diff options
Diffstat (limited to 'drivers/hwmon/pcf8591.c')
| -rw-r--r-- | drivers/hwmon/pcf8591.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/drivers/hwmon/pcf8591.c b/drivers/hwmon/pcf8591.c new file mode 100644 index 000000000..60e25c85e --- /dev/null +++ b/drivers/hwmon/pcf8591.c @@ -0,0 +1,335 @@ +/* + * 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 <jdelvare@suse.de> + * + * 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. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/i2c.h> +#include <linux/mutex.h> +#include <linux/err.h> +#include <linux/hwmon.h> + +/* Insmod parameters */ + +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 device *hwmon_dev; + 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 out0_output_show(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 out0_output_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + unsigned long val; + struct i2c_client *client = to_i2c_client(dev); + struct pcf8591_data *data = i2c_get_clientdata(client); + int err; + + err = kstrtoul(buf, 10, &val); + if (err) + return err; + + val /= 10; + if (val > 255) + return -EINVAL; + + data->aout = val; + i2c_smbus_write_byte_data(client, data->control, data->aout); + return count; +} + +static DEVICE_ATTR_RW(out0_output); + +static ssize_t out0_enable_show(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 out0_enable_store(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; + int err; + + err = kstrtoul(buf, 10, &val); + if (err) + return err; + + 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_RW(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 + */ + +static int pcf8591_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct pcf8591_data *data; + int err; + + data = devm_kzalloc(&client->dev, sizeof(struct pcf8591_data), + GFP_KERNEL); + if (!data) + return -ENOMEM; + + 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) + return err; + + /* Register input2 if not in "two differential inputs" mode */ + if (input_mode != 3) { + err = device_create_file(&client->dev, &dev_attr_in2_input); + if (err) + goto exit_sysfs_remove; + } + + /* Register input3 only in "four single ended inputs" mode */ + if (input_mode == 0) { + err = device_create_file(&client->dev, &dev_attr_in3_input); + if (err) + goto exit_sysfs_remove; + } + + data->hwmon_dev = hwmon_device_register(&client->dev); + if (IS_ERR(data->hwmon_dev)) { + err = PTR_ERR(data->hwmon_dev); + 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); + return err; +} + +static int pcf8591_remove(struct i2c_client *client) +{ + struct pcf8591_data *data = i2c_get_clientdata(client); + + hwmon_device_unregister(data->hwmon_dev); + sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt); + sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group); + 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, +}; + +static int __init pcf8591_init(void) +{ + if (input_mode < 0 || input_mode > 3) { + pr_warn("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); |