Re: [PATCH 3/5] auxdisplay: charlcd: add escape sequence for brightness on NEC µPD16314

[Sean Young]

On Mon, Feb 12, 2018 at 12:56:58PM +0100, Miguel Ojeda wrote:
> On Mon, Jan 15, 2018 at 10:58 AM, Sean Young  wrote:
> > The NEC µPD16314 can alter the the brightness of the LCD. Make it possible
> > to set this via escape sequence Y0 - Y3. B and R were already taken, so
> > I picked Y for luminance.
> >
> > Signed-off-by: Sean Young 
> 
> CC'ing Willy and Geert.
> 
> > ---
> >  drivers/auxdisplay/charlcd.c | 20 ++--
> >  1 file changed, 18 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c
> > index a16c72779722..7a671ad959d1 100644
> > --- a/drivers/auxdisplay/charlcd.c
> > +++ b/drivers/auxdisplay/charlcd.c
> > @@ -39,6 +39,8 @@
> >  #define LCD_FLAG_F 0x0020  /* Large font mode */
> >  #define LCD_FLAG_N 0x0040  /* 2-rows mode */
> >  #define LCD_FLAG_L 0x0080  /* Backlight enabled */
> > +#define LCD_BRIGHTNESS_MASK0x0300  /* Brightness */
> > +#define LCD_BRIGHTNESS_SHIFT   8
> 
> Not sure about the name (since the brightness is also used in
> priv->flags). By the way, should we start using the bitops.h stuff
> (e.g. BIT(9) | BIT(8), GENMASK(9, 8)...) in new code? Not sure how
> widespread they are.

The brightness is not really a flag, maybe it belongs in a separate field;
we could use bit fields in order to waste less space.

BIT() would be nicer and is more idiomatic by current standards.

Note that x, y and flags are currently unsigned long, they could be u8.

> 
> >
> >  /* LCD commands */
> >  #define LCD_CMD_DISPLAY_CLEAR  0x01/* Clear entire display */
> > @@ -490,6 +492,17 @@ static inline int handle_lcd_special_code(struct 
> > charlcd *lcd)
> > charlcd_gotoxy(lcd);
> > processed = 1;
> > break;
> > +   case 'Y':   /* brightness (luma) */
> > +   switch (esc[1]) {
> > +   case '0':   /* 25% */
> > +   case '1':   /* 50% */
> > +   case '2':   /* 75% */
> > +   case '3':   /* 100% */
> > +   priv->flags = (priv->flags & 
> > ~(LCD_BRIGHTNESS_MASK)) |
> > +   (('3' - esc[1]) << LCD_BRIGHTNESS_SHIFT);
> > +   processed =  1;
> > +   break;
> > +   }
> > }
> >
> > /* TODO: This indent party here got ugly, clean it! */
> > @@ -507,12 +520,15 @@ static inline int handle_lcd_special_code(struct 
> > charlcd *lcd)
> > ((priv->flags & LCD_FLAG_C) ? LCD_CMD_CURSOR_ON : 
> > 0) |
> > ((priv->flags & LCD_FLAG_B) ? LCD_CMD_BLINK_ON : 
> > 0));
> > /* check whether one of F,N flags was changed */
> 
> Should we add "or brightness" to the comment?

Indeed we should.

> 
> > -   else if ((oldflags ^ priv->flags) & (LCD_FLAG_F | LCD_FLAG_N))
> > +   else if ((oldflags ^ priv->flags) & (LCD_FLAG_F | LCD_FLAG_N |
> > +LCD_BRIGHTNESS_MASK))
> > lcd->ops->write_cmd(lcd,
> > LCD_CMD_FUNCTION_SET |
> > ((lcd->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
> > ((priv->flags & LCD_FLAG_F) ? 
> > LCD_CMD_FONT_5X10_DOTS : 0) |
> > -   ((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 
> > 0));
> > +   ((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 
> > 0) |
> > +   ((priv->flags & LCD_BRIGHTNESS_MASK) >>
> > +   
> > LCD_BRIGHTNESS_SHIFT));
> > /* check whether L flag was changed */
> > else if ((oldflags ^ priv->flags) & LCD_FLAG_L)
> > charlcd_backlight(lcd, !!(priv->flags & LCD_FLAG_L));
> > --
> > 2.14.3
> >

I've discovered an issue in my sasem driver, I'll send out a new version
of these patch series once that is resolved.

