i2c: Add support for designware i2c controller

Earlier, a driver exists in the u-boot source for designware i2c interface. That
driver was specific to spear platforms. This patch implements the i2c controller
as a generic driver which can be used by multiple platforms

The driver files are now renamed to designware_i2c.c and designware_i2c.h and
these are moved into drivers/i2c folder for reusability by other
platforms

Signed-off-by: Vipin Kumar <vipin.kumar@st.com>
Signed-off-by: Amit Virdi <amit.virdi@st.com>

1 files changed, 331 insertions, 0 deletions

diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c
new file mode 100644
index 0000000000..d352146081
--- /dev/null
+++ b/drivers/i2c/designware_i2c.c
@@ -0,0 +1,331 @@
+/*
+ * (C) Copyright 2009
+ * Vipin Kumar, ST Micoelectronics, vipin.kumar@st.com.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/hardware.h>
+#include "designware_i2c.h"
+
+static struct i2c_regs *const i2c_regs_p =
+    (struct i2c_regs *)CONFIG_SYS_I2C_BASE;
+
+/*
+ * set_speed - Set the i2c speed mode (standard, high, fast)
+ * @i2c_spd:	required i2c speed mode
+ *
+ * Set the i2c speed mode (standard, high, fast)
+ */
+static void set_speed(int i2c_spd)
+{
+	unsigned int cntl;
+	unsigned int hcnt, lcnt;
+	unsigned int high, low;
+
+	cntl = (readl(&i2c_regs_p->ic_con) & (~IC_CON_SPD_MSK));
+
+	switch (i2c_spd) {
+	case IC_SPEED_MODE_MAX:
+		cntl |= IC_CON_SPD_HS;
+		high = MIN_HS_SCL_HIGHTIME;
+		low = MIN_HS_SCL_LOWTIME;
+		break;
+
+	case IC_SPEED_MODE_STANDARD:
+		cntl |= IC_CON_SPD_SS;
+		high = MIN_SS_SCL_HIGHTIME;
+		low = MIN_SS_SCL_LOWTIME;
+		break;
+
+	case IC_SPEED_MODE_FAST:
+	default:
+		cntl |= IC_CON_SPD_FS;
+		high = MIN_FS_SCL_HIGHTIME;
+		low = MIN_FS_SCL_LOWTIME;
+		break;
+	}
+
+	writel(cntl, &i2c_regs_p->ic_con);
+
+	hcnt = (IC_CLK * high) / NANO_TO_MICRO;
+	writel(hcnt, &i2c_regs_p->ic_fs_scl_hcnt);
+
+	lcnt = (IC_CLK * low) / NANO_TO_MICRO;
+	writel(lcnt, &i2c_regs_p->ic_fs_scl_lcnt);
+}
+
+/*
+ * i2c_set_bus_speed - Set the i2c speed
+ * @speed:	required i2c speed
+ *
+ * Set the i2c speed.
+ */
+void i2c_set_bus_speed(int speed)
+{
+	if (speed >= I2C_MAX_SPEED)
+		set_speed(IC_SPEED_MODE_MAX);
+	else if (speed >= I2C_FAST_SPEED)
+		set_speed(IC_SPEED_MODE_FAST);
+	else
+		set_speed(IC_SPEED_MODE_STANDARD);
+}
+
+/*
+ * i2c_get_bus_speed - Gets the i2c speed
+ *
+ * Gets the i2c speed.
+ */
+int i2c_get_bus_speed(void)
+{
+	u32 cntl;
+
+	cntl = (readl(&i2c_regs_p->ic_con) & IC_CON_SPD_MSK);
+
+	if (cntl == IC_CON_SPD_HS)
+		return I2C_MAX_SPEED;
+	else if (cntl == IC_CON_SPD_FS)
+		return I2C_FAST_SPEED;
+	else if (cntl == IC_CON_SPD_SS)
+		return I2C_STANDARD_SPEED;
+
+	return 0;
+}
+
+/*
+ * i2c_init - Init function
+ * @speed:	required i2c speed
+ * @slaveadd:	slave address for the device
+ *
+ * Initialization function.
+ */
+void i2c_init(int speed, int slaveadd)
+{
+	unsigned int enbl;
+
+	/* Disable i2c */
+	enbl = readl(&i2c_regs_p->ic_enable);
+	enbl &= ~IC_ENABLE_0B;
+	writel(enbl, &i2c_regs_p->ic_enable);
+
+	writel((IC_CON_SD | IC_CON_SPD_FS | IC_CON_MM), &i2c_regs_p->ic_con);
+	writel(IC_RX_TL, &i2c_regs_p->ic_rx_tl);
+	writel(IC_TX_TL, &i2c_regs_p->ic_tx_tl);
+	i2c_set_bus_speed(speed);
+	writel(IC_STOP_DET, &i2c_regs_p->ic_intr_mask);
+	writel(slaveadd, &i2c_regs_p->ic_sar);
+
+	/* Enable i2c */
+	enbl = readl(&i2c_regs_p->ic_enable);
+	enbl |= IC_ENABLE_0B;
+	writel(enbl, &i2c_regs_p->ic_enable);
+}
+
+/*
+ * i2c_setaddress - Sets the target slave address
+ * @i2c_addr:	target i2c address
+ *
+ * Sets the target slave address.
+ */
+static void i2c_setaddress(unsigned int i2c_addr)
+{
