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>
23 #include <linux/slab.h>
25 #define MAX1111_TX_BUF_SIZE 1
26 #define MAX1111_RX_BUF_SIZE 2
28 /* MAX1111 Commands */
29 #define MAX1111_CTRL_PD0 (1u << 0)
30 #define MAX1111_CTRL_PD1 (1u << 1)
31 #define MAX1111_CTRL_SGL (1u << 2)
32 #define MAX1111_CTRL_UNI (1u << 3)
33 #define MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */
34 #define MAX1111_CTRL_STR (1u << 7)
37 struct spi_device *spi;
38 struct device *hwmon_dev;
39 struct spi_message msg;
40 struct spi_transfer xfer[2];
41 uint8_t tx_buf[MAX1111_TX_BUF_SIZE];
42 uint8_t rx_buf[MAX1111_RX_BUF_SIZE];
43 struct mutex drvdata_lock;
44 /* protect msg, xfer and buffers from multiple access */
47 static int max1111_read(struct device *dev, int channel)
49 struct max1111_data *data = dev_get_drvdata(dev);
53 /* writing to drvdata struct is not thread safe, wait on mutex */
54 mutex_lock(&data->drvdata_lock);
56 data->tx_buf[0] = (channel << MAX1111_CTRL_SEL_SH) |
57 MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 |
58 MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR;
60 err = spi_sync(data->spi, &data->msg);
62 dev_err(dev, "spi_sync failed with %d\n", err);
63 mutex_unlock(&data->drvdata_lock);
70 mutex_unlock(&data->drvdata_lock);
72 if ((v1 & 0xc0) || (v2 & 0x3f))
75 return (v1 << 2) | (v2 >> 6);
78 #ifdef CONFIG_SHARPSL_PM
79 static struct max1111_data *the_max1111;
81 int max1111_read_channel(int channel)
83 if (!the_max1111 || !the_max1111->spi)
86 return max1111_read(&the_max1111->spi->dev, channel);
88 EXPORT_SYMBOL(max1111_read_channel);
92 * NOTE: SPI devices do not have a default 'name' attribute, which is
93 * likely to be used by hwmon applications to distinguish between
94 * different devices, explicitly add a name attribute here.
96 static ssize_t show_name(struct device *dev,
97 struct device_attribute *attr, char *buf)
99 return sprintf(buf, "max1111\n");
102 static ssize_t show_adc(struct device *dev,
103 struct device_attribute *attr, char *buf)
105 int channel = to_sensor_dev_attr(attr)->index;
108 ret = max1111_read(dev, channel);
112 return sprintf(buf, "%d\n", ret);
115 #define MAX1111_ADC_ATTR(_id) \
116 SENSOR_DEVICE_ATTR(adc##_id##_in, S_IRUGO, show_adc, NULL, _id)
118 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
119 static MAX1111_ADC_ATTR(0);
120 static MAX1111_ADC_ATTR(1);
121 static MAX1111_ADC_ATTR(2);
122 static MAX1111_ADC_ATTR(3);
124 static struct attribute *max1111_attributes[] = {
126 &sensor_dev_attr_adc0_in.dev_attr.attr,
127 &sensor_dev_attr_adc1_in.dev_attr.attr,
128 &sensor_dev_attr_adc2_in.dev_attr.attr,
129 &sensor_dev_attr_adc3_in.dev_attr.attr,
133 static const struct attribute_group max1111_attr_group = {
134 .attrs = max1111_attributes,
137 static int __devinit setup_transfer(struct max1111_data *data)
139 struct spi_message *m;
140 struct spi_transfer *x;
147 x->tx_buf = &data->tx_buf[0];
148 x->len = MAX1111_TX_BUF_SIZE;
149 spi_message_add_tail(x, m);
152 x->rx_buf = &data->rx_buf[0];
153 x->len = MAX1111_RX_BUF_SIZE;
154 spi_message_add_tail(x, m);
159 static int __devinit max1111_probe(struct spi_device *spi)
161 struct max1111_data *data;
164 spi->bits_per_word = 8;
165 spi->mode = SPI_MODE_0;
166 err = spi_setup(spi);
170 data = kzalloc(sizeof(struct max1111_data), GFP_KERNEL);
172 dev_err(&spi->dev, "failed to allocate memory\n");
176 err = setup_transfer(data);
180 mutex_init(&data->drvdata_lock);
183 spi_set_drvdata(spi, data);
185 err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group);
187 dev_err(&spi->dev, "failed to create attribute group\n");
191 data->hwmon_dev = hwmon_device_register(&spi->dev);
192 if (IS_ERR(data->hwmon_dev)) {
193 dev_err(&spi->dev, "failed to create hwmon device\n");
194 err = PTR_ERR(data->hwmon_dev);
198 #ifdef CONFIG_SHARPSL_PM
204 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
210 static int __devexit max1111_remove(struct spi_device *spi)
212 struct max1111_data *data = spi_get_drvdata(spi);
214 #ifdef CONFIG_SHARPSL_PM
217 hwmon_device_unregister(data->hwmon_dev);
218 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
219 mutex_destroy(&data->drvdata_lock);
224 static struct spi_driver max1111_driver = {
227 .owner = THIS_MODULE,
229 .probe = max1111_probe,
230 .remove = __devexit_p(max1111_remove),
233 static int __init max1111_init(void)
235 return spi_register_driver(&max1111_driver);
237 module_init(max1111_init);
239 static void __exit max1111_exit(void)
241 spi_unregister_driver(&max1111_driver);
243 module_exit(max1111_exit);
245 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
246 MODULE_DESCRIPTION("MAX1111 ADC Driver");
247 MODULE_LICENSE("GPL");
248 MODULE_ALIAS("spi:max1111");