"
+	depends on PMIC_DA9052
+	help
+	  Say y here to support the ADC found on Dialog Semiconductor
+	  DA9052-BC and DA9053-AA/Bx PMICs.
+
+	  This driver can also be built as module. If so, the module
+	  will be called da9052-hwmon.
+
 config SENSORS_EXYNOS4_TMU
 	tristate "Temperature sensor on Samsung EXYNOS4"
 	depends on ARCH_EXYNOS4
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 6d3f11f..a950362 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -42,6 +42,7 @@ obj-$(CONFIG_SENSORS_APPLESMC)	+= applesmc.o
 obj-$(CONFIG_SENSORS_ASC7621)	+= asc7621.o
 obj-$(CONFIG_SENSORS_ATXP1)	+= atxp1.o
 obj-$(CONFIG_SENSORS_CORETEMP)	+= coretemp.o
+obj-$(CONFIG_SENSORS_DA9052_ADC)+= da9052-hwmon.o
 obj-$(CONFIG_SENSORS_DME1737)	+= dme1737.o
 obj-$(CONFIG_SENSORS_DS620)	+= ds620.o
 obj-$(CONFIG_SENSORS_DS1621)	+= ds1621.o
diff --git a/drivers/hwmon/da9052-hwmon.c b/drivers/hwmon/da9052-hwmon.c
new file mode 100644
index 0000000..7d356a9
--- /dev/null
+++ b/drivers/hwmon/da9052-hwmon.c
@@ -0,0 +1,344 @@
+/*
+ * HWMON Driver for Dialog DA9052
+ *
+ * Copyright(c) 2012 Dialog Semiconductor Ltd.
+ *
+ * Author: David Dajun Chen <dchen@xxxxxxxxxxx>
+ *
+ *  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.
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+
+#include <linux/mfd/da9052/da9052.h>
+#include <linux/mfd/da9052/reg.h>
+
+struct da9052_hwmon {
+	struct da9052	*da9052;
+	struct device	*class_device;
+	struct mutex	hwmon_lock;
+};
+
+static const char * const input_names[] = {
+	[DA9052_ADC_VDDOUT]	=	"VDDOUT",
+	[DA9052_ADC_ICH]	=	"CHARGING CURRENT",
+	[DA9052_ADC_TBAT]	=	"BATTERY TEMP",
+	[DA9052_ADC_VBAT]	=	"BATTERY VOLTAGE",
+	[DA9052_ADC_IN4]	=	"ADC IN4",
+	[DA9052_ADC_IN5]	=	"ADC IN5",
+	[DA9052_ADC_IN6]	=	"ADC IN6",
+	[DA9052_ADC_TJUNC]	=	"BATTERY JUNCTION TEMP",
+	[DA9052_ADC_VBBAT]	=	"BACK-UP BATTERY VOLTAGE",
+};
+
+/* Conversion function for VDDOUT and VBAT */
+static inline int volt_reg_to_mV(int value)
+{
+	return DIV_ROUND_CLOSEST(value * 1000, 512) + 2500;
+}
+
+/* Conversion function for ADC channels 4, 5 and 6 */
+static inline int input_reg_to_mV(int value)
+{
+	return DIV_ROUND_CLOSEST(value * 2500, 1023);
+}
+
+/* Conversion function for VBBAT */
+static inline int vbbat_reg_to_mV(int value)
+{
+	return DIV_ROUND_CLOSEST(value * 2500, 512);
+}
+
+static int da9052_enable_vddout_channel(struct da9052 *da9052)
+{
+	int ret;
+
+	ret = da9052_reg_read(da9052, DA9052_ADC_CONT_REG);
+	if (ret < 0)
+		return ret;
+
+	ret |= DA9052_ADCCONT_AUTOVDDEN;
+
+	return da9052_reg_write(da9052, DA9052_ADC_CONT_REG, ret);
+}
+
+static int da9052_disable_vddout_channel(struct da9052 *da9052)
+{
+	int ret;
+
+	ret = da9052_reg_read(da9052, DA9052_ADC_CONT_REG);
+	if (ret < 0)
+		return ret;
+
+	ret &= ~DA9052_ADCCONT_AUTOVDDEN;
+
+	return da9052_reg_write(da9052, DA9052_ADC_CONT_REG, ret);
+}
+
+static ssize_t da9052_read_vddout(struct device *dev,
+				  struct device_attribute *devattr, char *buf)
+{
+	struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+	int ret, vdd;
+
+	mutex_lock(&hwmon->hwmon_lock);
+
+	ret = da9052_enable_vddout_channel(hwmon->da9052);
+	if (ret < 0)
+		goto hwmon_err;
+
+	vdd = da9052_reg_read(hwmon->da9052, DA9052_VDD_RES_REG);
+	if (vdd < 0) {
+		ret = vdd;
+		goto hwmon_err_release;
+	}
+
+	ret = da9052_disable_vddout_channel(hwmon->da9052);
+	if (ret < 0)
+		goto hwmon_err;
+
+	mutex_unlock(&hwmon->hwmon_lock);
+	return sprintf(buf, "%d\n", volt_reg_to_mV(vdd));
+
+hwmon_err_release:
+	da9052_disable_vddout_channel(hwmon->da9052);
