ARM: HWMON: S3C24XX series ADC driver

Add support for the ADC controller on the S3C series of processors to
drivers/hwmon for use with hardware monitoring systems.
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

arch/arm/plat-s3c/include/plat/hwmon.h

+/* linux/arch/arm/plat-s3c/include/plat/hwmon.h
+ *
+ * Copyright 2005 Simtec Electronics
+ *	Ben Dooks <ben@simtec.co.uk>
+ *	http://armlinux.simtec.co.uk/
+ *
+ * S3C - HWMon interface for ADC
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#ifndef __ASM_ARCH_ADC_HWMON_H
+#define __ASM_ARCH_ADC_HWMON_H __FILE__
+
+/**
+ * s3c_hwmon_chcfg - channel configuration
+ * @name: The name to give this channel.
+ * @mult: Multiply the ADC value read by this.
+ * @div: Divide the value from the ADC by this.
+ *
+ * The value read from the ADC is converted to a value that
+ * hwmon expects (mV) by result = (value_read * @mult) / @div.
+ */
+struct s3c_hwmon_chcfg {
+	const char	*name;
+	unsigned int	mult;
+	unsigned int	div;
+};
+
+/**
+ * s3c_hwmon_pdata - HWMON platform data
+ * @in: One configuration for each possible channel used.
+ */
+struct s3c_hwmon_pdata {
+	struct s3c_hwmon_chcfg	*in[8];
+};
+
+#endif /* __ASM_ARCH_ADC_HWMON_H */
+

drivers/hwmon/Kconfig

@@ -702,6 +702,23 @@ config SENSORS_SHT15
 	  This driver can also be built as a module.  If so, the module
 	  will be called sht15.
 
+config SENSORS_S3C
+	tristate "S3C24XX/S3C64XX Inbuilt ADC"
+	depends on ARCH_S3C2410 || ARCH_S3C64XX
+	help
+	  If you say yes here you get support for the on-board ADCs of
+	  the Samsung S3C24XX or S3C64XX series of SoC
+
+	  This driver can also be built as a module. If so, the module
+	  will be called s3c-hwmo.
+
+config SENSORS_S3C_RAW
+	bool "Include raw channel attributes in sysfs"
+	depends on SENSORS_S3C
+	help
+	  Say Y here if you want to include raw copies of all the ADC
+	  channels in sysfs.
+
 config SENSORS_SIS5595
 	tristate "Silicon Integrated Systems Corp. SiS5595"
 	depends on PCI

drivers/hwmon/Makefile

@@ -76,6 +76,7 @@ obj-$(CONFIG_SENSORS_MAX6650)	+= max6650.o
 obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o
 obj-$(CONFIG_SENSORS_PC87427)	+= pc87427.o
 obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
+obj-$(CONFIG_SENSORS_S3C)	+= s3c-hwmon.o
 obj-$(CONFIG_SENSORS_SHT15)	+= sht15.o
 obj-$(CONFIG_SENSORS_SIS5595)	+= sis5595.o
 obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o

