[lm-sensors] HWMON: S3C24XX series ADC driver

[Ben Dooks <ben@simtec.co.uk>]

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>

Index: linux.git/drivers/hwmon/Kconfig
=================================--- linux.git.orig/drivers/hwmon/Kconfig	2009-05-20 22:02:06.000000000 +0100
+++ linux.git/drivers/hwmon/Kconfig	2009-05-20 22:02:43.000000000 +0100
@@ -702,6 +702,16 @@ config SENSORS_SHT15
 	  This driver can also be built as a module.  If so, the module
 	  will be called sht15.
 
+config SENSORS_S3C_ADC
+	tristate "S3C24XX/S3C64XX Inbuilt ADC"
+	depends on HWMON && (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-adc.
+
 config SENSORS_SIS5595
 	tristate "Silicon Integrated Systems Corp. SiS5595"
 	depends on PCI
Index: linux.git/drivers/hwmon/Makefile
=================================--- linux.git.orig/drivers/hwmon/Makefile	2009-05-20 22:02:06.000000000 +0100
+++ linux.git/drivers/hwmon/Makefile	2009-05-20 22:02:43.000000000 +0100
@@ -76,6 +76,7 @@ obj-$(CONFIG_SENSORS_MAX6650)	+= max6650
 obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o
 obj-$(CONFIG_SENSORS_PC87427)	+= pc87427.o
 obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
+obj-$(CONFIG_SENSORS_S3C_ADC)	+= s3c-adc.o
 obj-$(CONFIG_SENSORS_SHT15)	+= sht15.o
 obj-$(CONFIG_SENSORS_SIS5595)	+= sis5595.o
 obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
Index: linux.git/drivers/hwmon/s3c-adc.c
=================================--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux.git/drivers/hwmon/s3c-adc.c	2009-05-20 22:20:32.000000000 +0100
@@ -0,0 +1,371 @@
+/* linux/drivers/hwmon/s3c-adc.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 - ADC hwmon client information
+ * @lock: Access lock for conversion.
+ * @wait: Wait queue for conversions to complete.
+ * @client: The client we registered with the S3C ADC core.
+ * @dev: The platform device we bound to.
+ * @hwmon_dev: The hwmon device we created.
+ * @in_attr: The device attributes we created.
+*/
+struct s3c_hwmon {
+	struct semaphore	lock;
+	wait_queue_head_t	wait;
+	int			val;
+
+	struct s3c_hwmon_client	*client;
+	struct platform_device	*dev;
+	struct device		*hwmon_dev;
+
+	struct sensor_device_attribute *in_attr[8];
+};
+
+static inline struct s3c_hwmon *dev_to_ourhwmon(struct platform_device *dev)
+{
+	return (struct s3c_hwmon *)platform_get_drvdata(dev);
+}
+
+static struct s3c_hwmon *done_adc;
+
+/**
+ * s3c_hwmon_adcdone - ADC core callback
+ * @value: The value that we got from the ADC core
+ * @ignore: Only used for the touchscreen client.
+ * @left: The number of conversions left (not used here).
+ *
+ * This is called when the ADC has finished its conversion to
+ * inform us of the result.
+ */
+static void s3c_hwmon_adcdone(unsigned value, unsigned ignore, unsigned *left)
+{
+	struct s3c_hwmon *adc = done_adc;
+
+	hwmon->val = value;
+	wake_up(&hwmon->wait);
+}
+
+/**
+ * s3c_hwmon_read_ch - read a value from a given adc channel.
+ * @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 s3c_hwmon *hwmon, int channel)
+{
+	unsigned long timeout;
+	int ret;
+
+	ret = down_interruptible(&hwmon->lock);
+	if (ret < 0)
+		return ret;
+
+	dev_dbg(&hwmon->dev->dev, "reading channel %d\n", channel);
+
+	hwmon->val = -1;
+	done_adc = adc;
+
+	ret = s3c_adc_start(hwmon->client, channel, 1);
+	if (ret < 0)
+		goto err;
+
+	timeout = wait_event_timeout(hwmon->wait, hwmon->val >= 0, HZ / 2);
+	ret = (timeout = 0) ? -ETIMEDOUT : hwmon->val;
+
+ err:
+	up(&hwmon->lock);
+	return ret;
+}
+
+/**
+ * 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 = dev_to_ourhwmon(to_platform_device(dev));
+	int ret, nr;
+
+	nr = attr->attr.name[3] - '0';
+	ret = s3c_hwmon_read_ch(adc, nr);
+
+	return  (ret < 0) ? ret : snprintf(buf, PAGE_SIZE, "%d\n", ret);
+}
+
+#define DEF_ADC_ATTR(x)	\
+	static DEVICE_ATTR(adc##x##_raw, S_IRUGO, s3c_hwmon_show_raw, NULL)
+
+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 device_attribute *s3c_hwmon_attrs[8] = {
+	&dev_attr_adc0_raw,
+	&dev_attr_adc1_raw,
+	&dev_attr_adc2_raw,
+	&dev_attr_adc3_raw,
+	&dev_attr_adc4_raw,
+	&dev_attr_adc5_raw,
+	&dev_attr_adc6_raw,
