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i2c-designware: Allow mixed endianness accesses

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Allows CPUs of a given endianness to access a dw controller of a different
endianness. Endianncess difference is detected at run time through the dw
component type register.

Signed-off-by: Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Jean-Hugues Deschenes 2011-10-06 11:26:27 -07:00 committed by Ben Dooks
parent 4ff895bc8b
commit 18c4089e6c
1 changed files with 15 additions and 2 deletions
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17
drivers/i2c/busses/i2c-designware.c
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@ -37,6 +37,7 @@
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/swab.h>
/*
* Registers offset
@ -193,6 +194,7 @@ static char *abort_sources[] = {
* @status: i2c master status, one of STATUS_*
* @abort_source: copy of the TX_ABRT_SOURCE register
* @irq: interrupt number for the i2c master
* @swab: true if the instantiated IP is of different endianess
* @adapter: i2c subsystem adapter node
* @tx_fifo_depth: depth of the hardware tx fifo
* @rx_fifo_depth: depth of the hardware rx fifo
@ -216,6 +218,7 @@ struct dw_i2c_dev {
unsigned int status;
u32 abort_source;
int irq;
int swab;
struct i2c_adapter adapter;
unsigned int tx_fifo_depth;
unsigned int rx_fifo_depth;
@ -223,11 +226,19 @@ struct dw_i2c_dev {
static u32 dw_readl(struct dw_i2c_dev *dev, int offset)
{
return readl(dev->base + offset);
u32 value = readl(dev->base + offset);
if (dev->swab)
return swab32(value);
else
return value;
}
static void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset)
{
if (dev->swab)
b = swab32(b);
writel(b, dev->base + offset);
}
@ -760,7 +771,9 @@ static int __devinit dw_i2c_probe(struct platform_device *pdev)
}
reg = dw_readl(dev, DW_IC_COMP_TYPE);
if (reg != 0x44570140) {
if (reg == ___constant_swab32(0x44570140))
dev->swab = 1;
else if (reg != 0x44570140) {
dev_err(&pdev->dev, "Unknown Synopsys component type: "
"0x%08x\n", reg);
r = -ENODEV;