@@ -26,6 +26,7 @@
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/delay.h>
+#include <linux/of_gpio.h>
#define MV64XXX_I2C_ADDR_ADDR(val) ((val & 0x7f) << 1)
#define MV64XXX_I2C_BAUD_DIV_N(val) (val & 0x7)
@@ -104,6 +105,7 @@ enum {
MV64XXX_I2C_ACTION_RCV_DATA,
MV64XXX_I2C_ACTION_RCV_DATA_STOP,
MV64XXX_I2C_ACTION_SEND_STOP,
+ MV64XXX_I2C_ACTION_UNLOCK_BUS
};
struct mv64xxx_i2c_regs {
@@ -150,6 +152,12 @@ struct mv64xxx_i2c_data {
bool clk_n_base_0;
struct i2c_bus_recovery_info rinfo;
bool atomic;
+ /* I2C mpp states & gpios needed for arbitration lost recovery */
+ int scl_gpio, sda_gpio;
+ bool soft_reset;
+ struct pinctrl_state *i2c_mpp_state;
+ struct pinctrl_state *i2c_gpio_state;
+ struct pinctrl *pc;
};
static struct mv64xxx_i2c_regs mv64xxx_i2c_regs_mv64xxx = {
@@ -318,6 +326,11 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
drv_data->state = MV64XXX_I2C_STATE_IDLE;
break;
+ case MV64XXX_I2C_STATUS_MAST_LOST_ARB: /* 0x38 */
+ drv_data->action = MV64XXX_I2C_ACTION_UNLOCK_BUS;
+ drv_data->state = MV64XXX_I2C_STATE_IDLE;
+ break;
+
case MV64XXX_I2C_STATUS_MAST_WR_ADDR_NO_ACK: /* 0x20 */
case MV64XXX_I2C_STATUS_MAST_WR_NO_ACK: /* 30 */
case MV64XXX_I2C_STATUS_MAST_RD_ADDR_NO_ACK: /* 48 */
@@ -356,6 +369,9 @@ static void mv64xxx_i2c_send_start(struct mv64xxx_i2c_data *drv_data)
static void
mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
{
+ struct pinctrl *pc;
+ int i;
+
switch(drv_data->action) {
case MV64XXX_I2C_ACTION_SEND_RESTART:
/* We should only get here if we have further messages */
@@ -409,6 +425,54 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
drv_data->reg_base + drv_data->reg_offsets.control);
break;
+ case MV64XXX_I2C_ACTION_UNLOCK_BUS:
+ if (!drv_data->soft_reset)
+ break;
+
+ pc = drv_data->pc;
+ if (IS_ERR(pc)) {
+ dev_err(&drv_data->adapter.dev,
+ "failed to get pinctrl for bus unlock!\n");
+ break;
+ }
+
+ /* Change i2c MPPs state to act as GPIOs: */
+ if (pinctrl_select_state(pc, drv_data->i2c_gpio_state) >= 0) {
+ /*
+ * Toggle i2c scl (serial clock) 10 times.
+ * 10 clocks are enough to transfer a full
+ * byte plus extra as seen from tests with
+ * Ubiquity SFP module causing the issue.
+ * This allows the slave that occupies
+ * the bus to transmit its remaining data,
+ * so it can release the i2c bus:
+ */
+ for (i = 0; i < 10; i++) {
+ gpio_set_value(drv_data->scl_gpio, 1);
+ usleep_range(100, 1000);
+ gpio_set_value(drv_data->scl_gpio, 0);
+ };
+
+ /* restore i2c pin state to MPPs: */
+ pinctrl_select_state(pc, drv_data->i2c_mpp_state);
+ }
+
+ /*
+ * Trigger controller soft reset
+ * This register is write only, with none of the bits defined.
+ * So any value will do.
+ * 0x1 just seems more intuitive than 0x0 ...
+ */
+ writel(0x1, drv_data->reg_base + drv_data->reg_offsets.soft_reset);
+ /* wait for i2c controller to complete reset: */
+ usleep_range(100, 1000);
+ /*
+ * Need to proceed to the data stop condition generation clause.
+ * This is needed after clock toggling to put the i2c slave
+ * in the correct state.
+ */
+ fallthrough;
+
case MV64XXX_I2C_ACTION_RCV_DATA_STOP:
drv_data->msg->buf[drv_data->byte_posn++] =
readl(drv_data->reg_base + drv_data->reg_offsets.data);
@@ -950,6 +1014,8 @@ static int mv64xxx_i2c_init_recovery_info(struct mv64xxx_i2c_data *drv_data,
return -ENODEV;
}
+ rinfo->sda_gpiod = devm_gpiod_get(dev, "sda", GPIOD_OUT_HIGH);
+ rinfo->scl_gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH);
drv_data->adapter.bus_recovery_info = rinfo;
return 0;
}
@@ -985,6 +1051,7 @@ mv64xxx_i2c_probe(struct platform_device *pd)
{
struct mv64xxx_i2c_data *drv_data;
struct mv64xxx_i2c_pdata *pdata = dev_get_platdata(&pd->dev);
+ struct pinctrl *pc;
int rc;
if ((!pdata && !pd->dev.of_node))
@@ -1040,6 +1107,47 @@ mv64xxx_i2c_probe(struct platform_device *pd)
if (rc == -EPROBE_DEFER)
return rc;
+ /*
+ * Start with arbitration lost soft reset enabled as to false.
+ * Try to locate the necessary items in the device tree to
+ * make this feature work.
+ * Only after we verify that the device tree contains all of
+ * the needed information and that it is sound and usable,
+ * then we enable this flag.
+ * This information should be defined, but the driver maintains
+ * backward compatibility with old dts files, so it will not fail
+ * the probe in case these are missing.
+ */
+ drv_data->soft_reset = false;
+ pc = devm_pinctrl_get(&pd->dev);
+ if (!IS_ERR(pc)) {
+ drv_data->pc = pc;
+ drv_data->i2c_mpp_state =
+ pinctrl_lookup_state(pc, "default");
+ drv_data->i2c_gpio_state =
+ pinctrl_lookup_state(pc, "gpio");
+ drv_data->scl_gpio =
+ of_get_named_gpio(pd->dev.of_node, "scl-gpios", 0);
+ drv_data->sda_gpio =
+ of_get_named_gpio(pd->dev.of_node, "sda-gpios", 0);
+
+ if (!IS_ERR(drv_data->i2c_gpio_state) &&
+ !IS_ERR(drv_data->i2c_mpp_state) &&
+ gpio_is_valid(drv_data->scl_gpio) &&
+ gpio_is_valid(drv_data->sda_gpio)) {
+ rc = devm_gpio_request_one(&pd->dev, drv_data->scl_gpio,
+ GPIOF_DIR_OUT, NULL);
+ rc |= devm_gpio_request_one(&pd->dev, drv_data->sda_gpio,
+ GPIOF_DIR_OUT, NULL);
+ if (!rc)
+ drv_data->soft_reset = true;
+ }
+ }
+
+ if (!drv_data->soft_reset)
+ dev_info(&pd->dev,
+ "mv64xxx: missing arbitration-lost recovery definitions in dts file\n");
+
drv_data->adapter.dev.parent = &pd->dev;
drv_data->adapter.algo = &mv64xxx_i2c_algo;
drv_data->adapter.owner = THIS_MODULE;