Re: [PATCH V1 2/6] USB: serial: f81232: Force F81534A with RS232 mode

[Johan Hovold <johan@kernel.org>]

On Thu, Jun 06, 2019 at 10:54:12AM +0800, Ji-Ze Hong (Peter Hong) wrote:
> Force F81534A series UARTs with RS232 mode in port_probe().

Please expand on why you need this here.

> Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
> ---
>  drivers/usb/serial/f81232.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
> index 84efcc66aa56..75dfc0b9ef30 100644
> --- a/drivers/usb/serial/f81232.c
> +++ b/drivers/usb/serial/f81232.c
> @@ -83,12 +83,22 @@ MODULE_DEVICE_TABLE(usb, id_table);
>  #define F81232_F81232_TYPE		1
>  #define F81232_F81534A_TYPE		2
>  
> +/* Serial port self GPIO control, 2bytes [control&output data][input data] */
> +#define F81534A_GPIO_REG		0x10e
> +#define F81534A_GPIO_MODE2_DIR		BIT(6) /* 1: input, 0: output */
> +#define F81534A_GPIO_MODE1_DIR		BIT(5)
> +#define F81534A_GPIO_MODE0_DIR		BIT(4)
> +#define F81534A_GPIO_MODE2_OUTPUT	BIT(2)
> +#define F81534A_GPIO_MODE1_OUTPUT	BIT(1)
> +#define F81534A_GPIO_MODE0_OUTPUT	BIT(0)
> +
>  struct f81232_private {
>  	struct mutex lock;
>  	u8 modem_control;
>  	u8 modem_status;
>  	u8 shadow_lcr;
>  	u8 device_type;
> +	u8 gpio_mode;

Why store the mode? Are you going to use it later?

>  	speed_t baud_base;
>  	struct work_struct lsr_work;
>  	struct work_struct interrupt_work;
> @@ -871,6 +881,11 @@ static int f81232_port_probe(struct usb_serial_port *port)
>  	switch (priv->device_type) {
>  	case F81232_F81534A_TYPE:
>  		priv->process_read_urb = f81534a_process_read_urb;
> +		priv->gpio_mode = F81534A_GPIO_MODE2_DIR;
> +
> +		/* tri-state with pull-high, default RS232 Mode */
> +		status = f81232_set_register(port, F81534A_GPIO_REG,
> +					priv->gpio_mode);
>  		break;
>  
>  	case F81232_F81232_TYPE:

Johan