I2C: Add driver for ST-Ericsson U8500 i2c

Signed-off-by: John Rigby <john.rigby@linaro.org>
CC: Heiko Schocher <hs@denx.de>

1 files changed, 613 insertions, 0 deletions

diff --git a/drivers/i2c/u8500_i2c.c b/drivers/i2c/u8500_i2c.c
new file mode 100644
index 0000000000..ea8a71d866
--- /dev/null
+++ b/drivers/i2c/u8500_i2c.c
@@ -0,0 +1,613 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * Basic U-Boot I2C interface for STn8500/DB8500
+ * Author: Michael Brandt <Michael.Brandt@stericsson.com> for ST-Ericsson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * Only 7-bit I2C device addresses are supported.
+ */
+
+#include <common.h>
+#include <i2c.h>
+
+#include "u8500_i2c.h"
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+
+#define U8500_I2C_ENDAD_COUNTER	(CONFIG_SYS_HZ/100)	/* I2C bus timeout */
+#define U8500_I2C_FIFO_FLUSH_COUNTER	500000		/* flush "timeout" */
+#define U8500_I2C_SCL_FREQ		100000		/* I2C bus clock freq */
+#define U8500_I2C_INPUT_FREQ		48000000	/* Input clock freq */
+#define TX_FIFO_THRESHOLD	0x4
+#define RX_FIFO_THRESHOLD	0x4
+#define SLAVE_SETUP_TIME 14 /* Slave data setup time, 250ns for 48MHz i2c_clk */
+
+#define WRITE_FIELD(var, mask, shift, value) \
+			(var = ((var & ~(mask)) | ((value) << (shift))))
+
+static unsigned int bus_initialized[CONFIG_SYS_U8500_I2C_BUS_MAX];
+static unsigned int i2c_bus_num;
+static unsigned int i2c_bus_speed[] = {
+	CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SPEED,
+	CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SPEED
+};
+static struct u8500_i2c_regs *i2c_dev[] = {
+	(struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C0_BASE,
+	(struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C1_BASE,
+	(struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C2_BASE,
+	(struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C3_BASE,
+};
+
+static struct {
+	int periph;
+	int pcken;
+	int kcken;
+} i2c_clock_bits[] = {
+	{3, 3, 3}, /* I2C0 */
+	{1, 2, 2}, /* I2C1 */
+	{1, 6, 6}, /* I2C2 */
+	{2, 0, 0}, /* I2C3 */
+};
+
+static void i2c_set_bit(void *reg, u32 mask)
+{
+	writel(readl(reg) | mask, reg);
+}
+
+static void i2c_clr_bit(void *reg, u32 mask)
+{
+	writel(readl(reg) & ~mask, reg);
+}
+
+static void i2c_write_field(void *reg, u32 mask, uint shift, u32 value)
+{
+	writel((readl(reg) & ~mask) | (value << shift), reg);
+}
+
+static int __i2c_set_bus_speed(unsigned int speed)
+{
+	u32 value;
+	struct u8500_i2c_regs *i2c_regs;
+
+	i2c_regs = i2c_dev[i2c_bus_num];
+
+	/* Select standard (100 kbps) speed mode */
+	i2c_write_field(&i2c_regs->cr, U8500_I2C_CR_SM,
+			U8500_I2C_CR_SHIFT_SM, 0x0);
+
+	/*
+	 * Set the Baud Rate Counter 2 value
+	 * Baud rate (standard) = fi2cclk / ( (BRCNT2 x 2) + Foncycle )
+	 * Foncycle = 0 (no digital filtering)
+	 */
+	value = (u32) (U8500_I2C_INPUT_FREQ / (speed * 2));
+	i2c_write_field(&i2c_regs->brcr, U8500_I2C_BRCR_BRCNT2,
+			U8500_I2C_BRCR_SHIFT_BRCNT2, value);
+
+	/* ensure that BRCNT value is zero */
+	i2c_write_field(&i2c_regs->brcr, U8500_I2C_BRCR_BRCNT1,
+			U8500_I2C_BRCR_SHIFT_BRCNT1, 0);
+
+	return U8500_I2C_INPUT_FREQ/(value * 2);
+}
+
+/*
+ * i2c_init - initialize the i2c bus
+ *
+ *	speed: bus speed (in HZ)
+ *	slaveaddr: address of device in slave mode
+ *
+ *	Slave mode is not implemented.
