lpc32xx: i2c: add LPC32xx I2C interface support

Signed-off-by: Albert ARIBAUD (3ADEV) <albert.aribaud@3adev.fr>

1 files changed, 249 insertions, 0 deletions

diff --git a/drivers/i2c/lpc32xx_i2c.c b/drivers/i2c/lpc32xx_i2c.c
new file mode 100644
index 0000000..78d26e4
--- /dev/null
+++ b/drivers/i2c/lpc32xx_i2c.c
@@ -0,0 +1,249 @@
+/*
+ * LPC32xx I2C interface driver
+ *
+ * (C) Copyright 2014  DENX Software Engineering GmbH
+ * Written-by: Albert ARIBAUD - 3ADEV <albert.aribaud@3adev.fr>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <i2c.h>
+#include <asm/errno.h>
+#include <asm/arch/clk.h>
+
+/*
+ * Provide default speed and slave if target did not
+ */
+
+#if !defined(CONFIG_SYS_I2C_LPC32XX_SPEED)
+#define CONFIG_SYS_I2C_LPC32XX_SPEED 350000
+#endif
+
+#if !defined(CONFIG_SYS_I2C_LPC32XX_SLAVE)
+#define CONFIG_SYS_I2C_LPC32XX_SLAVE 0
+#endif
+
+/* i2c register set */
+struct lpc32xx_i2c_registers {
+	union {
+		u32 rx;
+		u32 tx;
+	};
+	u32 stat;
+	u32 ctrl;
+	u32 clk_hi;
+	u32 clk_lo;
+	u32 adr;
+	u32 rxfl;
+	u32 txfl;
+	u32 rxb;
+	u32 txb;
+	u32 stx;
+	u32 stxfl;
+};
+
+/* TX register fields */
+#define LPC32XX_I2C_TX_START		0x00000100
+#define LPC32XX_I2C_TX_STOP		0x00000200
+
+/* Control register values */
+#define LPC32XX_I2C_SOFT_RESET		0x00000100
+
+/* Status register values */
+#define LPC32XX_I2C_STAT_TFF		0x00000400
+#define LPC32XX_I2C_STAT_RFE		0x00000200
+#define LPC32XX_I2C_STAT_DRMI		0x00000008
+#define LPC32XX_I2C_STAT_NAI		0x00000004
+#define LPC32XX_I2C_STAT_TDI		0x00000001
+
+static struct lpc32xx_i2c_registers *lpc32xx_i2c[] = {
+	(struct lpc32xx_i2c_registers *)I2C1_BASE,
+	(struct lpc32xx_i2c_registers *)I2C2_BASE
+};
+
+/* Set I2C bus speed */
+static unsigned int lpc32xx_i2c_set_bus_speed(struct i2c_adapter *adap,
+			unsigned int speed)
+{
+	int half_period;
+
+	if (speed == 0)
+		return -EINVAL;
+
+	half_period = (105000000 / speed) / 2;
+
+	if ((half_period > 255) || (half_period < 0))
+		return -EINVAL;
+
+	writel(half_period, &lpc32xx_i2c[adap->hwadapnr]->clk_hi);
+	writel(half_period, &lpc32xx_i2c[adap->hwadapnr]->clk_lo);
+	return 0;
+}
+
+/* I2C init called by cmd_i2c when doing 'i2c reset'. */
+static void _i2c_init(struct i2c_adapter *adap,
+	int requested_speed, int slaveadd)
+{
+	struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
+
+	/* soft reset (auto-clears) */
+	writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
+	/* set HI and LO periods for about 350 kHz */
+	lpc32xx_i2c_set_bus_speed(adap, requested_speed);
+}
+
+/* I2C probe called by cmd_i2c when doing 'i2c probe'. */
+static int lpc32xx_i2c_probe(struct i2c_adapter *adap, u8 dev)
+{
+	struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
+	int stat;
+
+	/* Soft-reset the controller */
+	writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
+	while (readl(&i2c->ctrl) & LPC32XX_I2C_SOFT_RESET)
+		;
+	/* Addre slave for write with start before and stop after */
+	writel((dev<<1) | LPC32XX_I2C_TX_START | LPC32XX_I2C_TX_STOP,
+	       &i2c->tx);
+	/* wait for end of transation */
+	while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
+		;
+	/* was there no acknowledge? */
+	return (stat & LPC32XX_I2C_STAT_NAI) ? -1 : 0;
+}
+
+/*
+ * I2C read called by cmd_i2c when doing 'i2c read' and by cmd_eeprom.c
+ * Begin write, send address byte(s), begin read, receive data bytes, end.
+ */
+static int lpc32xx_i2c_read(struct i2c_adapter *adap, u8 dev, uint addr,
+			 int alen, u8 *data, int length)
+{
+	struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
+	int stat, wlen;
