[PATCH] Staging: olpc_dcon: replace some magic numbers

[PATCH] Staging: olpc_dcon: replace some magic numbers

[Jens Frederich]

This patch replace some magic numbers. I believe it makes
the driver more readable.

The magic number 0x26 is the XO system embedded controller
(EC) command 'DCON power enable/disable'.

Number 0x41, and 0x42 are special memory controller settings
register.  The 0x41 initialize bit sequence 0x101 means:
enable memory power down function and special SDRAM clock
delay for synchronize SDRAM output and clock signal.

The 0x42 initialize squence 0x101 is wrong.  According to
the specification Bit 8 is reserved, thus not in use.
I removed it.

Signed-off-by: Jens Frederich <jfrederich@gmail.com>

diff --git a/drivers/staging/olpc_dcon/olpc_dcon.c b/drivers/staging/olpc_dcon/olpc_dcon.c
index 7c460f2..5ca4fa4 100644
--- a/drivers/staging/olpc_dcon/olpc_dcon.c
+++ b/drivers/staging/olpc_dcon/olpc_dcon.c
@@ -90,9 +90,10 @@ static int dcon_hw_init(struct dcon_priv *dcon, int is_init)
 
 	/* SDRAM setup/hold time */
 	dcon_write(dcon, 0x3a, 0xc040);
-	dcon_write(dcon, 0x41, 0x0000);
-	dcon_write(dcon, 0x41, 0x0101);
-	dcon_write(dcon, 0x42, 0x0101);
+	dcon_write(dcon, DCON_REG_MEM_OPT_A, 0x0000);  /* clear option bits */
+	dcon_write(dcon, DCON_REG_MEM_OPT_A,
+				MEM_DLL_CLOCK_DELAY | MEM_POWER_DOWN);
+	dcon_write(dcon, DCON_REG_MEM_OPT_B, MEM_SOFT_RESET);
 
 	/* Colour swizzle, AA, no passthrough, backlight */
 	if (is_init) {
@@ -126,7 +127,7 @@ static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
 power_up:
 	if (is_powered_down) {
 		x = 1;
-		x = olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL, 0);
+		x = olpc_ec_cmd(EC_DCON_POWER_MODE, (u8 *)&x, 1, NULL, 0);
 		if (x) {
 			pr_warn("unable to force dcon to power up: %d!\n", x);
 			return x;
@@ -144,7 +145,7 @@ power_up:
 		pr_err("unable to stabilize dcon's smbus, reasserting power and praying.\n");
 		BUG_ON(olpc_board_at_least(olpc_board(0xc2)));
 		x = 0;
-		olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL, 0);
+		olpc_ec_cmd(EC_DCON_POWER_MODE, (u8 *)&x, 1, NULL, 0);
 		msleep(100);
 		is_powered_down = 1;
 		goto power_up;	/* argh, stupid hardware.. */
@@ -208,7 +209,7 @@ static void dcon_sleep(struct dcon_priv *dcon, bool sleep)
 
 	if (sleep) {
 		x = 0;
-		x = olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL, 0);
+		x = olpc_ec_cmd(EC_DCON_POWER_MODE, (u8 *)&x, 1, NULL, 0);
 		if (x)
 			pr_warn("unable to force dcon to power down: %d!\n", x);
 		else
diff --git a/drivers/staging/olpc_dcon/olpc_dcon.h b/drivers/staging/olpc_dcon/olpc_dcon.h
index 997bded..524ee49 100644
--- a/drivers/staging/olpc_dcon/olpc_dcon.h
+++ b/drivers/staging/olpc_dcon/olpc_dcon.h
@@ -22,15 +22,24 @@
 #define MODE_DEBUG	(1<<14)
 #define MODE_SELFTEST	(1<<15)
 
