Commit | Line | Data |
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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> |
4397c98a MF |
13 | |
14 | #include "ad7879.h" | |
15 | ||
16 | #define AD7879_DEVID 0x7A /* AD7879/AD7889 */ | |
17 | ||
18 | #define MAX_SPI_FREQ_HZ 5000000 | |
19 | #define AD7879_CMD_MAGIC 0xE000 | |
20 | #define AD7879_CMD_READ (1 << 10) | |
21 | #define AD7879_CMD(reg) (AD7879_CMD_MAGIC | ((reg) & 0xF)) | |
22 | #define AD7879_WRITECMD(reg) (AD7879_CMD(reg)) | |
23 | #define AD7879_READCMD(reg) (AD7879_CMD(reg) | AD7879_CMD_READ) | |
24 | ||
4397c98a MF |
25 | /* |
26 | * ad7879_read/write are only used for initial setup and for sysfs controls. | |
27 | * The main traffic is done in ad7879_collect(). | |
28 | */ | |
29 | ||
30 | static int ad7879_spi_xfer(struct spi_device *spi, | |
31 | u16 cmd, u8 count, u16 *tx_buf, u16 *rx_buf) | |
32 | { | |
33 | struct spi_message msg; | |
34 | struct spi_transfer *xfers; | |
35 | void *spi_data; | |
36 | u16 *command; | |
37 | u16 *_rx_buf = _rx_buf; /* shut gcc up */ | |
38 | u8 idx; | |
39 | int ret; | |
40 | ||
41 | xfers = spi_data = kzalloc(sizeof(*xfers) * (count + 2), GFP_KERNEL); | |
42 | if (!spi_data) | |
43 | return -ENOMEM; | |
44 | ||
45 | spi_message_init(&msg); | |
46 | ||
47 | command = spi_data; | |
48 | command[0] = cmd; | |
49 | if (count == 1) { | |
50 | /* ad7879_spi_{read,write} gave us buf on stack */ | |
51 | command[1] = *tx_buf; | |
52 | tx_buf = &command[1]; | |
53 | _rx_buf = rx_buf; | |
54 | rx_buf = &command[2]; | |
55 | } | |
56 | ||
57 | ++xfers; | |
58 | xfers[0].tx_buf = command; | |
59 | xfers[0].len = 2; | |
60 | spi_message_add_tail(&xfers[0], &msg); | |
61 | ++xfers; | |
62 | ||
63 | for (idx = 0; idx < count; ++idx) { | |
64 | if (rx_buf) | |
65 | xfers[idx].rx_buf = &rx_buf[idx]; | |
66 | if (tx_buf) | |
67 | xfers[idx].tx_buf = &tx_buf[idx]; | |
68 | xfers[idx].len = 2; | |
69 | spi_message_add_tail(&xfers[idx], &msg); | |
70 | } | |
71 | ||
72 | ret = spi_sync(spi, &msg); | |
73 | ||
74 | if (count == 1) | |
75 | _rx_buf[0] = command[2]; | |
76 | ||
77 | kfree(spi_data); | |
78 | ||
79 | return ret; | |
80 | } | |
81 | ||
82 | static int ad7879_spi_multi_read(struct device *dev, | |
83 | u8 first_reg, u8 count, u16 *buf) | |
84 | { | |
85 | struct spi_device *spi = to_spi_device(dev); | |
86 | ||
87 | return ad7879_spi_xfer(spi, AD7879_READCMD(first_reg), count, NULL, buf); | |
88 | } | |
89 | ||
90 | static int ad7879_spi_read(struct device *dev, u8 reg) | |
91 | { | |
92 | struct spi_device *spi = to_spi_device(dev); | |
93 | u16 ret, dummy; | |
94 | ||
95 | return ad7879_spi_xfer(spi, AD7879_READCMD(reg), 1, &dummy, &ret) ? : ret; | |
96 | } | |
97 | ||
98 | static int ad7879_spi_write(struct device *dev, u8 reg, u16 val) | |
99 | { | |
100 | struct spi_device *spi = to_spi_device(dev); | |
101 | u16 dummy; | |
102 | ||
103 | return ad7879_spi_xfer(spi, AD7879_WRITECMD(reg), 1, &val, &dummy); | |
104 | } | |
105 | ||
106 | static const struct ad7879_bus_ops ad7879_spi_bus_ops = { | |
107 | .bustype = BUS_SPI, | |
108 | .read = ad7879_spi_read, | |
109 | .multi_read = ad7879_spi_multi_read, | |
110 | .write = ad7879_spi_write, | |
111 | }; | |
112 | ||
5298cc4c | 113 | static int ad7879_spi_probe(struct spi_device *spi) |
4397c98a MF |
114 | { |
115 | struct ad7879 *ts; | |
447b9065 | 116 | int err; |
4397c98a MF |
117 | |
118 | /* don't exceed max specified SPI CLK frequency */ | |
119 | if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) { | |
120 | dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz); | |
121 | return -EINVAL; | |
122 | } | |
123 | ||
447b9065 MH |
124 | spi->bits_per_word = 16; |
125 | err = spi_setup(spi); | |
126 | if (err) { | |
127 | dev_dbg(&spi->dev, "spi master doesn't support 16 bits/word\n"); | |
128 | return err; | |
129 | } | |
130 | ||
4397c98a MF |
131 | ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, &ad7879_spi_bus_ops); |
132 | if (IS_ERR(ts)) | |
133 | return PTR_ERR(ts); | |
134 | ||
135 | spi_set_drvdata(spi, ts); | |
136 | ||
137 | return 0; | |
138 | } | |
139 | ||
e2619cf7 | 140 | static int ad7879_spi_remove(struct spi_device *spi) |
4397c98a MF |
141 | { |
142 | struct ad7879 *ts = spi_get_drvdata(spi); | |
143 | ||
144 | ad7879_remove(ts); | |
145 | spi_set_drvdata(spi, NULL); | |
146 | ||
147 | return 0; | |
148 | } | |
149 | ||
150 | static struct spi_driver ad7879_spi_driver = { | |
151 | .driver = { | |
152 | .name = "ad7879", | |
4397c98a | 153 | .owner = THIS_MODULE, |
8672bd93 | 154 | .pm = &ad7879_pm_ops, |
4397c98a MF |
155 | }, |
156 | .probe = ad7879_spi_probe, | |
1cb0aa88 | 157 | .remove = ad7879_spi_remove, |
4397c98a MF |
158 | }; |
159 | ||
ca83922e | 160 | module_spi_driver(ad7879_spi_driver); |
4397c98a MF |
161 | |
162 | MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); | |
163 | MODULE_DESCRIPTION("AD7879(-1) touchscreen SPI bus driver"); | |
164 | MODULE_LICENSE("GPL"); | |
165 | MODULE_ALIAS("spi:ad7879"); |