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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 <linux/i2c-omap.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>

#include <mach/irqs.h>
#include <plat/mux.h>
#include <plat/i2c.h>
#include <plat/omap-pm.h>
#include <plat/omap_device.h>

#define OMAP_I2C_SIZE         0x3f
#define OMAP1_I2C_BASE        0xfffb3800

static const char name[] = "omap_i2c";

#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) },
};

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

#define MAX_OMAP_I2C_HWMOD_NAME_LEN 16
#define OMAP_I2C_MAX_CONTROLLERS 4
static struct omap_i2c_bus_platform_data i2c_pdata[OMAP_I2C_MAX_CONTROLLERS];
static struct platform_device omap_i2c_devices[] = {
      I2C_DEV_BUILDER(1, i2c_resources[0], &i2c_pdata[0]),
};

#define OMAP_I2C_CMDLINE_SETUP      (BIT(31))

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;
      else if (cpu_is_omap44xx())
            ports = 4;

      return ports;
}

static inline int omap1_i2c_add_bus(int bus_id)
{
      struct platform_device *pdev;
      struct omap_i2c_bus_platform_data *pdata;
      struct resource *res;

      omap1_i2c_mux_pins(bus_id);

      pdev = &omap_i2c_devices[bus_id - 1];
      res = pdev->resource;
      res[0].start = OMAP1_I2C_BASE;
      res[0].end = res[0].start + OMAP_I2C_SIZE;
      res[1].start = INT_I2C;
      pdata = &i2c_pdata[bus_id - 1];

      return platform_device_register(pdev);
}


/*
 * XXX This function is a temporary compatibility wrapper - only
 * needed until the I2C driver can be converted to call
 * omap_pm_set_max_dev_wakeup_lat() and handle a return code.
 */
static void omap_pm_set_max_mpu_wakeup_lat_compat(struct device *dev, long t)
{
      omap_pm_set_max_mpu_wakeup_lat(dev, t);
}

static struct omap_device_pm_latency omap_i2c_latency[] = {
      [0] = {
            .deactivate_func  = omap_device_idle_hwmods,
            .activate_func          = omap_device_enable_hwmods,
            .flags                  = OMAP_DEVICE_LATENCY_AUTO_ADJUST,
      },
};

#ifdef CONFIG_ARCH_OMAP2PLUS
static inline int omap2_i2c_add_bus(int bus_id)
{
      int l;
      struct omap_hwmod *oh;
      struct omap_device *od;
      char oh_name[MAX_OMAP_I2C_HWMOD_NAME_LEN];
      struct omap_i2c_bus_platform_data *pdata;

      omap2_i2c_mux_pins(bus_id);

      l = snprintf(oh_name, MAX_OMAP_I2C_HWMOD_NAME_LEN, "i2c%d", bus_id);
      WARN(l >= MAX_OMAP_I2C_HWMOD_NAME_LEN,
            "String buffer overflow in I2C%d device setup\n", bus_id);
      oh = omap_hwmod_lookup(oh_name);
      if (!oh) {
                  pr_err("Could not look up %s\n", oh_name);
                  return -EEXIST;
      }

      pdata = &i2c_pdata[bus_id - 1];
      /*
       * When waiting for completion of a i2c transfer, we need to
       * set a wake up latency constraint for the MPU. This is to
       * ensure quick enough wakeup from idle, when transfer
       * completes.
       * Only omap3 has support for constraints
       */
      if (cpu_is_omap34xx())
            pdata->set_mpu_wkup_lat = omap_pm_set_max_mpu_wakeup_lat_compat;
      od = omap_device_build(name, bus_id, oh, pdata,
                  sizeof(struct omap_i2c_bus_platform_data),
                  omap_i2c_latency, ARRAY_SIZE(omap_i2c_latency), 0);
      WARN(IS_ERR(od), "Could not build omap_device for %s\n", name);

      return PTR_ERR(od);
}
#else
static inline int omap2_i2c_add_bus(int bus_id)
{
      return 0;
}
#endif

static int __init omap_i2c_add_bus(int bus_id)
{
      if (cpu_class_is_omap1())
            return omap1_i2c_add_bus(bus_id);
      else
            return omap2_i2c_add_bus(bus_id);
}

/**
 * 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_pdata[ints[1] - 1].clkrate = ints[2];
      i2c_pdata[ints[1] - 1].clkrate |= 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_pdata); i++)
            if (i2c_pdata[i].clkrate & OMAP_I2C_CMDLINE_SETUP) {
                  i2c_pdata[i].clkrate &= ~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_pdata[bus_id - 1].clkrate)
            i2c_pdata[bus_id - 1].clkrate = clkrate;

      i2c_pdata[bus_id - 1].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;

      return omap_i2c_add_bus(bus_id);
}

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