+ */
+void i2c_init(int speed, int slaveaddr)
+{
+	struct u8500_i2c_regs *i2c_regs;
+
+	debug("i2c_init bus %d, speed %d\n", i2c_bus_num, speed);
+
+	u8500_clock_enable(i2c_clock_bits[i2c_bus_num].periph,
+			   i2c_clock_bits[i2c_bus_num].pcken,
+			   i2c_clock_bits[i2c_bus_num].kcken);
+
+	i2c_regs = i2c_dev[i2c_bus_num];
+
+	/* Disable the controller */
+	i2c_clr_bit(&i2c_regs->cr, U8500_I2C_CR_PE);
+
+	/* Clear registers */
+	writel(0, &i2c_regs->cr);
+	writel(0, &i2c_regs->scr);
+	writel(0, &i2c_regs->hsmcr);
+	writel(0, &i2c_regs->tftr);
+	writel(0, &i2c_regs->rftr);
+	writel(0, &i2c_regs->dmar);
+
+	i2c_bus_speed[i2c_bus_num] = __i2c_set_bus_speed(speed);
+
+	/*
+	 * Set our own address.
+	 * Set slave address mode to 7 bit addressing mode
+	 */
+	i2c_clr_bit(&i2c_regs->cr, U8500_I2C_CR_SAM);
+	i2c_write_field(&i2c_regs->scr, U8500_I2C_SCR_ADDR,
+			U8500_I2C_SCR_SHIFT_ADDR, slaveaddr);
+	/* Slave Data Set up Time */
+	i2c_write_field(&i2c_regs->scr, U8500_I2C_SCR_DATA_SETUP_TIME,
+			U8500_I2C_SCR_SHIFT_DATA_SETUP_TIME, SLAVE_SETUP_TIME);
+
+	/* Disable the DMA sync logic */
+	i2c_write_field(&i2c_regs->cr, U8500_I2C_CR_DMA_SLE,
+			U8500_I2C_CR_SHIFT_DMA_SLE, 0);
+
+	/* Disable interrupts */
+	writel(0, &i2c_regs->imscr);
+
+	/* Configure bus master mode */
+	i2c_write_field(&i2c_regs->cr, U8500_I2C_CR_OM, U8500_I2C_CR_SHIFT_OM,
+			U8500_I2C_BUS_MASTER_MODE);
+	/* Set FIFO threshold values */
+	writel(TX_FIFO_THRESHOLD, &i2c_regs->tftr);
+	writel(RX_FIFO_THRESHOLD, &i2c_regs->rftr);
+
+	/* Enable the I2C Controller */
+	i2c_set_bit(&i2c_regs->cr, U8500_I2C_CR_PE);
+
+	bus_initialized[i2c_bus_num] = 1;
+}
+
+
+/*
+ * loop_till_bit_clear - polls on a bit till it clears
+ * ioreg: register where you want to check status
+ * mask: bit mask for the bit you wish to check
+ * timeout: timeout in ticks/s
+ */
+static int loop_till_bit_clear(void *io_reg, u32 mask, unsigned long timeout)
+{
+	unsigned long timebase = get_timer(0);
+
+	do {
+		if ((readl(io_reg) & mask) == 0x0UL)
+			return 0;
+	} while (get_timer(timebase) < timeout);
+
+	debug("loop_till_bit_clear timed out\n");
+	return -1;
+}
+
+/*
+ * loop_till_bit_set - polls on a bit till it is set.
