# \[PATCH v3\] staging: sm750fb: Code readability is improved

- Subsystems: STAGING - SILICON MOTION SM750 FRAME BUFFER DRIVER, STAGING SUBSYSTEM, THE REST
- Maintainers: Sudip Mukherjee, Teddy Wang, Sudip Mukherjee, Greg Kroah-Hartman, Linus Torvalds
- List: linux-fbdev
- 3 messages, 3 authors
- Page: https://ratatoskr.run/linux-fbdev/2017/03/4958053/t

## \[PATCH v3\] staging: sm750fb: Code readability is improved

- From: Arushi Singhal \<hidden\>
- Date: 2017-03-19 13:07:53 
- Message: https://ratatoskr.run/linux-fbdev/2017/03/4958053.md

```text
New variables are added to make the code more readable.

Signed-off-by: Arushi Singhal <redacted>
---
 changes in v3
 -try to make the code much more readable.
 
 drivers/staging/sm750fb/ddk750_mode.c | 61 ++++++++++++++++++++---------------
 1 file changed, 35 insertions(+), 26 deletions(-)

diff --git a/drivers/staging/sm750fb/ddk750_mode.c b/drivers/staging/sm750fb/ddk750_mode.c
index eea5aef2956f..5f18ce4d10de 100644
--- a/drivers/staging/sm750fb/ddk750_mode.c
+++ b/drivers/staging/sm750fb/ddk750_mode.c
@@ -81,33 +81,42 @@ static int programModeRegisters(mode_parameter_t *pModeParam, struct pll_value *
 	if (pll->clockType = SECONDARY_PLL) {
 		/* programe secondary pixel clock */
 		poke32(CRT_PLL_CTRL, sm750_format_pll_reg(pll));
-		poke32(CRT_HORIZONTAL_TOTAL,
-		       (((pModeParam->horizontal_total - 1) <<
-			 CRT_HORIZONTAL_TOTAL_TOTAL_SHIFT) &
-			CRT_HORIZONTAL_TOTAL_TOTAL_MASK) |
-		       ((pModeParam->horizontal_display_end - 1) &
-			CRT_HORIZONTAL_TOTAL_DISPLAY_END_MASK));
-
-		poke32(CRT_HORIZONTAL_SYNC,
-		       ((pModeParam->horizontal_sync_width <<
-			 CRT_HORIZONTAL_SYNC_WIDTH_SHIFT) &
-			CRT_HORIZONTAL_SYNC_WIDTH_MASK) |
-		       ((pModeParam->horizontal_sync_start - 1) &
-			CRT_HORIZONTAL_SYNC_START_MASK));
 
-		poke32(CRT_VERTICAL_TOTAL,
