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4397c98a MF |
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 */ | |
c7848c8e | 10 | #include <linux/pm.h> |
4397c98a | 11 | #include <linux/spi/spi.h> |
d2d8442d | 12 | #include <linux/module.h> |
fa6e3ca2 | 13 | #include <linux/of.h> |
4397c98a MF |
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 | ||
4397c98a MF |
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 | ||
31 | static 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 | ||
83 | static 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 | ||
91 | static 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 | ||
99 | static 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 | ||
107 | static 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 | ||
5298cc4c | 114 | static int ad7879_spi_probe(struct spi_device *spi) |
4397c98a MF |
115 | { |
116 | struct ad7879 *ts; | |
447b9065 | 117 | int err; |
4397c98a MF |
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 | ||
447b9065 MH |
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 | ||
4397c98a MF |
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 | ||
e2619cf7 | 141 | static int ad7879_spi_remove(struct spi_device *spi) |
4397c98a MF |
142 | { |
143 | struct ad7879 *ts = spi_get_drvdata(spi); | |
144 | ||
145 | ad7879_remove(ts); | |
4397c98a MF |
146 | |
147 | return 0; | |
148 | } | |
149 | ||
fa6e3ca2 SA |
150 | #ifdef CONFIG_OF |
151 | static const struct of_device_id ad7879_spi_dt_ids[] = { | |
152 | { .compatible = "adi,ad7879", }, | |
153 | { } | |
154 | }; | |
155 | MODULE_DEVICE_TABLE(of, ad7879_spi_dt_ids); | |
156 | #endif | |
157 | ||
4397c98a MF |
158 | static struct spi_driver ad7879_spi_driver = { |
159 | .driver = { | |
160 | .name = "ad7879", | |
8672bd93 | 161 | .pm = &ad7879_pm_ops, |
fa6e3ca2 | 162 | .of_match_table = of_match_ptr(ad7879_spi_dt_ids), |
4397c98a MF |
163 | }, |
164 | .probe = ad7879_spi_probe, | |
1cb0aa88 | 165 | .remove = ad7879_spi_remove, |
4397c98a MF |
166 | }; |
167 | ||
ca83922e | 168 | module_spi_driver(ad7879_spi_driver); |
4397c98a MF |
169 | |
170 | MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); | |
171 | MODULE_DESCRIPTION("AD7879(-1) touchscreen SPI bus driver"); | |
172 | MODULE_LICENSE("GPL"); | |
173 | MODULE_ALIAS("spi:ad7879"); |