[deliverable/linux.git] / arch / arm / mach-omap2 / i2c.c

/*
 * 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 <plat/i2c.h>
#include "common.h"
#include <plat/omap_hwmod.h>

#include "mux.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

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;
}
Commit	Line	Data
b63128e8 TL	1	/*
	2	* Helper module for board specific I2C bus registration
	3	*
	4	* Copyright (C) 2009 Nokia Corporation.
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* version 2 as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful, but
	11	* WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	* General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
	18	* 02110-1301 USA
	19	*
	20	*/
	21
b63128e8	22	#include <plat/i2c.h>
4e65331c	23	#include "common.h"
6d3c55fd	24	#include <plat/omap_hwmod.h>
b63128e8 TL	25
	26	#include "mux.h"
	27
6d3c55fd A	28	/* In register I2C_CON, Bit 15 is the I2C enable bit */
	29	#define I2C_EN BIT(15)
	30	#define OMAP2_I2C_CON_OFFSET 0x24
	31	#define OMAP4_I2C_CON_OFFSET 0xA4
	32
	33	/* Maximum microseconds to wait for OMAP module to softreset */
	34	#define MAX_MODULE_SOFTRESET_WAIT 10000
	35
9833eff3	36	void __init omap2_i2c_mux_pins(int bus_id)
b63128e8	37	{
f99bf16d	38	char mux_name[sizeof("i2c2_scl.i2c2_scl")];
b63128e8 TL	39
b63128e8 TL	40	/* First I2C bus is not muxable */
f99bf16d TL	41	if (bus_id == 1)
f99bf16d TL	42	return;
b63128e8	43
f99bf16d TL	44	sprintf(mux_name, "i2c%i_scl.i2c%i_scl", bus_id, bus_id);
	45	omap_mux_init_signal(mux_name, OMAP_PIN_INPUT);
	46	sprintf(mux_name, "i2c%i_sda.i2c%i_sda", bus_id, bus_id);
	47	omap_mux_init_signal(mux_name, OMAP_PIN_INPUT);
b63128e8	48	}
6d3c55fd A	49
	50	/**
	51	* omap_i2c_reset - reset the omap i2c module.
	52	* @oh: struct omap_hwmod *
	53	*
	54	* The i2c moudle in omap2, omap3 had a special sequence to reset. The
	55	* sequence is:
	56	* - Disable the I2C.
	57	* - Write to SOFTRESET bit.
	58	* - Enable the I2C.
	59	* - Poll on the RESETDONE bit.
	60	* The sequence is implemented in below function. This is called for 2420,
	61	* 2430 and omap3.
	62	*/
	63	int omap_i2c_reset(struct omap_hwmod *oh)
	64	{
	65	u32 v;
	66	u16 i2c_con;
	67	int c = 0;
	68
	69	if (oh->class->rev == OMAP_I2C_IP_VERSION_2) {
	70	i2c_con = OMAP4_I2C_CON_OFFSET;
	71	} else if (oh->class->rev == OMAP_I2C_IP_VERSION_1) {
	72	i2c_con = OMAP2_I2C_CON_OFFSET;
	73	} else {
	74	WARN(1, "Cannot reset I2C block %s: unsupported revision\n",
	75	oh->name);
	76	return -EINVAL;
	77	}
	78
	79	/* Disable I2C */
	80	v = omap_hwmod_read(oh, i2c_con);
	81	v &= ~I2C_EN;
	82	omap_hwmod_write(v, oh, i2c_con);
	83
	84	/* Write to the SOFTRESET bit */
	85	omap_hwmod_softreset(oh);
	86
	87	/* Enable I2C */
	88	v = omap_hwmod_read(oh, i2c_con);
	89	v \|= I2C_EN;
	90	omap_hwmod_write(v, oh, i2c_con);
	91
	92	/* Poll on RESETDONE bit */
	93	omap_test_timeout((omap_hwmod_read(oh,
	94	oh->class->sysc->syss_offs)
	95	& SYSS_RESETDONE_MASK),
	96	MAX_MODULE_SOFTRESET_WAIT, c);
	97
	98	if (c == MAX_MODULE_SOFTRESET_WAIT)
	99	pr_warning("%s: %s: softreset failed (waited %d usec)\n",
	100	__func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
	101	else
	102	pr_debug("%s: %s: softreset in %d usec\n", __func__,
	103	oh->name, c);
	104
	105	return 0;
	106	}