since commit 31964ffebb ("tty: serial: msm: Remove direct access to GSBI")'
serial hangs if earlyprintk are enabled.
This hang is noticed only when the GSBI driver is probed and all the
earlyprintks before gsbi probe are seen on the console.
The reason why it hangs is because GSBI driver disables hclk in its
probe function without realizing that the serial IP might be in use by
a bootconsole. As gsbi driver disables the clock in probe the
bootconsole locks up.
Turning off hclk's could be dangerous if there are system components
like earlyprintk using the hclk.
This patch fixes the issue by delegating the clock management to
probe and remove functions in gsbi rather than disabling the clock in probe.
More detailed problem description can be found here:
http://www.spinics.net/lists/linux-arm-msm/msg10589.html
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
fa9eb32418