On 07/17/2018 09:55 AM, Lokesh Vutla wrote:
On Tuesday 17 July 2018 12:32 PM, Felix Brack wrote:
This patch adds a new Kconfig variable that allows setting the register offset shift value for the ns16550 driver to some other value then 0 if not defined by the DT. All credit for this patch goes to Lokesh Vutla as it was his idea.
The motivation for writing this patch originates in the effort of synchronizing U-Boot DT to Linux DT for am33xx SOCs. The current am33xx.dtsi file from U-Boot defines the <reg-shift> property for all UART nodes. The actual (4.18+) am33xx.dtsi file from Linux does not define <reg-shift> anymore. To prevent (probably difficult) changes in many .dts and .dtsi files once the synchronization is done, one can use this new variable. For the pdu001 board, for example, SYS_NS16550_REG_SHIFT is set to 2; no need to clutter U-Boot and board specific dts files with <reg-shift> properties.
Signed-off-by: Felix Brack fb@ltec.ch
NAK. Please determine the shift value from the compatible instead. Ideally you would create a subclass of the ns16550 device class and set reg_shift in there.
Take a look at drivers/serial/serial_rockchip.c for an example.
Alex