+	&dev_attr_adc7_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_pdata *pdata = dev->platform_data;
+	struct s3c_hwmon *adc = dev_to_ourhwmon(to_platform_device(dev));
+	struct s3c_hwmon_chcfg *cfg;
+
+	int ret;
+
+	cfg = pdata->in[sen_attr->index];
+	if (!cfg)
+		return -EINVAL;
+
+	ret = s3c_hwmon_read_ch(adc,sen_attr->index);
+	if (ret < 0)
+		return ret;
+
+	ret *= cfg->mult;
+	ret /= cfg->div;
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", ret);
+}
+
+#define MAX_LABEL (16)
+
+/**
+ * s3c_hwmon_create_attr - create hwmon attribute for given channel.
+ * @hwmon: Our hwmon instance.
+ * @pdata: The platform data provided by the device.
+ * @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 s3c_hwmon *hwmon,
+				 struct s3c_hwmon_pdata *pdata,
+				 int channel)
+{
+	struct s3c_hwmon_chcfg *cfg = pdata->in[channel];
+	struct sensor_device_attribute *attr;
+	const char *name;
+
+	if (!cfg)
+		return 0;
+
+	attr = kzalloc(sizeof(*attr) + MAX_LABEL, GFP_KERNEL);
+	if (attr = NULL)
+		return -ENOMEM;
+
+	if (cfg->name)
+		name = cfg->name;
+	else {
+		name = (char *)(attr+1);
+		snprintf((char *)(attr+1), MAX_LABEL, "in_%d", channel);
+	}
+
+	attr->dev_attr.attr.name  = name;
+	attr->dev_attr.attr.mode  = S_IRUGO;
+	attr->dev_attr.attr.owner = THIS_MODULE;
+	attr->dev_attr.show = s3c_hwmon_ch_show;
+
+	attr->index = channel;
+	hwmon->in_attr[channel] = attr;
+
+	return device_create_file(&hwmon->dev->dev, &attr->dev_attr);
+}
+
+/**
+ * s3c_hwmon_probe - device probe entry.
+ * @dev: The device being probed.
+*/
+static int 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;
+
+	adc = kzalloc(sizeof(struct s3c_hwmon), GFP_KERNEL);
+	if (adc = NULL) {
+		dev_err(&dev->dev, "no memory\n");
+		return -ENOMEM;
+	}
+
+	platform_set_drvdata(dev, adc);
+	hwmon->dev = dev;
+
+	/* only enable the clock when we are actually using the adc */
+
+	init_waitqueue_head(&hwmon->wait);
+	init_MUTEX(&hwmon->lock);
+
+	/* Register with the core ADC driver. */
+
+	hwmon->client = s3c_adc_register(dev, NULL, s3c_hwmon_adcdone, 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. */
+
+	for (i = 0; i < ARRAY_SIZE(s3c_hwmon_attrs); i++) {
+		ret = device_create_file(&dev->dev, s3c_hwmon_attrs[i]);
+		if (ret) {
+			dev_err(&dev->dev, "error creating channel %d\n", i);
+
+			for (i--; i >= 0; i--)
+				device_remove_file(&dev->dev, s3c_hwmon_attrs[i]);
+
+			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_attribute;
+	}
+
+	if (pdata) {
+		for (i = 0; i < ARRAY_SIZE(pdata->in); i++)
+			s3c_hwmon_create_attr(adc, pdata, i);
+	}
+
+	return 0;
+
+ err_attribute:
+	for (i = 0; i < ARRAY_SIZE(s3c_hwmon_attrs); i++)
+		device_remove_file(&dev->dev, s3c_hwmon_attrs[i]);
+
+ err_registered:
+	s3c_adc_release(hwmon->client);
+
+ err_mem:
+	kfree(adc);
+	return ret;
+}
+
+static int __devexit s3c_hwmon_remove(struct platform_device *dev)
+{
+	struct s3c_hwmon *hwmon = dev_to_ourhwmon(dev);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(s3c_hwmon_attrs); i++)
+		device_remove_file(&dev->dev, s3c_hwmon_attrs[i]);
+
+	for (i = 0; i < ARRAY_SIZE(hwmon->in_attr); i++) {
+		if (!hwmon->in_attr[i])
+			continue;
+
+		device_remove_file(&dev->dev, &hwmon->in_attr[i]->dev_attr);
+		kfree(hwmon->in_attr[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_adc_init(void)
+{
+	return platform_driver_register(&s3c_hwmon_driver);
+}
+
+static void __exit s3c_adc_exit(void)
+{
+	platform_driver_unregister(&s3c_hwmon_driver);
+}
+
+module_init(s3c_adc_init);
+module_exit(s3c_adc_exit);
+
+MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
+MODULE_DESCRIPTION("S3C ADC HWMon driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:s3c-hwmon");
Index: linux.git/arch/arm/plat-s3c/include/plat/hwmon.h
=================================--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux.git/arch/arm/plat-s3c/include/plat/hwmon.h	2009-05-20 22:02:43.000000000 +0100
@@ -0,0 +1,43 @@
+/* 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	min;
+	unsigned int	max;
+	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 */
+

-- 
Ben (ben@fluff.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

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