Re: [PATCH v1 tty] 8250: microchip: Add 4 Mbps support in PCI1XXXX UART

From: Andy Shevchenko
Date: Sun Jan 28 2024 - 10:27:44 EST


On Thu, Jan 25, 2024 at 03:36:19PM +0530, Rengarajan S wrote:
> The current clock input is set to 62.5 MHz for supporting fractional
> divider, which enables generation of an acceptable baud rate from any
> frequency. With the current clock input the baud rate range is limited
> to 3.9 Mbps. Hence, the current range is extended to support 4 Mbps
> with Burst mode operation. Divisor calculation for a given baud rate is
> updated as the sampling rate is reduced from 16 to 8 for 4 Mbps.

..

> +#define UART_BAUD_4MBPS 4000000

(4 * MEGA) ? (will need to include units.h, if not yet)

..

> + frac_div = readl(port->membase + FRAC_DIV_CFG_REG);

> +

Unneeded blank line.

> + if (frac_div == UART_BIT_DIVISOR_16)
> + sample_cnt = UART_BIT_SAMPLE_CNT_16;
> + else
> + sample_cnt = UART_BIT_SAMPLE_CNT_8;

..

> + /*
> + * Microchip PCI1XXXX UART supports maximum baud rate up to 4 Mbps
> + */
> + if (up->port.type == PORT_MCHP16550A)
> + max = 4000000;

No. Please refactor the way the 8250_port won't be modified.

Also you have a define for this constant, use it.

--
With Best Regards,
Andy Shevchenko