From: Tim Sander <tim@xxxxxxxxxxxxxxx>
This patch contains much input from Phil Reid and has been tested
on Intel/Altera Cyclone V SOC Hardware with Altera GPIO's for the
SCL and SDA GPIO's.
Signed-off-by: Tim Sander <tim@xxxxxxxxxxxxxxx>
Signed-off-by: Phil Reid <preid@xxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-designware-common.c | 6 +++-
drivers/i2c/busses/i2c-designware-core.h | 1 +
drivers/i2c/busses/i2c-designware-master.c | 57 ++++++++++++++++++++++++++++++
3 files changed, 63 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
index 3d684c6..6b82809 100644
--- a/drivers/i2c/busses/i2c-designware-common.c
+++ b/drivers/i2c/busses/i2c-designware-common.c
@@ -230,7 +230,11 @@ int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
if (timeout <= 0) {
dev_warn(dev->dev, "timeout waiting for bus ready\n");
- return -ETIMEDOUT;
+ i2c_recover_bus(&dev->adapter);
+
+ if (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY)
+ return -ETIMEDOUT;
+ return 0;
}
timeout--;
usleep_range(1000, 1100);
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 33c6c8f..d58a336 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -286,6 +286,7 @@ struct dw_i2c_dev {
void (*disable_int)(struct dw_i2c_dev *dev);
int (*init)(struct dw_i2c_dev *dev);
int mode;
+ struct i2c_bus_recovery_info rinfo;
};
#define ACCESS_SWAP 0x00000001
diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index 418c233..ae69188 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -25,11 +25,13 @@
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/export.h>
+#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
+#include <linux/reset.h>
#include "i2c-designware-core.h"
@@ -443,6 +445,7 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
if (!wait_for_completion_timeout(&dev->cmd_complete, adap->timeout)) {
dev_err(dev->dev, "controller timed out\n");
/* i2c_dw_init implicitly disables the adapter */
+ i2c_recover_bus(&dev->adapter);
i2c_dw_init_master(dev);
ret = -ETIMEDOUT;
goto done;
@@ -613,6 +616,56 @@ static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
return IRQ_HANDLED;
}
+static void i2c_dw_prepare_recovery(struct i2c_adapter *adap)
+{
+ struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
+
+ i2c_dw_disable(dev);
+ reset_control_assert(dev->rst);
+ i2c_dw_prepare_clk(dev, false);
+}
+
+static void i2c_dw_unprepare_recovery(struct i2c_adapter *adap)
+{
+ struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
+
+ i2c_dw_prepare_clk(dev, true);
+ reset_control_deassert(dev->rst);
+ i2c_dw_init_master(dev);
+}
+
+static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
+{
+ struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
+ struct i2c_adapter *adap = &dev->adapter;
+ struct gpio_desc *gpio;
+ int r;
+
+ gpio = devm_gpiod_get(dev->dev, "scl", GPIOD_OUT_HIGH);
+ if (IS_ERR(gpio)) {
+ r = PTR_ERR(gpio);
+ if (r == -ENOENT)
+ return 0;
+ return r;
+ }
+ rinfo->scl_gpiod = gpio;
+
+ gpio = devm_gpiod_get_optional(dev->dev, "sda", GPIOD_IN);
+ if (IS_ERR(gpio))
+ return PTR_ERR(gpio);
+ rinfo->sda_gpiod = gpio;
+
+ rinfo->recover_bus = i2c_generic_scl_recovery;
+ rinfo->prepare_recovery = i2c_dw_prepare_recovery;
+ rinfo->unprepare_recovery = i2c_dw_unprepare_recovery;
+ adap->bus_recovery_info = rinfo;
+
+ dev_info(dev->dev, "running with gpio recovery mode! scl%s",
+ rinfo->sda_gpiod ? ",sda" : "");
+
+ return 0;
+}
+
int i2c_dw_probe(struct dw_i2c_dev *dev)
{
struct i2c_adapter *adap = &dev->adapter;
@@ -652,6 +705,10 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
return ret;
}
+ ret = i2c_dw_init_recovery_info(dev);
+ if (ret)
+ return ret;
+
/*
* Increment PM usage count during adapter registration in order to
* avoid possible spurious runtime suspend when adapter device is
--
1.8.3.1
