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