-		       (((pModeParam->vertical_total - 1) <<
-			 CRT_VERTICAL_TOTAL_TOTAL_SHIFT) &
-			CRT_VERTICAL_TOTAL_TOTAL_MASK) |
-		       ((pModeParam->vertical_display_end - 1) &
-			CRT_VERTICAL_TOTAL_DISPLAY_END_MASK));
-
-		poke32(CRT_VERTICAL_SYNC,
-		       ((pModeParam->vertical_sync_height <<
-			 CRT_VERTICAL_SYNC_HEIGHT_SHIFT) &
-			CRT_VERTICAL_SYNC_HEIGHT_MASK) |
-		       ((pModeParam->vertical_sync_start - 1) &
-			CRT_VERTICAL_SYNC_START_MASK));
+		unsigned int a = (pModeParam->horizontal_total - 1) <<
+				CRT_HORIZONTAL_TOTAL_TOTAL_SHIFT;
+		unsigned int b = a & CRT_HORIZONTAL_TOTAL_TOTAL_MASK;
+		unsigned int c = (pModeParam->horizontal_display_end - 1) &
+				CRT_HORIZONTAL_TOTAL_DISPLAY_END_MASK;
+		unsigned int temp = b | c;
+
+		poke32(CRT_HORIZONTAL_TOTAL, temp);
+
+		unsigned int a = (pModeParam->horizontal_sync_width <<
+				CRT_HORIZONTAL_SYNC_WIDTH_SHIFT);
+		unsigned int b = a & CRT_HORIZONTAL_SYNC_WIDTH_MASK;
+		unsigned int c = (pModeParam->horizontal_sync_start - 1) &
+				CRT_HORIZONTAL_SYNC_START_MASK;
+		unsigned int temp = b | c;
+
+		poke32(CRT_HORIZONTAL_SYNC, temp);
+
+		unsigned int a = (pModeParam->vertical_total - 1) <<
+				CRT_VERTICAL_TOTAL_TOTAL_SHIFT;
+		unsigned int b = a & CRT_VERTICAL_TOTAL_TOTAL_MASK;
+		unsigned int c = (pModeParam->vertical_display_end - 1) &
+				CRT_VERTICAL_TOTAL_DISPLAY_END_MASK;
+		unsigned int temp = b | c;
+
+		poke32(CRT_VERTICAL_TOTAL, temp);
+
+		unsigned int a = pModeParam->vertical_sync_height <<
+				CRT_VERTICAL_SYNC_HEIGHT_SHIFT;
+		unsigned int b = a & CRT_VERTICAL_SYNC_HEIGHT_MASK;
+		unsigned int c = (pModeParam->vertical_sync_start - 1) &
+				CRT_VERTICAL_SYNC_START_MASK;
+		unsigned int temp = b | c;
+
+		poke32(CRT_VERTICAL_SYNC, temp);
 
 		tmp = DISPLAY_CTRL_TIMING | DISPLAY_CTRL_PLANE;
 		if (pModeParam->vertical_sync_polarity)
-- 
2.11.0

