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1/*
2 * AD7879/AD7889 touchscreen (SPI bus)
3 *
4 * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
5 *
6 * Licensed under the GPL-2 or later.
7 */
8
9#include <linux/input.h> /* BUS_SPI */
10#include <linux/pm.h>
11#include <linux/spi/spi.h>
12#include <linux/module.h>
13#include <linux/of.h>
14
15#include "ad7879.h"
16
17#define AD7879_DEVID 0x7A /* AD7879/AD7889 */
18
19#define MAX_SPI_FREQ_HZ 5000000
20#define AD7879_CMD_MAGIC 0xE000
21#define AD7879_CMD_READ (1 << 10)
22#define AD7879_CMD(reg) (AD7879_CMD_MAGIC | ((reg) & 0xF))
23#define AD7879_WRITECMD(reg) (AD7879_CMD(reg))
24#define AD7879_READCMD(reg) (AD7879_CMD(reg) | AD7879_CMD_READ)
25
26/*
27 * ad7879_read/write are only used for initial setup and for sysfs controls.
28 * The main traffic is done in ad7879_collect().
29 */
30
31static int ad7879_spi_xfer(struct spi_device *spi,
32 u16 cmd, u8 count, u16 *tx_buf, u16 *rx_buf)
33{
34 struct spi_message msg;
35 struct spi_transfer *xfers;
36 void *spi_data;
37 u16 *command;
38 u16 *_rx_buf = _rx_buf; /* shut gcc up */
39 u8 idx;
40 int ret;
41
42 xfers = spi_data = kzalloc(sizeof(*xfers) * (count + 2), GFP_KERNEL);
43 if (!spi_data)
44 return -ENOMEM;
45
46 spi_message_init(&msg);
47
48 command = spi_data;
49 command[0] = cmd;
50 if (count == 1) {
51 /* ad7879_spi_{read,write} gave us buf on stack */
52 command[1] = *tx_buf;
53 tx_buf = &command[1];
54 _rx_buf = rx_buf;
55 rx_buf = &command[2];
56 }
57
58 ++xfers;
59 xfers[0].tx_buf = command;
60 xfers[0].len = 2;
61 spi_message_add_tail(&xfers[0], &msg);
62 ++xfers;
63
64 for (idx = 0; idx < count; ++idx) {
65 if (rx_buf)
66 xfers[idx].rx_buf = &rx_buf[idx];
67 if (tx_buf)
68 xfers[idx].tx_buf = &tx_buf[idx];
69 xfers[idx].len = 2;
70 spi_message_add_tail(&xfers[idx], &msg);
71 }
72
73 ret = spi_sync(spi, &msg);
74
75 if (count == 1)
76 _rx_buf[0] = command[2];
77
78 kfree(spi_data);
79
80 return ret;
81}
82
83static int ad7879_spi_multi_read(struct device *dev,
84 u8 first_reg, u8 count, u16 *buf)
85{
86 struct spi_device *spi = to_spi_device(dev);
87
88 return ad7879_spi_xfer(spi, AD7879_READCMD(first_reg), count, NULL, buf);
89}
90
91static int ad7879_spi_read(struct device *dev, u8 reg)
92{
93 struct spi_device *spi = to_spi_device(dev);
94 u16 ret, dummy;
95
96 return ad7879_spi_xfer(spi, AD7879_READCMD(reg), 1, &dummy, &ret) ? : ret;
97}
98
99static int ad7879_spi_write(struct device *dev, u8 reg, u16 val)
100{
101 struct spi_device *spi = to_spi_device(dev);
102 u16 dummy;
103
104 return ad7879_spi_xfer(spi, AD7879_WRITECMD(reg), 1, &val, &dummy);
105}
106
107static const struct ad7879_bus_ops ad7879_spi_bus_ops = {
108 .bustype = BUS_SPI,
109 .read = ad7879_spi_read,
110 .multi_read = ad7879_spi_multi_read,
111 .write = ad7879_spi_write,
112};
113
114static int ad7879_spi_probe(struct spi_device *spi)
115{
116 struct ad7879 *ts;
117 int err;
118
119 /* don't exceed max specified SPI CLK frequency */
120 if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
121 dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz);
122 return -EINVAL;
123 }
124
125 spi->bits_per_word = 16;
126 err = spi_setup(spi);
127 if (err) {
128 dev_dbg(&spi->dev, "spi master doesn't support 16 bits/word\n");
129 return err;
130 }
131
132 ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, &ad7879_spi_bus_ops);
133 if (IS_ERR(ts))
134 return PTR_ERR(ts);
135
136 spi_set_drvdata(spi, ts);
137
138 return 0;
139}
140
141static int ad7879_spi_remove(struct spi_device *spi)
142{
143 struct ad7879 *ts = spi_get_drvdata(spi);
144
145 ad7879_remove(ts);
146
147 return 0;
148}
149
150#ifdef CONFIG_OF
151static const struct of_device_id ad7879_spi_dt_ids[] = {
152 { .compatible = "adi,ad7879", },
153 { }
154};
155MODULE_DEVICE_TABLE(of, ad7879_spi_dt_ids);
156#endif
157
158static struct spi_driver ad7879_spi_driver = {
159 .driver = {
160 .name = "ad7879",
161 .pm = &ad7879_pm_ops,
162 .of_match_table = of_match_ptr(ad7879_spi_dt_ids),
163 },
164 .probe = ad7879_spi_probe,
165 .remove = ad7879_spi_remove,
166};
167
168module_spi_driver(ad7879_spi_driver);
169
170MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
171MODULE_DESCRIPTION("AD7879(-1) touchscreen SPI bus driver");
172MODULE_LICENSE("GPL");
173MODULE_ALIAS("spi:ad7879");
1/*
2 * AD7879/AD7889 touchscreen (SPI bus)
3 *
4 * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
5 *
6 * Licensed under the GPL-2 or later.
