LXR linux/arch/arm/plat-omap/i2c.c

   1/*
   2 * linux/arch/arm/plat-omap/i2c.c
   3 *
   4 * Helper module for board specific I2C bus registration
   5 *
   6 * Copyright (C) 2007 Nokia Corporation.
   7 *
   8 * Contact: Jarkko Nikula <jhnikula@gmail.com>
   9 *
  10 * This program is free software; you can redistribute it and/or
  11 * modify it under the terms of the GNU General Public License
  12 * version 2 as published by the Free Software Foundation.
  13 *
  14 * This program is distributed in the hope that it will be useful, but
  15 * WITHOUT ANY WARRANTY; without even the implied warranty of
  16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17 * General Public License for more details.
  18 *
  19 * You should have received a copy of the GNU General Public License
  20 * along with this program; if not, write to the Free Software
  21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  22 * 02110-1301 USA
  23 *
  24 */
  25
  26#include <linux/kernel.h>
  27#include <linux/platform_device.h>
  28#include <linux/i2c.h>
  29#include <linux/i2c-omap.h>
  30#include <linux/slab.h>
  31#include <linux/err.h>
  32#include <linux/clk.h>
  33
  34#include <plat/i2c.h>
  35
  36#define OMAP_I2C_MAX_CONTROLLERS 4
  37static struct omap_i2c_bus_platform_data i2c_pdata[OMAP_I2C_MAX_CONTROLLERS];
  38
  39#define OMAP_I2C_CMDLINE_SETUP  (BIT(31))
  40
  41/**
  42 * omap_i2c_bus_setup - Process command line options for the I2C bus speed
  43 * @str: String of options
  44 *
  45 * This function allow to override the default I2C bus speed for given I2C
  46 * bus with a command line option.
  47 *
  48 * Format: i2c_bus=bus_id,clkrate (in kHz)
  49 *
  50 * Returns 1 on success, 0 otherwise.
  51 */
  52static int __init omap_i2c_bus_setup(char *str)
  53{
  54        int ints[3];
  55
  56        get_options(str, 3, ints);
  57        if (ints[0] < 2 || ints[1] < 1 ||
  58                        ints[1] > OMAP_I2C_MAX_CONTROLLERS)
  59                return 0;
  60        i2c_pdata[ints[1] - 1].clkrate = ints[2];
  61        i2c_pdata[ints[1] - 1].clkrate |= OMAP_I2C_CMDLINE_SETUP;
  62
  63        return 1;
  64}
  65__setup("i2c_bus=", omap_i2c_bus_setup);
  66
  67/*
  68 * Register busses defined in command line but that are not registered with
  69 * omap_register_i2c_bus from board initialization code.
  70 */
  71int __init omap_register_i2c_bus_cmdline(void)
  72{
  73        int i, err = 0;
  74
  75        for (i = 0; i < ARRAY_SIZE(i2c_pdata); i++)
  76                if (i2c_pdata[i].clkrate & OMAP_I2C_CMDLINE_SETUP) {
  77                        i2c_pdata[i].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
  78                        err = omap_i2c_add_bus(&i2c_pdata[i], i + 1);
  79                        if (err)
  80                                goto out;
  81                }
  82
  83out:
  84        return err;
  85}
  86
  87/**
  88 * omap_register_i2c_bus - register I2C bus with device descriptors
  89 * @bus_id: bus id counting from number 1
  90 * @clkrate: clock rate of the bus in kHz
  91 * @info: pointer into I2C device descriptor table or NULL
  92 * @len: number of descriptors in the table
  93 *
  94 * Returns 0 on success or an error code.
  95 */
  96int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
  97                          struct i2c_board_info const *info,
  98                          unsigned len)
  99{
 100        int err;
 101
 102        BUG_ON(bus_id < 1 || bus_id > OMAP_I2C_MAX_CONTROLLERS);
 103
 104        if (info) {
 105                err = i2c_register_board_info(bus_id, info, len);
 106                if (err)
 107                        return err;
 108        }
 109
 110        if (!i2c_pdata[bus_id - 1].clkrate)
 111                i2c_pdata[bus_id - 1].clkrate = clkrate;
 112
 113        i2c_pdata[bus_id - 1].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
 114
 115        return omap_i2c_add_bus(&i2c_pdata[bus_id - 1], bus_id);
 116}
 117