On Thu, Jul 07, 2022 at 04:53:54PM +0200, Marek Behún wrote:
> From: Pali Rohár <pali@xxxxxxxxxx>
>
> Calculate baudrate value in c_*speed fields to the real value which was set
> to hardware. For this operation add a new set of functions divisor_to_baud
> for each chip and use it for calculating the real baudrate value.
>
> Each divisor_to_baud function is constructed as an inverse function of
> corresponding baud_to_divisor function.
>
> Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
> Tested-by: Marek Behún <kabel@xxxxxxxxxx>
> ---
> drivers/usb/serial/ftdi_sio.c | 79 +++++++++++++++++++++++++++++++++++
> 1 file changed, 79 insertions(+)
>
> diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
> index 3bf5750e76de..1f78ae695a1b 100644
> --- a/drivers/usb/serial/ftdi_sio.c
> +++ b/drivers/usb/serial/ftdi_sio.c
> @@ -1167,6 +1167,23 @@ static u32 ftdi_sio_baud_to_divisor(int baud)
> }
> }
>
> +static int ftdi_sdio_divisor_to_baud(u32 divisor)
> +{
> + switch (divisor) {
> + case ftdi_sio_b300: return 300;
> + case ftdi_sio_b600: return 600;
> + case ftdi_sio_b1200: return 1200;
> + case ftdi_sio_b2400: return 2400;
> + case ftdi_sio_b4800: return 4800;
> + case ftdi_sio_b9600: return 9600;
> + case ftdi_sio_b19200: return 19200;
> + case ftdi_sio_b38400: return 38400;
> + case ftdi_sio_b57600: return 57600;
> + case ftdi_sio_b115200: return 115200;
> + default: return 9600;
> + }
> +}
> +
> static unsigned short int ftdi_232am_baud_base_to_divisor(int baud, int base)
> {
> unsigned short int divisor;
> @@ -1189,11 +1206,27 @@ static unsigned short int ftdi_232am_baud_base_to_divisor(int baud, int base)
> return divisor;
> }
>
> +static int ftdi_232am_divisor_base_to_baud(unsigned short int divisor, int base)
> +{
> + static const unsigned char divfrac_inv[4] = { 0, 4, 2, 1 };
> + unsigned int divisor3;
> + if (divisor == 0)
> + divisor = 1;
> + divisor3 = (GENMASK(13, 0) & divisor) << 3;
> + divisor3 |= divfrac_inv[(divisor >> 14) & 0x3];
> + return DIV_ROUND_CLOSEST(base, 2 * divisor3);
> +}
> +
> static unsigned short int ftdi_232am_baud_to_divisor(int baud)
> {
> return ftdi_232am_baud_base_to_divisor(baud, 48000000);
> }
>
> +static int ftdi_232am_divisor_to_baud(unsigned short int divisor)
> +{
> + return ftdi_232am_divisor_base_to_baud(divisor, 48000000);
> +}
> +
> static u32 ftdi_232bm_baud_base_to_divisor(int baud, int base)
> {
> static const unsigned char divfrac[8] = { 0, 3, 2, 4, 1, 5, 6, 7 };
> @@ -1212,11 +1245,30 @@ static u32 ftdi_232bm_baud_base_to_divisor(int baud, int base)
> return divisor;
> }
>
> +static int ftdi_232bm_divisor_base_to_baud(u32 divisor, int base)
> +{
> + static const unsigned char divfrac_inv[8] = { 0, 4, 2, 1, 3, 5, 6, 7 };
> + u32 divisor3;
> + /* Deal with special cases for highest baud rates. */
> + if (divisor == 0)
> + divisor = 1; /* 1.0 */
> + else if (divisor == 1)
> + divisor = 0x4001; /* 1.5 */
> + divisor3 = (GENMASK(13, 0) & divisor) << 3;
> + divisor3 |= divfrac_inv[(divisor >> 14) & 0x7];
> + return DIV_ROUND_CLOSEST(base, 2 * divisor3);
> +}
Always run your patches through checkpatch so you do not get grumpy
maintainers telling you to run your patches through checkpatch...
thanks,
greg k-h
