Merge branches 'work.misc' and 'work.dcache' of git://git.kernel.org/pub/scm/linux...

[sfrench/cifs-2.6.git] / drivers / i2c / busses / i2c-rcar.c

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 5e310efd94464897d9db7becf89294a8b2adc4f6..3c1c817f6968e43fdafd73ff6f53d381c2528b96 100644 (file)
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -32,6 +32,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 
 /* register offsets */
@@ -111,8 +112,9 @@
 #define ID_ARBLOST     (1 << 3)
 #define ID_NACK                (1 << 4)
 /* persistent flags */
+#define ID_P_NO_RXDMA  (1 << 30) /* HW forbids RXDMA sometimes */
 #define ID_P_PM_BLOCKED        (1 << 31)
-#define ID_P_MASK      ID_P_PM_BLOCKED
+#define ID_P_MASK      (ID_P_PM_BLOCKED | ID_P_NO_RXDMA)
 
 enum rcar_i2c_type {
        I2C_RCAR_GEN1,
@@ -141,6 +143,8 @@ struct rcar_i2c_priv {
        struct dma_chan *dma_rx;
        struct scatterlist sg;
        enum dma_data_direction dma_direction;
+
+       struct reset_control *rstc;
 };
 
 #define rcar_i2c_priv_to_dev(p)                ((p)->adap.dev.parent)
@@ -370,6 +374,11 @@ static void rcar_i2c_dma_unmap(struct rcar_i2c_priv *priv)
        dma_unmap_single(chan->device->dev, sg_dma_address(&priv->sg),
                         sg_dma_len(&priv->sg), priv->dma_direction);
 
+       /* Gen3 can only do one RXDMA per transfer and we just completed it */
+       if (priv->devtype == I2C_RCAR_GEN3 &&
+           priv->dma_direction == DMA_FROM_DEVICE)
+               priv->flags |= ID_P_NO_RXDMA;
+
        priv->dma_direction = DMA_NONE;
 }
 
@@ -407,8 +416,9 @@ static void rcar_i2c_dma(struct rcar_i2c_priv *priv)
        unsigned char *buf;
        int len;
 
-       /* Do not use DMA if it's not available or for messages < 8 bytes */
-       if (IS_ERR(chan) || msg->len < 8 || !(msg->flags & I2C_M_DMA_SAFE))
+       /* Do various checks to see if DMA is feasible at all */
+       if (IS_ERR(chan) || msg->len < 8 || !(msg->flags & I2C_M_DMA_SAFE) ||
+           (read && priv->flags & ID_P_NO_RXDMA))
                return;
 
        if (read) {
@@ -739,6 +749,25 @@ static void rcar_i2c_release_dma(struct rcar_i2c_priv *priv)
        }
 }
 
+/* I2C is a special case, we need to poll the status of a reset */
+static int rcar_i2c_do_reset(struct rcar_i2c_priv *priv)
+{
+       int i, ret;
+
+       ret = reset_control_reset(priv->rstc);
+       if (ret)
+               return ret;
+
+       for (i = 0; i < LOOP_TIMEOUT; i++) {
+               ret = reset_control_status(priv->rstc);
+               if (ret == 0)
+                       return 0;
+               udelay(1);
+       }
+
+       return -ETIMEDOUT;
+}
+
 static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
                                struct i2c_msg *msgs,
                                int num)
@@ -750,6 +779,16 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
 
        pm_runtime_get_sync(dev);
 
+       /* Gen3 needs a reset before allowing RXDMA once */
+       if (priv->devtype == I2C_RCAR_GEN3) {
+               priv->flags |= ID_P_NO_RXDMA;
+               if (!IS_ERR(priv->rstc)) {
+                       ret = rcar_i2c_do_reset(priv);
+                       if (ret == 0)
+                               priv->flags &= ~ID_P_NO_RXDMA;
+               }
+       }
+
        rcar_i2c_init(priv);
 
        ret = rcar_i2c_bus_barrier(priv);
@@ -920,6 +959,15 @@ static int rcar_i2c_probe(struct platform_device *pdev)
        if (ret < 0)
                goto out_pm_put;
 
+       if (priv->devtype == I2C_RCAR_GEN3) {
+               priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+               if (!IS_ERR(priv->rstc)) {
+                       ret = reset_control_status(priv->rstc);
+                       if (ret < 0)
+                               priv->rstc = ERR_PTR(-ENOTSUPP);
+               }
+       }
+
        /* Stay always active when multi-master to keep arbitration working */
        if (of_property_read_bool(dev->of_node, "multi-master"))
                priv->flags |= ID_P_PM_BLOCKED;