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
  37 static 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  */
  52 static 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  */
  71 int __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
  83 out:
  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  */
  96 int __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 }