Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c fixes from Wolfram Sang:
 "Some driver bugfixes"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: imx: use open drain for recovery GPIO
  i2c: rcar: handle RXDMA HW behaviour on Gen3
  i2c: imx: Fix reinit_completion() use
  i2c: davinci: Avoid zero value of CLKH

3 files changed, 59 insertions, 8 deletions

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 75d6ab177055..7379043711df 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -237,12 +237,16 @@ static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
         /*
          * It's not always possible to have 1 to 2 ratio when d=7, so fall back
          * to minimal possible clkh in this case.
+         *
+         * Note:
+         * CLKH is not allowed to be 0, in this case I2C clock is not generated
+         * at all
          */
-        if (clk >= clkl + d) {
+        if (clk > clkl + d) {
                 clkh = clk - clkl - d;
                 clkl -= d;
         } else {
-                clkh = 0;
+                clkh = 1;
                 clkl = clk - (d << 1);
         }
 
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 0207e194f84b..498c5e891649 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -368,6 +368,7 @@ static int i2c_imx_dma_xfer(struct imx_i2c_struct *i2c_imx,
                 goto err_desc;
         }
 
+        reinit_completion(&dma->cmd_complete);
         txdesc->callback = i2c_imx_dma_callback;
         txdesc->callback_param = i2c_imx;
         if (dma_submit_error(dmaengine_submit(txdesc))) {
@@ -622,7 +623,6 @@ static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx,
          * The first byte must be transmitted by the CPU.
          */
         imx_i2c_write_reg(i2c_8bit_addr_from_msg(msgs), i2c_imx, IMX_I2C_I2DR);
-        reinit_completion(&i2c_imx->dma->cmd_complete);
         time_left = wait_for_completion_timeout(
                                 &i2c_imx->dma->cmd_complete,
                                 msecs_to_jiffies(DMA_TIMEOUT));
@@ -681,7 +681,6 @@ static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx,
         if (result)
                 return result;
 
-        reinit_completion(&i2c_imx->dma->cmd_complete);
         time_left = wait_for_completion_timeout(
                                 &i2c_imx->dma->cmd_complete,
                                 msecs_to_jiffies(DMA_TIMEOUT));
@@ -1010,7 +1009,7 @@ static int i2c_imx_init_recovery_info(struct imx_i2c_struct *i2c_imx,
         i2c_imx->pinctrl_pins_gpio = pinctrl_lookup_state(i2c_imx->pinctrl,
                         "gpio");
         rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN);
-        rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl", GPIOD_OUT_HIGH);
+        rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
 
         if (PTR_ERR(rinfo->sda_gpiod) == -EPROBE_DEFER ||
             PTR_ERR(rinfo->scl_gpiod) == -EPROBE_DEFER) {
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 5e310efd9446..3c1c817f6968 100644
--- 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;