mirror of
https://github.com/torvalds/linux.git
synced 2024-11-07 12:41:55 +00:00
6d3c55fd4f
The sequence of _ocp_softreset doesn't work for i2c. The i2c module has a special sequence to reset the module. The sequence is - Disable the I2C. - Write to SOFTRESET bit. - Enable the I2C. - Poll on the RESETDONE bit. The sequence is implemented as a function and the i2c_class is updated with the correct 'reset' pointer. omap_hwmod_softreset function is implemented which triggers the softreset by writing into sysconfig register. On following this sequence, i2c module resets properly and timeouts are not seen. Cc: Rajendra Nayak <rnayak@ti.com> Cc: Paul Walmsley <paul@pwsan.com> Cc: Benoit Cousson <b-cousson@ti.com> Cc: Kevin Hilman <khilman@ti.com> Signed-off-by: Avinash.H.M <avinashhm@ti.com> [paul@pwsan.com: combined this patch with a patch to remove HWMOD_INIT_NO_RESET from the 44xx hwmod flags; change register offset conditional code to use the IP block revision; minor code cleanup] Signed-off-by: Paul Walmsley <paul@pwsan.com>
108 lines
2.9 KiB
C
108 lines
2.9 KiB
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/cpu.h>
|
|
#include <plat/i2c.h>
|
|
#include <plat/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;
|
|
}
|