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arm-soc: add stmp-dev library code

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A number of devices are using a common register layout, this adds support
 code for it in lib/stmp_device.c so we do not need to duplicate it in
 each driver.
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Merge tag 'stmp-dev' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

Pull arm-soc stmp-dev library code from Olof Johansson:
 "A number of devices are using a common register layout, this adds
  support code for it in lib/stmp_device.c so we do not need to
  duplicate it in each driver."

Fix up trivial conflicts in drivers/i2c/busses/i2c-mxs.c and
lib/Makefile

* tag 'stmp-dev' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  i2c: mxs: use global reset function
  lib: add support for stmp-style devices
This commit is contained in:
Linus Torvalds 2012-05-26 12:50:04 -07:00
commit 39b6cc668c
6 changed files with 108 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/i2c/busses/Kconfig
View File

@ -483,6 +483,7 @@ config I2C_MV64XXX
config I2C_MXS
tristate "Freescale i.MX28 I2C interface"
depends on SOC_IMX28
select STMP_DEVICE
help
Say Y here if you want to use the I2C bus controller on
the Freescale i.MX28 processors.

9
drivers/i2c/busses/i2c-mxs.c
View File

@ -27,8 +27,7 @@
#include <linux/jiffies.h>
#include <linux/io.h>
#include <linux/pinctrl/consumer.h>
#include <mach/common.h>
#include <linux/stmp_device.h>
#define DRIVER_NAME "mxs-i2c"
@ -112,13 +111,9 @@ struct mxs_i2c_dev {
struct i2c_adapter adapter;
};
/*
* TODO: check if calls to here are really needed. If not, we could get rid of
* mxs_reset_block and the mach-dependency. Needs an I2C analyzer, probably.
*/
static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
{
mxs_reset_block(i2c->regs);
stmp_reset_block(i2c->regs);
writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
i2c->regs + MXS_I2C_QUEUECTRL_SET);

20
include/linux/stmp_device.h Normal file
View File

@ -0,0 +1,20 @@
/*
* basic functions for devices following the "stmp" style register layout
*
* Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#ifndef __STMP_DEVICE_H__
#define __STMP_DEVICE_H__
#define STMP_OFFSET_REG_SET 0x4
#define STMP_OFFSET_REG_CLR 0x8
#define STMP_OFFSET_REG_TOG 0xc
extern int stmp_reset_block(void __iomem *);
#endif /* __STMP_DEVICE_H__ */

3
lib/Kconfig
View File

@ -36,6 +36,9 @@ config GENERIC_IO
boolean
default n
config STMP_DEVICE
bool
config CRC_CCITT
tristate "CRC-CCITT functions"
help

2
lib/Makefile
View File

@ -127,6 +127,8 @@ obj-$(CONFIG_DDR) += jedec_ddr_data.o
obj-$(CONFIG_GENERIC_STRNCPY_FROM_USER) += strncpy_from_user.o
obj-$(CONFIG_STMP_DEVICE) += stmp_device.o
hostprogs-y := gen_crc32table
clean-files := crc32table.h

80
lib/stmp_device.c Normal file
View File

@ -0,0 +1,80 @@
/*
* Copyright (C) 1999 ARM Limited
* Copyright (C) 2000 Deep Blue Solutions Ltd
* Copyright 2006-2007,2010 Freescale Semiconductor, Inc. All Rights Reserved.
* Copyright 2008 Juergen Beisert, kernel@pengutronix.de
* Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, yanok@emcraft.com
* Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/io.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/stmp_device.h>
#define STMP_MODULE_CLKGATE (1 << 30)
#define STMP_MODULE_SFTRST (1 << 31)
/*
* Clear the bit and poll it cleared. This is usually called with
* a reset address and mask being either SFTRST(bit 31) or CLKGATE
* (bit 30).
*/
static int stmp_clear_poll_bit(void __iomem *addr, u32 mask)
{
int timeout = 0x400;
writel(mask, addr + STMP_OFFSET_REG_CLR);
udelay(1);
while ((readl(addr) & mask) && --timeout)
/* nothing */;
return !timeout;
}
int stmp_reset_block(void __iomem *reset_addr)
{
int ret;
int timeout = 0x400;
/* clear and poll SFTRST */
ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
if (unlikely(ret))
goto error;
/* clear CLKGATE */
writel(STMP_MODULE_CLKGATE, reset_addr + STMP_OFFSET_REG_CLR);
/* set SFTRST to reset the block */
writel(STMP_MODULE_SFTRST, reset_addr + STMP_OFFSET_REG_SET);
udelay(1);
/* poll CLKGATE becoming set */
while ((!(readl(reset_addr) & STMP_MODULE_CLKGATE)) && --timeout)
/* nothing */;
if (unlikely(!timeout))
goto error;
/* clear and poll SFTRST */
ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_SFTRST);
if (unlikely(ret))
goto error;
/* clear and poll CLKGATE */
ret = stmp_clear_poll_bit(reset_addr, STMP_MODULE_CLKGATE);
if (unlikely(ret))
goto error;
return 0;
error:
pr_err("%s(%p): module reset timeout\n", __func__, reset_addr);
return -ETIMEDOUT;
}
EXPORT_SYMBOL(stmp_reset_block);