hwmon: Add Freescale MC13783 ADC driver

This driver provides support for the ADC integrated into the
Freescale MC13783 PMIC.

Signed-off-by: Luotao Fu <l.fu@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Cc: Eric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Documentation/hwmon/mc13783-adc

@@ -0,0 +1,50 @@
+Kernel driver mc13783-adc
+=========================
+
+Supported chips:
+  * Freescale Atlas MC13783
+    Prefix: 'mc13783_adc'
+    Datasheet: http://www.freescale.com/files/rf_if/doc/data_sheet/MC13783.pdf?fsrch=1
+
+Authors:
+    Sascha Hauer <s.hauer@pengutronix.de>
+    Luotao Fu <l.fu@pengutronix.de>
+
+Description
+-----------
+
+The Freescale MC13783 is a Power Management and Audio Circuit. Among
+other things it contains a 10-bit A/D converter. The converter has 16
+channels which can be used in different modes.
+The A/D converter has a resolution of 2.25mV. Channels 0-4 have
+a dedicated meaning with chip internal scaling applied. Channels 5-7
+can be used as general purpose inputs or alternatively in a dedicated
+mode. Channels 12-15 are occupied by the touchscreen if it's active.
+
+Currently the driver only supports channels 2 and 5-15 with no alternative
+modes for channels 5-7.
+
+See this table for the meaning of the different channels and their chip
+internal scaling:
+
+Channel	Signal						Input Range	Scaling
+-------------------------------------------------------------------------------
+0	Battery Voltage (BATT)				2.50 - 4.65V	-2.40V
+1	Battery Current (BATT - BATTISNS)		-50 - 50 mV	x20
+2	Application Supply (BP)				2.50 - 4.65V	-2.40V
+3	Charger Voltage (CHRGRAW)			0 - 10V /	/5
+							0 - 20V		/10
+4	Charger Current (CHRGISNSP-CHRGISNSN)		-0.25V - 0.25V	x4
+5	General Purpose ADIN5 / Battery Pack Thermistor	0 - 2.30V	No
+6	General Purpose ADIN6 / Backup Voltage (LICELL)	0 - 2.30V /	No /
+							1.50 - 3.50V	-1.20V
+7	General Purpose ADIN7 / UID / Die Temperature	0 - 2.30V /	No /
+							0 - 2.55V /	x0.9 / No
+8	General Purpose ADIN8				0 - 2.30V	No
+9	General Purpose ADIN9				0 - 2.30V	No
+10	General Purpose ADIN10				0 - 2.30V	No
+11	General Purpose ADIN11				0 - 2.30V	No
+12	General Purpose TSX1 / Touchscreen X-plate 1	0 - 2.30V	No
+13	General Purpose TSX2 / Touchscreen X-plate 2	0 - 2.30V	No
+14	General Purpose TSY1 / Touchscreen Y-plate 1	0 - 2.30V	No
+15	General Purpose TSY2 / Touchscreen Y-plate 2	0 - 2.30V	No

drivers/hwmon/Kconfig

@@ -1017,6 +1017,12 @@ config SENSORS_APPLESMC
 	  Say Y here if you have an applicable laptop and want to experience
 	  the awesome power of applesmc.
 
+config SENSORS_MC13783_ADC
+        tristate "Freescale MC13783 ADC"
+        depends on MFD_MC13783
+        help
+          Support for the A/D converter on MC13783 PMIC.
+
 if ACPI
 
 comment "ACPI drivers"

drivers/hwmon/Makefile

@@ -74,6 +74,7 @@ obj-$(CONFIG_SENSORS_LTC4245)	+= ltc4245.o
 obj-$(CONFIG_SENSORS_MAX1111)	+= max1111.o
 obj-$(CONFIG_SENSORS_MAX1619)	+= max1619.o
 obj-$(CONFIG_SENSORS_MAX6650)	+= max6650.o
+obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
 obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o
 obj-$(CONFIG_SENSORS_PC87427)	+= pc87427.o
 obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o

