i2c: mv64xxx: Add bus error recovery

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 <mark.tomlinson@alliedtelesis.co.nz>
[wsa: added some curly braces]
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index e0e45fc19b8f1a910fe1a25d32e99316c75dd00e..5cfe70aedcedbd0ddd10f887b7a17749fa2f79cb 100644 (file)
--- 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;
        }
 }
 
@@ -561,6 +564,7 @@ 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);
@@ -870,6 +874,25 @@ 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_info(dev, "can't get pinctrl, bus recovery not supported\n");
+               return PTR_ERR(rinfo->pinctrl);
+       } else if (!rinfo->pinctrl) {
+               return -ENODEV;
+       }
+
+       drv_data->adapter.bus_recovery_info = rinfo;
+       return 0;
+}
+
 static int
 mv64xxx_i2c_probe(struct platform_device *pd)
 {
@@ -926,6 +949,10 @@ 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;