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gerrit-public.fairphone.software / kernel / msm-4.9 / 6436b6a7a64f946c5a5f3d8a8c0e6404e2bda8d5 / . / drivers / mfd / ab8500-spi.c
blob: e1c8b62b086d506ef46d8a52ccb6d5c4d73e0a18 [file] [log] [blame]
Rabin Vincent62579262010-05-19 11:39:02 +0200[diff] [blame]1/*
2 * Copyright (C) ST-Ericsson SA 2010
3 *
4 * License Terms: GNU General Public License v2
5 * Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
6 */
7
8#include <linux/kernel.h>
9#include <linux/slab.h>
10#include <linux/init.h>
11#include <linux/module.h>
12#include <linux/platform_device.h>
13#include <linux/spi/spi.h>
14#include <linux/mfd/ab8500.h>
15
16/*
17 * This funtion writes to any AB8500 registers using
18 * SPI protocol & before it writes it packs the data
19 * in the below 24 bit frame format
20 *
21 * *|------------------------------------|
22 * *| 23|22...18|17.......10|9|8|7......0|
23 * *| r/w bank adr data |
24 * * ------------------------------------
25 *
26 * This function shouldn't be called from interrupt
27 * context
28 */
29static int ab8500_spi_write(struct ab8500 *ab8500, u16 addr, u8 data)
30{
31 struct spi_device *spi = container_of(ab8500->dev, struct spi_device,
32 dev);
33 unsigned long spi_data = addr << 10 | data;
34 struct spi_transfer xfer;
35 struct spi_message msg;
36
37 ab8500->tx_buf[0] = spi_data;
38 ab8500->rx_buf[0] = 0;
39
40 xfer.tx_buf = ab8500->tx_buf;
41 xfer.rx_buf = NULL;
42 xfer.len = sizeof(unsigned long);
43
44 spi_message_init(&msg);
45 spi_message_add_tail(&xfer, &msg);
46
47 return spi_sync(spi, &msg);
48}
49
50static int ab8500_spi_read(struct ab8500 *ab8500, u16 addr)
51{
52 struct spi_device *spi = container_of(ab8500->dev, struct spi_device,
53 dev);
54 unsigned long spi_data = 1 << 23 | addr << 10;
55 struct spi_transfer xfer;
56 struct spi_message msg;
57 int ret;
58
59 ab8500->tx_buf[0] = spi_data;
60 ab8500->rx_buf[0] = 0;
61
62 xfer.tx_buf = ab8500->tx_buf;
63 xfer.rx_buf = ab8500->rx_buf;
64 xfer.len = sizeof(unsigned long);
65
66 spi_message_init(&msg);
67 spi_message_add_tail(&xfer, &msg);
68
69 ret = spi_sync(spi, &msg);
70 if (!ret)
Linus Walleijc0d40102010-05-28 02:59:44 +0200[diff] [blame]71 /*
72 * Only the 8 lowermost bytes are
73 * defined with value, the rest may
74 * vary depending on chip/board noise.
75 */
76 ret = ab8500->rx_buf[0] & 0xFFU;
Rabin Vincent62579262010-05-19 11:39:02 +0200[diff] [blame]77
78 return ret;
79}
80
81static int __devinit ab8500_spi_probe(struct spi_device *spi)
82{
83 struct ab8500 *ab8500;
84 int ret;
85
86 ab8500 = kzalloc(sizeof *ab8500, GFP_KERNEL);
87 if (!ab8500)
88 return -ENOMEM;
89
90 ab8500->dev = &spi->dev;
91 ab8500->irq = spi->irq;
92
93 ab8500->read = ab8500_spi_read;
94 ab8500->write = ab8500_spi_write;
95
96 spi_set_drvdata(spi, ab8500);
97
98 ret = ab8500_init(ab8500);
99 if (ret)
100 kfree(ab8500);
101
102 return ret;
103}
104
105static int __devexit ab8500_spi_remove(struct spi_device *spi)
106{
107 struct ab8500 *ab8500 = spi_get_drvdata(spi);
108
109 ab8500_exit(ab8500);
110 kfree(ab8500);
111
112 return 0;
113}
114
115static struct spi_driver ab8500_spi_driver = {
116 .driver = {
117 .name = "ab8500",
118 .owner = THIS_MODULE,
119 },
120 .probe = ab8500_spi_probe,
121 .remove = __devexit_p(ab8500_spi_remove)
122};
123
124static int __init ab8500_spi_init(void)
125{
126 return spi_register_driver(&ab8500_spi_driver);
127}
128subsys_initcall(ab8500_spi_init);
129
130static void __exit ab8500_spi_exit(void)
131{
132 spi_unregister_driver(&ab8500_spi_driver);
133}
134module_exit(ab8500_spi_exit);
135
136MODULE_AUTHOR("Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com");
137MODULE_DESCRIPTION("AB8500 SPI");
138MODULE_LICENSE("GPL v2");