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>

1 files changed, 405 insertions, 0 deletions

diff --git a/drivers/hwmon/s3c-hwmon.c b/drivers/hwmon/s3c-hwmon.c
new file mode 100644
index 000000000000..3a524f2fe493
--- /dev/null
+++ b/drivers/hwmon/s3c-hwmon.c
@@ -0,0 +1,405 @@
+/* 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");