i2c: atmel: add i2c driver

Add i2c driver.

Signed-off-by: Songjun Wu <songjun.wu@atmel.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>
diff --git a/drivers/i2c/at91_i2c.h b/drivers/i2c/at91_i2c.h
new file mode 100644
index 0000000..87f02bf
--- /dev/null
+++ b/drivers/i2c/at91_i2c.h
@@ -0,0 +1,77 @@
+#ifndef _AT91_I2C_H
+#define _AT91_I2C_H
+
+#define	TWI_CR_START		BIT(0)	/* Send a Start Condition */
+#define	TWI_CR_MSEN		BIT(2)	/* Master Transfer Enable */
+#define	TWI_CR_STOP		BIT(1)	/* Send a Stop Condition */
+#define	TWI_CR_SVDIS		BIT(5)	/* Slave Transfer Disable */
+#define	TWI_CR_SWRST		BIT(7)	/* Software Reset */
+#define	TWI_CR_ACMEN		BIT(16) /* Alternative Command Mode Enable */
+#define	TWI_CR_ACMDIS		BIT(17) /* Alternative Command Mode Disable */
+#define	TWI_CR_LOCKCLR		BIT(26) /* Lock Clear */
+
+#define	TWI_MMR_MREAD		BIT(12) /* Master Read Direction */
+#define	TWI_MMR_IADRSZ_1	BIT(8)	/* Internal Device Address Size */
+
+#define	TWI_SR_TXCOMP		BIT(0)	/* Transmission Complete */
+#define	TWI_SR_RXRDY		BIT(1)	/* Receive Holding Register Ready */
+#define	TWI_SR_TXRDY		BIT(2)	/* Transmit Holding Register Ready */
+#define	TWI_SR_OVRE		BIT(6)	/* Overrun Error */
+#define	TWI_SR_UNRE		BIT(7)	/* Underrun Error */
+#define	TWI_SR_NACK		BIT(8)	/* Not Acknowledged */
+#define	TWI_SR_LOCK		BIT(23) /* TWI Lock due to Frame Errors */
+
+#define	TWI_ACR_DATAL(len)	((len) & 0xff)
+#define	TWI_ACR_DIR_READ	BIT(8)
+
+#define	TWI_CWGR_HOLD_MAX	0x1f
+#define	TWI_CWGR_HOLD(x)	(((x) & TWI_CWGR_HOLD_MAX) << 24)
+
+struct at91_i2c_regs {
+	u32 cr;
+	u32 mmr;
+	u32 smr;
+	u32 iadr;
+	u32 cwgr;
+	u32 rev_0[3];
+	u32 sr;
+	u32 ier;
+	u32 idr;
+	u32 imr;
+	u32 rhr;
+	u32 thr;
+	u32 smbtr;
+	u32 rev_1;
+	u32 acr;
+	u32 filtr;
+	u32 rev_2;
+	u32 swmr;
+	u32 fmr;
+	u32 flr;
+	u32 rev_3;
+	u32 fsr;
+	u32 fier;
+	u32 fidr;
+	u32 fimr;
+	u32 rev_4[29];
+	u32 wpmr;
+	u32 wpsr;
+	u32 rev_5[6];
+};
+
+struct at91_i2c_pdata {
+	unsigned clk_max_div;
+	unsigned clk_offset;
+};
+
+struct at91_i2c_bus {
+	struct at91_i2c_regs *regs;
+	u32 status;
+	ulong bus_clk_rate;
+	u32 clock_frequency;
+	u32 speed;
+	u32 cwgr_val;
+	const struct at91_i2c_pdata *pdata;
+};
+
+#endif