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Merge branch 'stmp_device' of git://git.pengutronix.de/git/wsa/linux into next/stmp-dev

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Wolfram Sang <w.sang@pengutronix.de> writes:
  This series makes support for a certain type of devices mach independant. We
  want that because such devices (having a special register layout) have been
  found in mach-mxs and mach-mx6 meanwhile.

Since there is no subsystem maintainer for lib/ and the use case is
currently only for ARM systems, I have agreed to merge these through
the arm-soc tree.

* 'stmp_device' of git://git.pengutronix.de/git/wsa/linux:
  i2c: mxs: use global reset function
  lib: add support for stmp-style devices

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann 2012-04-22 22:54:46 +02:00
commit 3f81b2c49d
6 changed files with 108 additions and 7 deletions
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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

@ -26,8 +26,7 @@
#include <linux/platform_device.h>
#include <linux/jiffies.h>
#include <linux/io.h>
#include <mach/common.h>
#include <linux/stmp_device.h>
#define DRIVER_NAME "mxs-i2c"
@ -111,13 +110,9 @@ 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

@ -33,6 +33,9 @@ config GENERIC_IO
boolean
default n
config STMP_DEVICE
bool
config CRC_CCITT
tristate "CRC-CCITT functions"
help

2
lib/Makefile
View File

@ -123,6 +123,8 @@ obj-$(CONFIG_SIGNATURE) += digsig.o
obj-$(CONFIG_CLZ_TAB) += clz_tab.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);