imx-common: add i2c.c for bus recovery support

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>

1 files changed, 99 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/imx-common/i2c.c b/arch/arm/cpu/armv7/imx-common/i2c.c
new file mode 100644
index 0000000000..da2b26f43f
--- /dev/null
+++ b/arch/arm/cpu/armv7/imx-common/i2c.c
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2012 Boundary Devices Inc.
+ *
+ * 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/arch/clock.h>
+#include <asm/arch/imx-regs.h>
+#include <asm/errno.h>
+#include <asm/gpio.h>
+#include <asm/imx-common/mxc_i2c.h>
+#include <watchdog.h>
+
+static int force_idle_bus(void *priv)
+{
+	int i;
+	int sda, scl;
+	ulong elapsed, start_time;
+	struct i2c_pads_info *p = (struct i2c_pads_info *)priv;
+	int ret = 0;
+
+	gpio_direction_input(p->sda.gp);
+	gpio_direction_input(p->scl.gp);
+
+	imx_iomux_v3_setup_pad(p->sda.gpio_mode);
+	imx_iomux_v3_setup_pad(p->scl.gpio_mode);
+
+	sda = gpio_get_value(p->sda.gp);
+	scl = gpio_get_value(p->scl.gp);
+	if ((sda & scl) == 1)
+		goto exit;		/* Bus is idle already */
+
+	printf("%s: sda=%d scl=%d sda.gp=0x%x scl.gp=0x%x\n", __func__,
+		sda, scl, p->sda.gp, p->scl.gp);
+	/* Send high and low on the SCL line */
+	for (i = 0; i < 9; i++) {
+		gpio_direction_output(p->scl.gp, 0);
+		udelay(50);
+		gpio_direction_input(p->scl.gp);
+		udelay(50);
+	}
+	start_time = get_timer(0);
+	for (;;) {
+		sda = gpio_get_value(p->sda.gp);
+		scl = gpio_get_value(p->scl.gp);
+		if ((sda & scl) == 1)
+			break;
+		WATCHDOG_RESET();
+		elapsed = get_timer(start_time);
+		if (elapsed > (CONFIG_SYS_HZ / 5)) {	/* .2 seconds */
+			ret = -EBUSY;
+			printf("%s: failed to clear bus, sda=%d scl=%d\n",
+					__func__, sda, scl);
+			break;
+		}
+	}
+exit:
+	imx_iomux_v3_setup_pad(p->sda.i2c_mode);
+	imx_iomux_v3_setup_pad(p->scl.i2c_mode);
+	return ret;
+}
+
+static void * const i2c_bases[] = {
+	(void *)I2C1_BASE_ADDR,
+	(void *)I2C2_BASE_ADDR,
+#ifdef I2C3_BASE_ADDR
+	(void *)I2C3_BASE_ADDR,
+#endif
+};
+
+/* i2c_index can be from 0 - 2 */
+void setup_i2c(unsigned i2c_index, int speed, int slave_addr,
+		struct i2c_pads_info *p)
+{
+	if (i2c_index >= ARRAY_SIZE(i2c_bases))
+		return;
+	/* Enable i2c clock */
+	enable_i2c_clk(1, i2c_index);
+	/* Make sure bus is idle */
+	force_idle_bus(p);
+	bus_i2c_init(i2c_bases[i2c_index], speed, slave_addr,
+			force_idle_bus, p);
+}