hwmon: Add WM835x PMIC hardware monitoring driver

This driver provides reporting of the status supply voltage rails
of the WM835x series of PMICs via the hwmon API.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

6 files changed, 197 insertions, 0 deletions

diff --git a/Documentation/hwmon/wm8350 b/Documentation/hwmon/wm8350
new file mode 100644
index 000000000000..98f923bd2e92
--- /dev/null
+++ b/Documentation/hwmon/wm8350
@@ -0,0 +1,26 @@
+Kernel driver wm8350-hwmon
+==========================
+
+Supported chips:
+  * Wolfson Microelectronics WM835x PMICs
+    Prefix: 'wm8350'
+    Datasheet:
+        http://www.wolfsonmicro.com/products/WM8350
+        http://www.wolfsonmicro.com/products/WM8351
+        http://www.wolfsonmicro.com/products/WM8352
+
+Authors: Mark Brown <broonie@opensource.wolfsonmicro.com>
+
+Description
+-----------
+
+The WM835x series of PMICs include an AUXADC which can be used to
+monitor a range of system operating parameters, including the voltages
+of the major supplies within the system.  Currently the driver provides
+simple access to these major supplies.
+
+Voltage Monitoring
+------------------
+
+Voltages are sampled by a 12 bit ADC.  For the internal supplies the ADC
+is referenced to the system VRTC.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 2e25b7a827d3..120085ce651a 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -937,6 +937,16 @@ config SENSORS_W83627EHF
           This driver can also be built as a module.  If so, the module
           will be called w83627ehf.
 
+config SENSORS_WM8350
+        tristate "Wolfson Microelectronics WM835x"
+        depends on MFD_WM8350
+        help
+          If you say yes here you get support for the hardware
+          monitoring features of the WM835x series of PMICs.
+
+          This driver can also be built as a module.  If so, the module
+          will be called wm8350-hwmon.
+
 config SENSORS_ULTRA45
         tristate "Sun Ultra45 PIC16F747"
         depends on SPARC64
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 7f239a247c33..ed5f1781b8c4 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -90,6 +90,7 @@ obj-$(CONFIG_SENSORS_VT8231)	+= vt8231.o
 obj-$(CONFIG_SENSORS_W83627EHF) += w83627ehf.o
 obj-$(CONFIG_SENSORS_W83L785TS) += w83l785ts.o
 obj-$(CONFIG_SENSORS_W83L786NG) += w83l786ng.o
+obj-$(CONFIG_SENSORS_WM8350)    += wm8350-hwmon.o
 
