1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
/*
* AD7879/AD7889 touchscreen (SPI bus)
*
* Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <linux/input.h> /* BUS_SPI */
#include <linux/pm.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include "ad7879.h"
#define AD7879_DEVID 0x7A /* AD7879/AD7889 */
#define MAX_SPI_FREQ_HZ 5000000
#define AD7879_CMD_MAGIC 0xE000
#define AD7879_CMD_READ (1 << 10)
#define AD7879_CMD(reg) (AD7879_CMD_MAGIC | ((reg) & 0xF))
#define AD7879_WRITECMD(reg) (AD7879_CMD(reg))
#define AD7879_READCMD(reg) (AD7879_CMD(reg) | AD7879_CMD_READ)
/*
* ad7879_read/write are only used for initial setup and for sysfs controls.
* The main traffic is done in ad7879_collect().
*/
static int ad7879_spi_xfer(struct spi_device *spi,
u16 cmd, u8 count, u16 *tx_buf, u16 *rx_buf)
{
struct spi_message msg;
struct spi_transfer *xfers;
void *spi_data;
u16 *command;
u16 *_rx_buf = _rx_buf; /* shut gcc up */
u8 idx;
int ret;
xfers = spi_data = kzalloc(sizeof(*xfers) * (count + 2), GFP_KERNEL);
if (!spi_data)
return -ENOMEM;
spi_message_init(&msg);
command = spi_data;
command[0] = cmd;
if (count == 1) {
/* ad7879_spi_{read,write} gave us buf on stack */
command[1] = *tx_buf;
tx_buf = &command[1];
_rx_buf = rx_buf;
rx_buf = &command[2];
}
++xfers;
xfers[0].tx_buf = command;
xfers[0].len = 2;
spi_message_add_tail(&xfers[0], &msg);
++xfers;
for (idx = 0; idx < count; ++idx) {
if (rx_buf)
xfers[idx].rx_buf = &rx_buf[idx];
if (tx_buf)
xfers[idx].tx_buf = &tx_buf[idx];
xfers[idx].len = 2;
spi_message_add_tail(&xfers[idx], &msg);
}
ret = spi_sync(spi, &msg);
if (count == 1)
_rx_buf[0] = command[2];
kfree(spi_data);
return ret;
}
static int ad7879_spi_multi_read(struct device *dev,
u8 first_reg, u8 count, u16 *buf)
{
struct spi_device *spi = to_spi_device(dev);
return ad7879_spi_xfer(spi, AD7879_READCMD(first_reg), count, NULL, buf);
}
static int ad7879_spi_read(struct device *dev, u8 reg)
{
struct spi_device *spi = to_spi_device(dev);
u16 ret, dummy;
return ad7879_spi_xfer(spi, AD7879_READCMD(reg), 1, &dummy, &ret) ? : ret;
}
static int ad7879_spi_write(struct device *dev, u8 reg, u16 val)
{
struct spi_device *spi = to_spi_device(dev);
u16 dummy;
return ad7879_spi_xfer(spi, AD7879_WRITECMD(reg), 1, &val, &dummy);
}
static const struct ad7879_bus_ops ad7879_spi_bus_ops = {
.bustype = BUS_SPI,
.read = ad7879_spi_read,
.multi_read = ad7879_spi_multi_read,
.write = ad7879_spi_write,
};
static int ad7879_spi_probe(struct spi_device *spi)
{
struct ad7879 *ts;
int err;
/* don't exceed max specified SPI CLK frequency */
if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz);
return -EINVAL;
}
spi->bits_per_word = 16;
err = spi_setup(spi);
if (err) {
dev_dbg(&spi->dev, "spi master doesn't support 16 bits/word\n");
return err;
}
ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, &ad7879_spi_bus_ops);
if (IS_ERR(ts))
return PTR_ERR(ts);
spi_set_drvdata(spi, ts);
return 0;
}
static int ad7879_spi_remove(struct spi_device *spi)
{
struct ad7879 *ts = spi_get_drvdata(spi);
ad7879_remove(ts);
return 0;
}
static struct spi_driver ad7879_spi_driver = {
.driver = {
.name = "ad7879",
.owner = THIS_MODULE,
.pm = &ad7879_pm_ops,
},
.probe = ad7879_spi_probe,
.remove = ad7879_spi_remove,
};
module_spi_driver(ad7879_spi_driver);
MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("AD7879(-1) touchscreen SPI bus driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:ad7879");
|
