diff options
| author | Alok Chauhan <alokc@nvidia.com> | 2011-07-26 16:00:32 +0530 |
|---|---|---|
| committer | Dan Willemsen <dwillemsen@nvidia.com> | 2011-11-30 21:48:08 -0800 |
| commit | 92692aa917457cbc595948f4eab10bd1cfe065a4 (patch) | |
| tree | f7343989a45fef3866ba863aafa70d4ef16849af /arch/arm/mach-tegra/i2c_error_recovery.c | |
| parent | e806e28f31c46b73ca965954c717af405376ae8e (diff) | |
arm: tegra: cardhu: Added I2C arbitration lost recovery mechanism
Added the code for arbitration lost recovery mechanism for i2c
driver and Initialize gpio number for i2c clock and data as
part of platform data.
bug 854305
Original-Change-Id: Icdc243a5025c766d65816542a6d5aabd61e6eee1
Reviewed-on: http://git-master/r/43200
Reviewed-by: Bandi Krishna Chaitanya <bandik@nvidia.com>
Tested-by: Bandi Krishna Chaitanya <bandik@nvidia.com>
Reviewed-by: Alok Chauhan <alokc@nvidia.com>
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>
Rebase-Id: R11e00587725418e6e6ef5d0fa2f718424cc0635e
Diffstat (limited to 'arch/arm/mach-tegra/i2c_error_recovery.c')
| -rw-r--r-- | arch/arm/mach-tegra/i2c_error_recovery.c | 104 |
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;
+}
+
|