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>

diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index f4a01675fa71b4a18ac2b35714425be363442528..2cb0317b14fb094e0a6645d304c7af4af7094fbd 100644 (file)
--- 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,