drivers/hwmon/s3c-hwmon.c

+/* linux/drivers/hwmon/s3c-hwmon.c
+ *
+ * Copyright (C) 2005, 2008, 2009 Simtec Electronics
+ *	http://armlinux.simtec.co.uk/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C24XX/S3C64XX ADC hwmon support
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License 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.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+
+#include <plat/adc.h>
+#include <plat/hwmon.h>
+
+struct s3c_hwmon_attr {
+	struct sensor_device_attribute	in;
+	struct sensor_device_attribute	label;
+	char				in_name[12];
+	char				label_name[12];
+};
+
+/**
+ * struct s3c_hwmon - ADC hwmon client information
+ * @lock: Access lock to serialise the conversions.
+ * @client: The client we registered with the S3C ADC core.
+ * @hwmon_dev: The hwmon device we created.
+ * @attr: The holders for the channel attributes.
+*/
+struct s3c_hwmon {
+	struct semaphore	lock;
+	struct s3c_adc_client	*client;
+	struct device		*hwmon_dev;
+
+	struct s3c_hwmon_attr	attrs[8];
+};
+
+/**
+ * s3c_hwmon_read_ch - read a value from a given adc channel.
+ * @dev: The device.
+ * @hwmon: Our state.
+ * @channel: The channel we're reading from.
+ *
+ * Read a value from the @channel with the proper locking and sleep until
+ * either the read completes or we timeout awaiting the ADC core to get
+ * back to us.
+ */
+static int s3c_hwmon_read_ch(struct device *dev,
+			     struct s3c_hwmon *hwmon, int channel)
+{
+	int ret;
+
+	ret = down_interruptible(&hwmon->lock);
+	if (ret < 0)
+		return ret;
+
+	dev_dbg(dev, "reading channel %d\n", channel);
+
+	ret = s3c_adc_read(hwmon->client, channel);
+	up(&hwmon->lock);
+
+	return ret;
+}
+
+#ifdef CONFIG_SENSORS_S3C_RAW
+/**
+ * s3c_hwmon_show_raw - show a conversion from the raw channel number.
+ * @dev: The device that the attribute belongs to.
+ * @attr: The attribute being read.
+ * @buf: The result buffer.
+ *
+ * This show deals with the raw attribute, registered for each possible
+ * ADC channel. This does a conversion and returns the raw (un-scaled)
+ * value returned from the hardware.
+ */
+static ssize_t s3c_hwmon_show_raw(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct s3c_hwmon *adc = platform_get_drvdata(to_platform_device(dev));
+	struct sensor_device_attribute *sa = to_sensor_dev_attr(attr);
+	int ret;
+
+	ret = s3c_hwmon_read_ch(dev, adc, sa->index);
+
+	return  (ret < 0) ? ret : snprintf(buf, PAGE_SIZE, "%d\n", ret);
+}
+
+#define DEF_ADC_ATTR(x)	\
+	static SENSOR_DEVICE_ATTR(adc##x##_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, x)
+
+DEF_ADC_ATTR(0);
+DEF_ADC_ATTR(1);
+DEF_ADC_ATTR(2);
+DEF_ADC_ATTR(3);
+DEF_ADC_ATTR(4);
+DEF_ADC_ATTR(5);
+DEF_ADC_ATTR(6);
+DEF_ADC_ATTR(7);
+
+static struct attribute *s3c_hwmon_attrs[9] = {
+	&sensor_dev_attr_adc0_raw.dev_attr.attr,
+	&sensor_dev_attr_adc1_raw.dev_attr.attr,
+	&sensor_dev_attr_adc2_raw.dev_attr.attr,
+	&sensor_dev_attr_adc3_raw.dev_attr.attr,
+	&sensor_dev_attr_adc4_raw.dev_attr.attr,
+	&sensor_dev_attr_adc5_raw.dev_attr.attr,
+	&sensor_dev_attr_adc6_raw.dev_attr.attr,
+	&sensor_dev_attr_adc7_raw.dev_attr.attr,
+	NULL,
+};
+
+static struct attribute_group s3c_hwmon_attrgroup = {
+	.attrs	= s3c_hwmon_attrs,
+};
+
+static inline int s3c_hwmon_add_raw(struct device *dev)
+{
+	return sysfs_create_group(&dev->kobj, &s3c_hwmon_attrgroup);
