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 <mach/irqs.h>
  35 #include <plat/cpu.h>
  36
  37 #include "i2c.h"
  38
  39 #define OMAP_I2C_MAX_CONTROLLERS 4
  40 static struct omap_i2c_bus_platform_data i2c_pdata[OMAP_I2C_MAX_CONTROLLERS];
  41
  42 #define OMAP_I2C_CMDLINE_SETUP  (BIT(31))
  43
  44 static int __init omap_i2c_nr_ports(void)
  45 {
  46         int ports = 0;
  47
  48         if (cpu_class_is_omap1())
  49                 ports = 1;
  50         else if (cpu_is_omap24xx())
  51                 ports = 2;
  52         else if (cpu_is_omap34xx())
  53                 ports = 3;
  54         else if (cpu_is_omap44xx())
  55                 ports = 4;
  56
  57         return ports;
  58 }
  59
  60 /**
  61  * omap_i2c_bus_setup - Process command line options for the I2C bus speed
  62  * @str: String of options
  63  *
  64  * This function allow to override the default I2C bus speed for given I2C
  65  * bus with a command line option.
  66  *
  67  * Format: i2c_bus=bus_id,clkrate (in kHz)
  68  *
  69  * Returns 1 on success, 0 otherwise.
  70  */
  71 static int __init omap_i2c_bus_setup(char *str)
  72 {
  73         int ports;
  74         int ints[3];
  75
  76         ports = omap_i2c_nr_ports();
  77         get_options(str, 3, ints);
  78         if (ints[0] < 2 || ints[1] < 1 || ints[1] > ports)
  79                 return 0;
  80         i2c_pdata[ints[1] - 1].clkrate = ints[2];
  81         i2c_pdata[ints[1] - 1].clkrate |= OMAP_I2C_CMDLINE_SETUP;
  82
  83         return 1;
  84 }
  85 __setup("i2c_bus=", omap_i2c_bus_setup);
  86
  87 /*
  88  * Register busses defined in command line but that are not registered with
  89  * omap_register_i2c_bus from board initialization code.
  90  */
  91 static int __init omap_register_i2c_bus_cmdline(void)
  92 {
  93         int i, err = 0;
  94
  95         for (i = 0; i < ARRAY_SIZE(i2c_pdata); i++)
  96                 if (i2c_pdata[i].clkrate & OMAP_I2C_CMDLINE_SETUP) {
  97                         i2c_pdata[i].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
  98                         err = omap_i2c_add_bus(&i2c_pdata[i], i + 1);
  99                         if (err)
 100                                 goto out;
 101                 }
 102
 103 out:
 104         return err;
 105 }
 106 subsys_initcall(omap_register_i2c_bus_cmdline);
 107
 108 /**
 109  * omap_register_i2c_bus - register I2C bus with device descriptors
 110  * @bus_id: bus id counting from number 1
 111  * @clkrate: clock rate of the bus in kHz
 112  * @info: pointer into I2C device descriptor table or NULL
 113  * @len: number of descriptors in the table
 114  *
 115  * Returns 0 on success or an error code.
 116  */
 117 int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
 118                           struct i2c_board_info const *info,
 119                           unsigned len)
 120 {
 121         int err;
 122
 123         BUG_ON(bus_id < 1 || bus_id > omap_i2c_nr_ports());
 124
 125         if (info) {
 126                 err = i2c_register_board_info(bus_id, info, len);
 127                 if (err)
 128                         return err;
 129         }
 130
 131         if (!i2c_pdata[bus_id - 1].clkrate)
 132                 i2c_pdata[bus_id - 1].clkrate = clkrate;
 133
 134         i2c_pdata[bus_id - 1].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
 135
 136         return omap_i2c_add_bus(&i2c_pdata[bus_id - 1], bus_id);
 137 }