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Date: Mon, 18 Dec 2017 16:14:39 +0100
From: Johan Hovold <johan@...nel.org>
To: "Ji-Ze Hong (Peter Hong)" <hpeter@...il.com>
Cc: johan@...nel.org, gregkh@...uxfoundation.org,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
"Ji-Ze Hong (Peter Hong)" <hpeter+linux_kernel@...il.com>
Subject: Re: [PATCH V1 1/4] usb: serial: f81534: add high baud rate support
On Thu, Nov 16, 2017 at 03:46:06PM +0800, Ji-Ze Hong (Peter Hong) wrote:
> The F81532/534 had 4 clocksource 1.846/18.46/14.77/24MHz and baud rates can
> be up to 1.5Mbits with 24MHz.
>
> F81532/534 Clock register (offset +08h)
>
> Bit0: UART Enable (always on)
> Bit2-1: Clock source selector
> 00: 1.846MHz.
> 01: 18.46MHz.
> 10: 24MHz.
> 11: 14.77MHz.
>
> Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@...il.com>
> ---
> drivers/usb/serial/f81534.c | 84 ++++++++++++++++++++++++++++++++++++---------
> 1 file changed, 68 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c
> index cb8214860192..76c676ef5f0d 100644
> --- a/drivers/usb/serial/f81534.c
> +++ b/drivers/usb/serial/f81534.c
> @@ -45,6 +45,7 @@
> #define F81534_MODEM_CONTROL_REG (0x04 + F81534_UART_BASE_ADDRESS)
> #define F81534_LINE_STATUS_REG (0x05 + F81534_UART_BASE_ADDRESS)
> #define F81534_MODEM_STATUS_REG (0x06 + F81534_UART_BASE_ADDRESS)
> +#define F81534_CLOCK_REG (0x08 + F81534_UART_BASE_ADDRESS)
> #define F81534_CONFIG1_REG (0x09 + F81534_UART_BASE_ADDRESS)
>
> #define F81534_DEF_CONF_ADDRESS_START 0x3000
> @@ -61,7 +62,7 @@
>
> /* Default URB timeout for USB operations */
> #define F81534_USB_MAX_RETRY 10
> -#define F81534_USB_TIMEOUT 1000
> +#define F81534_USB_TIMEOUT 2000
You need to at least mention in the commit message why this is needed.
> #define F81534_SET_GET_REGISTER 0xA0
>
> #define F81534_NUM_PORT 4
> @@ -100,7 +101,6 @@
> #define F81534_CMD_READ 0x03
>
> #define F81534_DEFAULT_BAUD_RATE 9600
> -#define F81534_MAX_BAUDRATE 115200
>
> #define F81534_PORT_CONF_DISABLE_PORT BIT(3)
> #define F81534_PORT_CONF_NOT_EXIST_PORT BIT(7)
> @@ -110,6 +110,22 @@
> #define F81534_1X_RXTRIGGER 0xc3
> #define F81534_8X_RXTRIGGER 0xcf
>
> +/*
> + * F81532/534 Clock registers (offset +08h)
> + *
> + * Bit0: UART Enable (always on)
> + * Bit2-1: Clock source selector
> + * 00: 1.846MHz.
> + * 01: 18.46MHz.
> + * 10: 24MHz.
> + * 11: 14.77MHz.
> + */
> +
> +#define F81534_CLK_1_846_MHZ BIT(0)
> +#define F81534_CLK_18_46_MHZ (BIT(0) | BIT(1))
> +#define F81534_CLK_24_MHZ (BIT(0) | BIT(2))
> +#define F81534_CLK_14_77_MHZ (BIT(0) | BIT(1) | BIT(2))
Use a separate define for the enable bit.
> +
> static const struct usb_device_id f81534_id_table[] = {
> { USB_DEVICE(FINTEK_VENDOR_ID_1, FINTEK_DEVICE_ID) },
> { USB_DEVICE(FINTEK_VENDOR_ID_2, FINTEK_DEVICE_ID) },
> @@ -133,6 +149,7 @@ struct f81534_port_private {
> struct usb_serial_port *port;
> unsigned long tx_empty;
> spinlock_t msr_lock;
> + u32 baud_base;
> u8 shadow_mcr;
> u8 shadow_lcr;
> u8 shadow_msr;
> @@ -464,13 +481,51 @@ static u32 f81534_calc_baud_divisor(u32 baudrate, u32 clockrate)
> return DIV_ROUND_CLOSEST(clockrate, baudrate);
> }
>
> -static int f81534_set_port_config(struct usb_serial_port *port, u32 baudrate,
> - u8 lcr)
> +static int f81534_set_port_config(struct usb_serial_port *port,
> + struct tty_struct *tty, u32 baudrate, u32 old_baudrate, u8 lcr)
> {
> struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
> u32 divisor;
> int status;
> + int idx;
> u8 value;
> + static u32 const baudrate_table[] = {115200, 921600, 1152000,
> + 1500000};
> + static u8 const clock_table[] = {F81534_CLK_1_846_MHZ,
> + F81534_CLK_14_77_MHZ, F81534_CLK_18_46_MHZ,
> + F81534_CLK_24_MHZ};
> +
> + do {
> + for (idx = 0; idx < ARRAY_SIZE(baudrate_table); ++idx) {
> + if (baudrate <= baudrate_table[idx] &&
> + baudrate_table[idx] % baudrate == 0)
> + break;
> + }
> +
> + /* Found acceptable baud rate */
> + if (idx != ARRAY_SIZE(baudrate_table))
> + break;
> +
> + if (baudrate == old_baudrate &&
> + old_baudrate != F81534_DEFAULT_BAUD_RATE)
> + old_baudrate = F81534_DEFAULT_BAUD_RATE;
> +
> + dev_warn(&port->dev,
> + "baudrate: %d not supported, change to: %d\n",
> + baudrate, old_baudrate);
No need to warn here as you report back the chosen speed in the termios.
> +
> + baudrate = old_baudrate;
> + tty_encode_baud_rate(tty, baudrate, baudrate);
> +
> + } while (1);
This looks scary. Try to clean it up by adding helper function to
determine the base.
> +
> + port_priv->baud_base = baudrate_table[idx];
> + status = f81534_set_port_register(port, F81534_CLOCK_REG,
> + clock_table[idx]);
> + if (status) {
> + dev_err(&port->dev, "CLOCK_REG setting failed\n");
> + return status;
> + }
I suggest you add a shadow clock register which keeps the enable bit
set. This should allow for a cleaner implementation of the auto-RTS
handling in later patches.
>
> if (baudrate <= 1200)
> value = F81534_1X_RXTRIGGER; /* 128 FIFO & TL: 1x */
> @@ -486,7 +541,7 @@ static int f81534_set_port_config(struct usb_serial_port *port, u32 baudrate,
> if (baudrate <= 1200)
> value = UART_FCR_TRIGGER_1 | UART_FCR_ENABLE_FIFO; /* TL: 1 */
> else
> - value = UART_FCR_R_TRIG_11 | UART_FCR_ENABLE_FIFO; /* TL: 14 */
> + value = UART_FCR_TRIGGER_8 | UART_FCR_ENABLE_FIFO; /* TL: 8 */
This should probably go in it's own patch, or at least be mentioned in
the commit message.
Johan
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