Move the pcf8591 driver to hwmon

Directory drivers/i2c/chips is going away, so drivers there must find
new homes. For the pcf8591 driver, the best choice seems to be the
hwmon subsystem. While the Philips PCF8591 device isn't a typical
hardware monitoring chip, its DAC interface is compatible with the
hwmon one, so it fits somewhat.

If a better subsystem is ever created for ADC/DAC chips, the driver
could be moved there.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>

1 files changed, 325 insertions, 0 deletions

diff --git a/drivers/hwmon/pcf8591.c b/drivers/hwmon/pcf8591.c
new file mode 100644
index 000000000000..1d7ffebd679d
--- /dev/null
+++ b/drivers/hwmon/pcf8591.c
@@ -0,0 +1,325 @@
+/*
+    Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net>
+    Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
+    the help of Jean Delvare <khali@linux-fr.org>
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+
+/* Addresses to scan */
+static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
+                                        0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD_1(pcf8591);
+
+static int input_mode;
+module_param(input_mode, int, 0);
+MODULE_PARM_DESC(input_mode,
+        "Analog input mode:\n"
+        " 0 = four single ended inputs\n"
+        " 1 = three differential inputs\n"
+        " 2 = single ended and differential mixed\n"
+        " 3 = two differential inputs\n");
+
+/* The PCF8591 control byte
+      7    6    5    4    3    2    1    0
+   |  0 |AOEF|   AIP   |  0 |AINC|  AICH   | */
+
+/* Analog Output Enable Flag (analog output active if 1) */
+#define PCF8591_CONTROL_AOEF            0x40
+
+/* Analog Input Programming
+   0x00 = four single ended inputs
+   0x10 = three differential inputs
+   0x20 = single ended and differential mixed
+   0x30 = two differential inputs */
+#define PCF8591_CONTROL_AIP_MASK        0x30
+
+/* Autoincrement Flag (switch on if 1) */
+#define PCF8591_CONTROL_AINC            0x04
+
+/* Channel selection
+   0x00 = channel 0
+   0x01 = channel 1
+   0x02 = channel 2
+   0x03 = channel 3 */
+#define PCF8591_CONTROL_AICH_MASK       0x03
+
+/* Initial values */
+#define PCF8591_INIT_CONTROL    ((input_mode << 4) | PCF8591_CONTROL_AOEF)
+#define PCF8591_INIT_AOUT       0       /* DAC out = 0 */
+
+/* Conversions */
+#define REG_TO_SIGNED(reg)      (((reg) & 0x80)?((reg) - 256):(reg))
+
+struct pcf8591_data {
+        struct mutex update_lock;
+
+        u8 control;
+        u8 aout;
+};
+
+static void pcf8591_init_client(struct i2c_client *client);
+static int pcf8591_read_channel(struct device *dev, int channel);
+
+/* following are the sysfs callback functions */
+#define show_in_channel(channel)                                        \
+static ssize_t show_in##channel##_input(struct device *dev, struct device_attribute *attr, char *buf)   \
+{                                                                       \
+        return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
+}                                                                       \
+static DEVICE_ATTR(in##channel##_input, S_IRUGO,                        \
+                   show_in##channel##_input, NULL);
+
+show_in_channel(0);
+show_in_channel(1);
+show_in_channel(2);
+show_in_channel(3);
+
+static ssize_t show_out0_ouput(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
+        return sprintf(buf, "%d\n", data->aout * 10);
+}
+
+static ssize_t set_out0_output(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
+{
+        unsigned int value;
+        struct i2c_client *client = to_i2c_client(dev);
+        struct pcf8591_data *data = i2c_get_clientdata(client);
+        if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
+                data->aout = value;
+                i2c_smbus_write_byte_data(client, data->control, data->aout);
+                return count;
+        }
+        return -EINVAL;
+}
+
+static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
+                   show_out0_ouput, set_out0_output);
+
+static ssize_t show_out0_enable(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
+        return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
+}
+
+static ssize_t set_out0_enable(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct pcf8591_data *data = i2c_get_clientdata(client);
+        unsigned long val = simple_strtoul(buf, NULL, 10);
+
+        mutex_lock(&data->update_lock);
+        if (val)
+                data->control |= PCF8591_CONTROL_AOEF;
+        else
+                data->control &= ~PCF8591_CONTROL_AOEF;
+        i2c_smbus_write_byte(client, data->control);
+        mutex_unlock(&data->update_lock);
+        return count;
+}
+
+static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
+                   show_out0_enable, set_out0_enable);
+
+static struct attribute *pcf8591_attributes[] = {
+        &dev_attr_out0_enable.attr,
+        &dev_attr_out0_output.attr,
+        &dev_attr_in0_input.attr,
+        &dev_attr_in1_input.attr,
+        NULL
+};
+
+static const struct attribute_group pcf8591_attr_group = {
+        .attrs = pcf8591_attributes,
+};
+
+static struct attribute *pcf8591_attributes_opt[] = {
