i2c: tegra: proper handling of error cases

[cascardo/linux.git] / drivers / i2c / busses / i2c-tegra.c

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 2437535..c15d575 100644 (file)
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -196,6 +196,7 @@ struct tegra_i2c_dev {
        u16 clk_divisor_non_hs_mode;
        bool is_suspended;
        bool is_multimaster_mode;
+       spinlock_t xfer_lock;
 };
 
 static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
@@ -542,14 +543,27 @@ err:
        return err;
 }
 
+static int tegra_i2c_disable_packet_mode(struct tegra_i2c_dev *i2c_dev)
+{
+       u32 cnfg;
+
+       cnfg = i2c_readl(i2c_dev, I2C_CNFG);
+       if (cnfg & I2C_CNFG_PACKET_MODE_EN)
+               i2c_writel(i2c_dev, cnfg & ~I2C_CNFG_PACKET_MODE_EN, I2C_CNFG);
+
+       return tegra_i2c_wait_for_config_load(i2c_dev);
+}
+
 static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 {
        u32 status;
        const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
        struct tegra_i2c_dev *i2c_dev = dev_id;
+       unsigned long flags;
 
        status = i2c_readl(i2c_dev, I2C_INT_STATUS);
 
+       spin_lock_irqsave(&i2c_dev->xfer_lock, flags);
        if (status == 0) {
                dev_warn(i2c_dev->dev, "irq status 0 %08x %08x %08x\n",
                         i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS),
@@ -565,6 +579,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
        }
 
        if (unlikely(status & status_err)) {
+               tegra_i2c_disable_packet_mode(i2c_dev);
                if (status & I2C_INT_NO_ACK)
                        i2c_dev->msg_err |= I2C_ERR_NO_ACK;
                if (status & I2C_INT_ARBITRATION_LOST)
@@ -594,7 +609,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
                BUG_ON(i2c_dev->msg_buf_remaining);
                complete(&i2c_dev->msg_complete);
        }
-       return IRQ_HANDLED;
+       goto done;
 err:
        /* An error occurred, mask all interrupts */
        tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST |
@@ -605,6 +620,8 @@ err:
                dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
 
        complete(&i2c_dev->msg_complete);
+done:
+       spin_unlock_irqrestore(&i2c_dev->xfer_lock, flags);
        return IRQ_HANDLED;
 }
 
@@ -614,6 +631,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
        u32 packet_header;
        u32 int_mask;
        unsigned long time_left;
+       unsigned long flags;
 
        tegra_i2c_flush_fifos(i2c_dev);
 
@@ -626,6 +644,11 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
        i2c_dev->msg_read = (msg->flags & I2C_M_RD);
        reinit_completion(&i2c_dev->msg_complete);
 
+       spin_lock_irqsave(&i2c_dev->xfer_lock, flags);
+
+       int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
+       tegra_i2c_unmask_irq(i2c_dev, int_mask);
+
        packet_header = (0 << PACKET_HEADER0_HEADER_SIZE_SHIFT) |
                        PACKET_HEADER0_PROTOCOL_I2C |
                        (i2c_dev->cont_id << PACKET_HEADER0_CONT_ID_SHIFT) |
@@ -655,14 +678,15 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
        if (!(msg->flags & I2C_M_RD))
                tegra_i2c_fill_tx_fifo(i2c_dev);
 
-       int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
        if (i2c_dev->hw->has_per_pkt_xfer_complete_irq)
                int_mask |= I2C_INT_PACKET_XFER_COMPLETE;
        if (msg->flags & I2C_M_RD)
                int_mask |= I2C_INT_RX_FIFO_DATA_REQ;
        else if (i2c_dev->msg_buf_remaining)
                int_mask |= I2C_INT_TX_FIFO_DATA_REQ;
+
        tegra_i2c_unmask_irq(i2c_dev, int_mask);
+       spin_unlock_irqrestore(&i2c_dev->xfer_lock, flags);
        dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n",
                i2c_readl(i2c_dev, I2C_INT_MASK));
 
@@ -899,6 +923,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
        i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node,
                                                  "nvidia,tegra20-i2c-dvc");
        init_completion(&i2c_dev->msg_complete);
+       spin_lock_init(&i2c_dev->xfer_lock);
 
        if (!i2c_dev->hw->has_single_clk_source) {
                fast_clk = devm_clk_get(&pdev->dev, "fast-clk");