+ * ioreg: register where you want to check status
+ * mask: bit mask for the bit you wish to check
+ * timeout: timeout in ticks/s
+ */
+static int loop_till_bit_set(void *io_reg, u32 mask, unsigned long timeout)
+{
+	unsigned long timebase = get_timer(0);
+
+	do {
+		if ((readl(io_reg) & mask) != 0x0UL)
+			return 0;
+	} while (get_timer(timebase) < timeout);
+
+	debug("loop_till_bit_set timed out\n");
+	return -1;
+}
+
+/*
+ * flush_fifo - flush the I2C TX and RX FIFOs
+ */
+static void flush_fifo(struct u8500_i2c_regs *i2c_regs)
+{
+	int counter = U8500_I2C_FIFO_FLUSH_COUNTER;
+
+	/* Flush Tx FIFO */
+	i2c_set_bit(&i2c_regs->cr, U8500_I2C_CR_FTX);
+	/* Flush Rx FIFO */
+	i2c_set_bit(&i2c_regs->cr, U8500_I2C_CR_FRX);
+	while (counter--) {
+		if (!(readl(&i2c_regs->cr) &
+				(U8500_I2C_CR_FTX | U8500_I2C_CR_FRX)))
+			break;
+	}
+	return;
+}
+
+#ifdef DEBUG
+static void print_abort_reason(struct u8500_i2c_regs *i2c_regs)
+{
+	int cause;
+
+	printf("abort: risr %08x, sr %08x\n", i2c_regs->risr, i2c_regs->sr);
+	cause = (readl(&i2c_regs->sr) & U8500_I2C_SR_CAUSE) >>
+				U8500_I2C_SR_SHIFT_CAUSE;
+	switch (cause) {
+	case U8500_I2C_NACK_ADDR:
+		printf("No Ack received after Slave Address xmission\n");
+		break;
+	case U8500_I2C_NACK_DATA:
+		printf("Valid for MASTER_WRITE: No Ack received "
+				"during data phase\n");
+		break;
+	case U8500_I2C_ACK_MCODE:
+		printf("Master recv ack after xmission of master code"
+				"in hs mode\n");
+		break;
+	case U8500_I2C_ARB_LOST:
+		printf("Master Lost arbitration\n");
+		break;
+	case U8500_I2C_BERR_START:
+		printf("Slave restarts\n");
+		break;
+	case U8500_I2C_BERR_STOP:
+		printf("Slave reset\n");
+		break;
+	case U8500_I2C_OVFL:
+		printf("Overflow\n");
+		break;
+	default:
+		printf("Unknown error type\n");
+	}
+}
+#endif
+
+/*
+ * i2c_abort - called when a I2C transaction failed
+ */
+static void i2c_abort(struct u8500_i2c_regs *i2c_regs)
+{
+#ifdef DEBUG
+	print_abort_reason(i2c_regs);
+#endif
+	/* flush RX and TX fifos */
+	flush_fifo(i2c_regs);
+
+	/* Acknowledge the Master Transaction Done */
+	i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
+
+	/* Acknowledge the Master Transaction Done Without Stop */
+	i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
+
+	i2c_init(i2c_bus_speed[i2c_bus_num], CONFIG_SYS_I2C_SLAVE);
+}
+
+/*
+ * write addr, alias index, to I2C bus.
+ */
+static int i2c_write_addr(struct u8500_i2c_regs *i2c_regs, uint addr, int alen)
+{
+	while (alen--) {
+		/* Wait until the Tx Fifo is not full */
+		if (loop_till_bit_clear((void *)&i2c_regs->risr,
+					U8500_I2C_INT_TXFF,
+					U8500_I2C_ENDAD_COUNTER)) {
+			i2c_abort(i2c_regs);
+			return -1;
+		}
+
+		/* MSB first */
+		writeb((addr >> (alen * 8)) & 0xff, &i2c_regs->tfr);
+	}
+
+	return 0;
+}
+
+/*
+ * Internal simplified read function:
+ *   i2c_regs:	Pointer to I2C registers for current bus
+ *   chip:	I2C chip address, range 0..127
+ *   addr:	Memory (register) address within the chip
+ *   alen:	Number of bytes to use for addr (typically 1, 2 for larger
+ *		memories, 0 for register type devices with only one register)
+ *   value:	Where to put the data
+ *
+ *   Returns:	0 on success, not 0 on failure
+ */
+static int i2c_read_byte(struct u8500_i2c_regs *i2c_regs, uchar chip,
+		uint addr, int alen, uchar *value)
+{
+	u32   mcr = 0;
+
+	/* Set the address mode to 7 bit */
+	WRITE_FIELD(mcr, U8500_I2C_MCR_AM, U8500_I2C_MCR_SHIFT_AM, 1);
+
+	/* Store the slave address in the master control register */
+	WRITE_FIELD(mcr, U8500_I2C_MCR_A7, U8500_I2C_MCR_SHIFT_A7, chip);
+
+	if (alen != 0) {
+		/* Master write operation */
+		mcr &= ~(U8500_I2C_MCR_OP);
+
+		/* Configure the Frame length to one byte */
+		WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH,
+				U8500_I2C_MCR_SHIFT_LENGTH, 1);
+