+hwmon_err:
+	mutex_unlock(&hwmon->hwmon_lock);
+	return ret;
+}
+
+static ssize_t da9052_read_ich(struct device *dev,
+			       struct device_attribute *devattr, char *buf)
+{
+	struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+	int ret;
+
+	ret = da9052_reg_read(hwmon->da9052, DA9052_ICHG_AV_REG);
+	if (ret < 0)
+		return ret;
+
+	/* Equivalent to 3.9mA/bit in register ICHG_AV */
+	return sprintf(buf, "%d\n", DIV_ROUND_CLOSEST(ret * 39, 10));
+}
+
+static ssize_t da9052_read_tbat(struct device *dev,
+				struct device_attribute *devattr, char *buf)
+{
+	struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", da9052_adc_read_temp(hwmon->da9052));
+}
+
+static ssize_t da9052_read_vbat(struct device *dev,
+				struct device_attribute *devattr, char *buf)
+{
+	struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+	int ret;
+
+	ret = da9052_adc_manual_read(hwmon->da9052, DA9052_ADC_VBAT);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", volt_reg_to_mV(ret));
+}
+
+static ssize_t da9052_read_misc_channel(struct device *dev,
+					struct device_attribute *devattr,
+					char *buf)
+{
+	struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+	int channel = to_sensor_dev_attr(devattr)->index;
+	int ret;
+
+	ret = da9052_adc_manual_read(hwmon->da9052, channel);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", input_reg_to_mV(ret));
+}
+
+static ssize_t da9052_read_tjunc(struct device *dev,
+				 struct device_attribute *devattr, char *buf)
+{
+	struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+	int tjunc;
+	int toffset;
+
+	tjunc = da9052_reg_read(hwmon->da9052, DA9052_TJUNC_RES_REG);
+	if (tjunc < 0)
+		return tjunc;
+
+	toffset = da9052_reg_read(hwmon->da9052, DA9052_T_OFFSET_REG);
+	if (toffset < 0)
+		return toffset;
+
+	/*
+	 * Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8
+	 * T_OFFSET is a trim value used to improve accuracy of the result
+	 */
+	return sprintf(buf, "%d\n", 1708 * (tjunc - toffset) - 108800);
+}
+
+static ssize_t da9052_read_vbbat(struct device *dev,
+				 struct device_attribute *devattr, char *buf)
+{
+	struct da9052_hwmon *hwmon = dev_get_drvdata(dev);
+	int ret;
+
+	ret = da9052_adc_manual_read(hwmon->da9052, DA9052_ADC_VBBAT);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", vbbat_reg_to_mV(ret));
+}
+
+static ssize_t da9052_hwmon_show_name(struct device *dev,
+				      struct device_attribute *devattr,
+				      char *buf)
+{
+	return sprintf(buf, "da9052-hwmon\n");
+}
+
+static ssize_t show_label(struct device *dev,
+			  struct device_attribute *devattr, char *buf)
+{
+	return sprintf(buf, "%s\n",
+		       input_names[to_sensor_dev_attr(devattr)->index]);
+}
+
+static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, da9052_read_vddout, NULL,
+			  DA9052_ADC_VDDOUT);
+static SENSOR_DEVICE_ATTR(in0_label, S_IRUGO, show_label, NULL,
+			  DA9052_ADC_VDDOUT);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, da9052_read_vbat, NULL,
+			  DA9052_ADC_VBAT);
+static SENSOR_DEVICE_ATTR(in3_label, S_IRUGO, show_label, NULL,
+			  DA9052_ADC_VBAT);
+static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, da9052_read_misc_channel, NULL,
+			  DA9052_ADC_IN4);
+static SENSOR_DEVICE_ATTR(in4_label, S_IRUGO, show_label, NULL,
+			  DA9052_ADC_IN4);
+static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, da9052_read_misc_channel, NULL,
+			  DA9052_ADC_IN5);
+static SENSOR_DEVICE_ATTR(in5_label, S_IRUGO, show_label, NULL,
+			  DA9052_ADC_IN5);