+        &dev_attr_in2_input.attr,
+        &dev_attr_in3_input.attr,
+        NULL
+};
+
+static const struct attribute_group pcf8591_attr_group_opt = {
+        .attrs = pcf8591_attributes_opt,
+};
+
+/*
+ * Real code
+ */
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int pcf8591_detect(struct i2c_client *client, int kind,
+                          struct i2c_board_info *info)
+{
+        struct i2c_adapter *adapter = client->adapter;
+
+        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
+                                     | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
+                return -ENODEV;
+
+        /* Now, we would do the remaining detection. But the PCF8591 is plainly
+           impossible to detect! Stupid chip. */
+
+        strlcpy(info->type, "pcf8591", I2C_NAME_SIZE);
+
+        return 0;
+}
+
+static int pcf8591_probe(struct i2c_client *client,
+                         const struct i2c_device_id *id)
+{
+        struct pcf8591_data *data;
+        int err;
+
+        if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
+                err = -ENOMEM;
+                goto exit;
+        }
+
+        i2c_set_clientdata(client, data);
+        mutex_init(&data->update_lock);
+
+        /* Initialize the PCF8591 chip */
+        pcf8591_init_client(client);
+
+        /* Register sysfs hooks */
+        err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
+        if (err)
+                goto exit_kfree;
+
+        /* Register input2 if not in "two differential inputs" mode */
+        if (input_mode != 3) {
+                if ((err = device_create_file(&client->dev,
+                                              &dev_attr_in2_input)))
+                        goto exit_sysfs_remove;
+        }
+
+        /* Register input3 only in "four single ended inputs" mode */
+        if (input_mode == 0) {
+                if ((err = device_create_file(&client->dev,
+                                              &dev_attr_in3_input)))
+                        goto exit_sysfs_remove;
+        }
+
+        return 0;
+
+exit_sysfs_remove:
+        sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
+        sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
+exit_kfree:
+        kfree(data);
+exit:
+        return err;
+}
+
+static int pcf8591_remove(struct i2c_client *client)
+{
+        sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
+        sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
+        kfree(i2c_get_clientdata(client));
+        return 0;
+}
+
+/* Called when we have found a new PCF8591. */
+static void pcf8591_init_client(struct i2c_client *client)
+{
+        struct pcf8591_data *data = i2c_get_clientdata(client);
+        data->control = PCF8591_INIT_CONTROL;
+        data->aout = PCF8591_INIT_AOUT;
+
+        i2c_smbus_write_byte_data(client, data->control, data->aout);
+
+        /* The first byte transmitted contains the conversion code of the
+           previous read cycle. FLUSH IT! */
+        i2c_smbus_read_byte(client);
+}
+
+static int pcf8591_read_channel(struct device *dev, int channel)
+{
+        u8 value;
+        struct i2c_client *client = to_i2c_client(dev);
+        struct pcf8591_data *data = i2c_get_clientdata(client);
+
+        mutex_lock(&data->update_lock);
+
+        if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
+                data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
+                              | channel;
+                i2c_smbus_write_byte(client, data->control);
+
+                /* The first byte transmitted contains the conversion code of
+                   the previous read cycle. FLUSH IT! */
+                i2c_smbus_read_byte(client);
+        }
+        value = i2c_smbus_read_byte(client);
+
+        mutex_unlock(&data->update_lock);
+
+        if ((channel == 2 && input_mode == 2) ||
+            (channel != 3 && (input_mode == 1 || input_mode == 3)))
+                return (10 * REG_TO_SIGNED(value));
+        else
+                return (10 * value);
+}
+
+static const struct i2c_device_id pcf8591_id[] = {
+        { "pcf8591", 0 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, pcf8591_id);
+
+static struct i2c_driver pcf8591_driver = {
+        .driver = {
+                .name   = "pcf8591",
+        },
+        .probe          = pcf8591_probe,
+        .remove         = pcf8591_remove,
+        .id_table       = pcf8591_id,
+
+        .class          = I2C_CLASS_HWMON,      /* Nearest choice */
+        .detect         = pcf8591_detect,
+        .address_data   = &addr_data,
+};
+
+static int __init pcf8591_init(void)
+{
+        if (input_mode < 0 || input_mode > 3) {
+                printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
+                       input_mode);
+                input_mode = 0;
+        }
+        return i2c_add_driver(&pcf8591_driver);
+}
+
+static void __exit pcf8591_exit(void)
+{
+        i2c_del_driver(&pcf8591_driver);
+}
+
+MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
+MODULE_DESCRIPTION("PCF8591 driver");
+MODULE_LICENSE("GPL");
+
+module_init(pcf8591_init);
+module_exit(pcf8591_exit);