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i2c: designware: Add support for 16bit register access

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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: Stefan Roese <sr@denx.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
This commit is contained in:
Stefan Roese 2012-04-18 15:01:41 +02:00 committed by Wolfram Sang
parent 44454baa7c
commit a8a9f3fef1
2 changed files with 25 additions and 11 deletions
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31
drivers/i2c/busses/i2c-designware-core.c
View file

@ -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;
@ -174,10 +180,15 @@ 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);
writel(b, dev->base + offset);
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
@ -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;

5
drivers/i2c/busses/i2c-designware-core.h
View file

@ -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);