 ifeq ($(CONFIG_HWMON_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/hwmon/wm8350-hwmon.c b/drivers/hwmon/wm8350-hwmon.c
new file mode 100644
index 000000000000..13290595ca86
--- /dev/null
+++ b/drivers/hwmon/wm8350-hwmon.c
@@ -0,0 +1,151 @@
+/*
+ * drivers/hwmon/wm8350-hwmon.c - Wolfson Microelectronics WM8350 PMIC
+ *                                  hardware monitoring features.
+ *
+ * Copyright (C) 2009 Wolfson Microelectronics plc
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License v2 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+
+#include <linux/mfd/wm8350/core.h>
+#include <linux/mfd/wm8350/comparator.h>
+
+static ssize_t show_name(struct device *dev,
+                         struct device_attribute *attr, char *buf)
+{
+        return sprintf(buf, "wm8350\n");
+}
+
+static const char *input_names[] = {
+        [WM8350_AUXADC_USB]  = "USB",
+        [WM8350_AUXADC_LINE] = "Line",
+        [WM8350_AUXADC_BATT] = "Battery",
+};
+
+
+static ssize_t show_voltage(struct device *dev,
+                            struct device_attribute *attr, char *buf)
+{
+        struct wm8350 *wm8350 = dev_get_drvdata(dev);
+        int channel = to_sensor_dev_attr(attr)->index;
+        int val;
+
+        val = wm8350_read_auxadc(wm8350, channel, 0, 0) * WM8350_AUX_COEFF;
+        val = DIV_ROUND_CLOSEST(val, 1000);
+
+        return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t show_label(struct device *dev,
+                          struct device_attribute *attr, char *buf)
+{
+        int channel = to_sensor_dev_attr(attr)->index;
+
+        return sprintf(buf, "%s\n", input_names[channel]);
+}
+
+#define WM8350_NAMED_VOLTAGE(id, name) \
+        static SENSOR_DEVICE_ATTR(in##id##_input, S_IRUGO, show_voltage,\
+                                  NULL, name);          \
+        static SENSOR_DEVICE_ATTR(in##id##_label, S_IRUGO, show_label,  \
+                                  NULL, name)
+
+static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
+
+WM8350_NAMED_VOLTAGE(0, WM8350_AUXADC_USB);
+WM8350_NAMED_VOLTAGE(1, WM8350_AUXADC_BATT);
+WM8350_NAMED_VOLTAGE(2, WM8350_AUXADC_LINE);
+
+static struct attribute *wm8350_attributes[] = {
+        &dev_attr_name.attr,
+
+        &sensor_dev_attr_in0_input.dev_attr.attr,
+        &sensor_dev_attr_in0_label.dev_attr.attr,
+        &sensor_dev_attr_in1_input.dev_attr.attr,
+        &sensor_dev_attr_in1_label.dev_attr.attr,
+        &sensor_dev_attr_in2_input.dev_attr.attr,
+        &sensor_dev_attr_in2_label.dev_attr.attr,
+
+        NULL,
+};
+
+static const struct attribute_group wm8350_attr_group = {
+        .attrs  = wm8350_attributes,
+};
+
+static int __devinit wm8350_hwmon_probe(struct platform_device *pdev)
+{
+        struct wm8350 *wm8350 = platform_get_drvdata(pdev);
+        int ret;
+
+        ret = sysfs_create_group(&pdev->dev.kobj, &wm8350_attr_group);
+        if (ret)
+                goto err;
+
+        wm8350->hwmon.classdev = hwmon_device_register(&pdev->dev);
+        if (IS_ERR(wm8350->hwmon.classdev)) {
+                ret = PTR_ERR(wm8350->hwmon.classdev);
+                goto err_group;
+        }
+
+        return 0;
+
+err_group:
+        sysfs_remove_group(&pdev->dev.kobj, &wm8350_attr_group);
+err:
+        return ret;
+}
+
+static int __devexit wm8350_hwmon_remove(struct platform_device *pdev)
+{
+        struct wm8350 *wm8350 = platform_get_drvdata(pdev);
+
+        hwmon_device_unregister(wm8350->hwmon.classdev);
+        sysfs_remove_group(&pdev->dev.kobj, &wm8350_attr_group);
+
+        return 0;
+}
+
+static struct platform_driver wm8350_hwmon_driver = {
+        .probe = wm8350_hwmon_probe,
+        .remove = __devexit_p(wm8350_hwmon_remove),
+        .driver = {
+                .name = "wm8350-hwmon",
+                .owner = THIS_MODULE,
+        },
+};
+
+static int __init wm8350_hwmon_init(void)
+{
+        return platform_driver_register(&wm8350_hwmon_driver);
+}
+module_init(wm8350_hwmon_init);
+
+static void __exit wm8350_hwmon_exit(void)
+{
+        platform_driver_unregister(&wm8350_hwmon_driver);
+}
+module_exit(wm8350_hwmon_exit);
+
+MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
+MODULE_DESCRIPTION("WM8350 Hardware Monitoring");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:wm8350-hwmon");
diff --git a/drivers/mfd/wm8350-core.c b/drivers/mfd/wm8350-core.c
index fe24079387c5..9d662a576a41 100644
--- a/drivers/mfd/wm8350-core.c
+++ b/drivers/mfd/wm8350-core.c
@@ -1472,6 +1472,8 @@ int wm8350_device_init(struct wm8350 *wm8350, int irq,
                                    &(wm8350->codec.pdev));
         wm8350_client_dev_register(wm8350, "wm8350-gpio",
                                    &(wm8350->gpio.pdev));
+        wm8350_client_dev_register(wm8350, "wm8350-hwmon",
+                                   &(wm8350->hwmon.pdev));
         wm8350_client_dev_register(wm8350, "wm8350-power",
                                    &(wm8350->power.pdev));
         wm8350_client_dev_register(wm8350, "wm8350-rtc", &(wm8350->rtc.pdev));
@@ -1498,6 +1500,7 @@ void wm8350_device_exit(struct wm8350 *wm8350)
         platform_device_unregister(wm8350->wdt.pdev);
         platform_device_unregister(wm8350->rtc.pdev);
         platform_device_unregister(wm8350->power.pdev);
+        platform_device_unregister(wm8350->hwmon.pdev);
         platform_device_unregister(wm8350->gpio.pdev);
         platform_device_unregister(wm8350->codec.pdev);
 
diff --git a/include/linux/mfd/wm8350/core.h b/include/linux/mfd/wm8350/core.h
index 42cca672f340..969b0b55615c 100644
--- a/include/linux/mfd/wm8350/core.h
+++ b/include/linux/mfd/wm8350/core.h
@@ -605,6 +605,11 @@ struct wm8350_irq {
         void *data;
 };
 
+struct wm8350_hwmon {
+        struct platform_device *pdev;
+        struct device *classdev;
+};
+
 struct wm8350 {
         struct device *dev;
 
@@ -629,6 +634,7 @@ struct wm8350 {
         /* Client devices */
         struct wm8350_codec codec;
         struct wm8350_gpio gpio;
+        struct wm8350_hwmon hwmon;
         struct wm8350_pmic pmic;
         struct wm8350_power power;
         struct wm8350_rtc rtc;