Rabin Vincent | 6257926 | 2010-05-19 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 | */ |
| 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 | ret = ab8500->rx_buf[0]; |
| 72 | |
| 73 | return ret; |
| 74 | } |
| 75 | |
| 76 | static int __devinit ab8500_spi_probe(struct spi_device *spi) |
| 77 | { |
| 78 | struct ab8500 *ab8500; |
| 79 | int ret; |
| 80 | |
| 81 | ab8500 = kzalloc(sizeof *ab8500, GFP_KERNEL); |
| 82 | if (!ab8500) |
| 83 | return -ENOMEM; |
| 84 | |
| 85 | ab8500->dev = &spi->dev; |
| 86 | ab8500->irq = spi->irq; |
| 87 | |
| 88 | ab8500->read = ab8500_spi_read; |
| 89 | ab8500->write = ab8500_spi_write; |
| 90 | |
| 91 | spi_set_drvdata(spi, ab8500); |
| 92 | |
| 93 | ret = ab8500_init(ab8500); |
| 94 | if (ret) |
| 95 | kfree(ab8500); |
| 96 | |
| 97 | return ret; |
| 98 | } |
| 99 | |
| 100 | static int __devexit ab8500_spi_remove(struct spi_device *spi) |
| 101 | { |
| 102 | struct ab8500 *ab8500 = spi_get_drvdata(spi); |
| 103 | |
| 104 | ab8500_exit(ab8500); |
| 105 | kfree(ab8500); |
| 106 | |
| 107 | return 0; |
| 108 | } |
| 109 | |
| 110 | static struct spi_driver ab8500_spi_driver = { |
| 111 | .driver = { |
| 112 | .name = "ab8500", |
| 113 | .owner = THIS_MODULE, |
| 114 | }, |
| 115 | .probe = ab8500_spi_probe, |
| 116 | .remove = __devexit_p(ab8500_spi_remove) |
| 117 | }; |
| 118 | |
| 119 | static int __init ab8500_spi_init(void) |
| 120 | { |
| 121 | return spi_register_driver(&ab8500_spi_driver); |
| 122 | } |
| 123 | subsys_initcall(ab8500_spi_init); |
| 124 | |
| 125 | static void __exit ab8500_spi_exit(void) |
| 126 | { |
| 127 | spi_unregister_driver(&ab8500_spi_driver); |
| 128 | } |
| 129 | module_exit(ab8500_spi_exit); |
| 130 | |
| 131 | MODULE_AUTHOR("Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com"); |
| 132 | MODULE_DESCRIPTION("AB8500 SPI"); |
| 133 | MODULE_LICENSE("GPL v2"); |