+}
+
+static inline void s3c_hwmon_remove_raw(struct device *dev)
+{
+	sysfs_remove_group(&dev->kobj, &s3c_hwmon_attrgroup);
+}
+
+#else
+
+static inline int s3c_hwmon_add_raw(struct device *dev) { return 0; }
+static inline void s3c_hwmon_remove_raw(struct device *dev) { }
+
+#endif /* CONFIG_SENSORS_S3C_RAW */
+
+/**
+ * s3c_hwmon_ch_show - show value of a given channel
+ * @dev: The device that the attribute belongs to.
+ * @attr: The attribute being read.
+ * @buf: The result buffer.
+ *
+ * Read a value from the ADC and scale it before returning it to the
+ * caller. The scale factor is gained from the channel configuration
+ * passed via the platform data when the device was registered.
+ */
+static ssize_t s3c_hwmon_ch_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
+	struct s3c_hwmon *hwmon = platform_get_drvdata(to_platform_device(dev));
+	struct s3c_hwmon_pdata *pdata = dev->platform_data;
+	struct s3c_hwmon_chcfg *cfg;
+	int ret;
+
+	cfg = pdata->in[sen_attr->index];
+
+	ret = s3c_hwmon_read_ch(dev, hwmon, sen_attr->index);
+	if (ret < 0)
+		return ret;
+
+	ret *= cfg->mult;
+	ret = DIV_ROUND_CLOSEST(ret, cfg->div);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", ret);
+}
+
+/**
+ * s3c_hwmon_label_show - show label name of the given channel.
+ * @dev: The device that the attribute belongs to.
+ * @attr: The attribute being read.
+ * @buf: The result buffer.
+ *
+ * Return the label name of a given channel
+ */
+static ssize_t s3c_hwmon_label_show(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
+	struct s3c_hwmon_pdata *pdata = dev->platform_data;
+	struct s3c_hwmon_chcfg *cfg;
+
+	cfg = pdata->in[sen_attr->index];
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", cfg->name);
+}
+
+/**
+ * s3c_hwmon_create_attr - create hwmon attribute for given channel.
+ * @dev: The device to create the attribute on.
+ * @cfg: The channel configuration passed from the platform data.
+ * @channel: The ADC channel number to process.
+ *
+ * Create the scaled attribute for use with hwmon from the specified
+ * platform data in @pdata. The sysfs entry is handled by the routine
+ * s3c_hwmon_ch_show().
+ *
+ * The attribute name is taken from the configuration data if present
+ * otherwise the name is taken by concatenating in_ with the channel
+ * number.
+ */
+static int s3c_hwmon_create_attr(struct device *dev,
+				 struct s3c_hwmon_chcfg *cfg,
+				 struct s3c_hwmon_attr *attrs,
+				 int channel)
+{
+	struct sensor_device_attribute *attr;
+	int ret;
+
+	snprintf(attrs->in_name, sizeof(attrs->in_name), "in%d_input", channel);
+
+	attr = &attrs->in;
+	attr->index = channel;
+	attr->dev_attr.attr.name  = attrs->in_name;
+	attr->dev_attr.attr.mode  = S_IRUGO;
+	attr->dev_attr.attr.owner = THIS_MODULE;
+	attr->dev_attr.show = s3c_hwmon_ch_show;
+
+	ret =  device_create_file(dev, &attr->dev_attr);
+	if (ret < 0) {
+		dev_err(dev, "failed to create input attribute\n");
+		return ret;
+	}
+
+	/* if this has a name, add a label */
+	if (cfg->name) {
+		snprintf(attrs->label_name, sizeof(attrs->label_name),
+			 "in%d_label", channel);
+
+		attr = &attrs->label;
+		attr->index = channel;
+		attr->dev_attr.attr.name  = attrs->label_name;
+		attr->dev_attr.attr.mode  = S_IRUGO;
+		attr->dev_attr.attr.owner = THIS_MODULE;
+		attr->dev_attr.show = s3c_hwmon_label_show;
+
