@@ -197,25 +197,7 @@ static int ulpi_of_register(struct ulpi *ulpi)
static int ulpi_register(struct device *dev, struct ulpi *ulpi)
{
- int ret;
-
- /* Test the interface */
- ret = ulpi_write(ulpi, ULPI_SCRATCH, 0xaa);
- if (ret < 0)
- return ret;
-
- ret = ulpi_read(ulpi, ULPI_SCRATCH);
- if (ret < 0)
- return ret;
-
- if (ret != 0xaa)
- return -ENODEV;
-
- ulpi->id.vendor = ulpi_read(ulpi, ULPI_VENDOR_ID_LOW);
- ulpi->id.vendor |= ulpi_read(ulpi, ULPI_VENDOR_ID_HIGH) << 8;
-
- ulpi->id.product = ulpi_read(ulpi, ULPI_PRODUCT_ID_LOW);
- ulpi->id.product |= ulpi_read(ulpi, ULPI_PRODUCT_ID_HIGH) << 8;
+ int ret = -ENODEV;
ulpi->dev.parent = dev;
ulpi->dev.bus = &ulpi_bus;
@@ -230,6 +212,26 @@ static int ulpi_register(struct device *dev, struct ulpi *ulpi)
return ret;
}
+ if (ret) {
+ /* Test the interface */
+ ret = ulpi_write(ulpi, ULPI_SCRATCH, 0xaa);
+ if (ret < 0)
+ return ret;
+
+ ret = ulpi_read(ulpi, ULPI_SCRATCH);
+ if (ret < 0)
+ return ret;
+
+ if (ret != 0xaa)
+ return -ENODEV;
+
+ ulpi->id.vendor = ulpi_read(ulpi, ULPI_VENDOR_ID_LOW);
+ ulpi->id.vendor |= ulpi_read(ulpi, ULPI_VENDOR_ID_HIGH) << 8;
+
+ ulpi->id.product = ulpi_read(ulpi, ULPI_PRODUCT_ID_LOW);
+ ulpi->id.product |= ulpi_read(ulpi, ULPI_PRODUCT_ID_HIGH) << 8;
+ }
+
if (of_device_request_module(&ulpi->dev))
request_module("ulpi:v%04xp%04x", ulpi->id.vendor,
ulpi->id.product);
ULPI devices are matched up against ULPI drivers by reading the vendor id and product id registers in the ULPI address space. Before we try to read those registers we'll do a scratch write to test the interface. Unfortunately, this doesn't work well if the ULPI device is not powered at the time of device creation. In that case, the scratch register writes fail and product and vendor ids can't be read. If the ULPI spec had some way to describe generic power requirements for the scratch, product, and vendor registers we could but power sequencing into the ULPI bus layer and power up the device before touching the hardware. Unfortunately this doesn't exist. Furthermore, the power information is device specific, so it varies from device to device and is not standard. Let's punt on doing the reads/writes here when we're using DT backed ULPI devices. This avoids any problems where we need to power on the device but haven't figured out which device it is yet to know what sort of regulators, clks, etc. that need to be turned on for it to work. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org> --- drivers/usb/common/ulpi.c | 40 +++++++++++++++++++++------------------- 1 file changed, 21 insertions(+), 19 deletions(-) -- 2.9.0.rc2.8.ga28705d -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html