drivers/hwmon/mc13783-adc.c

@@ -0,0 +1,236 @@
+/*
+ * Driver for the Freescale Semiconductor MC13783 adc.
+ *
+ * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright (C) 2009 Sascha Hauer, Pengutronix
+ *
+ * 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.
+ *
+ * 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 St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/mfd/mc13783-private.h>
+#include <linux/platform_device.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/hwmon.h>
+#include <linux/init.h>
+#include <linux/err.h>
+
+#define MC13783_ADC_NAME	"mc13783-adc"
+
+struct mc13783_adc_priv {
+	struct mc13783 *mc13783;
+	struct device *hwmon_dev;
+};
+
+static ssize_t mc13783_adc_show_name(struct device *dev, struct device_attribute
+			      *devattr, char *buf)
+{
+	return sprintf(buf, "mc13783_adc\n");
+}
+
+static int mc13783_adc_read(struct device *dev,
+		struct device_attribute *devattr, unsigned int *val)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	unsigned int channel = attr->index;
+	unsigned int sample[4];
+	int ret;
+
+	ret = mc13783_adc_do_conversion(priv->mc13783,
+			MC13783_ADC_MODE_MULT_CHAN,
+			channel, sample);
+	if (ret)
+		return ret;
+
+	channel &= 0x7;
+
+	*val = (sample[channel % 4] >> (channel > 3 ? 14 : 2)) & 0x3ff;
+
+	return 0;
+}
+
+static ssize_t mc13783_adc_read_bp(struct device *dev,
+		struct device_attribute *devattr, char *buf)
+{
+	unsigned val;
+	int ret = mc13783_adc_read(dev, devattr, &val);
+
+	if (ret)
+		return ret;
+
+	/*
+	 * BP (channel 2) reports with offset 2.4V to the actual value to fit
+	 * the input range of the ADC.  unit = 2.25mV = 9/4 mV.
+	 */
+	val = DIV_ROUND_CLOSEST(val * 9, 4) + 2400;
+
+	return sprintf(buf, "%u\n", val);
+}
+
+static ssize_t mc13783_adc_read_gp(struct device *dev,
+		struct device_attribute *devattr, char *buf)
+{
+	unsigned val;
+	int ret = mc13783_adc_read(dev, devattr, &val);
+
+	if (ret)
+		return ret;
+
+	/*
+	 * input range is [0, 2.3V], val has 10 bits, so each bit
+	 * is worth 9/4 mV.
+	 */
+	val = DIV_ROUND_CLOSEST(val * 9, 4);
+
+	return sprintf(buf, "%u\n", val);
+}
+
+static DEVICE_ATTR(name, S_IRUGO, mc13783_adc_show_name, NULL);
+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, mc13783_adc_read_bp, NULL, 2);
+static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, mc13783_adc_read_gp, NULL, 5);
+static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, mc13783_adc_read_gp, NULL, 6);
+static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, mc13783_adc_read_gp, NULL, 7);
+static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, mc13783_adc_read_gp, NULL, 8);
+static SENSOR_DEVICE_ATTR(in9_input, S_IRUGO, mc13783_adc_read_gp, NULL, 9);
+static SENSOR_DEVICE_ATTR(in10_input, S_IRUGO, mc13783_adc_read_gp, NULL, 10);
+static SENSOR_DEVICE_ATTR(in11_input, S_IRUGO, mc13783_adc_read_gp, NULL, 11);
+static SENSOR_DEVICE_ATTR(in12_input, S_IRUGO, mc13783_adc_read_gp, NULL, 12);
+static SENSOR_DEVICE_ATTR(in13_input, S_IRUGO, mc13783_adc_read_gp, NULL, 13);
+static SENSOR_DEVICE_ATTR(in14_input, S_IRUGO, mc13783_adc_read_gp, NULL, 14);
