From: Juergen Beisert <[email protected]> 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 <[email protected]> Signed-off-by: Juergen Beisert <[email protected]> Cc: Alexandre Belloni <[email protected]> Cc: Christoph Baumann <[email protected]> Cc: Fabio Estevam <[email protected]> Cc: Shawn Guo <[email protected]> Cc: Torsten Fleischer <[email protected]> Cc: Wolfram Sang <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
