diff options
Diffstat (limited to 'drivers/i2c/chips/pcf8591.c')
| -rw-r--r-- | drivers/i2c/chips/pcf8591.c | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/drivers/i2c/chips/pcf8591.c b/drivers/i2c/chips/pcf8591.c new file mode 100644 index 0000000..16ce3e1 --- /dev/null +++ b/drivers/i2c/chips/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); |