```

## Re: \[Outreachy kernel\] \[PATCH v3\] staging: sm750fb: Code readability is improved

- From: Julia Lawall \<hidden\>
- Date: 2017-03-19 13:14:12 
- Message: https://ratatoskr.run/linux-fbdev/2017/03/4958054.md

```text


On Sun, 19 Mar 2017, Arushi Singhal wrote:

> New variables are added to make the code more readable.
>
> Signed-off-by: Arushi Singhal <redacted>
> ---
>  changes in v3
>  -try to make the code much more readable.
>
>  drivers/staging/sm750fb/ddk750_mode.c | 61 ++++++++++++++++++++---------------
>  1 file changed, 35 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/staging/sm750fb/ddk750_mode.c b/drivers/staging/sm750fb/ddk750_mode.c
> index eea5aef2956f..5f18ce4d10de 100644
> --- a/drivers/staging/sm750fb/ddk750_mode.c
> +++ b/drivers/staging/sm750fb/ddk750_mode.c
> @@ -81,33 +81,42 @@ static int programModeRegisters(mode_parameter_t *pModeParam, struct pll_value *
>  	if (pll->clockType = SECONDARY_PLL) {
>  		/* programe secondary pixel clock */
>  		poke32(CRT_PLL_CTRL, sm750_format_pll_reg(pll));
> -		poke32(CRT_HORIZONTAL_TOTAL,
> -		       (((pModeParam->horizontal_total - 1) <<
> -			 CRT_HORIZONTAL_TOTAL_TOTAL_SHIFT) &
> -			CRT_HORIZONTAL_TOTAL_TOTAL_MASK) |
> -		       ((pModeParam->horizontal_display_end - 1) &
> -			CRT_HORIZONTAL_TOTAL_DISPLAY_END_MASK));
> -
> -		poke32(CRT_HORIZONTAL_SYNC,
> -		       ((pModeParam->horizontal_sync_width <<
> -			 CRT_HORIZONTAL_SYNC_WIDTH_SHIFT) &
> -			CRT_HORIZONTAL_SYNC_WIDTH_MASK) |
> -		       ((pModeParam->horizontal_sync_start - 1) &
> -			CRT_HORIZONTAL_SYNC_START_MASK));
>
> -		poke32(CRT_VERTICAL_TOTAL,
> -		       (((pModeParam->vertical_total - 1) <<
> -			 CRT_VERTICAL_TOTAL_TOTAL_SHIFT) &
> -			CRT_VERTICAL_TOTAL_TOTAL_MASK) |
> -		       ((pModeParam->vertical_display_end - 1) &
> -			CRT_VERTICAL_TOTAL_DISPLAY_END_MASK));
> -
> -		poke32(CRT_VERTICAL_SYNC,
> -		       ((pModeParam->vertical_sync_height <<
> -			 CRT_VERTICAL_SYNC_HEIGHT_SHIFT) &
> -			CRT_VERTICAL_SYNC_HEIGHT_MASK) |
> -		       ((pModeParam->vertical_sync_start - 1) &
> -			CRT_VERTICAL_SYNC_START_MASK));
> +		unsigned int a = (pModeParam->horizontal_total - 1) <<
> +				CRT_HORIZONTAL_TOTAL_TOTAL_SHIFT;
> +		unsigned int b = a & CRT_HORIZONTAL_TOTAL_TOTAL_MASK;
> +		unsigned int c = (pModeParam->horizontal_display_end - 1) &
> +				CRT_HORIZONTAL_TOTAL_DISPLAY_END_MASK;
> +		unsigned int temp = b | c;
> +
> +		poke32(CRT_HORIZONTAL_TOTAL, temp);
> +
> +		unsigned int a = (pModeParam->horizontal_sync_width <<
> +				CRT_HORIZONTAL_SYNC_WIDTH_SHIFT);
> +		unsigned int b = a & CRT_HORIZONTAL_SYNC_WIDTH_MASK;
> +		unsigned int c = (pModeParam->horizontal_sync_start - 1) &
> +				CRT_HORIZONTAL_SYNC_START_MASK;
> +		unsigned int temp = b | c;

This is back to the original incorrect solution.  You can't declare
variables on the fly in Linux code.  Variables have to be declared at the
top of a block.

But you can reuse the same variables over and over, if no one cares about
their previous values.

julia


> +
> +		poke32(CRT_HORIZONTAL_SYNC, temp);
> +
> +		unsigned int a = (pModeParam->vertical_total - 1) <<
> +				CRT_VERTICAL_TOTAL_TOTAL_SHIFT;
> +		unsigned int b = a & CRT_VERTICAL_TOTAL_TOTAL_MASK;
> +		unsigned int c = (pModeParam->vertical_display_end - 1) &
> +				CRT_VERTICAL_TOTAL_DISPLAY_END_MASK;
> +		unsigned int temp = b | c;
> +
> +		poke32(CRT_VERTICAL_TOTAL, temp);
> +
> +		unsigned int a = pModeParam->vertical_sync_height <<
> +				CRT_VERTICAL_SYNC_HEIGHT_SHIFT;
> +		unsigned int b = a & CRT_VERTICAL_SYNC_HEIGHT_MASK;
> +		unsigned int c = (pModeParam->vertical_sync_start - 1) &
> +				CRT_VERTICAL_SYNC_START_MASK;
> +		unsigned int temp = b | c;
> +
> +		poke32(CRT_VERTICAL_SYNC, temp);
>
>  		tmp = DISPLAY_CTRL_TIMING | DISPLAY_CTRL_PLANE;
>  		if (pModeParam->vertical_sync_polarity)
> --
> 2.11.0
>
> --
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>
```