+		/* Repeated start, no stop */
+		mcr &= ~(U8500_I2C_MCR_STOP);
+
+		/* Write Master Control Register */
+		writel(mcr, &i2c_regs->mcr);
+
+		/* send addr/index */
+		if (i2c_write_addr(i2c_regs, addr, alen) != 0)
+			return -1;
+
+		/* Check for the Master Transaction Done Without Stop */
+		if (loop_till_bit_set((void *)&i2c_regs->risr,
+					U8500_I2C_INT_MTDWS,
+					U8500_I2C_ENDAD_COUNTER)) {
+			return -1;
+		}
+
+		/* Acknowledge the Master Transaction Done Without Stop */
+		i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
+	}
+
+	/* Master control configuration for read operation  */
+	mcr |= U8500_I2C_MCR_OP;
+
+	/* Configure the STOP condition, we read only one byte */
+	mcr |= U8500_I2C_MCR_STOP;
+
+	/* Set the frame length to one byte, we support only 1 byte reads */
+	WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH, U8500_I2C_MCR_SHIFT_LENGTH, 1);
+
+	i2c_write_field(&i2c_regs->mcr, U8500_I2C_MCR_LENGTH_STOP_OP,
+			U8500_I2C_MCR_SHIFT_LENGTH_STOP_OP, mcr);
+
+	/*
+	 * receive_data_polling
+	 */
+
+	/* Wait until the Rx FIFO is not empty */
+	if (loop_till_bit_clear((void *)&i2c_regs->risr,
+					U8500_I2C_INT_RXFE,
+					U8500_I2C_ENDAD_COUNTER))
+		return -1;
+
+	/* Read the data byte from Rx FIFO */
+	*value = readb(&i2c_regs->rfr);
+
+	/* Wait until the work is done */
+	if (loop_till_bit_set((void *)&i2c_regs->risr, U8500_I2C_INT_MTD,
+				U8500_I2C_ENDAD_COUNTER))
+		return -1;
+
+	/* Acknowledge the Master Transaction Done */
+	i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
+
+	/* If MTD is set, Master Transaction Done Without Stop is set too */
+	i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
+
+	return 0;
+}
+
+/*
+ * Internal simplified write function:
+ *   i2c_regs:	Pointer to I2C registers for current bus
+ *   chip:	I2C chip address, range 0..127
+ *   addr:	Memory (register) address within the chip
+ *   alen:	Number of bytes to use for addr (typically 1, 2 for larger
+ *		memories, 0 for register type devices with only one register)
+ *   data:	Where to read the data
+ *   len:	How many bytes to write
+ *
+ *   Returns:	0 on success, not 0 on failure
+ */
+static int __i2c_write(struct u8500_i2c_regs *i2c_regs, u8 chip, uint addr,
+		int alen, u8 *data, int len)
+{
+	int i;
+	u32 mcr = 0;
+
+	/* Set the address mode to 7 bit */
+	WRITE_FIELD(mcr, U8500_I2C_MCR_AM, U8500_I2C_MCR_SHIFT_AM, 1);
+
+	/* Store the slave address in the master control register */
+	WRITE_FIELD(mcr, U8500_I2C_MCR_A7, U8500_I2C_MCR_SHIFT_A7, chip);
+
+	/* Write operation */
+	mcr &= ~(U8500_I2C_MCR_OP);
+
+	/* Current transaction is terminated by STOP condition */
+	mcr |= U8500_I2C_MCR_STOP;
+
+	/* Frame length: addr byte + len */
+	WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH, U8500_I2C_MCR_SHIFT_LENGTH,
+			(alen + len));
+
+	/* Write MCR register */
+	writel(mcr, &i2c_regs->mcr);
+
+	if (i2c_write_addr(i2c_regs, addr, alen) != 0)
+		return -1;
+
+	for (i = 0; i < len; i++) {
+		/* Wait until the Tx FIFO is not full */
+		if (loop_till_bit_clear((void *)&i2c_regs->risr,
+					U8500_I2C_INT_TXFF,
+					U8500_I2C_ENDAD_COUNTER))
+			return -1;
+
+		/* it is a 32 bit register with upper 24 reserved R/O */
+		writeb(data[i], &i2c_regs->tfr);
+	}
+
+	/* Check for Master Transaction Done */
+	if (loop_till_bit_set((void *)&i2c_regs->risr,
+					U8500_I2C_INT_MTD,
+					U8500_I2C_ENDAD_COUNTER)) {
+		printf("i2c_write_byte error2: risr %08x\n",
+				i2c_regs->risr);
+		return -1;
+	}
+
+	/* Acknowledge Master Transaction Done */
+	i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
+
+	/* Acknowledge Master Transaction Done Without Stop */
+	i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
+
+	return 0;
+}
+
+/*
+ * Probe the given I2C chip address. Returns 0 if a chip responded,
+ * not 0 on failure.
