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/*
* Helper module for board specific I2C bus registration
*
* Copyright (C) 2009 Nokia Corporation.
*
* 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 "common.h"
#include "omap_hwmod.h"
#include "omap_device.h"
#include "mux.h"
#include "i2c.h"
/* In register I2C_CON, Bit 15 is the I2C enable bit */
#define I2C_EN BIT(15)
#define OMAP2_I2C_CON_OFFSET 0x24
#define OMAP4_I2C_CON_OFFSET 0xA4
/* Maximum microseconds to wait for OMAP module to softreset */
#define MAX_MODULE_SOFTRESET_WAIT 10000
#define MAX_OMAP_I2C_HWMOD_NAME_LEN 16
static void __init omap2_i2c_mux_pins(int bus_id)
{
char mux_name[sizeof("i2c2_scl.i2c2_scl")];
/* First I2C bus is not muxable */
if (bus_id == 1)
return;
sprintf(mux_name, "i2c%i_scl.i2c%i_scl", bus_id, bus_id);
omap_mux_init_signal(mux_name, OMAP_PIN_INPUT);
sprintf(mux_name, "i2c%i_sda.i2c%i_sda", bus_id, bus_id);
omap_mux_init_signal(mux_name, OMAP_PIN_INPUT);
}
/**
* omap_i2c_reset - reset the omap i2c module.
* @oh: struct omap_hwmod *
*
* The i2c moudle in omap2, omap3 had a special sequence to reset. The
* sequence is:
* - Disable the I2C.
* - Write to SOFTRESET bit.
* - Enable the I2C.
* - Poll on the RESETDONE bit.
* The sequence is implemented in below function. This is called for 2420,
* 2430 and omap3.
*/
int omap_i2c_reset(struct omap_hwmod *oh)
{
u32 v;
u16 i2c_con;
int c = 0;
if (oh->class->rev == OMAP_I2C_IP_VERSION_2) {
i2c_con = OMAP4_I2C_CON_OFFSET;
} else if (oh->class->rev == OMAP_I2C_IP_VERSION_1) {
i2c_con = OMAP2_I2C_CON_OFFSET;
} else {
WARN(1, "Cannot reset I2C block %s: unsupported revision\n",
oh->name);
return -EINVAL;
}
/* Disable I2C */
v = omap_hwmod_read(oh, i2c_con);
v &= ~I2C_EN;
omap_hwmod_write(v, oh, i2c_con);
/* Write to the SOFTRESET bit */
omap_hwmod_softreset(oh);
/* Enable I2C */
v = omap_hwmod_read(oh, i2c_con);
v |= I2C_EN;
omap_hwmod_write(v, oh, i2c_con);
/* Poll on RESETDONE bit */
omap_test_timeout((omap_hwmod_read(oh,
oh->class->sysc->syss_offs)
& SYSS_RESETDONE_MASK),
MAX_MODULE_SOFTRESET_WAIT, c);
if (c == MAX_MODULE_SOFTRESET_WAIT)
pr_warning("%s: %s: softreset failed (waited %d usec)\n",
__func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
else
pr_debug("%s: %s: softreset in %d usec\n", __func__,
oh->name, c);
return 0;
}
static const char name[] = "omap_i2c";
int __init omap_i2c_add_bus(struct omap_i2c_bus_platform_data *i2c_pdata,
int bus_id)
{
int l;
struct omap_hwmod *oh;
struct platform_device *pdev;
char oh_name[MAX_OMAP_I2C_HWMOD_NAME_LEN];
struct omap_i2c_bus_platform_data *pdata;
struct omap_i2c_dev_attr *dev_attr;
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;
/*
* pass the hwmod class's CPU-specific knowledge of I2C IP revision in
* use, and functionality implementation flags, up to the OMAP I2C
* driver via platform data
*/
pdata->rev = oh->class->rev;
dev_attr = (struct omap_i2c_dev_attr *)oh->dev_attr;
pdata->flags = dev_attr->flags;
pdev = omap_device_build(name, bus_id, oh, pdata,
sizeof(struct omap_i2c_bus_platform_data),
NULL, 0, 0);
WARN(IS_ERR(pdev), "Could not build omap_device for %s\n", name);
return PTR_RET(pdev);
}
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