## Re: \[Outreachy kernel\] \[PATCH v3\] staging: sm750fb: Code readability is improved

- From: Geert Uytterhoeven \<geert@linux-m68k.org\>
- Date: 2017-03-19 14:04:58 
- Message: https://ratatoskr.run/linux-fbdev/2017/03/4958065.md

```text
On Sun, Mar 19, 2017 at 2:11 PM, Julia Lawall [ref] wrote:
> On Sun, 19 Mar 2017, Arushi Singhal wrote:
>> New variables are added to make the code more readable.
>>
>> Signed-off-by: Arushi Singhal <redacted>
>> ---
>>  changes in v3
>>  -try to make the code much more readable.
>>
>>  drivers/staging/sm750fb/ddk750_mode.c | 61 ++++++++++++++++++++---------------
>>  1 file changed, 35 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/staging/sm750fb/ddk750_mode.c b/drivers/staging/sm750fb/ddk750_mode.c
>> index eea5aef2956f..5f18ce4d10de 100644
>> --- a/drivers/staging/sm750fb/ddk750_mode.c
>> +++ b/drivers/staging/sm750fb/ddk750_mode.c
>> @@ -81,33 +81,42 @@ static int programModeRegisters(mode_parameter_t *pModeParam, struct pll_value *
>>       if (pll->clockType = SECONDARY_PLL) {
>>               /* programe secondary pixel clock */
>>               poke32(CRT_PLL_CTRL, sm750_format_pll_reg(pll));
>> -             poke32(CRT_HORIZONTAL_TOTAL,
>> -                    (((pModeParam->horizontal_total - 1) <<
>> -                      CRT_HORIZONTAL_TOTAL_TOTAL_SHIFT) &
>> -                     CRT_HORIZONTAL_TOTAL_TOTAL_MASK) |
>> -                    ((pModeParam->horizontal_display_end - 1) &
>> -                     CRT_HORIZONTAL_TOTAL_DISPLAY_END_MASK));
>> -
>> -             poke32(CRT_HORIZONTAL_SYNC,
>> -                    ((pModeParam->horizontal_sync_width <<
>> -                      CRT_HORIZONTAL_SYNC_WIDTH_SHIFT) &
>> -                     CRT_HORIZONTAL_SYNC_WIDTH_MASK) |
>> -                    ((pModeParam->horizontal_sync_start - 1) &
>> -                     CRT_HORIZONTAL_SYNC_START_MASK));
>>
>> -             poke32(CRT_VERTICAL_TOTAL,
>> -                    (((pModeParam->vertical_total - 1) <<
>> -                      CRT_VERTICAL_TOTAL_TOTAL_SHIFT) &
>> -                     CRT_VERTICAL_TOTAL_TOTAL_MASK) |
>> -                    ((pModeParam->vertical_display_end - 1) &
>> -                     CRT_VERTICAL_TOTAL_DISPLAY_END_MASK));
>> -
>> -             poke32(CRT_VERTICAL_SYNC,
>> -                    ((pModeParam->vertical_sync_height <<
>> -                      CRT_VERTICAL_SYNC_HEIGHT_SHIFT) &
>> -                     CRT_VERTICAL_SYNC_HEIGHT_MASK) |
>> -                    ((pModeParam->vertical_sync_start - 1) &
>> -                     CRT_VERTICAL_SYNC_START_MASK));
>> +             unsigned int a = (pModeParam->horizontal_total - 1) <<
>> +                             CRT_HORIZONTAL_TOTAL_TOTAL_SHIFT;
>> +             unsigned int b = a & CRT_HORIZONTAL_TOTAL_TOTAL_MASK;
>> +             unsigned int c = (pModeParam->horizontal_display_end - 1) &
>> +                             CRT_HORIZONTAL_TOTAL_DISPLAY_END_MASK;
>> +             unsigned int temp = b | c;
>> +
>> +             poke32(CRT_HORIZONTAL_TOTAL, temp);
>> +
>> +             unsigned int a = (pModeParam->horizontal_sync_width <<
>> +                             CRT_HORIZONTAL_SYNC_WIDTH_SHIFT);
>> +             unsigned int b = a & CRT_HORIZONTAL_SYNC_WIDTH_MASK;
>> +             unsigned int c = (pModeParam->horizontal_sync_start - 1) &
>> +                             CRT_HORIZONTAL_SYNC_START_MASK;
>> +             unsigned int temp = b | c;
>
> This is back to the original incorrect solution.  You can't declare
> variables on the fly in Linux code.  Variables have to be declared at the
> top of a block.

Arushi: have you tried to compile this?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
```