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i2c.c

/*
 * linux/arch/arm/plat-omap/i2c.c
 *
 * Helper module for board specific I2C bus registration
 *
 * Copyright (C) 2007 Nokia Corporation.
 *
 * Contact: Jarkko Nikula <jhnikula@gmail.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <mach/irqs.h>
#include <mach/mux.h>

#define OMAP_I2C_SIZE         0x3f
#define OMAP1_I2C_BASE        0xfffb3800
#define OMAP2_I2C_BASE1       0x48070000
#define OMAP2_I2C_BASE2       0x48072000
#define OMAP2_I2C_BASE3       0x48060000

static const char name[] = "i2c_omap";

#define I2C_RESOURCE_BUILDER(base, irq)               \
      {                                   \
            .start      = (base),               \
            .end  = (base) + OMAP_I2C_SIZE,     \
            .flags      = IORESOURCE_MEM,       \
      },                                  \
      {                                   \
            .start      = (irq),                \
            .flags      = IORESOURCE_IRQ,       \
      },

static struct resource i2c_resources[][2] = {
      { I2C_RESOURCE_BUILDER(0, 0) },
#if   defined(CONFIG_ARCH_OMAP24XX) || defined(CONFIG_ARCH_OMAP34XX)
      { I2C_RESOURCE_BUILDER(OMAP2_I2C_BASE2, INT_24XX_I2C2_IRQ) },
#endif
#if   defined(CONFIG_ARCH_OMAP34XX)
      { I2C_RESOURCE_BUILDER(OMAP2_I2C_BASE3, INT_34XX_I2C3_IRQ) },
#endif
};

#define I2C_DEV_BUILDER(bus_id, res, data)            \
      {                                   \
            .id   = (bus_id),             \
            .name = name,                       \
            .num_resources    = ARRAY_SIZE(res),      \
            .resource   = (res),          \
            .dev        = {               \
                  .platform_data    = (data),   \
            },                            \
      }

static u32 i2c_rate[ARRAY_SIZE(i2c_resources)];
static struct platform_device omap_i2c_devices[] = {
      I2C_DEV_BUILDER(1, i2c_resources[0], &i2c_rate[0]),
#if   defined(CONFIG_ARCH_OMAP24XX) || defined(CONFIG_ARCH_OMAP34XX)
      I2C_DEV_BUILDER(2, i2c_resources[1], &i2c_rate[1]),
#endif
#if   defined(CONFIG_ARCH_OMAP34XX)
      I2C_DEV_BUILDER(3, i2c_resources[2], &i2c_rate[2]),
#endif
};

#if defined(CONFIG_ARCH_OMAP24XX)
static const int omap24xx_pins[][2] = {
      { M19_24XX_I2C1_SCL, L15_24XX_I2C1_SDA },
      { J15_24XX_I2C2_SCL, H19_24XX_I2C2_SDA },
};
#else
static const int omap24xx_pins[][2] = {};
#endif
#if defined(CONFIG_ARCH_OMAP34XX)
static const int omap34xx_pins[][2] = {
      { K21_34XX_I2C1_SCL, J21_34XX_I2C1_SDA},
      { AF15_34XX_I2C2_SCL, AE15_34XX_I2C2_SDA},
      { AF14_34XX_I2C3_SCL, AG14_34XX_I2C3_SDA},
};
#else
static const int omap34xx_pins[][2] = {};
#endif

#define OMAP_I2C_CMDLINE_SETUP      (BIT(31))

static void __init omap_i2c_mux_pins(int bus)
{
      int scl, sda;

      if (cpu_class_is_omap1()) {
            scl = I2C_SCL;
            sda = I2C_SDA;
      } else if (cpu_is_omap24xx()) {
            scl = omap24xx_pins[bus][0];
            sda = omap24xx_pins[bus][1];
      } else if (cpu_is_omap34xx()) {
            scl = omap34xx_pins[bus][0];
            sda = omap34xx_pins[bus][1];
      } else {
            return;
      }

      omap_cfg_reg(sda);
      omap_cfg_reg(scl);
}

static int __init omap_i2c_nr_ports(void)
{
      int ports = 0;

      if (cpu_class_is_omap1())
            ports = 1;
      else if (cpu_is_omap24xx())
            ports = 2;
      else if (cpu_is_omap34xx())
            ports = 3;

      return ports;
}

static int __init omap_i2c_add_bus(int bus_id)
{
      struct platform_device *pdev;
      struct resource *res;
      resource_size_t base, irq;

      pdev = &omap_i2c_devices[bus_id - 1];
      if (bus_id == 1) {
            res = pdev->resource;
            if (cpu_class_is_omap1()) {
                  base = OMAP1_I2C_BASE;
                  irq = INT_I2C;
            } else {
                  base = OMAP2_I2C_BASE1;
                  irq = INT_24XX_I2C1_IRQ;
            }
            res[0].start = base;
            res[0].end = base + OMAP_I2C_SIZE;
            res[1].start = irq;
      }

      omap_i2c_mux_pins(bus_id - 1);
      return platform_device_register(pdev);
}

/**
 * omap_i2c_bus_setup - Process command line options for the I2C bus speed
 * @str: String of options
 *
 * This function allow to override the default I2C bus speed for given I2C
 * bus with a command line option.
 *
 * Format: i2c_bus=bus_id,clkrate (in kHz)
 *
 * Returns 1 on success, 0 otherwise.
 */
static int __init omap_i2c_bus_setup(char *str)
{
      int ports;
      int ints[3];

      ports = omap_i2c_nr_ports();
      get_options(str, 3, ints);
      if (ints[0] < 2 || ints[1] < 1 || ints[1] > ports)
            return 0;
      i2c_rate[ints[1] - 1] = ints[2];
      i2c_rate[ints[1] - 1] |= OMAP_I2C_CMDLINE_SETUP;

      return 1;
}
__setup("i2c_bus=", omap_i2c_bus_setup);

/*
 * Register busses defined in command line but that are not registered with
 * omap_register_i2c_bus from board initialization code.
 */
static int __init omap_register_i2c_bus_cmdline(void)
{
      int i, err = 0;

      for (i = 0; i < ARRAY_SIZE(i2c_rate); i++)
            if (i2c_rate[i] & OMAP_I2C_CMDLINE_SETUP) {
                  i2c_rate[i] &= ~OMAP_I2C_CMDLINE_SETUP;
                  err = omap_i2c_add_bus(i + 1);
                  if (err)
                        goto out;
            }

out:
      return err;
}
subsys_initcall(omap_register_i2c_bus_cmdline);

/**
 * omap_register_i2c_bus - register I2C bus with device descriptors
 * @bus_id: bus id counting from number 1
 * @clkrate: clock rate of the bus in kHz
 * @info: pointer into I2C device descriptor table or NULL
 * @len: number of descriptors in the table
 *
 * Returns 0 on success or an error code.
 */
int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
                    struct i2c_board_info const *info,
                    unsigned len)
{
      int err;

      BUG_ON(bus_id < 1 || bus_id > omap_i2c_nr_ports());

      if (info) {
            err = i2c_register_board_info(bus_id, info, len);
            if (err)
                  return err;
      }

      if (!i2c_rate[bus_id - 1])
            i2c_rate[bus_id - 1] = clkrate;
      i2c_rate[bus_id - 1] &= ~OMAP_I2C_CMDLINE_SETUP;

      return omap_i2c_add_bus(bus_id);
}

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