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Subject[PATCH] Staging: olpc_dcon: replace some magic numbers
Date
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


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