+static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, da9052_read_misc_channel, NULL,
+			  DA9052_ADC_IN6);
+static SENSOR_DEVICE_ATTR(in6_label, S_IRUGO, show_label, NULL,
+			  DA9052_ADC_IN6);
+static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, da9052_read_vbbat, NULL,
+			  DA9052_ADC_VBBAT);
+static SENSOR_DEVICE_ATTR(in9_label, S_IRUGO, show_label, NULL,
+			  DA9052_ADC_VBBAT);
+
+static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, da9052_read_ich, NULL,
+			  DA9052_ADC_ICH);
+static SENSOR_DEVICE_ATTR(curr1_label, S_IRUGO, show_label, NULL,
+			  DA9052_ADC_ICH);
+
+static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, da9052_read_tbat, NULL,
+			  DA9052_ADC_TBAT);
+static SENSOR_DEVICE_ATTR(temp2_label, S_IRUGO, show_label, NULL,
+			  DA9052_ADC_TBAT);
+static SENSOR_DEVICE_ATTR(temp8_input, S_IRUGO, da9052_read_tjunc, NULL,
+			  DA9052_ADC_TJUNC);
+static SENSOR_DEVICE_ATTR(temp8_label, S_IRUGO, show_label, NULL,
+			  DA9052_ADC_TJUNC);
+
+static DEVICE_ATTR(name, S_IRUGO, da9052_hwmon_show_name, NULL);
+
+static struct attribute *da9052_attr[] = {
+	&dev_attr_name.attr,
+	&sensor_dev_attr_in0_input.dev_attr.attr,
+	&sensor_dev_attr_in0_label.dev_attr.attr,
+	&sensor_dev_attr_in3_input.dev_attr.attr,
+	&sensor_dev_attr_in3_label.dev_attr.attr,
+	&sensor_dev_attr_in4_input.dev_attr.attr,
+	&sensor_dev_attr_in4_label.dev_attr.attr,
+	&sensor_dev_attr_in5_input.dev_attr.attr,
+	&sensor_dev_attr_in5_label.dev_attr.attr,
+	&sensor_dev_attr_in6_input.dev_attr.attr,
+	&sensor_dev_attr_in6_label.dev_attr.attr,
+	&sensor_dev_attr_in9_input.dev_attr.attr,
+	&sensor_dev_attr_in9_label.dev_attr.attr,
+	&sensor_dev_attr_curr1_input.dev_attr.attr,
+	&sensor_dev_attr_curr1_label.dev_attr.attr,
+	&sensor_dev_attr_temp2_input.dev_attr.attr,
+	&sensor_dev_attr_temp2_label.dev_attr.attr,
+	&sensor_dev_attr_temp8_input.dev_attr.attr,
+	&sensor_dev_attr_temp8_label.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group da9052_attr_group = {.attrs = da9052_attr};
+
+static int __init da9052_hwmon_probe(struct platform_device *pdev)
+{
+	struct da9052_hwmon *hwmon;
+	int ret;
+
+	hwmon = devm_kzalloc(&pdev->dev, sizeof(struct da9052_hwmon),
+			     GFP_KERNEL);
+	if (!hwmon)
+		return -ENOMEM;
+
+	mutex_init(&hwmon->hwmon_lock);
+	hwmon->da9052 = dev_get_drvdata(pdev->dev.parent);
+
+	platform_set_drvdata(pdev, hwmon);
+
+	ret = sysfs_create_group(&pdev->dev.kobj, &da9052_attr_group);
+	if (ret)
+		goto err_mem;
+
+	hwmon->class_device = hwmon_device_register(&pdev->dev);
+	if (IS_ERR(hwmon->class_device)) {
+		ret = PTR_ERR(hwmon->class_device);
+		goto err_sysfs;
+	}
+
+	return 0;
+
+err_sysfs:
+	sysfs_remove_group(&pdev->dev.kobj, &da9052_attr_group);
+err_mem:
+	return ret;
+}
+
+static int __devexit da9052_hwmon_remove(struct platform_device *pdev)
+{
+	struct da9052_hwmon *hwmon = platform_get_drvdata(pdev);
+
+	hwmon_device_unregister(hwmon->class_device);
+	sysfs_remove_group(&pdev->dev.kobj, &da9052_attr_group);
+
+	return 0;
+}
+
+static struct platform_driver da9052_hwmon_driver = {
+	.probe = da9052_hwmon_probe,
+	.remove = __devexit_p(da9052_hwmon_remove),
+	.driver = {
+		.name = "da9052-hwmon",
+		.owner = THIS_MODULE,
+	},
+};
+
+module_platform_driver(da9052_hwmon_driver);
+
+MODULE_AUTHOR("David Dajun Chen <dchen@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("DA9052 HWMON driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:da9052-hwmon");


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