@@ -51,6 +51,7 @@
#define I2C_FIFO_STATUS_RX_SHIFT 0
#define I2C_INT_MASK 0x064
#define I2C_INT_STATUS 0x068
+#define I2C_INT_BUS_CLR_DONE BIT(11)
#define I2C_INT_PACKET_XFER_COMPLETE BIT(7)
#define I2C_INT_ALL_PACKETS_XFER_COMPLETE BIT(6)
#define I2C_INT_TX_FIFO_OVERFLOW BIT(5)
@@ -93,6 +94,15 @@
#define I2C_HEADER_MASTER_ADDR_SHIFT 12
#define I2C_HEADER_SLAVE_ADDR_SHIFT 1
+#define I2C_BUS_CLEAR_CNFG 0x084
+#define I2C_BC_SCLK_THRESHOLD 9
+#define I2C_BC_SCLK_THRESHOLD_SHIFT 16
+#define I2C_BC_STOP_COND BIT(2)
+#define I2C_BC_TERMINATE BIT(1)
+#define I2C_BC_ENABLE BIT(0)
+#define I2C_BUS_CLEAR_STATUS 0x088
+#define I2C_BC_STATUS BIT(0)
+
#define I2C_CONFIG_LOAD 0x08C
#define I2C_MSTR_CONFIG_LOAD BIT(0)
#define I2C_SLV_CONFIG_LOAD BIT(1)
@@ -154,6 +164,8 @@ enum msg_end_type {
* be transferred in one go.
* @quirks: i2c adapter quirks for limiting write/read transfer size and not
* allowing 0 length transfers.
+ * @supports_bus_clear: Bus Clear support to recover from bus hang during
+ * SDA stuck low from device for some unknown reasons.
*/
struct tegra_i2c_hw_feature {
bool has_continue_xfer_support;
@@ -167,6 +179,7 @@ struct tegra_i2c_hw_feature {
bool has_slcg_override_reg;
bool has_mst_fifo;
const struct i2c_adapter_quirks *quirks;
+ bool supports_bus_clear;
};
/**
@@ -640,6 +653,13 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
goto err;
}
+ /*
+ * I2C transfer is terminated during the bus clear so skip
+ * processing the other interrupts.
+ */
+ if (i2c_dev->hw->supports_bus_clear && (status & I2C_INT_BUS_CLR_DONE))
+ goto err;
+
if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) {
if (i2c_dev->msg_buf_remaining)
tegra_i2c_empty_rx_fifo(i2c_dev);
@@ -668,6 +688,8 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST |
I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ |
I2C_INT_RX_FIFO_DATA_REQ);
+ if (i2c_dev->hw->supports_bus_clear)
+ tegra_i2c_mask_irq(i2c_dev, I2C_INT_BUS_CLR_DONE);
i2c_writel(i2c_dev, status, I2C_INT_STATUS);
if (i2c_dev->is_dvc)
dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
@@ -678,6 +700,44 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
+{
+ struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
+ int err;
+ unsigned long time_left;
+ u32 reg;
+
+ reinit_completion(&i2c_dev->msg_complete);
+ reg = (I2C_BC_SCLK_THRESHOLD << I2C_BC_SCLK_THRESHOLD_SHIFT) |
+ I2C_BC_STOP_COND | I2C_BC_TERMINATE;
+ i2c_writel(i2c_dev, reg, I2C_BUS_CLEAR_CNFG);
+ if (i2c_dev->hw->has_config_load_reg) {
+ err = tegra_i2c_wait_for_config_load(i2c_dev);
+ if (err)
+ return err;
+ }
+
+ reg |= I2C_BC_ENABLE;
+ i2c_writel(i2c_dev, reg, I2C_BUS_CLEAR_CNFG);
+ tegra_i2c_unmask_irq(i2c_dev, I2C_INT_BUS_CLR_DONE);
+
+ time_left = wait_for_completion_timeout(&i2c_dev->msg_complete,
+ TEGRA_I2C_TIMEOUT);
+ if (time_left == 0) {
+ dev_err(i2c_dev->dev, "timed out for bus clear\n");
+ return -ETIMEDOUT;
+ }
+
+ reg = i2c_readl(i2c_dev, I2C_BUS_CLEAR_STATUS);
+ if (!(reg & I2C_BC_STATUS)) {
+ dev_err(i2c_dev->dev,
+ "un-recovered arbitration lost\n");
