Commit 98d4f93c authored by Jens Frederich's avatar Jens Frederich Committed by Greg Kroah-Hartman
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Staging: olpc_dcon: replace some magic numbers 



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: default avatarJens Frederich <jfrederich@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 01f865ba

drivers/staging/olpc_dcon/olpc_dcon.c

+7 −6
Original line number Diff line number Diff line
@@ -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 @@ static int dcon_bus_stabilize(struct dcon_priv *dcon, int is_powered_down) 
		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

drivers/staging/olpc_dcon/olpc_dcon.h

+18 −9
Original line number Diff line number Diff line
@@ -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 */

include/linux/olpc-ec.h

+1 −0
Original line number Diff line number Diff line
@@ -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