diff options
| author | Daniel Mack <zonque@gmail.com> | 2014-04-16 17:11:16 +0200 |
|---|---|---|
| committer | Felipe Balbi <balbi@ti.com> | 2014-04-21 10:21:24 -0500 |
| commit | a31a942a148e0083ce560ffeb54fb60e06ab7201 (patch) | |
| tree | 61b9882c9d76d86f19f9bf3c7fd9d7206cef0e0b /drivers | |
| parent | 2656c9e28125e96bee212f146cc3f2419fd3ffef (diff) | |
usb: phy: am335x-control: wait 1ms after power-up transitions
Tests have shown that when a power-up transition is followed by other
PHY operations too quickly, the USB port appears dead. Waiting 1ms fixes
this problem.
Signed-off-by: Daniel Mack <zonque@gmail.com>
Cc: stable@vger.kernel.org [3.14]
Signed-off-by: Felipe Balbi <balbi@ti.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/phy/phy-am335x-control.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/usb/phy/phy-am335x-control.c b/drivers/usb/phy/phy-am335x-control.c index d75196ad5f2..35b6083b799 100644 --- a/drivers/usb/phy/phy-am335x-control.c +++ b/drivers/usb/phy/phy-am335x-control.c @@ -3,6 +3,7 @@ #include <linux/err.h> #include <linux/of.h> #include <linux/io.h> +#include <linux/delay.h> #include "am35x-phy-control.h" struct am335x_control_usb { @@ -86,6 +87,14 @@ static void am335x_phy_power(struct phy_control *phy_ctrl, u32 id, bool on) } writel(val, usb_ctrl->phy_reg + reg); + + /* + * Give the PHY ~1ms to complete the power up operation. + * Tests have shown unstable behaviour if other USB PHY related + * registers are written too shortly after such a transition. + */ + if (on) + mdelay(1); } static const struct phy_control ctrl_am335x = { |