i2c: mxs: distinguish i.MX23 and i.MX28 based I2C controller

It seems the PIO mode does not work, or at least not like it works
on a i.MX28. Each short transfer needs about one second (without an
error message) but does not send anything on the I2C lines.

Signed-off-by: Juergen Beisert <jbe@pengutronix.de>
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

1 files changed, 34 insertions, 6 deletions

diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index f4a01675fa71..2cb0317b14fb 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -95,10 +95,17 @@
 #define MXS_CMD_I2C_READ        (MXS_I2C_CTRL0_SEND_NAK_ON_LAST | \
                                  MXS_I2C_CTRL0_MASTER_MODE)
 
+enum mxs_i2c_devtype {
+        MXS_I2C_UNKNOWN = 0,
+        MXS_I2C_V1,
+        MXS_I2C_V2,
+};
+
 /**
  * struct mxs_i2c_dev - per device, private MXS-I2C data
  *
  * @dev: driver model device node
+ * @dev_type: distinguish i.MX23/i.MX28 features
  * @regs: IO registers pointer
  * @cmd_complete: completion object for transaction wait
  * @cmd_err: error code for last transaction
@@ -106,6 +113,7 @@
  */
 struct mxs_i2c_dev {
         struct device *dev;
+        enum mxs_i2c_devtype dev_type;
         void __iomem *regs;
         struct completion cmd_complete;
         int cmd_err;
@@ -495,6 +503,7 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
          * is set to 8 bytes, transfers shorter than 8 bytes are transfered
          * using PIO mode while longer transfers use DMA. The 8 byte border is
          * based on this empirical measurement and a lot of previous frobbing.
+         * Note: this special feature only works on i.MX28 SoC
          */
         i2c->cmd_err = 0;
         if (0) {        /* disable PIO mode until a proper fix is made */
@@ -680,8 +689,28 @@ static int mxs_i2c_get_ofdata(struct mxs_i2c_dev *i2c)
         return 0;
 }
 
+static struct platform_device_id mxs_i2c_devtype[] = {
+        {
+                .name = "imx23-i2c",
+                .driver_data = MXS_I2C_V1,
+        }, {
+                .name = "imx28-i2c",
+                .driver_data = MXS_I2C_V2,
+        }, { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, mxs_i2c_devtype);
+
+static const struct of_device_id mxs_i2c_dt_ids[] = {
+        { .compatible = "fsl,imx23-i2c", .data = &mxs_i2c_devtype[0], },
+        { .compatible = "fsl,imx28-i2c", .data = &mxs_i2c_devtype[1], },
+        { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mxs_i2c_dt_ids);
+
 static int mxs_i2c_probe(struct platform_device *pdev)
 {
+        const struct of_device_id *of_id =
+                                of_match_device(mxs_i2c_dt_ids, &pdev->dev);
         struct device *dev = &pdev->dev;
         struct mxs_i2c_dev *i2c;
         struct i2c_adapter *adap;
@@ -693,6 +722,11 @@ static int mxs_i2c_probe(struct platform_device *pdev)
         if (!i2c)
                 return -ENOMEM;
 
+        if (of_id) {
+                const struct platform_device_id *device_id = of_id->data;
+                i2c->dev_type = device_id->driver_data;
+        }
+
         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         irq = platform_get_irq(pdev, 0);
 
@@ -768,12 +802,6 @@ static int mxs_i2c_remove(struct platform_device *pdev)
         return 0;
 }
 
-static const struct of_device_id mxs_i2c_dt_ids[] = {
-        { .compatible = "fsl,imx28-i2c", },
-        { /* sentinel */ }
-};
-MODULE_DEVICE_TABLE(of, mxs_i2c_dt_ids);
-
 static struct platform_driver mxs_i2c_driver = {
         .driver = {
                    .name = DRIVER_NAME,