Thanks,

Sean

Re: [PATCH 3/5] auxdisplay: charlcd: add escape sequence for brightness on NEC µPD16314

[Miguel Ojeda]

On Mon, Jan 15, 2018 at 10:58 AM, Sean Young  wrote:
> The NEC µPD16314 can alter the the brightness of the LCD. Make it possible
> to set this via escape sequence Y0 - Y3. B and R were already taken, so
> I picked Y for luminance.
>
> Signed-off-by: Sean Young 

CC'ing Willy and Geert.

> ---
>  drivers/auxdisplay/charlcd.c | 20 ++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c
> index a16c72779722..7a671ad959d1 100644
> --- a/drivers/auxdisplay/charlcd.c
> +++ b/drivers/auxdisplay/charlcd.c
> @@ -39,6 +39,8 @@
>  #define LCD_FLAG_F 0x0020  /* Large font mode */
>  #define LCD_FLAG_N 0x0040  /* 2-rows mode */
>  #define LCD_FLAG_L 0x0080  /* Backlight enabled */
> +#define LCD_BRIGHTNESS_MASK0x0300  /* Brightness */
> +#define LCD_BRIGHTNESS_SHIFT   8

Not sure about the name (since the brightness is also used in
priv->flags). By the way, should we start using the bitops.h stuff
(e.g. BIT(9) | BIT(8), GENMASK(9, 8)...) in new code? Not sure how
widespread they are.

>
>  /* LCD commands */
>  #define LCD_CMD_DISPLAY_CLEAR  0x01/* Clear entire display */
> @@ -490,6 +492,17 @@ static inline int handle_lcd_special_code(struct charlcd 
> *lcd)
> charlcd_gotoxy(lcd);
> processed = 1;
> break;
> +   case 'Y':   /* brightness (luma) */
> +   switch (esc[1]) {
> +   case '0':   /* 25% */
> +   case '1':   /* 50% */
> +   case '2':   /* 75% */
> +   case '3':   /* 100% */
> +   priv->flags = (priv->flags & ~(LCD_BRIGHTNESS_MASK)) |
> +   (('3' - esc[1]) << LCD_BRIGHTNESS_SHIFT);
> +   processed =  1;
> +   break;
> +   }
> }
>
> /* TODO: This indent party here got ugly, clean it! */
> @@ -507,12 +520,15 @@ static inline int handle_lcd_special_code(struct 
> charlcd *lcd)
> ((priv->flags & LCD_FLAG_C) ? LCD_CMD_CURSOR_ON : 0) |
> ((priv->flags & LCD_FLAG_B) ? LCD_CMD_BLINK_ON : 0));
> /* check whether one of F,N flags was changed */

Should we add "or brightness" to the comment?

> -   else if ((oldflags ^ priv->flags) & (LCD_FLAG_F | LCD_FLAG_N))
> +   else if ((oldflags ^ priv->flags) & (LCD_FLAG_F | LCD_FLAG_N |
> +LCD_BRIGHTNESS_MASK))
> lcd->ops->write_cmd(lcd,
> LCD_CMD_FUNCTION_SET |
> ((lcd->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
> ((priv->flags & LCD_FLAG_F) ? LCD_CMD_FONT_5X10_DOTS 
> : 0) |
> -   ((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 0));
> +   ((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 0) |
> +   ((priv->flags & LCD_BRIGHTNESS_MASK) >>
> +   
> LCD_BRIGHTNESS_SHIFT));
> /* check whether L flag was changed */
> else if ((oldflags ^ priv->flags) & LCD_FLAG_L)
> charlcd_backlight(lcd, !!(priv->flags & LCD_FLAG_L));
> --
> 2.14.3
>