1 files changed, 104 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/i2c_error_recovery.c b/arch/arm/mach-tegra/i2c_error_recovery.c
new file mode 100644
index 000000000000..bea3133b48c1
--- /dev/null
+++ b/arch/arm/mach-tegra/i2c_error_recovery.c
@@ -0,0 +1,104 @@
+/*
+ * arch/arm/mach-tegra/i2c_error_recovery.c
+ *
+ * Copyright (c) 2011, NVIDIA Corporation.
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#include <linux/gpio.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+
+#include "gpio-names.h"
+#include "board.h"
+
+#define RETRY_MAX_COUNT (9*8+1) /*I2C controller supports eight-byte burst transfer*/
+
+int arb_lost_recovery(int scl_gpio, int sda_gpio)
+{
+	int ret;
+	int retry = RETRY_MAX_COUNT;
+	int recovered_successfully = 0;
+	int val;
+
+	if ((!scl_gpio) || (!sda_gpio)) {
+		pr_err("not proper input:scl_gpio 0x%08x,"
+			"sda_gpio 0x%08x\n", scl_gpio, sda_gpio);
+		return -EINVAL;;
+	}
+
+	ret = gpio_request(scl_gpio, "scl_gpio");
+	if (ret < 0) {
+		pr_err("error in gpio 0x%08x request 0x%08x\n",
+			scl_gpio, ret);
+		return -EINVAL;;
+	}
+	tegra_gpio_enable(scl_gpio);
+
+	ret = gpio_request(sda_gpio, "sda_gpio");
+	if (ret < 0) {
+		pr_err("error in gpio 0x%08x request 0x%08x\n",
+			sda_gpio, ret);
+		goto err;
+	}
+	tegra_gpio_enable(sda_gpio);
+	gpio_direction_input(sda_gpio);
+
+	while (retry--) {
+		gpio_direction_output(scl_gpio,0);
+		udelay(5);
+		gpio_direction_output(scl_gpio,1);
+		udelay(5);
+
+		/* check whether sda struct low release */
+		val = gpio_get_value(sda_gpio);
+		if (val) {
+			/* send START */
+			gpio_direction_output(sda_gpio,0);
+			udelay(5);
+
+			/* send STOP in next clock cycle */
+			gpio_direction_output(scl_gpio,0);
+			udelay(5);
+			gpio_direction_output(scl_gpio,1);
+			udelay(5);
+			gpio_direction_output(sda_gpio,1);
+			udelay(5);
+
+			recovered_successfully = 1;
+			break;
+		}
+	}
+
+	gpio_free(scl_gpio);
+	tegra_gpio_disable(scl_gpio);
+	gpio_free(sda_gpio);
+	tegra_gpio_disable(sda_gpio);
+
+	if (likely(recovered_successfully)) {
+		pr_err("arbitration lost recovered by re-try-count 0x%08x\n",
+			RETRY_MAX_COUNT - retry);
+		return 0;
+	} else {
+		pr_err("Un-recovered arbitration lost.\n");
+		return -EINVAL;
+	}
+
+err:
+	gpio_free(scl_gpio);
+	tegra_gpio_disable(scl_gpio);
+	return ret;
+}
+