+
+	/* Soft-reset the controller */
+	writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
+	while (readl(&i2c->ctrl) & LPC32XX_I2C_SOFT_RESET)
+		;
+	/* do we need to write an address at all? */
+	if (alen) {
+		/* Address slave in write mode */
+		writel((dev<<1) | LPC32XX_I2C_TX_START, &i2c->tx);
+		/* write address bytes */
+		while (alen--) {
+			/* compute address byte + stop for the last one */
+			int a = (addr >> (8 * alen)) & 0xff;
+			if (!alen)
+				a |= LPC32XX_I2C_TX_STOP;
+			/* Send address byte */
+			writel(a, &i2c->tx);
+		}
+		/* wait for end of transation */
+		while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
+			;
+		/* clear end-of-transaction flag */
+		writel(1, &i2c->stat);
+	}
+	/* do we have to read data at all? */
+	if (length) {
+		/* Address slave in read mode */
+		writel(1 | (dev<<1) | LPC32XX_I2C_TX_START, &i2c->tx);
+		wlen = length;
+		/* get data */
+		while (length | wlen) {
+			/* read status for TFF and RFE */
+			stat = readl(&i2c->stat);
+			/* must we, can we write a trigger byte? */
+			if ((wlen > 0)
+			   & (!(stat & LPC32XX_I2C_STAT_TFF))) {
+				wlen--;
+				/* write trigger byte + stop if last */
+				writel(wlen ? 0 :
+				LPC32XX_I2C_TX_STOP, &i2c->tx);
+			}
+			/* must we, can we read a data byte? */
+			if ((length > 0)
+			   & (!(stat & LPC32XX_I2C_STAT_RFE))) {
+				length--;
+				/* read byte */
+				*(data++) = readl(&i2c->rx);
+			}
+		}
+	}
+	/* wait for end of transation */
+	while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
+		;
+	/* clear end-of-transaction flag */
+	writel(1, &i2c->stat);
+	/* success */
+	return 0;
+}
+
+/*
+ * I2C write called by cmd_i2c when doing 'i2c write' and by cmd_eeprom.c
+ * Begin write, send address byte(s), send data bytes, end.
+ */
+static int lpc32xx_i2c_write(struct i2c_adapter *adap, u8 dev, uint addr,
+			  int alen, u8 *data, int length)
+{
+	struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
+	int stat;
+
+	/* Soft-reset the controller */
+	writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
+	while (readl(&i2c->ctrl) & LPC32XX_I2C_SOFT_RESET)
+		;
+	/* do we need to write anything at all? */
+	if (alen | length)
+		/* Address slave in write mode */
+		writel((dev<<1) | LPC32XX_I2C_TX_START, &i2c->tx);
+	/* write address bytes */
+	while (alen) {
+		/* wait for transmit fifo not full */
+		stat = readl(&i2c->stat);
+		if (!(stat & LPC32XX_I2C_STAT_TFF)) {
+			alen--;
+			int a = (addr >> (8 * alen)) & 0xff;
+			if (!(alen | length))
+				a |= LPC32XX_I2C_TX_STOP;
+			/* Send address byte */
+			writel(a, &i2c->tx);
+		}
+	}
+	while (length) {
+		/* wait for transmit fifo not full */
+		stat = readl(&i2c->stat);
+		if (!(stat & LPC32XX_I2C_STAT_TFF)) {
+			/* compute data byte, add stop if length==0 */
+			length--;
+			int d = *(data++);
+			if (!length)
+				d |= LPC32XX_I2C_TX_STOP;
+			/* Send data byte */
+			writel(d, &i2c->tx);
+		}
+	}
+	/* wait for end of transation */
+	while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
+		;
+	/* clear end-of-transaction flag */
+	writel(1, &i2c->stat);
+	return 0;
+}
+
+U_BOOT_I2C_ADAP_COMPLETE(lpc32xx_0, _i2c_init, lpc32xx_i2c_probe,
+			 lpc32xx_i2c_read, lpc32xx_i2c_write,
+			 lpc32xx_i2c_set_bus_speed,
+			 CONFIG_SYS_I2C_LPC32XX_SPEED,
+			 CONFIG_SYS_I2C_LPC32XX_SLAVE,
+			 0)
+
+U_BOOT_I2C_ADAP_COMPLETE(lpc32xx_1, _i2c_init, lpc32xx_i2c_probe,
+			 lpc32xx_i2c_read, lpc32xx_i2c_write,
+			 lpc32xx_i2c_set_bus_speed,
+			 CONFIG_SYS_I2C_LPC32XX_SPEED,
+			 CONFIG_SYS_I2C_LPC32XX_SLAVE,
+			 1)