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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Tue, 13 Feb 2018 18:52:41 +0200
Message-ID: <CAHp75VcCj2PtPgMEb+9ZmO-1t_K16oyY97vn3FbHr=LkGvna-Q@mail.gmail.com>
Subject: Re: [PATCH] serial: 8250: Add Nuvoton NPCM UART
To:     Joel Stanley <joel@jms.id.au>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        linux-serial@vger.kernel.org,
        devicetree <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Tomer Maimon <tomer.maimon@nuvoton.com>,
        Avi Fishman <Avi.Fishman@nuvoton.com>,
        Jeremy Kerr <jk@ozlabs.org>
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On Mon, Feb 12, 2018 at 6:48 AM, Joel Stanley <joel@jms.id.au> wrote:
> The Nuvoton UART is almost compatible with the 8250 driver when probed
> via the 8250_of driver, however it requires some extra configuration
> at startup.


> +       [PORT_NPCM] = {
> +               .name           = "Nuvoton 16550",
> +               .fifo_size      = 16,
> +               .tx_loadsz      = 16,
> +               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
> +                                 UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
> +               .rxtrig_bytes   = {1, 4, 8, 14},
> +               .flags          = UART_CAP_FIFO,

> +

Redundant.

> +       },

> +               /*
> +                * Nuvoton calls the scratch register 'UART_TOR' (timeout
> +                * register). Enable it, and set TIOC (timeout interrupt
> +                * comparator) to be 0x20 for correct operation.
> +                */
> +               serial_port_out(port, UART_NPCM_TOR, UART_NPCM_TOIE | 0x20);

> +/* Nuvoton NPCM UARTs have a custom divisor calculation */
> +       return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;

Is there any link to datasheet?

> +/* Nuvoton UART */
> +#define PORT_NPCM      118

We have gaps there. #40 is perfect place for this one.

> +/* Nuvoton NPCM timeout register */
> +#define UART_NPCM_TOR          7
> +#define UART_NPCM_TOIE         BIT(7)  /* Timeout Interrupt Enable */

-- 
With Best Regards,
Andy Shevchenko