-#define DCON_REG_HRES		2
-#define DCON_REG_HTOTAL		3
-#define DCON_REG_HSYNC_WIDTH	4
-#define DCON_REG_VRES		5
-#define DCON_REG_VTOTAL		6
-#define DCON_REG_VSYNC_WIDTH	7
-#define DCON_REG_TIMEOUT	8
-#define DCON_REG_SCAN_INT	9
-#define DCON_REG_BRIGHT		10
+#define DCON_REG_HRES		0x2
+#define DCON_REG_HTOTAL		0x3
+#define DCON_REG_HSYNC_WIDTH	0x4
+#define DCON_REG_VRES		0x5
+#define DCON_REG_VTOTAL		0x6
+#define DCON_REG_VSYNC_WIDTH	0x7
+#define DCON_REG_TIMEOUT	0x8
+#define DCON_REG_SCAN_INT	0x9
+#define DCON_REG_BRIGHT		0x10
+#define DCON_REG_MEM_OPT_A	0x41
+#define DCON_REG_MEM_OPT_B	0x42
+
+/* Load Delay Locked Loop (DLL) settings for clock delay */
+#define MEM_DLL_CLOCK_DELAY	(1<<0)
+/* Memory controller power down function */
+#define MEM_POWER_DOWN  	(1<<8)
+/* Memory controller software reset */
+#define MEM_SOFT_RESET		(1<<0)
 
 /* Status values */
 
diff --git a/include/linux/olpc-ec.h b/include/linux/olpc-ec.h
index 5bb6e76..2925df3 100644
--- a/include/linux/olpc-ec.h
+++ b/include/linux/olpc-ec.h
@@ -6,6 +6,7 @@
 #define EC_WRITE_SCI_MASK		0x1b
 #define EC_WAKE_UP_WLAN			0x24
 #define EC_WLAN_LEAVE_RESET		0x25
+#define EC_DCON_POWER_MODE		0x26
 #define EC_READ_EB_MODE			0x2a
 #define EC_SET_SCI_INHIBIT		0x32
 #define EC_SET_SCI_INHIBIT_RELEASE	0x34
-- 
1.7.9.5

Re: [PATCH] Staging: olpc_dcon: replace some magic numbers

[Andres Salomon]

Please Cc Daniel on these.  Cjb and myself are no longer at olpc. 



On Sat,  3 Aug 2013 22:44:35 +0200
Jens Frederich <jfrederich@gmail.com> wrote:

> This patch replace some magic numbers. I believe it makes
> the driver more readable.
> 
> The magic number 0x26 is the XO system embedded controller
> (EC) command 'DCON power enable/disable'.
> 
> Number 0x41, and 0x42 are special memory controller settings
> register.  The 0x41 initialize bit sequence 0x101 means:
> enable memory power down function and special SDRAM clock
> delay for synchronize SDRAM output and clock signal.
> 
> The 0x42 initialize squence 0x101 is wrong.  According to
> the specification Bit 8 is reserved, thus not in use.
> I removed it.
> 
> Signed-off-by: Jens Frederich <jfrederich@gmail.com>
> 
> diff --git a/drivers/staging/olpc_dcon/olpc_dcon.c
> b/drivers/staging/olpc_dcon/olpc_dcon.c index 7c460f2..5ca4fa4 100644
> --- a/drivers/staging/olpc_dcon/olpc_dcon.c
> +++ b/drivers/staging/olpc_dcon/olpc_dcon.c
> @@ -90,9 +90,10 @@ static int dcon_hw_init(struct dcon_priv *dcon,
> int is_init) 
>  	/* SDRAM setup/hold time */
>  	dcon_write(dcon, 0x3a, 0xc040);
> -	dcon_write(dcon, 0x41, 0x0000);
> -	dcon_write(dcon, 0x41, 0x0101);
> -	dcon_write(dcon, 0x42, 0x0101);
> +	dcon_write(dcon, DCON_REG_MEM_OPT_A, 0x0000);  /* clear
> option bits */
> +	dcon_write(dcon, DCON_REG_MEM_OPT_A,
> +				MEM_DLL_CLOCK_DELAY |
> MEM_POWER_DOWN);
> +	dcon_write(dcon, DCON_REG_MEM_OPT_B, MEM_SOFT_RESET);
>  
>  	/* Colour swizzle, AA, no passthrough, backlight */
>  	if (is_init) {
> @@ -126,7 +127,7 @@ static int dcon_bus_stabilize(struct dcon_priv
> *dcon, int is_powered_down) power_up:
>  	if (is_powered_down) {
>  		x = 1;
> -		x = olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL,
> 0);
> +		x = olpc_ec_cmd(EC_DCON_POWER_MODE, (u8 *)&x, 1,
> NULL, 0); if (x) {
>  			pr_warn("unable to force dcon to power up:
> %d!\n", x); return x;
> @@ -144,7 +145,7 @@ power_up:
>  		pr_err("unable to stabilize dcon's smbus,
> reasserting power and praying.\n");
> BUG_ON(olpc_board_at_least(olpc_board(0xc2))); x = 0;
> -		olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL, 0);
> +		olpc_ec_cmd(EC_DCON_POWER_MODE, (u8 *)&x, 1, NULL,
> 0); msleep(100);
>  		is_powered_down = 1;
>  		goto power_up;	/* argh, stupid hardware.. */
> @@ -208,7 +209,7 @@ static void dcon_sleep(struct dcon_priv *dcon,
> bool sleep) 
>  	if (sleep) {
>  		x = 0;
> -		x = olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL,
> 0);
> +		x = olpc_ec_cmd(EC_DCON_POWER_MODE, (u8 *)&x, 1,
> NULL, 0); if (x)
>  			pr_warn("unable to force dcon to power down:
> %d!\n", x); else
> diff --git a/drivers/staging/olpc_dcon/olpc_dcon.h
> b/drivers/staging/olpc_dcon/olpc_dcon.h index 997bded..524ee49 100644
> --- a/drivers/staging/olpc_dcon/olpc_dcon.h
> +++ b/drivers/staging/olpc_dcon/olpc_dcon.h
> @@ -22,15 +22,24 @@
>  #define MODE_DEBUG	(1<<14)
>  #define MODE_SELFTEST	(1<<15)
>  
> -#define DCON_REG_HRES		2
> -#define DCON_REG_HTOTAL		3
> -#define DCON_REG_HSYNC_WIDTH	4
> -#define DCON_REG_VRES		5
> -#define DCON_REG_VTOTAL		6
> -#define DCON_REG_VSYNC_WIDTH	7
> -#define DCON_REG_TIMEOUT	8
> -#define DCON_REG_SCAN_INT	9
> -#define DCON_REG_BRIGHT		10
> +#define DCON_REG_HRES		0x2
> +#define DCON_REG_HTOTAL		0x3
> +#define DCON_REG_HSYNC_WIDTH	0x4
> +#define DCON_REG_VRES		0x5
> +#define DCON_REG_VTOTAL		0x6
> +#define DCON_REG_VSYNC_WIDTH	0x7
> +#define DCON_REG_TIMEOUT	0x8
> +#define DCON_REG_SCAN_INT	0x9
> +#define DCON_REG_BRIGHT		0x10
> +#define DCON_REG_MEM_OPT_A	0x41
> +#define DCON_REG_MEM_OPT_B	0x42
> +
> +/* Load Delay Locked Loop (DLL) settings for clock delay */
> +#define MEM_DLL_CLOCK_DELAY	(1<<0)
> +/* Memory controller power down function */
> +#define MEM_POWER_DOWN  	(1<<8)
> +/* Memory controller software reset */
> +#define MEM_SOFT_RESET		(1<<0)
>  
>  /* Status values */
>  
> diff --git a/include/linux/olpc-ec.h b/include/linux/olpc-ec.h
> index 5bb6e76..2925df3 100644
> --- a/include/linux/olpc-ec.h
> +++ b/include/linux/olpc-ec.h
> @@ -6,6 +6,7 @@
>  #define EC_WRITE_SCI_MASK		0x1b
>  #define EC_WAKE_UP_WLAN			0x24
>  #define EC_WLAN_LEAVE_RESET		0x25
> +#define EC_DCON_POWER_MODE		0x26
>  #define EC_READ_EB_MODE			0x2a
>  #define EC_SET_SCI_INHIBIT		0x32
>  #define EC_SET_SCI_INHIBIT_RELEASE	0x34

Re: [PATCH] Staging: olpc_dcon: replace some magic numbers

[Jens Frederich]

On Sat, Aug 3, 2013 at 11:16 PM, Andres Salomon <dilinger@queued.net> wrote:
> Please Cc Daniel on these.  Cjb and myself are no longer at olpc.
>
Sorry, I've forgotten it. I will update the the TODO list.

Re: [PATCH] Staging: olpc_dcon: replace some magic numbers

[Jens Frederich]

On Sat, Aug 3, 2013 at 11:16 PM, Andres Salomon <dilinger@queued.net> wrote:
> Please Cc Daniel on these.  Cjb and myself are no longer at olpc.
>

Do you know what's with Jon Nettleton? He is also on the TODO list?

Re: [PATCH] Staging: olpc_dcon: replace some magic numbers

[Andres Salomon]

On Sat, 3 Aug 2013 23:36:15 +0200
Jens Frederich <jfrederich@gmail.com> wrote:

> On Sat, Aug 3, 2013 at 11:16 PM, Andres Salomon <dilinger@queued.net>
> wrote:
> > Please Cc Daniel on these.  Cjb and myself are no longer at olpc.
> >
> 
> Do you know what's with Jon Nettleton? He is also on the TODO list?

