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commite2860e1f62("serial: 8250_of: Add reset support") introduced reset support for the 8250_of driver. However it unconditionally uses the assert/deassert pair to deassert reset on the device at probe and assert it at remove. This does not work with systems that have a self-deasserting reset controller, such as Gemini, that recently added a reset controller. As a result, the console will not probe on the Gemini with this message: Serial: 8250/16550 driver, 1 ports, IRQ sharing disabled of_serial: probe of 42000000.serial failed with error -524 This (-ENOTSUPP) is the error code returned by the deassert() operation on self-deasserting reset controllers. To work around this, implement dummy .assert() and .deassert() operations in the Gemini combined clock and reset controller. This fixes the issue on this system. Cc: Joel Stanley <joel@jms.id.au> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-serial@vger.kernel.org Fixes:e2860e1f62("serial: 8250_of: Add reset support") Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.