tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * AD714X CapTouch Programmable Controller driver (SPI bus)
3 *
4 * Copyright 2009-2011 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2 or later.
7 */
8
9#include <linux/input.h> /* BUS_SPI */
10#include <linux/module.h>
11#include <linux/spi/spi.h>
12#include <linux/pm.h>
13#include <linux/types.h>
14#include "ad714x.h"
15
16#define AD714x_SPI_CMD_PREFIX 0xE000 /* bits 15:11 */
17#define AD714x_SPI_READ BIT(10)
18
19#ifdef CONFIG_PM
20static int ad714x_spi_suspend(struct device *dev)
21{
22 return ad714x_disable(spi_get_drvdata(to_spi_device(dev)));
23}
24
25static int ad714x_spi_resume(struct device *dev)
26{
27 return ad714x_enable(spi_get_drvdata(to_spi_device(dev)));
28}
29#endif
30
31static SIMPLE_DEV_PM_OPS(ad714x_spi_pm, ad714x_spi_suspend, ad714x_spi_resume);
32
33static int ad714x_spi_read(struct ad714x_chip *chip,
34 unsigned short reg, unsigned short *data, size_t len)
35{
36 struct spi_device *spi = to_spi_device(chip->dev);
37 struct spi_message message;
38 struct spi_transfer xfer[2];
39 int i;
40 int error;
41
42 spi_message_init(&message);
43 memset(xfer, 0, sizeof(xfer));
44
45 chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX |
46 AD714x_SPI_READ | reg);
47 xfer[0].tx_buf = &chip->xfer_buf[0];
48 xfer[0].len = sizeof(chip->xfer_buf[0]);
49 spi_message_add_tail(&xfer[0], &message);
50
51 xfer[1].rx_buf = &chip->xfer_buf[1];
52 xfer[1].len = sizeof(chip->xfer_buf[1]) * len;
53 spi_message_add_tail(&xfer[1], &message);
54
55 error = spi_sync(spi, &message);
56 if (unlikely(error)) {
57 dev_err(chip->dev, "SPI read error: %d\n", error);
58 return error;
59 }
60
61 for (i = 0; i < len; i++)
62 data[i] = be16_to_cpu(chip->xfer_buf[i + 1]);
63
64 return 0;
65}
66
67static int ad714x_spi_write(struct ad714x_chip *chip,
68 unsigned short reg, unsigned short data)
69{
70 struct spi_device *spi = to_spi_device(chip->dev);
71 int error;
72
73 chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg);
74 chip->xfer_buf[1] = cpu_to_be16(data);
75
76 error = spi_write(spi, (u8 *)chip->xfer_buf,
77 2 * sizeof(*chip->xfer_buf));
78 if (unlikely(error)) {
79 dev_err(chip->dev, "SPI write error: %d\n", error);
80 return error;
81 }
82
83 return 0;
84}
85
86static int __devinit ad714x_spi_probe(struct spi_device *spi)
87{
88 struct ad714x_chip *chip;
89 int err;
90
91 spi->bits_per_word = 8;
92 err = spi_setup(spi);
93 if (err < 0)
94 return err;
95
96 chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq,
97 ad714x_spi_read, ad714x_spi_write);
98 if (IS_ERR(chip))
99 return PTR_ERR(chip);
100
101 spi_set_drvdata(spi, chip);
102
103 return 0;
104}
105
106static int __devexit ad714x_spi_remove(struct spi_device *spi)
107{
108 struct ad714x_chip *chip = spi_get_drvdata(spi);
109
110 ad714x_remove(chip);
111 spi_set_drvdata(spi, NULL);
112
113 return 0;
114}
115
116static struct spi_driver ad714x_spi_driver = {
117 .driver = {
118 .name = "ad714x_captouch",
119 .owner = THIS_MODULE,
120 .pm = &ad714x_spi_pm,
121 },
122 .probe = ad714x_spi_probe,
123 .remove = __devexit_p(ad714x_spi_remove),
124};
125
126module_spi_driver(ad714x_spi_driver);
127
128MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
129MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
130MODULE_LICENSE("GPL");