summaryrefslogtreecommitdiffstats
path: root/arch/arm/cpu/armv7/imx-common/i2c.c
diff options
context:
space:
mode:
authorTroy Kisky <troy.kisky@boundarydevices.com>2012-07-19 08:18:25 +0000
committerHeiko Schocher <hs@denx.de>2012-07-31 08:00:57 +0200
commitcc54a0f7cccf976d350801d39c406e75465ebdd1 (patch)
treec28139c6518e37fd16786cd011bbb5b5f0556a0b /arch/arm/cpu/armv7/imx-common/i2c.c
parentdf369dcdb05729304761748856a2513d9ddac272 (diff)
downloadblackbird-obmc-uboot-cc54a0f7cccf976d350801d39c406e75465ebdd1.tar.gz
blackbird-obmc-uboot-cc54a0f7cccf976d350801d39c406e75465ebdd1.zip
imx-common: add i2c.c for bus recovery support
Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Diffstat (limited to 'arch/arm/cpu/armv7/imx-common/i2c.c')
-rw-r--r--arch/arm/cpu/armv7/imx-common/i2c.c99
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);
+}
OpenPOWER on IntegriCloud