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Commit a8a9f3fe authored by Stefan Roese's avatar Stefan Roese Committed by Wolfram Sang
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i2c: designware: Add support for 16bit register access 



The STM SPEAr platform can only access the i2c controller register
via 16bit read/write functions. This patch adds support to
automatically detect this 16bit access mode.

Signed-off-by: default avatarStefan Roese <sr@denx.de>
Signed-off-by: default avatarWolfram Sang <w.sang@pengutronix.de>
parent 44454baa

drivers/i2c/busses/i2c-designware-core.c

+21 −10
Original line number Diff line number Diff line
@@ -164,9 +164,15 @@ static char *abort_sources[] = { 


u32 dw_readl(struct dw_i2c_dev *dev, int offset)

{

	u32 value = readl(dev->base + offset);

	u32 value;



	if (dev->swab)

	if (dev->accessor_flags & ACCESS_16BIT)

		value = readw(dev->base + offset) |

			(readw(dev->base + offset + 2) << 16);

	else

		value = readl(dev->base + offset);



	if (dev->accessor_flags & ACCESS_SWAP)

		return swab32(value);

	else

		return value;
@@ -174,11 +180,16 @@ u32 dw_readl(struct dw_i2c_dev *dev, int offset) 


void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset)

{

	if (dev->swab)

	if (dev->accessor_flags & ACCESS_SWAP)

		b = swab32(b);



	if (dev->accessor_flags & ACCESS_16BIT) {

		writew((u16)b, dev->base + offset);

		writew((u16)(b >> 16), dev->base + offset + 2);

	} else {

		writel(b, dev->base + offset);

	}

}



static u32

i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset)
@@ -251,14 +262,14 @@ int i2c_dw_init(struct dw_i2c_dev *dev) 


	input_clock_khz = dev->get_clk_rate_khz(dev);



	/* Configure register endianess access */

	reg = dw_readl(dev, DW_IC_COMP_TYPE);

	if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {

		dev->swab = 1;

		reg = DW_IC_COMP_TYPE_VALUE;

	}



	if (reg != DW_IC_COMP_TYPE_VALUE) {

		/* Configure register endianess access */

		dev->accessor_flags |= ACCESS_SWAP;

	} else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) {

		/* Configure register access mode 16bit */

		dev->accessor_flags |= ACCESS_16BIT;

	} else if (reg != DW_IC_COMP_TYPE_VALUE) {

		dev_err(dev->dev, "Unknown Synopsys component type: "

			"0x%08x\n", reg);

		return -ENODEV;

drivers/i2c/busses/i2c-designware-core.h

+4 −1
Original line number Diff line number Diff line
@@ -82,7 +82,7 @@ struct dw_i2c_dev { 
	unsigned int		status;

	u32			abort_source;

	int			irq;

	int			swab;

	u32			accessor_flags;

	struct i2c_adapter	adapter;

	u32			functionality;

	u32			master_cfg;
@@ -90,6 +90,9 @@ struct dw_i2c_dev { 
	unsigned int		rx_fifo_depth;

};



#define ACCESS_SWAP		0x00000001

#define ACCESS_16BIT		0x00000002



extern u32 dw_readl(struct dw_i2c_dev *dev, int offset);

extern void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset);

extern int i2c_dw_init(struct dw_i2c_dev *dev);