Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 1 | /* |
| 2 | pcf8575.c |
| 3 | |
| 4 | About the PCF8575 chip: the PCF8575 is a 16-bit I/O expander for the I2C bus |
| 5 | produced by a.o. Philips Semiconductors. |
| 6 | |
| 7 | Copyright (C) 2006 Michael Hennerich, Analog Devices Inc. |
| 8 | <hennerich@blackfin.uclinux.org> |
| 9 | Based on pcf8574.c. |
| 10 | |
| 11 | Copyright (c) 2007 Bart Van Assche <bart.vanassche@gmail.com>. |
| 12 | Ported this driver from ucLinux to the mainstream Linux kernel. |
| 13 | |
| 14 | This program is free software; you can redistribute it and/or modify |
| 15 | it under the terms of the GNU General Public License as published by |
| 16 | the Free Software Foundation; either version 2 of the License, or |
| 17 | (at your option) any later version. |
| 18 | |
| 19 | This program is distributed in the hope that it will be useful, |
| 20 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | GNU General Public License for more details. |
| 23 | |
| 24 | You should have received a copy of the GNU General Public License |
| 25 | along with this program; if not, write to the Free Software |
| 26 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 27 | */ |
| 28 | |
| 29 | #include <linux/module.h> |
| 30 | #include <linux/init.h> |
| 31 | #include <linux/i2c.h> |
| 32 | #include <linux/slab.h> /* kzalloc() */ |
| 33 | #include <linux/sysfs.h> /* sysfs_create_group() */ |
| 34 | |
Jean Delvare | 97addff | 2008-07-16 19:30:06 +0200 | [diff] [blame] | 35 | /* Addresses to scan: none, device can't be detected */ |
| 36 | static const unsigned short normal_i2c[] = { I2C_CLIENT_END }; |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 37 | |
| 38 | /* Insmod parameters */ |
| 39 | I2C_CLIENT_INSMOD; |
| 40 | |
| 41 | |
| 42 | /* Each client has this additional data */ |
| 43 | struct pcf8575_data { |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 44 | int write; /* last written value, or error code */ |
| 45 | }; |
| 46 | |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 47 | /* following are the sysfs callback functions */ |
| 48 | static ssize_t show_read(struct device *dev, struct device_attribute *attr, |
| 49 | char *buf) |
| 50 | { |
| 51 | struct i2c_client *client = to_i2c_client(dev); |
| 52 | u16 val; |
| 53 | u8 iopin_state[2]; |
| 54 | |
| 55 | i2c_master_recv(client, iopin_state, 2); |
| 56 | |
| 57 | val = iopin_state[0]; |
| 58 | val |= iopin_state[1] << 8; |
| 59 | |
| 60 | return sprintf(buf, "%u\n", val); |
| 61 | } |
| 62 | |
| 63 | static DEVICE_ATTR(read, S_IRUGO, show_read, NULL); |
| 64 | |
| 65 | static ssize_t show_write(struct device *dev, struct device_attribute *attr, |
| 66 | char *buf) |
| 67 | { |
| 68 | struct pcf8575_data *data = dev_get_drvdata(dev); |
| 69 | if (data->write < 0) |
| 70 | return data->write; |
| 71 | return sprintf(buf, "%d\n", data->write); |
| 72 | } |
| 73 | |
| 74 | static ssize_t set_write(struct device *dev, struct device_attribute *attr, |
| 75 | const char *buf, size_t count) |
| 76 | { |
| 77 | struct i2c_client *client = to_i2c_client(dev); |
| 78 | struct pcf8575_data *data = i2c_get_clientdata(client); |
| 79 | unsigned long val = simple_strtoul(buf, NULL, 10); |
| 80 | u8 iopin_state[2]; |
| 81 | |
| 82 | if (val > 0xffff) |
| 83 | return -EINVAL; |
| 84 | |
| 85 | data->write = val; |
| 86 | |
| 87 | iopin_state[0] = val & 0xFF; |
| 88 | iopin_state[1] = val >> 8; |
| 89 | |
| 90 | i2c_master_send(client, iopin_state, 2); |
| 91 | |
| 92 | return count; |
| 93 | } |
| 94 | |
| 95 | static DEVICE_ATTR(write, S_IWUSR | S_IRUGO, show_write, set_write); |
| 96 | |
| 97 | static struct attribute *pcf8575_attributes[] = { |
| 98 | &dev_attr_read.attr, |
| 99 | &dev_attr_write.attr, |
| 100 | NULL |
| 101 | }; |
| 102 | |
| 103 | static const struct attribute_group pcf8575_attr_group = { |
| 104 | .attrs = pcf8575_attributes, |
| 105 | }; |
| 106 | |
