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i2c-s3c2410: Simplify bus frequency calculation

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The platform data for the i2c-s3c2410 driver used to allow a min,
max and desired frequency for the I2C bus. This patch reduces it
to simply a desired frequency ceiling and corrects all the uses
of the platform data appropriately.

This means, for example, that on a system with a 66MHz fclk, a
request for 100KHz will achieve 65KHz which is safe and
acceptable, rather than 378KHz which it would have achieved
without this change.

Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
Signed-off-by: Daniel Silverstone <dsilvers@simtec.co.uk>
[ben-linux@fluff.org: tidy subject and description]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Daniel Silverstone
2009-03-13 13:53:46 +00:00
committed by Ben Dooks
parent a192f7153b
commit c564e6ae6c
7 changed files with 40 additions and 68 deletions
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5
arch/arm/plat-s3c/dev-i2c0.c
View File

@@ -1,6 +1,6 @@
/* linux/arch/arm/plat-s3c/dev-i2c0.c
*
* Copyright 2008 Simtec Electronics
* Copyright 2008,2009 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
* http://armlinux.simtec.co.uk/
*
@@ -50,8 +50,7 @@ struct platform_device s3c_device_i2c0 = {
static struct s3c2410_platform_i2c default_i2c_data0 __initdata = {
.flags = 0,
.slave_addr = 0x10,
.bus_freq = 100*1000,
.max_freq = 400*1000,
.frequency = 100*1000,
.sda_delay = 100,
};

5
arch/arm/plat-s3c/dev-i2c1.c
View File

@@ -1,6 +1,6 @@
/* linux/arch/arm/plat-s3c/dev-i2c1.c
*
* Copyright 2008 Simtec Electronics
* Copyright 2008,2009 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
* http://armlinux.simtec.co.uk/
*
@@ -47,8 +47,7 @@ static struct s3c2410_platform_i2c default_i2c_data1 __initdata = {
.flags = 0,
.bus_num = 1,
.slave_addr = 0x10,
.bus_freq = 100*1000,
.max_freq = 400*1000,
.frequency = 100*1000,
.sda_delay = 100,
};

33
arch/arm/plat-s3c/include/plat/iic.h
View File

@@ -1,9 +1,9 @@
/* arch/arm/mach-s3c2410/include/mach/iic.h
/* arch/arm/plat-s3c/include/plat/iic.h
*
* Copyright (c) 2004 Simtec Electronics
* Copyright 2004,2009 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
*
* S3C2410 - I2C Controller platfrom_device info
* S3C - I2C Controller platform_device info
*
* 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
@@ -15,19 +15,24 @@
#define S3C_IICFLG_FILTER (1<<0) /* enable s3c2440 filter */
/* Notes:
* 1) All frequencies are expressed in Hz
* 2) A value of zero is `do not care`
*/
/**
* struct s3c2410_platform_i2c - Platform data for s3c I2C.
* @bus_num: The bus number to use (if possible).
* @flags: Any flags for the I2C bus (E.g. S3C_IICFLK_FILTER).
* @slave_addr: The I2C address for the slave device (if enabled).
* @frequency: The desired frequency in Hz of the bus. This is
* guaranteed to not be exceeded. If the caller does
* not care, use zero and the driver will select a
* useful default.
* @sda_delay: The delay (in ns) applied to SDA edges.
* @cfg_gpio: A callback to configure the pins for I2C operation.
*/
struct s3c2410_platform_i2c {
int bus_num; /* bus number to use */
int bus_num;
unsigned int flags;
unsigned int slave_addr; /* slave address for controller */
unsigned long bus_freq; /* standard bus frequency */
unsigned long max_freq; /* max frequency for the bus */
unsigned long min_freq; /* min frequency for the bus */
unsigned int sda_delay; /* pclks (s3c2440 only) */
unsigned int slave_addr;
unsigned long frequency;
unsigned int sda_delay;
void (*cfg_gpio)(struct platform_device *dev);
};