drivers/mfd/ab4500-core.c

   1 /*
   2  * Copyright (C) 2009 ST-Ericsson
   3  *
   4  * Author: Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com>
   5  *
   6  * This program is free software; you can redistribute it
   7  * and/or modify it under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation.
   9  *
  10  * AB4500 is a companion power management chip used with U8500.
  11  * On this platform, this is interfaced with SSP0 controller
  12  * which is a ARM primecell pl022.
  13  *
  14  * At the moment the module just exports read/write features.
  15  * Interrupt management to be added - TODO.
  16  */
  17 #include <linux/kernel.h>
  18 #include <linux/slab.h>
  19 #include <linux/init.h>
  20 #include <linux/module.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/spi/spi.h>
  23 #include <linux/mfd/ab4500.h>
  24
  25 /* just required if probe fails, we need to
  26  * unregister the device
  27  */
  28 static struct spi_driver ab4500_driver;
  29
  30 /*
  31  * This funtion writes to any AB4500 registers using
  32  * SPI protocol &  before it writes it packs the data
  33  * in the below 24 bit frame format
  34  *
  35  *       *|------------------------------------|
  36  *       *| 23|22...18|17.......10|9|8|7......0|
  37  *       *| r/w  bank       adr          data  |
  38  *       * ------------------------------------
  39  *
  40  * This function shouldn't be called from interrupt
  41  * context
  42  */
  43 int ab4500_write(struct ab4500 *ab4500, unsigned char block,
  44                 unsigned long addr, unsigned char data)
  45 {
  46         struct spi_transfer xfer;
  47         struct spi_message      msg;
  48         int err;
  49         unsigned long spi_data =
  50                 block << 18 | addr << 10 | data;
  51
  52         mutex_lock(&ab4500->lock);
  53         ab4500->tx_buf[0] = spi_data;
  54         ab4500->rx_buf[0] = 0;
  55
  56         xfer.tx_buf     = ab4500->tx_buf;
  57         xfer.rx_buf     = NULL;
  58         xfer.len        = sizeof(unsigned long);
  59
  60         spi_message_init(&msg);
  61         spi_message_add_tail(&xfer, &msg);
  62
  63         err = spi_sync(ab4500->spi, &msg);
  64         mutex_unlock(&ab4500->lock);
  65
  66         return err;
  67 }
  68 EXPORT_SYMBOL(ab4500_write);
  69
  70 int ab4500_read(struct ab4500 *ab4500, unsigned char block,
  71                 unsigned long addr)
  72 {
  73         struct spi_transfer xfer;
  74         struct spi_message      msg;
  75         unsigned long spi_data =
  76                 1 << 23 | block << 18 | addr << 10;
  77
  78         mutex_lock(&ab4500->lock);
  79         ab4500->tx_buf[0] = spi_data;
  80         ab4500->rx_buf[0] = 0;
  81
  82         xfer.tx_buf     = ab4500->tx_buf;
  83         xfer.rx_buf     = ab4500->rx_buf;
  84         xfer.len        = sizeof(unsigned long);
  85
  86         spi_message_init(&msg);
  87         spi_message_add_tail(&xfer, &msg);
  88
  89         spi_sync(ab4500->spi, &msg);
  90         mutex_unlock(&ab4500->lock);
  91
  92         return  ab4500->rx_buf[0];
  93 }
  94 EXPORT_SYMBOL(ab4500_read);
  95
  96 /* ref: ab3100 core */
  97 #define AB4500_DEVICE(devname, devid)                           \
  98 static struct platform_device ab4500_##devname##_device = {     \
  99         .name   = devid,                                        \
 100         .id     = -1,                                           \
 101 }
 102
 103 /* list of childern devices of ab4500 - all are
 104  * not populated here - TODO
 105  */
 106 AB4500_DEVICE(charger, "ab4500-charger");
 107 AB4500_DEVICE(audio, "ab4500-audio");
 108 AB4500_DEVICE(usb, "ab4500-usb");
 109 AB4500_DEVICE(tvout, "ab4500-tvout");
 110 AB4500_DEVICE(sim, "ab4500-sim");
 111 AB4500_DEVICE(gpadc, "ab4500-gpadc");
 112 AB4500_DEVICE(clkmgt, "ab4500-clkmgt");
 113 AB4500_DEVICE(misc, "ab4500-misc");
 114
 115 static struct platform_device *ab4500_platform_devs[] = {
 116         &ab4500_charger_device,
 117         &ab4500_audio_device,
 118         &ab4500_usb_device,
 119         &ab4500_tvout_device,
 120         &ab4500_sim_device,
 121         &ab4500_gpadc_device,
 122         &ab4500_clkmgt_device,
 123         &ab4500_misc_device,
 124 };
 125
 126 static int __init ab4500_probe(struct spi_device *spi)
 127 {
 128         struct ab4500   *ab4500;
 129         unsigned char revision;
 130         int err = 0;
 131         int i;
 132
 133         ab4500 = kzalloc(sizeof *ab4500, GFP_KERNEL);
 134         if (!ab4500) {
 135                 dev_err(&spi->dev, "could not allocate AB4500\n");
 136                 err = -ENOMEM;
 137                 goto not_detect;
 138         }
 139
 140         ab4500->spi = spi;
 141         spi_set_drvdata(spi, ab4500);
 142
 143         mutex_init(&ab4500->lock);
 144
 145         /* read the revision register */
 146         revision = ab4500_read(ab4500, AB4500_MISC, AB4500_REV_REG);
 147
 148         /* revision id 0x0 is for early drop, 0x10 is for cut1.0 */
 149         if (revision == 0x0 || revision == 0x10)
 150                 dev_info(&spi->dev, "Detected chip: %s, revision = %x\n",
 151                         ab4500_driver.driver.name, revision);
 152         else    {
 153                 dev_err(&spi->dev, "unknown chip: 0x%x\n", revision);
 154                 goto not_detect;
 155         }
 156
 157         for (i = 0; i < ARRAY_SIZE(ab4500_platform_devs); i++)  {
 158                 ab4500_platform_devs[i]->dev.parent =
 159                         &spi->dev;
 160                 platform_set_drvdata(ab4500_platform_devs[i], ab4500);
 161         }
 162
 163         /* register the ab4500 platform devices */
 164         platform_add_devices(ab4500_platform_devs,
 165                         ARRAY_SIZE(ab4500_platform_devs));
 166
 167         return err;
 168
 169  not_detect:
 170         spi_unregister_driver(&ab4500_driver);
 171         kfree(ab4500);
 172         return err;
 173 }
 174
 175 static int __devexit ab4500_remove(struct spi_device *spi)
 176 {
 177         struct ab4500 *ab4500 =
 178                 spi_get_drvdata(spi);
 179
 180         kfree(ab4500);
 181
 182         return 0;
 183 }
 184
 185 static struct spi_driver ab4500_driver = {
 186         .driver = {
 187                 .name = "ab4500",
 188                 .owner = THIS_MODULE,
 189         },
 190         .probe = ab4500_probe,
 191         .remove = __devexit_p(ab4500_remove)
 192 };
 193
 194 static int __devinit ab4500_init(void)
 195 {
 196         return spi_register_driver(&ab4500_driver);
 197 }
 198
 199 static void __exit ab4500_exit(void)
 200 {
 201         spi_unregister_driver(&ab4500_driver);
 202 }
 203
 204 subsys_initcall(ab4500_init);
 205 module_exit(ab4500_exit);
 206
 207 MODULE_AUTHOR("Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com");
 208 MODULE_DESCRIPTION("AB4500 core driver");
 209 MODULE_LICENSE("GPL");