linux/arch/arm/plat-omap/i2c.c
Paul Walmsley 9aadd70aed Revert "ARM: OMAP: convert I2C driver to PM QoS for MPU latency constraints"
This reverts commit 3db11feffc
(ARM: OMAP: convert I2C driver to PM QoS for MPU latency constraints).
This commit causes I2C timeouts to appear on several OMAP3430/3530-based
boards:

  http://marc.info/?l=linux-arm-kernel&m=135071372426971&w=2
  http://marc.info/?l=linux-arm-kernel&m=135067558415214&w=2
  http://marc.info/?l=linux-arm-kernel&m=135216013608196&w=2

and appears to have been sent for merging before one of its prerequisites
was merged:

  http://marc.info/?l=linux-arm-kernel&m=135219411617621&w=2

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
2012-11-14 11:54:41 +01:00

118 lines
3.1 KiB
C

/*
* linux/arch/arm/plat-omap/i2c.c
*
* Helper module for board specific I2C bus registration
*
* Copyright (C) 2007 Nokia Corporation.
*
* Contact: Jarkko Nikula <jhnikula@gmail.com>
*
* 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 <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/i2c-omap.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <plat/i2c.h>
#define OMAP_I2C_MAX_CONTROLLERS 4
static struct omap_i2c_bus_platform_data i2c_pdata[OMAP_I2C_MAX_CONTROLLERS];
#define OMAP_I2C_CMDLINE_SETUP (BIT(31))
/**
* omap_i2c_bus_setup - Process command line options for the I2C bus speed
* @str: String of options
*
* This function allow to override the default I2C bus speed for given I2C
* bus with a command line option.
*
* Format: i2c_bus=bus_id,clkrate (in kHz)
*
* Returns 1 on success, 0 otherwise.
*/
static int __init omap_i2c_bus_setup(char *str)
{
int ints[3];
get_options(str, 3, ints);
if (ints[0] < 2 || ints[1] < 1 ||
ints[1] > OMAP_I2C_MAX_CONTROLLERS)
return 0;
i2c_pdata[ints[1] - 1].clkrate = ints[2];
i2c_pdata[ints[1] - 1].clkrate |= OMAP_I2C_CMDLINE_SETUP;
return 1;
}
__setup("i2c_bus=", omap_i2c_bus_setup);
/*
* Register busses defined in command line but that are not registered with
* omap_register_i2c_bus from board initialization code.
*/
static int __init omap_register_i2c_bus_cmdline(void)
{
int i, err = 0;
for (i = 0; i < ARRAY_SIZE(i2c_pdata); i++)
if (i2c_pdata[i].clkrate & OMAP_I2C_CMDLINE_SETUP) {
i2c_pdata[i].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
err = omap_i2c_add_bus(&i2c_pdata[i], i + 1);
if (err)
goto out;
}
out:
return err;
}
subsys_initcall(omap_register_i2c_bus_cmdline);
/**
* omap_register_i2c_bus - register I2C bus with device descriptors
* @bus_id: bus id counting from number 1
* @clkrate: clock rate of the bus in kHz
* @info: pointer into I2C device descriptor table or NULL
* @len: number of descriptors in the table
*
* Returns 0 on success or an error code.
*/
int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
struct i2c_board_info const *info,
unsigned len)
{
int err;
BUG_ON(bus_id < 1 || bus_id > OMAP_I2C_MAX_CONTROLLERS);
if (info) {
err = i2c_register_board_info(bus_id, info, len);
if (err)
return err;
}
if (!i2c_pdata[bus_id - 1].clkrate)
i2c_pdata[bus_id - 1].clkrate = clkrate;
i2c_pdata[bus_id - 1].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
return omap_i2c_add_bus(&i2c_pdata[bus_id - 1], bus_id);
}