cpu/allwinner/a10: Add basic TWI (I²C) driver

Change-Id: I11b10301199e5ff1a45d9b7d2958cc7b6667a29c
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/4588
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

1 files changed, 58 insertions, 0 deletions

diff --git a/src/cpu/allwinner/a10/twi.h b/src/cpu/allwinner/a10/twi.h
new file mode 100644
index 0000000000..c5f2974140
--- /dev/null
+++ b/src/cpu/allwinner/a10/twi.h
@@ -0,0 +1,58 @@
+/*
+ * Definitions Two Wire Interface (TWI) (I²C) Allwinner CPUs
+ *
+ * Copyright (C) 2013  Alexandru Gagniuc <mr.nuke.me@gmail.com>
+ * Subject to the GNU GPL v2, or (at your option) any later version.
+ */
+
+#ifndef CPU_ALLWINNER_A10_TWI_H
+#define CPU_ALLWINNER_A10_TWI_H
+
+#include <types.h>
+
+/* TWI_CTL values */
+#define TWI_CTL_INT_EN		(1 << 7)
+#define TWI_CTL_BUS_EN		(1 << 6)
+#define TWI_CTL_M_START		(1 << 5)
+#define TWI_CTL_M_STOP		(1 << 4)
+#define TWI_CTL_INT_FLAG	(1 << 3)
+#define TWI_CTL_A_ACK	(1 << 2)
+
+/* TWI_STAT values */
+enum twi_status {
+	TWI_STAT_BUS_ERROR 	= 0x00,		/**< Bus error */
+	TWI_STAT_TX_START	= 0x08,		/**< START sent */
+	TWI_STAT_TX_RSTART	= 0x10,		/**< Repeated START sent */
+	TWI_STAT_TX_AW_ACK	= 0x18,		/**< Sent address+read, ACK */
+	TWI_STAT_TX_AW_NAK	= 0x20,		/**< Sent address+read, NAK */
+	TWI_STAT_TXD_ACK	= 0x28,		/**< Sent data, got ACK */
+	TWI_STAT_TXD_NAK	= 0x30,		/**< Sent data, no ACK */
+	TWI_STAT_LOST_ARB	= 0x38,		/**< Lost arbitration */
+	TWI_STAT_TX_AR_ACK	= 0x40,		/**< Sent address+write, ACK */
+	TWI_STAT_TX_AR_NAK	= 0x48,		/**< Sent address+write, NAK */
+	TWI_STAT_RXD_ACK	= 0x50,		/**< Got data, sent ACK */
+	TWI_STAT_RXD_NAK	= 0x58,		/**< Got data, no ACK */
+	TWI_STAT_IDLE		= 0xf8,		/**< Bus idle*/
+};
+
+/* TWI_CLK values */
+#define TWI_CLK_M_MASK		(0xf << 3)
+#define TWI_CLK_M(m)		(((m - 1) << 3) & TWI_CLK_M_MASK)
+#define TWI_CLK_N_MASK		(0x7 << 0)
+#define TWI_CLK_N(n)		(((n) << 3) & TWI_CLK_N_MASK)
+
+struct a1x_twi {
+	u32 addr;	/**< 0x00: Slave address */
+	u32 xaddr;	/**< 0x04: Extended slave address */
+	u32 data;	/**< 0x08: Data byte */
+	u32 ctl;	/**< 0x0C: Control register */
+	u32 stat;	/**< 0x10: Status register */
+	u32 clk;	/**< 0x14: Clock control register */
+	u32 reset;	/**< 0x18: Software reset */
+	u32 efr;	/**< 0x1C: Enhanced Feature register */
+	u32 lcr;	/**< 0x20: Line control register */
+};
+
+void a1x_twi_init(u8 bus, u32 speed_hz);
+
+#endif				/* CPU_ALLWINNER_A10_TWI_H */