| 107 | /* |
| 108 | * Real code |
| 109 | */ |
| 110 | |
Jean Delvare | 97addff | 2008-07-16 19:30:06 +0200 | [diff] [blame] | 111 | /* Return 0 if detection is successful, -ENODEV otherwise */ |
| 112 | static int pcf8575_detect(struct i2c_client *client, int kind, |
| 113 | struct i2c_board_info *info) |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 114 | { |
Jean Delvare | 97addff | 2008-07-16 19:30:06 +0200 | [diff] [blame] | 115 | struct i2c_adapter *adapter = client->adapter; |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 116 | |
| 117 | if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) |
Jean Delvare | 97addff | 2008-07-16 19:30:06 +0200 | [diff] [blame] | 118 | return -ENODEV; |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 119 | |
Jean Delvare | 97addff | 2008-07-16 19:30:06 +0200 | [diff] [blame] | 120 | /* This is the place to detect whether the chip at the specified |
| 121 | address really is a PCF8575 chip. However, there is no method known |
| 122 | to detect whether an I2C chip is a PCF8575 or any other I2C chip. */ |
| 123 | |
| 124 | strlcpy(info->type, "pcf8575", I2C_NAME_SIZE); |
| 125 | |
| 126 | return 0; |
| 127 | } |
| 128 | |
| 129 | static int pcf8575_probe(struct i2c_client *client, |
| 130 | const struct i2c_device_id *id) |
| 131 | { |
| 132 | struct pcf8575_data *data; |
| 133 | int err; |
| 134 | |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 135 | data = kzalloc(sizeof(struct pcf8575_data), GFP_KERNEL); |
| 136 | if (!data) { |
| 137 | err = -ENOMEM; |
| 138 | goto exit; |
| 139 | } |
| 140 | |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 141 | i2c_set_clientdata(client, data); |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 142 | data->write = -EAGAIN; |
| 143 | |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 144 | /* Register sysfs hooks */ |
| 145 | err = sysfs_create_group(&client->dev.kobj, &pcf8575_attr_group); |
| 146 | if (err) |
Jean Delvare | 97addff | 2008-07-16 19:30:06 +0200 | [diff] [blame] | 147 | goto exit_free; |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 148 | |
| 149 | return 0; |
| 150 | |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 151 | exit_free: |
| 152 | kfree(data); |
| 153 | exit: |
| 154 | return err; |
| 155 | } |
| 156 | |
Jean Delvare | 97addff | 2008-07-16 19:30:06 +0200 | [diff] [blame] | 157 | static int pcf8575_remove(struct i2c_client *client) |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 158 | { |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 159 | sysfs_remove_group(&client->dev.kobj, &pcf8575_attr_group); |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 160 | kfree(i2c_get_clientdata(client)); |
| 161 | return 0; |
| 162 | } |
| 163 | |
Jean Delvare | 97addff | 2008-07-16 19:30:06 +0200 | [diff] [blame] | 164 | static const struct i2c_device_id pcf8575_id[] = { |
| 165 | { "pcf8575", 0 }, |
| 166 | { } |
| 167 | }; |
| 168 | |
| 169 | static struct i2c_driver pcf8575_driver = { |
| 170 | .driver = { |
| 171 | .owner = THIS_MODULE, |
| 172 | .name = "pcf8575", |
| 173 | }, |
| 174 | .probe = pcf8575_probe, |
| 175 | .remove = pcf8575_remove, |
| 176 | .id_table = pcf8575_id, |
| 177 | |
| 178 | .detect = pcf8575_detect, |
| 179 | .address_data = &addr_data, |
| 180 | }; |
| 181 | |
Bart Van Assche | 5864ae0 | 2008-01-27 18:14:45 +0100 | [diff] [blame] | 182 | static int __init pcf8575_init(void) |
| 183 | { |
| 184 | return i2c_add_driver(&pcf8575_driver); |
| 185 | } |
| 186 | |
| 187 | static void __exit pcf8575_exit(void) |
| 188 | { |
| 189 | i2c_del_driver(&pcf8575_driver); |
| 190 | } |
| 191 | |
| 192 | MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>, " |
| 193 | "Bart Van Assche <bart.vanassche@gmail.com>"); |
| 194 | MODULE_DESCRIPTION("pcf8575 driver"); |
| 195 | MODULE_LICENSE("GPL"); |
| 196 | |
| 197 | module_init(pcf8575_init); |
| 198 | module_exit(pcf8575_exit); |