mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-06 02:50:43 +00:00
![Tony Lindgren](/assets/img/avatar_default.png)
We can now initialize I2C for mach-omap2 using device tree. And we can move the remaining code in plat-omap/i2c.c into mach-omap1/i2c.c. Note that we cannot remove some of the I2C bus reset functions as they are being used by hwmod code. Signed-off-by: Tony Lindgren <tony@atomide.com>
94 lines
2.5 KiB
C
94 lines
2.5 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 "soc.h"
|
|
#include "omap_hwmod.h"
|
|
#include "omap_device.h"
|
|
#include "omap-pm.h"
|
|
|
|
#include "prm.h"
|
|
#include "common.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
|
|
|
|
#define MAX_OMAP_I2C_HWMOD_NAME_LEN 16
|
|
|
|
/**
|
|
* 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_warn("%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;
|
|
}
|