Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[linux-2.6.git] / drivers / mfd / ab8500-spi.c
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  */
29 static 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
50 static 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)
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;
77
78         return ret;
79 }
80
81 static int __devinit ab8500_spi_probe(struct spi_device *spi)
82 {
83         struct ab8500 *ab8500;
84         int ret;
85
86         spi->bits_per_word = 24;
87         ret = spi_setup(spi);
88         if (ret < 0)
89                 return ret;
90
91         ab8500 = kzalloc(sizeof *ab8500, GFP_KERNEL);
92         if (!ab8500)
93                 return -ENOMEM;
94
95         ab8500->dev = &spi->dev;
96         ab8500->irq = spi->irq;
97
98         ab8500->read = ab8500_spi_read;
99         ab8500->write = ab8500_spi_write;
100
101         spi_set_drvdata(spi, ab8500);
102
103         ret = ab8500_init(ab8500);
104         if (ret)
105                 kfree(ab8500);
106
107         return ret;
108 }
109
110 static int __devexit ab8500_spi_remove(struct spi_device *spi)
111 {
112         struct ab8500 *ab8500 = spi_get_drvdata(spi);
113
114         ab8500_exit(ab8500);
115         kfree(ab8500);
116
117         return 0;
118 }
119
120 static struct spi_driver ab8500_spi_driver = {
121         .driver = {
122                 .name = "ab8500",
123                 .owner = THIS_MODULE,
124         },
125         .probe  = ab8500_spi_probe,
126         .remove = __devexit_p(ab8500_spi_remove)
127 };
128
129 static int __init ab8500_spi_init(void)
130 {
131         return spi_register_driver(&ab8500_spi_driver);
132 }
133 subsys_initcall(ab8500_spi_init);
134
135 static void __exit ab8500_spi_exit(void)
136 {
137         spi_unregister_driver(&ab8500_spi_driver);
138 }
139 module_exit(ab8500_spi_exit);
140
141 MODULE_AUTHOR("Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com");
142 MODULE_DESCRIPTION("AB8500 SPI");
143 MODULE_LICENSE("GPL v2");