7 */
8
9#include <linux/input.h> /* BUS_SPI */
10#include <linux/pm.h>
11#include <linux/spi/spi.h>
12#include <linux/module.h>
13#include <linux/of.h>
14
15#include "ad7879.h"
16
17#define AD7879_DEVID 0x7A /* AD7879/AD7889 */
18
19#define MAX_SPI_FREQ_HZ 5000000
20#define AD7879_CMD_MAGIC 0xE000
21#define AD7879_CMD_READ (1 << 10)
22#define AD7879_CMD(reg) (AD7879_CMD_MAGIC | ((reg) & 0xF))
23#define AD7879_WRITECMD(reg) (AD7879_CMD(reg))
24#define AD7879_READCMD(reg) (AD7879_CMD(reg) | AD7879_CMD_READ)
25
26/*
27 * ad7879_read/write are only used for initial setup and for sysfs controls.
28 * The main traffic is done in ad7879_collect().
29 */
30
31static int ad7879_spi_xfer(struct spi_device *spi,
32 u16 cmd, u8 count, u16 *tx_buf, u16 *rx_buf)
33{
34 struct spi_message msg;
35 struct spi_transfer *xfers;
36 void *spi_data;
37 u16 *command;
38 u16 *_rx_buf = _rx_buf; /* shut gcc up */
39 u8 idx;
40 int ret;
41
42 xfers = spi_data = kzalloc(sizeof(*xfers) * (count + 2), GFP_KERNEL);
43 if (!spi_data)
44 return -ENOMEM;
45
46 spi_message_init(&msg);
47
48 command = spi_data;
49 command[0] = cmd;
50 if (count == 1) {
51 /* ad7879_spi_{read,write} gave us buf on stack */
52 command[1] = *tx_buf;
53 tx_buf = &command[1];
54 _rx_buf = rx_buf;
55 rx_buf = &command[2];
56 }
57
58 ++xfers;
59 xfers[0].tx_buf = command;
60 xfers[0].len = 2;
61 spi_message_add_tail(&xfers[0], &msg);
62 ++xfers;
63
64 for (idx = 0; idx < count; ++idx) {
65 if (rx_buf)
66 xfers[idx].rx_buf = &rx_buf[idx];
67 if (tx_buf)
68 xfers[idx].tx_buf = &tx_buf[idx];
69 xfers[idx].len = 2;
70 spi_message_add_tail(&xfers[idx], &msg);
71 }
72
73 ret = spi_sync(spi, &msg);
74
75 if (count == 1)
76 _rx_buf[0] = command[2];
77
78 kfree(spi_data);
79
80 return ret;
81}
82
83static int ad7879_spi_multi_read(struct device *dev,
84 u8 first_reg, u8 count, u16 *buf)
85{
86 struct spi_device *spi = to_spi_device(dev);
87
88 return ad7879_spi_xfer(spi, AD7879_READCMD(first_reg), count, NULL, buf);
89}
90
91static int ad7879_spi_read(struct device *dev, u8 reg)
92{
93 struct spi_device *spi = to_spi_device(dev);
94 u16 ret, dummy;
95
96 return ad7879_spi_xfer(spi, AD7879_READCMD(reg), 1, &dummy, &ret) ? : ret;
97}
98
99static int ad7879_spi_write(struct device *dev, u8 reg, u16 val)
100{
101 struct spi_device *spi = to_spi_device(dev);
102 u16 dummy;
103
104 return ad7879_spi_xfer(spi, AD7879_WRITECMD(reg), 1, &val, &dummy);
105}
106
107static const struct ad7879_bus_ops ad7879_spi_bus_ops = {
108 .bustype = BUS_SPI,
109 .read = ad7879_spi_read,
110 .multi_read = ad7879_spi_multi_read,
111 .write = ad7879_spi_write,
112};
113
114static int ad7879_spi_probe(struct spi_device *spi)
115{
116 struct ad7879 *ts;
117 int err;
118
119 /* don't exceed max specified SPI CLK frequency */
120 if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
121 dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz);
122 return -EINVAL;
123 }
124
125 spi->bits_per_word = 16;
126 err = spi_setup(spi);
127 if (err) {
128 dev_dbg(&spi->dev, "spi master doesn't support 16 bits/word\n");
129 return err;
130 }
131
132 ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, &ad7879_spi_bus_ops);
133 if (IS_ERR(ts))
134 return PTR_ERR(ts);
135
136 spi_set_drvdata(spi, ts);
137
138 return 0;
139}
140
141static int ad7879_spi_remove(struct spi_device *spi)
142{
143 struct ad7879 *ts = spi_get_drvdata(spi);
144
145 ad7879_remove(ts);
146
147 return 0;
148}
149
150#ifdef CONFIG_OF
151static const struct of_device_id ad7879_spi_dt_ids[] = {
152 { .compatible = "adi,ad7879", },
153 { }
154};
155MODULE_DEVICE_TABLE(of, ad7879_spi_dt_ids);
156#endif
157
158static struct spi_driver ad7879_spi_driver = {
159 .driver = {
160 .name = "ad7879",
161 .pm = &ad7879_pm_ops,
162 .of_match_table = of_match_ptr(ad7879_spi_dt_ids),
163 },
164 .probe = ad7879_spi_probe,
165 .remove = ad7879_spi_remove,
166};
167
168module_spi_driver(ad7879_spi_driver);
169
170MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
171MODULE_DESCRIPTION("AD7879(-1) touchscreen SPI bus driver");
172MODULE_LICENSE("GPL");
173MODULE_ALIAS("spi:ad7879");