linux/arch/arm/mach-omap2/i2c.c
Tony Lindgren 44773ba170 ARM: OMAP2+: Drop unused pm-noop
Looks like these functions don't do anything in the mainline kernel so
we can just drop it.

Note that we must now also remove ir-rx51 pdata as it relies on the dummy
platform data that does not do anything. And ir-rx51 is calling a pdata
callback that doesn't do anything without checking if it exists first.

For configuring device specific minimal latencies, the interface to use
is pm_qos_add_request(). For an example, see what was done in commit
9834ffd1ec ("ASoC: omap-mcbsp: Add PM QoS support for McBSP to prevent
glitches"). I've added some comments to ir-rx51 so people using it can
add pm_qos support and test it.

Cc: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2018-04-16 10:22:40 -07:00

94 lines
2.4 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 "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;
}