+	writel(i2c_addr, &i2c_regs_p->ic_tar);
+}
+
+/*
+ * i2c_flush_rxfifo - Flushes the i2c RX FIFO
+ *
+ * Flushes the i2c RX FIFO
+ */
+static void i2c_flush_rxfifo(void)
+{
+	while (readl(&i2c_regs_p->ic_status) & IC_STATUS_RFNE)
+		readl(&i2c_regs_p->ic_cmd_data);
+}
+
+/*
+ * i2c_wait_for_bb - Waits for bus busy
+ *
+ * Waits for bus busy
+ */
+static int i2c_wait_for_bb(void)
+{
+	unsigned long start_time_bb = get_timer(0);
+
+	while ((readl(&i2c_regs_p->ic_status) & IC_STATUS_MA) ||
+	       !(readl(&i2c_regs_p->ic_status) & IC_STATUS_TFE)) {
+
+		/* Evaluate timeout */
+		if (get_timer(start_time_bb) > (unsigned long)(I2C_BYTE_TO_BB))
+			return 1;
+	}
+
+	return 0;
+}
+
+/* check parameters for i2c_read and i2c_write */
+static int check_params(uint addr, int alen, uchar *buffer, int len)
+{
+	if (buffer == NULL) {
+		printf("Buffer is invalid\n");
+		return 1;
+	}
+
+	if (alen > 1) {
+		printf("addr len %d not supported\n", alen);
+		return 1;
+	}
+
+	if (addr + len > 256) {
+		printf("address out of range\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+static int i2c_xfer_init(uchar chip, uint addr)
+{
+	if (i2c_wait_for_bb()) {
+		printf("Timed out waiting for bus\n");
+		return 1;
+	}
+
+	i2c_setaddress(chip);
+	writel(addr, &i2c_regs_p->ic_cmd_data);
+
+	return 0;
+}
+
+static int i2c_xfer_finish(void)
+{
+	ulong start_stop_det = get_timer(0);
+
+	while (1) {
+		if ((readl(&i2c_regs_p->ic_raw_intr_stat) & IC_STOP_DET)) {
+			readl(&i2c_regs_p->ic_clr_stop_det);
+			break;
+		} else if (get_timer(start_stop_det) > I2C_STOPDET_TO) {
+			break;
+		}
+	}
+
+	if (i2c_wait_for_bb()) {
+		printf("Timed out waiting for bus\n");
+		return 1;
+	}
+
+	i2c_flush_rxfifo();
+
+	/* Wait for read/write operation to complete on actual memory */
+	udelay(10000);
+
+	return 0;
+}
+
+/*
+ * i2c_read - Read from i2c memory
+ * @chip:	target i2c address
+ * @addr:	address to read from
+ * @alen:
+ * @buffer:	buffer for read data
+ * @len:	no of bytes to be read
+ *
+ * Read from i2c memory.
+ */
+int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
+{
+	unsigned long start_time_rx;
+
+	if (check_params(addr, alen, buffer, len))
+		return 1;
+
+	if (i2c_xfer_init(chip, addr))
+		return 1;
+
+	start_time_rx = get_timer(0);
+	while (len) {
+		writel(IC_CMD, &i2c_regs_p->ic_cmd_data);
+
+		if (readl(&i2c_regs_p->ic_status) & IC_STATUS_RFNE) {
+			*buffer++ = (uchar)readl(&i2c_regs_p->ic_cmd_data);
+			len--;
+			start_time_rx = get_timer(0);
+
+		} else if (get_timer(start_time_rx) > I2C_BYTE_TO) {
+				printf("Timed out. i2c read Failed\n");
+				return 1;
+		}
+	}
+
+	return i2c_xfer_finish();
+}
+
+/*
+ * i2c_write - Write to i2c memory
+ * @chip:	target i2c address
+ * @addr:	address to read from
+ * @alen:
+ * @buffer:	buffer for read data
+ * @len:	no of bytes to be read
+ *
+ * Write to i2c memory.
+ */
+int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
+{
+	int nb = len;
+	unsigned long start_time_tx;
+
+	if (check_params(addr, alen, buffer, len))
+		return 1;
+
+	if (i2c_xfer_init(chip, addr))
+		return 1;
+
+	start_time_tx = get_timer(0);
+	while (len) {
+		if (readl(&i2c_regs_p->ic_status) & IC_STATUS_TFNF) {
+			writel(*buffer, &i2c_regs_p->ic_cmd_data);
+			buffer++;
+			len--;
+			start_time_tx = get_timer(0);
+
+		} else if (get_timer(start_time_tx) > (nb * I2C_BYTE_TO)) {
+				printf("Timed out. i2c write Failed\n");
+				return 1;
+		}
+	}
+
+	return i2c_xfer_finish();
+}
+
+/*
+ * i2c_probe - Probe the i2c chip
+ */
+int i2c_probe(uchar chip)
+{
+	u32 tmp;
+
+	/*
+	 * Try to read the first location of the chip.
+	 */
+	return i2c_read(chip, 0, 1, (uchar *)&tmp, 1);
+}