2 * max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs
4 * Based on arch/arm/mach-pxa/corgi_ssp.c
6 * Copyright (C) 2004-2005 Richard Purdie
8 * Copyright (C) 2008 Marvell International Ltd.
9 * Eric Miao <eric.miao@marvell.com>
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * publishhed by the Free Software Foundation.
16 #include <linux/module.h>
17 #include <linux/kernel.h>
18 #include <linux/init.h>
19 #include <linux/err.h>
20 #include <linux/hwmon.h>
21 #include <linux/hwmon-sysfs.h>
22 #include <linux/spi/spi.h>
24 #define MAX1111_TX_BUF_SIZE 1
25 #define MAX1111_RX_BUF_SIZE 2
27 /* MAX1111 Commands */
28 #define MAX1111_CTRL_PD0 (1u << 0)
29 #define MAX1111_CTRL_PD1 (1u << 1)
30 #define MAX1111_CTRL_SGL (1u << 2)
31 #define MAX1111_CTRL_UNI (1u << 3)
32 #define MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */
33 #define MAX1111_CTRL_STR (1u << 7)
36 struct spi_device *spi;
37 struct device *hwmon_dev;
38 struct spi_message msg;
39 struct spi_transfer xfer[2];
44 static int max1111_read(struct device *dev, int channel)
46 struct max1111_data *data = dev_get_drvdata(dev);
50 data->tx_buf[0] = (channel << MAX1111_CTRL_SEL_SH) |
51 MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 |
52 MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR;
54 err = spi_sync(data->spi, &data->msg);
56 dev_err(dev, "spi_sync failed with %d\n", err);
63 if ((v1 & 0xc0) || (v2 & 0x3f))
66 return (v1 << 2) | (v2 >> 6);
69 #ifdef CONFIG_SHARPSL_PM
70 static struct max1111_data *the_max1111;
72 int max1111_read_channel(int channel)
74 return max1111_read(&the_max1111->spi->dev, channel);
76 EXPORT_SYMBOL(max1111_read_channel);
80 * NOTE: SPI devices do not have a default 'name' attribute, which is
81 * likely to be used by hwmon applications to distinguish between
82 * different devices, explicitly add a name attribute here.
84 static ssize_t show_name(struct device *dev,
85 struct device_attribute *attr, char *buf)
87 return sprintf(buf, "max1111\n");
90 static ssize_t show_adc(struct device *dev,
91 struct device_attribute *attr, char *buf)
93 int channel = to_sensor_dev_attr(attr)->index;
96 ret = max1111_read(dev, channel);
100 return sprintf(buf, "%d\n", ret);
103 #define MAX1111_ADC_ATTR(_id) \
104 SENSOR_DEVICE_ATTR(adc##_id##_in, S_IRUGO, show_adc, NULL, _id)
106 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
107 static MAX1111_ADC_ATTR(0);
108 static MAX1111_ADC_ATTR(1);
109 static MAX1111_ADC_ATTR(2);
110 static MAX1111_ADC_ATTR(3);
112 static struct attribute *max1111_attributes[] = {
114 &sensor_dev_attr_adc0_in.dev_attr.attr,
115 &sensor_dev_attr_adc1_in.dev_attr.attr,
116 &sensor_dev_attr_adc2_in.dev_attr.attr,
117 &sensor_dev_attr_adc3_in.dev_attr.attr,
121 static const struct attribute_group max1111_attr_group = {
122 .attrs = max1111_attributes,
125 static int setup_transfer(struct max1111_data *data)
127 struct spi_message *m;
128 struct spi_transfer *x;
130 data->tx_buf = kmalloc(MAX1111_TX_BUF_SIZE, GFP_KERNEL);
134 data->rx_buf = kmalloc(MAX1111_RX_BUF_SIZE, GFP_KERNEL);
145 x->tx_buf = &data->tx_buf[0];
147 spi_message_add_tail(x, m);
150 x->rx_buf = &data->rx_buf[0];
152 spi_message_add_tail(x, m);
157 static int __devinit max1111_probe(struct spi_device *spi)
159 struct max1111_data *data;
162 spi->bits_per_word = 8;
163 spi->mode = SPI_MODE_0;
164 err = spi_setup(spi);
168 data = kzalloc(sizeof(struct max1111_data), GFP_KERNEL);
170 dev_err(&spi->dev, "failed to allocate memory\n");
174 err = setup_transfer(data);
179 spi_set_drvdata(spi, data);
181 err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group);
183 dev_err(&spi->dev, "failed to create attribute group\n");
187 data->hwmon_dev = hwmon_device_register(&spi->dev);
188 if (IS_ERR(data->hwmon_dev)) {
189 dev_err(&spi->dev, "failed to create hwmon device\n");
190 err = PTR_ERR(data->hwmon_dev);
194 #ifdef CONFIG_SHARPSL_PM
200 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
209 static int __devexit max1111_remove(struct spi_device *spi)
211 struct max1111_data *data = spi_get_drvdata(spi);
213 hwmon_device_unregister(data->hwmon_dev);
214 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
221 static struct spi_driver max1111_driver = {
224 .owner = THIS_MODULE,
226 .probe = max1111_probe,
227 .remove = __devexit_p(max1111_remove),
230 static int __init max1111_init(void)
232 return spi_register_driver(&max1111_driver);
234 module_init(max1111_init);
236 static void __exit max1111_exit(void)
238 spi_unregister_driver(&max1111_driver);
240 module_exit(max1111_exit);
242 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
243 MODULE_DESCRIPTION("MAX1111 ADC Driver");
244 MODULE_LICENSE("GPL");