This adds i2c bus recovery to the mv64xxx driver.
Implement bus recovery to recover from SCL/SDA stuck low.
This uses the generic recovery function, setting the clock/data lines as
GPIO pins, and sending 9 clocks to try and recover the bus.
Signed-off-by: Mark Tomlinson <[email protected]>
---
Changes in v2:
- use generic GPIO recovery function.
drivers/i2c/busses/i2c-mv64xxx.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 8d9d4ffdcd24..e0f0c76c0d3b 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -17,6 +17,7 @@
#include <linux/interrupt.h>
#include <linux/mv643xx_i2c.h>
#include <linux/platform_device.h>
+#include <linux/pinctrl/consumer.h>
#include <linux/reset.h>
#include <linux/io.h>
#include <linux/of.h>
@@ -147,6 +148,7 @@ struct mv64xxx_i2c_data {
bool irq_clear_inverted;
/* Clk div is 2 to the power n, not 2 to the power n + 1 */
bool clk_n_base_0;
+ struct i2c_bus_recovery_info rinfo;
};
static struct mv64xxx_i2c_regs mv64xxx_i2c_regs_mv64xxx = {
@@ -325,7 +327,8 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
drv_data->msg->flags);
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
mv64xxx_i2c_hw_init(drv_data);
- drv_data->rc = -EIO;
+ i2c_recover_bus(&drv_data->adapter);
+ drv_data->rc = -EAGAIN;
}
}
@@ -562,6 +565,7 @@ mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data)
"time_left: %d\n", drv_data->block,
(int)time_left);
mv64xxx_i2c_hw_init(drv_data);
+ i2c_recover_bus(&drv_data->adapter);
}
} else
spin_unlock_irqrestore(&drv_data->lock, flags);
@@ -871,6 +875,22 @@ mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data,
}
#endif /* CONFIG_OF */
+static int mv64xxx_i2c_init_recovery_info(struct mv64xxx_i2c_data *drv_data,
+ struct device *dev)
+{
+ struct i2c_bus_recovery_info *rinfo = &drv_data->rinfo;
+
+ rinfo->pinctrl = devm_pinctrl_get(dev);
+ if (IS_ERR(rinfo->pinctrl)) {
+ if (PTR_ERR(rinfo->pinctrl) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ dev_err(dev, "can't get pinctrl, bus recovery not supported\n");
+ return PTR_ERR(rinfo->pinctrl);
+ }
+ drv_data->adapter.bus_recovery_info = rinfo;
+ return 0;
+}
+
static int
mv64xxx_i2c_probe(struct platform_device *pd)
{
@@ -927,6 +947,10 @@ mv64xxx_i2c_probe(struct platform_device *pd)
goto exit_reset;
}
+ rc = mv64xxx_i2c_init_recovery_info(drv_data, &pd->dev);
+ if (rc == -EPROBE_DEFER)
+ goto exit_reset;
+
drv_data->adapter.dev.parent = &pd->dev;
drv_data->adapter.algo = &mv64xxx_i2c_algo;
drv_data->adapter.owner = THIS_MODULE;
@@ -950,6 +974,7 @@ mv64xxx_i2c_probe(struct platform_device *pd)
"mv64xxx: Can't add i2c adapter, rc: %d\n", -rc);
goto exit_free_irq;
}
+ i2c_recover_bus(&drv_data->adapter);
return 0;
--
2.28.0
On Tue, Aug 25, 2020 at 10:52:54AM +1200, Mark Tomlinson wrote:
> This adds i2c bus recovery to the mv64xxx driver.
>
> Implement bus recovery to recover from SCL/SDA stuck low.
>
> This uses the generic recovery function, setting the clock/data lines as
> GPIO pins, and sending 9 clocks to try and recover the bus.
>
> Signed-off-by: Mark Tomlinson <[email protected]>
> ---
> Changes in v2:
> - use generic GPIO recovery function.
Thank you for doing that! Glad to see the new helper function works for
you as well. The initialization code is all well, but I wonder about the
use of i2c_recover_bus(). Recovery should be tried only if it is
detected that SDA is pulled low when the bus should be free. So, you
shouldn't call i2c_recover_bus() in unconditionally in probe(). Can your
HW detect if SDA is stuck low?
On Tue, 2020-08-25 at 11:26 +0200, Wolfram Sang wrote:
> On Tue, Aug 25, 2020 at 10:52:54AM +1200, Mark Tomlinson wrote:
>
> This adds i2c bus recovery to the mv64xxx driver.
>
> Implement bus recovery to recover from SCL/SDA stuck low.
>
> This uses the generic recovery function, setting the clock/data lines as
> GPIO pins, and sending 9 clocks to try and recover the bus.
>
> Signed-off-by: Mark Tomlinson <[email protected]>
> ---
> Changes in v2:
> - use generic GPIO recovery function.
>
> Thank you for doing that! Glad to see the new helper function works for
> you as well. The initialization code is all well, but I wonder about the
> use of i2c_recover_bus(). Recovery should be tried only if it is
> detected that SDA is pulled low when the bus should be free. So, you
> shouldn't call i2c_recover_bus() in unconditionally in probe(). Can your
> HW detect if SDA is stuck low?
We actually don't need this call, as the bootloader checks and leaves the
bus in a good state. I will remove this from the patch.