[U-Boot] [PATCH 3/4] sunxi: usbc: Wait for vbus to fall after disabling it
Hans de Goede
hdegoede at redhat.com
Fri Mar 27 22:06:42 CET 2015
When u-boot boots the board may be powering vbus, we turn off vbus in
sunxi_usbc_request_resources, if we are too quick with reading vusb-detect
after this we may see a residual charge and assume we've an external vusb
connected even though we do not. So when we see an external vusb wait a bit
and try again.
Without this when dealing with a pmic controller vbus and doing "reset" on
the u-boot console the musb host will only init once every other boot, because
the other boot it thinks an external vbus is present, this commit fixes this.
Signed-off-by: Hans de Goede <hdegoede at redhat.com>
---
arch/arm/cpu/armv7/sunxi/usbc.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/arm/cpu/armv7/sunxi/usbc.c b/arch/arm/cpu/armv7/sunxi/usbc.c
index 6285fa5..a0e9604 100644
--- a/arch/arm/cpu/armv7/sunxi/usbc.c
+++ b/arch/arm/cpu/armv7/sunxi/usbc.c
@@ -286,12 +286,23 @@ void sunxi_usbc_vbus_disable(int index)
int sunxi_usbc_vbus_detect(int index)
{
struct sunxi_usbc_hcd *sunxi_usbc = &sunxi_usbc_hcd[index];
- int err;
+ int err, retries = 3;
if (sunxi_usbc->gpio_vbus_det == -1) {
eprintf("Error: invalid vbus detection pin\n");
return -1;
}
- return gpio_get_value(sunxi_usbc->gpio_vbus_det);
+ err = gpio_get_value(sunxi_usbc->gpio_vbus_det);
+ /*
+ * Vbus may have been provided by the board and just been turned of
+ * some milliseconds ago on reset, what we're measuring then is a
+ * residual charge on Vbus, sleep a bit and try again.
+ */
+ while (err > 0 && retries--) {
+ mdelay(100);
+ err = gpio_get_value(sunxi_usbc->gpio_vbus_det);
+ }
+
+ return err;
}
--
2.3.4
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