From: Juergen Beisert <jbe@xxxxxxxxxxxxxx>
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.
From: Juergen Beisert <jbe@xxxxxxxxxxxxxx>
Signed-off-by: Juergen Beisert <jbe@xxxxxxxxxxxxxx>
Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Baumann <cb@xxxxxxx>
Cc: Fabio Estevam <r49496@xxxxxxxxxxxxx>
Cc: Shawn Guo <shawn.guo@xxxxxxxxxx>
Cc: Torsten Fleischer <to-fleischer@xxxxxxxxxxx>
Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-mxs.c | 42 +++++++++++++++++++++++++++++++++++-------
1 file changed, 35 insertions(+), 7 deletions(-)
diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index df8ff5a..ca54ac4 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -96,10 +96,17 @@
#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
@@ -107,6 +114,7 @@
*/
struct mxs_i2c_dev {
struct device *dev;
+ enum mxs_i2c_devtype dev_type;
void __iomem *regs;
struct completion cmd_complete;
int cmd_err;
@@ -491,9 +499,10 @@ 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 (msg->len < 8) {
+ if (i2c->dev_type == MXS_I2C_V2 && msg->len < 8) {
ret = mxs_i2c_pio_setup_xfer(adap, msg, flags);
if (ret)
mxs_i2c_reset(i2c);
@@ -632,8 +641,28 @@ 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;
@@ -645,6 +674,11 @@ 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);
@@ -720,12 +754,6 @@ 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,
--
1.7.10.4
--
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