Let's ask.  Jon, do you still want to be Cc'd on DCON and other OLPC
patches?

Re: [PATCH] Staging: olpc_dcon: replace some magic numbers

[Dan Carpenter]

On Sat, Aug 03, 2013 at 10:44:35PM +0200, Jens Frederich wrote:
> @@ -126,7 +127,7 @@ static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
>  power_up:
>  	if (is_powered_down) {
>  		x = 1;
> -		x = olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL, 0);
> +		x = olpc_ec_cmd(EC_DCON_POWER_MODE, (u8 *)&x, 1, NULL, 0);
                                                    ^^^^^^^^
You didn't introduce this but using "x" as the inbuf here messy.
It should be char instead of an int.  The code won't work on big
endian systems.  I know this hardware is only available on little
endian systems and that's why it's not a bug.  It's just an ugly
thing to do.

(Since you didn't introduce this, it means your patch is fine and
you can ignore this email.  I am just commenting in case anyone
wants to fix clean it up).

>  		if (x) {
>  			pr_warn("unable to force dcon to power up: %d!\n", x);
>  			return x;

regards,
dan carpenter

Re: [PATCH] Staging: olpc_dcon: replace some magic numbers

[Dan Carpenter]

On Sat, Aug 03, 2013 at 02:38:45PM -0700, Andres Salomon wrote:
> On Sat, 3 Aug 2013 23:36:15 +0200
> Jens Frederich <jfrederich@gmail.com> wrote:
> 
> > On Sat, Aug 3, 2013 at 11:16 PM, Andres Salomon <dilinger@queued.net>
> > wrote:
> > > Please Cc Daniel on these.  Cjb and myself are no longer at olpc.
> > >
> > 
> > Do you know what's with Jon Nettleton? He is also on the TODO list?
> 
> Let's ask.  Jon, do you still want to be Cc'd on DCON and other OLPC
> patches?

No one reads the TODO files...  Just update MAINTAINERS so that
get_maintainer.pl CC's the right people automatically.

regards,
dan carpenter

Re: [PATCH] Staging: olpc_dcon: replace some magic numbers

[Jens Frederich]

On Sun, Aug 4, 2013 at 5:57 AM, Jon Nettleton <jon.nettleton@gmail.com> wrote:
>
> On Aug 3, 2013 11:38 PM, "Andres Salomon" <dilinger@queued.net> wrote:
>>
>> On Sat, 3 Aug 2013 23:36:15 +0200
>> Jens Frederich <jfrederich@gmail.com> wrote:
>>
>> > On Sat, Aug 3, 2013 at 11:16 PM, Andres Salomon <dilinger@queued.net>
>> > wrote:
>> > > Please Cc Daniel on these.  Cjb and myself are no longer at olpc.
>> > >
>> >
>> > Do you know what's with Jon Nettleton? He is also on the TODO list?
>>
>> Let's ask.  Jon, do you still want to be Cc'd on DCON and other OLPC
>> patches?
>
> Please. I still get enough support requests in the side that keeping up to
> date in changes us helpful.
>

Okay Jon, you're still on the OLPC CC list.

thanks,
Jens

Re: [PATCH] Staging: olpc_dcon: replace some magic numbers

[Jens Frederich]

On Sun, Aug 4, 2013 at 1:14 AM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> On Sat, Aug 03, 2013 at 10:44:35PM +0200, Jens Frederich wrote:
>> @@ -126,7 +127,7 @@ static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down)
>>  power_up:
>>       if (is_powered_down) {
>>               x = 1;
>> -             x = olpc_ec_cmd(0x26, (unsigned char *)&x, 1, NULL, 0);
>> +             x = olpc_ec_cmd(EC_DCON_POWER_MODE, (u8 *)&x, 1, NULL, 0);
>                                                     ^^^^^^^^
> You didn't introduce this but using "x" as the inbuf here messy.
> It should be char instead of an int.  The code won't work on big
> endian systems.  I know this hardware is only available on little
> endian systems and that's why it's not a bug.  It's just an ugly
> thing to do.
>

Hello Dan, you're right. It doesn't matter whether the current
hardware is little or big endian. The driver should be able to
support both. I will fix it soon.

thanks,
Jens