+ return -EIO;
+ }
+
+ return -EAGAIN;
+}
+
static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
struct i2c_msg *msg, enum msg_end_type end_state)
{
@@ -759,6 +819,13 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
return 0;
tegra_i2c_init(i2c_dev);
+ /* start recovery upon arbitration loss in single master mode */
+ if (i2c_dev->msg_err == I2C_ERR_ARBITRATION_LOST) {
+ if (!i2c_dev->is_multimaster_mode)
+ return i2c_recover_bus(&i2c_dev->adapter);
+ return -EAGAIN;
+ }
+
if (i2c_dev->msg_err == I2C_ERR_NO_ACK) {
if (msg->flags & I2C_M_IGNORE_NAK)
return 0;
@@ -841,6 +908,10 @@ static const struct i2c_adapter_quirks tegra194_i2c_quirks = {
.flags = I2C_AQ_NO_ZERO_LEN,
};
+static struct i2c_bus_recovery_info tegra_i2c_recovery_info = {
+ .recover_bus = tegra_i2c_issue_bus_clear,
+};
+
static const struct tegra_i2c_hw_feature tegra20_i2c_hw = {
.has_continue_xfer_support = false,
.has_per_pkt_xfer_complete_irq = false,
@@ -853,6 +924,7 @@ static const struct tegra_i2c_hw_feature tegra20_i2c_hw = {
.has_slcg_override_reg = false,
.has_mst_fifo = false,
.quirks = &tegra_i2c_quirks,
+ .supports_bus_clear = false,
};
static const struct tegra_i2c_hw_feature tegra30_i2c_hw = {
@@ -867,6 +939,7 @@ static const struct tegra_i2c_hw_feature tegra30_i2c_hw = {
.has_slcg_override_reg = false,
.has_mst_fifo = false,
.quirks = &tegra_i2c_quirks,
+ .supports_bus_clear = false,
};
static const struct tegra_i2c_hw_feature tegra114_i2c_hw = {
@@ -881,6 +954,7 @@ static const struct tegra_i2c_hw_feature tegra114_i2c_hw = {
.has_slcg_override_reg = false,
.has_mst_fifo = false,
.quirks = &tegra_i2c_quirks,
+ .supports_bus_clear = true,
};
static const struct tegra_i2c_hw_feature tegra124_i2c_hw = {
@@ -895,6 +969,7 @@ static const struct tegra_i2c_hw_feature tegra124_i2c_hw = {
.has_slcg_override_reg = true,
.has_mst_fifo = false,
.quirks = &tegra_i2c_quirks,
+ .supports_bus_clear = true,
};
static const struct tegra_i2c_hw_feature tegra210_i2c_hw = {
@@ -909,6 +984,7 @@ static const struct tegra_i2c_hw_feature tegra210_i2c_hw = {
.has_slcg_override_reg = true,
.has_mst_fifo = false,
.quirks = &tegra_i2c_quirks,
+ .supports_bus_clear = true,
};
static const struct tegra_i2c_hw_feature tegra194_i2c_hw = {
@@ -923,6 +999,7 @@ static const struct tegra_i2c_hw_feature tegra194_i2c_hw = {
.has_slcg_override_reg = true,
.has_mst_fifo = true,
.quirks = &tegra194_i2c_quirks,
+ .supports_bus_clear = true,
};
/* Match table for of_platform binding */
@@ -974,6 +1051,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
i2c_dev->base = base;
i2c_dev->div_clk = div_clk;
i2c_dev->adapter.algo = &tegra_i2c_algo;
+ i2c_dev->adapter.retries = 1;
i2c_dev->irq = irq;
i2c_dev->cont_id = pdev->id;
i2c_dev->dev = &pdev->dev;
@@ -1051,6 +1129,9 @@ static int tegra_i2c_probe(struct platform_device *pdev)
}
}
+ if (i2c_dev->hw->supports_bus_clear)
+ i2c_dev->adapter.bus_recovery_info = &tegra_i2c_recovery_info;
+
ret = tegra_i2c_init(i2c_dev);
if (ret) {
dev_err(&pdev->dev, "Failed to initialize i2c controller\n");