+ */
+int i2c_probe(uchar chip)
+{
+	u32 mcr = 0;
+	struct u8500_i2c_regs *i2c_regs;
+
+	if (chip == CONFIG_SYS_I2C_SLAVE)
+		return 1;
+
+	i2c_regs = i2c_dev[i2c_bus_num];
+
+	/* Set the address mode to 7 bit */
+	WRITE_FIELD(mcr, U8500_I2C_MCR_AM, U8500_I2C_MCR_SHIFT_AM, 1);
+
+	/* Store the slave address in the master control register */
+	WRITE_FIELD(mcr, U8500_I2C_MCR_A10, U8500_I2C_MCR_SHIFT_A7, chip);
+
+	/* Read operation */
+	mcr |= U8500_I2C_MCR_OP;
+
+	/* Set the frame length to one byte */
+	WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH, U8500_I2C_MCR_SHIFT_LENGTH, 1);
+
+	/* Current transaction is terminated by STOP condition */
+	mcr |= U8500_I2C_MCR_STOP;
+
+	/* Write MCR register */
+	writel(mcr, &i2c_regs->mcr);
+
+	/* Wait until the Rx Fifo is not empty */
+	if (loop_till_bit_clear((void *)&i2c_regs->risr,
+					U8500_I2C_INT_RXFE,
+					U8500_I2C_ENDAD_COUNTER)) {
+		i2c_abort(i2c_regs);
+		return -1;
+	}
+
+	flush_fifo(i2c_regs);
+
+	/* Acknowledge the Master Transaction Done */
+	i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
+
+	/* Acknowledge the Master Transaction Done Without Stop */
+	i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
+
+	return 0;
+}
+
+/*
+ * Read/Write interface:
+ *   chip:    I2C chip address, range 0..127
+ *   addr:    Memory (register) address within the chip
+ *   alen:    Number of bytes to use for addr (typically 1, 2 for larger
+ *              memories, 0 for register type devices with only one
+ *              register)
+ *   buffer:  Where to read/write the data
+ *   len:     How many bytes to read/write
+ *
+ *   Returns: 0 on success, not 0 on failure
+ */
+int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
+{
+	int i;
+	int rc;
+	struct u8500_i2c_regs *i2c_regs;
+
+	if (alen > 2) {
+		debug("I2C read: addr len %d not supported\n", alen);
+		return 1;
+	}
+
+	i2c_regs = i2c_dev[i2c_bus_num];
+
+	for (i = 0; i < len; i++) {
+		rc = i2c_read_byte(i2c_regs, chip, addr + i, alen, &buffer[i]);
+		if (rc != 0) {
+			debug("I2C read: I/O error: %d\n", rc);
+			i2c_abort(i2c_regs);
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
+{
+	int rc;
+	struct u8500_i2c_regs *i2c_regs;
+	i2c_regs = i2c_dev[i2c_bus_num];
+
+	rc = __i2c_write(i2c_regs, chip, addr, alen, buffer,
+			len);
+	if (rc != 0) {
+		debug("I2C write: I/O error\n");
+		i2c_abort(i2c_regs);
+		return rc;
+	}
+	return 0;
+}
+
+int i2c_set_bus_num(unsigned int bus)
+{
+	if (bus > ARRAY_SIZE(i2c_dev) - 1) {
+		debug("i2c_set_bus_num: only up to bus %d supported\n",
+				ARRAY_SIZE(i2c_dev)-1);
+		return -1;
+	}
+
+	i2c_bus_num = bus;
+
+	if (!bus_initialized[i2c_bus_num])
+		i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
+
+	return 0;
+}
+
+int i2c_set_bus_speed(unsigned int speed)
+{
+
+	if (speed > U8500_I2C_MAX_STANDARD_SCL) {
+		debug("i2c_set_bus_speed: only up to %d supported\n",
+				U8500_I2C_MAX_STANDARD_SCL);
+		return -1;
+	}
+
+	/* sets as side effect i2c_bus_speed[i2c_bus_num] */
+	i2c_init(speed, CONFIG_SYS_I2C_SLAVE);
+
+	return 0;
+}
+
+unsigned int i2c_get_bus_num(void)
+{
+	return i2c_bus_num;
+}
+
+unsigned int i2c_get_bus_speed(void)
+{
+	return i2c_bus_speed[i2c_bus_num];
+}