+		ret = device_create_file(dev, &attr->dev_attr);
+		if (ret < 0) {
+			device_remove_file(dev, &attrs->in.dev_attr);
+			dev_err(dev, "failed to create label attribute\n");
+		}
+	}
+
+	return ret;
+}
+
+static void s3c_hwmon_remove_attr(struct device *dev,
+				  struct s3c_hwmon_attr *attrs)
+{
+	device_remove_file(dev, &attrs->in.dev_attr);
+	device_remove_file(dev, &attrs->label.dev_attr);
+}
+
+/**
+ * s3c_hwmon_probe - device probe entry.
+ * @dev: The device being probed.
+*/
+static int __devinit s3c_hwmon_probe(struct platform_device *dev)
+{
+	struct s3c_hwmon_pdata *pdata = dev->dev.platform_data;
+	struct s3c_hwmon *hwmon;
+	int ret = 0;
+	int i;
+
+	if (!pdata) {
+		dev_err(&dev->dev, "no platform data supplied\n");
+		return -EINVAL;
+	}
+
+	hwmon = kzalloc(sizeof(struct s3c_hwmon), GFP_KERNEL);
+	if (hwmon == NULL) {
+		dev_err(&dev->dev, "no memory\n");
+		return -ENOMEM;
+	}
+
+	platform_set_drvdata(dev, hwmon);
+
+	init_MUTEX(&hwmon->lock);
+
+	/* Register with the core ADC driver. */
+
+	hwmon->client = s3c_adc_register(dev, NULL, NULL, 0);
+	if (IS_ERR(hwmon->client)) {
+		dev_err(&dev->dev, "cannot register adc\n");
+		ret = PTR_ERR(hwmon->client);
+		goto err_mem;
+	}
+
+	/* add attributes for our adc devices. */
+
+	ret = s3c_hwmon_add_raw(&dev->dev);
+	if (ret)
+		goto err_registered;
+
+	/* register with the hwmon core */
+
+	hwmon->hwmon_dev = hwmon_device_register(&dev->dev);
+	if (IS_ERR(hwmon->hwmon_dev)) {
+		dev_err(&dev->dev, "error registering with hwmon\n");
+		ret = PTR_ERR(hwmon->hwmon_dev);
+		goto err_raw_attribute;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(pdata->in); i++) {
+		if (!pdata->in[i])
+			continue;
+
+		if (pdata->in[i]->mult >= 0x10000)
+			dev_warn(&dev->dev,
+				 "channel %d multiplier too large\n",
+				 i);
+
+		ret = s3c_hwmon_create_attr(&dev->dev, pdata->in[i],
+					    &hwmon->attrs[i], i);
+		if (ret) {
+			dev_err(&dev->dev,
+					"error creating channel %d\n", i);
+
+			for (i--; i >= 0; i--)
+				s3c_hwmon_remove_attr(&dev->dev,
+							      &hwmon->attrs[i]);
+
+			goto err_hwmon_register;
+		}
+	}
+
+	return 0;
+
+ err_hwmon_register:
+	hwmon_device_unregister(hwmon->hwmon_dev);
+
+ err_raw_attribute:
+	s3c_hwmon_remove_raw(&dev->dev);
+
+ err_registered:
+	s3c_adc_release(hwmon->client);
+
+ err_mem:
+	kfree(hwmon);
+	return ret;
+}
+
+static int __devexit s3c_hwmon_remove(struct platform_device *dev)
+{
+	struct s3c_hwmon *hwmon = platform_get_drvdata(dev);
+	int i;
+
+	s3c_hwmon_remove_raw(&dev->dev);
+
+	for (i = 0; i < ARRAY_SIZE(hwmon->attrs); i++)
+		s3c_hwmon_remove_attr(&dev->dev, &hwmon->attrs[i]);
+
+	hwmon_device_unregister(hwmon->hwmon_dev);
+	s3c_adc_release(hwmon->client);
+
+	return 0;
+}
+
+static struct platform_driver s3c_hwmon_driver = {
+	.driver	= {
+		.name		= "s3c-hwmon",
+		.owner		= THIS_MODULE,
+	},
+	.probe		= s3c_hwmon_probe,
+	.remove		= __devexit_p(s3c_hwmon_remove),
+};
+
+static int __init s3c_hwmon_init(void)
+{
+	return platform_driver_register(&s3c_hwmon_driver);
+}
+
+static void __exit s3c_hwmon_exit(void)
+{
+	platform_driver_unregister(&s3c_hwmon_driver);
+}
+
+module_init(s3c_hwmon_init);
+module_exit(s3c_hwmon_exit);
+
+MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
+MODULE_DESCRIPTION("S3C ADC HWMon driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:s3c-hwmon");