[PATCH 4/7] serial: ns16550: add compatible entry for "ingenic, jz4740-uart"

[Sascha Hauer]

On Sat, Mar 22, 2014 at 03:29:54PM +0400, Antony Pavlov wrote:
> Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
> ---
>  drivers/serial/serial_ns16550.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
> index aa0992f..7130871 100644
> --- a/drivers/serial/serial_ns16550.c
> +++ b/drivers/serial/serial_ns16550.c
> @@ -257,6 +257,30 @@ static __maybe_unused struct ns16550_drvdata omap_drvdata = {
>  	.linux_console_name = "ttyO",
>  };
>  
> +#define JZ_UART_SHIFT	2
> +
> +static void jz_serial_reg_write(unsigned int val, unsigned long base,
> +	unsigned char reg_offset)
> +{
> +	switch (reg_offset) {
> +	case (fcr << JZ_UART_SHIFT):
> +		val |= 0x10; /* Enable uart module */
> +		break;

You could also do this by overwriting .init_port.

> +	case (ier << JZ_UART_SHIFT):
> +		val |= (val & 0x4) << 2;

What does this bit do?

Putting driver logic into the register writes is not good. Where this
leads to can be seen in drivers/mmc/host/sdhci-esdhc-imx.c in the
kernel. Could we make fcrval overwritable in drvdata? Or just special
case the fcr register access in ns16550_setbaudrate?

Sascha


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