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-rw-r--r--drivers/i2c/busses/i2c-xiic.c58
1 files changed, 53 insertions, 5 deletions
diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c
index cc65ea0..522916a 100644
--- a/drivers/i2c/busses/i2c-xiic.c
+++ b/drivers/i2c/busses/i2c-xiic.c
@@ -46,6 +46,11 @@ enum xilinx_i2c_state {
STATE_START
};
+enum xiic_endian {
+ LITTLE,
+ BIG
+};
+
/**
* struct xiic_i2c - Internal representation of the XIIC I2C bus
* @base: Memory base of the HW registers
@@ -70,6 +75,7 @@ struct xiic_i2c {
enum xilinx_i2c_state state;
struct i2c_msg *rx_msg;
int rx_pos;
+ enum xiic_endian endianness;
};
@@ -170,29 +176,58 @@ struct xiic_i2c {
static void xiic_start_xfer(struct xiic_i2c *i2c);
static void __xiic_start_xfer(struct xiic_i2c *i2c);
+/*
+ * For the register read and write functions, a little-endian and big-endian
+ * version are necessary. Endianness is detected during the probe function.
+ * Only the least significant byte [doublet] of the register are ever
+ * accessed. This requires an offset of 3 [2] from the base address for
+ * big-endian systems.
+ */
+
static inline void xiic_setreg8(struct xiic_i2c *i2c, int reg, u8 value)
{
- iowrite8(value, i2c->base + reg);
+ if (i2c->endianness == LITTLE)
+ iowrite8(value, i2c->base + reg);
+ else
+ iowrite8(value, i2c->base + reg + 3);
}
static inline u8 xiic_getreg8(struct xiic_i2c *i2c, int reg)
{
- return ioread8(i2c->base + reg);
+ u8 ret;
+
+ if (i2c->endianness == LITTLE)
+ ret = ioread8(i2c->base + reg);
+ else
+ ret = ioread8(i2c->base + reg + 3);
+ return ret;
}
static inline void xiic_setreg16(struct xiic_i2c *i2c, int reg, u16 value)
{
- iowrite16(value, i2c->base + reg);
+ if (i2c->endianness == LITTLE)
+ iowrite16(value, i2c->base + reg);
+ else
+ iowrite16be(value, i2c->base + reg + 2);
}
static inline void xiic_setreg32(struct xiic_i2c *i2c, int reg, int value)
{
- iowrite32(value, i2c->base + reg);
+ if (i2c->endianness == LITTLE)
+ iowrite32(value, i2c->base + reg);
+ else
+ iowrite32be(value, i2c->base + reg);
}
static inline int xiic_getreg32(struct xiic_i2c *i2c, int reg)
{
- return ioread32(i2c->base + reg);
+ u32 ret;
+
+ if (i2c->endianness == LITTLE)
+ ret = ioread32(i2c->base + reg);
+ else
+ ret = ioread32be(i2c->base + reg);
+ return ret;
}
static inline void xiic_irq_dis(struct xiic_i2c *i2c, u32 mask)
@@ -692,6 +727,7 @@ static int xiic_i2c_probe(struct platform_device *pdev)
struct resource *res;
int ret, irq;
u8 i;
+ u32 sr;
i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
if (!i2c)
@@ -724,6 +760,18 @@ static int xiic_i2c_probe(struct platform_device *pdev)
return ret;
}
+ /*
+ * Detect endianness
+ * Try to reset the TX FIFO. Then check the EMPTY flag. If it is not
+ * set, assume that the endianness was wrong and swap.
+ */
+ i2c->endianness = LITTLE;
+ xiic_setreg32(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK);
+ /* Reset is cleared in xiic_reinit */
+ sr = xiic_getreg32(i2c, XIIC_SR_REG_OFFSET);
+ if (!(sr & XIIC_SR_TX_FIFO_EMPTY_MASK))
+ i2c->endianness = BIG;
+
xiic_reinit(i2c);
/* add i2c adapter to i2c tree */
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