+static SENSOR_DEVICE_ATTR(in15_input, S_IRUGO, mc13783_adc_read_gp, NULL, 15);
+
+static struct attribute *mc13783_attr[] = {
+	&dev_attr_name.attr,
+	&sensor_dev_attr_in2_input.dev_attr.attr,
+	&sensor_dev_attr_in5_input.dev_attr.attr,
+	&sensor_dev_attr_in6_input.dev_attr.attr,
+	&sensor_dev_attr_in7_input.dev_attr.attr,
+	&sensor_dev_attr_in8_input.dev_attr.attr,
+	&sensor_dev_attr_in9_input.dev_attr.attr,
+	&sensor_dev_attr_in10_input.dev_attr.attr,
+	&sensor_dev_attr_in11_input.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group mc13783_group = {
+	.attrs = mc13783_attr,
+};
+
+/* last four channels may be occupied by the touchscreen */
+static struct attribute *mc13783_attr_ts[] = {
+	&sensor_dev_attr_in12_input.dev_attr.attr,
+	&sensor_dev_attr_in13_input.dev_attr.attr,
+	&sensor_dev_attr_in14_input.dev_attr.attr,
+	&sensor_dev_attr_in15_input.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group mc13783_group_ts = {
+	.attrs = mc13783_attr_ts,
+};
+
+static int __init mc13783_adc_probe(struct platform_device *pdev)
+{
+	struct mc13783_adc_priv *priv;
+	int ret;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->mc13783 = dev_get_drvdata(pdev->dev.parent);
+
+	platform_set_drvdata(pdev, priv);
+
+	/* Register sysfs hooks */
+	ret = sysfs_create_group(&pdev->dev.kobj, &mc13783_group);
+	if (ret)
+		goto out_err_create1;
+
+	if (!(priv->mc13783->flags & MC13783_USE_TOUCHSCREEN))
+		ret = sysfs_create_group(&pdev->dev.kobj, &mc13783_group_ts);
+		if (ret)
+			goto out_err_create2;
+
+	priv->hwmon_dev = hwmon_device_register(&pdev->dev);
+	if (IS_ERR(priv->hwmon_dev)) {
+		ret = PTR_ERR(priv->hwmon_dev);
+		dev_err(&pdev->dev,
+				"hwmon_device_register failed with %d.\n", ret);
+		goto out_err_register;
+	}
+
+
+	return 0;
+
+out_err_register:
+
+	if (!(priv->mc13783->flags & MC13783_USE_TOUCHSCREEN))
+		sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_ts);
+out_err_create2:
+
+	sysfs_remove_group(&pdev->dev.kobj, &mc13783_group);
+out_err_create1:
+
+	platform_set_drvdata(pdev, NULL);
+	kfree(priv);
+
+	return ret;
+}
+
+static int __devexit mc13783_adc_remove(struct platform_device *pdev)
+{
+	struct mc13783_adc_priv *priv = platform_get_drvdata(pdev);
+
+	hwmon_device_unregister(priv->hwmon_dev);
+
+	if (!(priv->mc13783->flags & MC13783_USE_TOUCHSCREEN))
+		sysfs_remove_group(&pdev->dev.kobj, &mc13783_group_ts);
+
+	sysfs_remove_group(&pdev->dev.kobj, &mc13783_group);
+
+	platform_set_drvdata(pdev, NULL);
+	kfree(priv);
+
+	return 0;
+}
+
+static struct platform_driver mc13783_adc_driver = {
+	.remove 	= __devexit_p(mc13783_adc_remove),
+	.driver		= {
+		.owner	= THIS_MODULE,
+		.name	= MC13783_ADC_NAME,
+	},
+};
+
+static int __init mc13783_adc_init(void)
+{
+	return platform_driver_probe(&mc13783_adc_driver, mc13783_adc_probe);
+}
+
+static void __exit mc13783_adc_exit(void)
+{
+	platform_driver_unregister(&mc13783_adc_driver);
+}
+
+module_init(mc13783_adc_init);
+module_exit(mc13783_adc_exit);
+
+MODULE_DESCRIPTION("MC13783 ADC driver");
+MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" MC13783_ADC_NAME);