Re: [PATCH] [PATCH v7] USB: serial: pl2303: Add new PID to support PL2303HXN (TYPE_HXN)

[Charles Yeh <charlesyeh522@gmail.com>]

Johan Hovold <johan@kernel.org> 於 2019年7月16日 週二 下午4:49寫道：
> >  #define PL2303_FLOWCTRL_MASK         0xf0
> > +#define PL2303_HXN_FLOWCTRL_MASK     0x1C
> > +#define PL2303_HXN_FLOWCTRL          0x0A
>
> I asked you to keep related defines together (and to move the mask where
> the register define was, not the other way round). Please move these to
> the other HXN defines below, and keep the register address defines
> before the corresponding bit defines.

Charles Ans:
I am not 100% sure what you mean, please see if it is defined below

#define PL2303_FLOWCTRL_MASK        0xf0

#define PL2303_READ_TYPE_HX_STATUS    0x8080

#define PL2303_HXN_CTRL_XON_XOFF    0x0C
#define PL2303_HXN_CTRL_RTS_CTS        0x18
#define PL2303_HXN_CTRL_NONE        0x1C
#define PL2303_HXN_FLOWCTRL_MASK    0x1C
#define PL2303_HXN_FLOWCTRL        0x0A

#define PL2303_HXN_RESET_UP_DOWNSTREAM_DATA_PIPE    0x03
#define PL2303_HXN_RESET_UP_DOWNSTREAM_DATA_PIPE_MASK    0x03
#define PL2303_HXN_RESET_CONTROL    0x07

> > +
> > +#define PL2303_HXN_RESET_CONTROL_MASK        0x03
> This makes no sense. The whole register is used for reset. If you want a
> define that can be used for resetting both pipes then add two separate
> defines for up and down respectively, and add a third define for
> resetting both buffer as a bitwise OR of the two.

Charles Ans:
Yes,The whole register is used for reset.
Bit 0 and bit 1 are used for up & downstream data pipe,
Bit 2 for interface reset
Bit 4 for chip reset.

But I only reset bit 0 & bit 1.


> Also move this one after the corresponding register address define
> below.
>
> > +#define PL2303_HXN_RESET_CONTROL     0x07
> > +#define PL2303_HXN_CTRL_XON_XOFF     0x0C
> > +#define PL2303_HXN_CTRL_RTS_CTS              0x18
> > +#define PL2303_HXN_CTRL_NONE         0x1C

Charles Ans:
I am not 100% sure what you mean, please see if it is defined below

#define PL2303_FLOWCTRL_MASK        0xf0

#define PL2303_READ_TYPE_HX_STATUS    0x8080

#define PL2303_HXN_CTRL_XON_XOFF    0x0C
#define PL2303_HXN_CTRL_RTS_CTS        0x18
#define PL2303_HXN_CTRL_NONE        0x1C
#define PL2303_HXN_FLOWCTRL_MASK    0x1C
#define PL2303_HXN_FLOWCTRL        0x0A

#define PL2303_HXN_RESET_UP_DOWNSTREAM_DATA_PIPE    0x03
#define PL2303_HXN_RESET_UP_DOWNSTREAM_DATA_PIPE_MASK    0x03
#define PL2303_HXN_RESET_CONTROL    0x07

> > +     } else if (spriv->type == &pl2303_type_data[TYPE_HXN]) {
> >               /* reset upstream data pipes */
>
> This comment belongs in the last else block. Your new code shouldn't
> need one.

Charles Ans:
OK, I will remove this comment.


>
> > +             pl2303_update_reg(serial, PL2303_HXN_RESET_CONTROL,
> > +                             PL2303_HXN_RESET_CONTROL_MASK, 0x03);
>
> So two things; first, do you really need to read back the current value?
> I would assume that it always reads back as 0 and that writing 0x03 in
> this case would be sufficient to reset both buffers.
>

Charles Ans:
 Yes, I want to read back the current value.
because the whole register is used for reset.
Bit 0 and bit 1 are used for up & downstream data pipe,
Bit 2 for interface reset
Bit 4 for chip reset.

But I only reset bit 0 & bit 1.

> Second, please use a define for 0x03; no magic constants, as we have
> discussed before. You don't need a separate mask define if you're always
> resetting both buffers together (just use the same value define twice).

Charles Ans:
OK, I will define for 0x03.

#define PL2303_HXN_RESET_UP_DOWNSTREAM_DATA_PIPE    0x03


Charles Yeh.