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Commit 18c4089e authored by Jean-Hugues Deschenes's avatar Jean-Hugues Deschenes Committed by Ben Dooks
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i2c-designware: Allow mixed endianness accesses 



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: default avatarJean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>
Signed-off-by: default avatarDirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: default avatarBen Dooks <ben-linux@fluff.org>
parent 4ff895bc

drivers/i2c/busses/i2c-designware.c

+15 −2
Original line number Diff line number Diff line
@@ -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;