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: Jens Frederich <jfrederich@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 26 insertions, 15 deletions

diff --git a/drivers/staging/olpc_dcon/olpc_dcon.c b/drivers/staging/olpc_dcon/olpc_dcon.c
index 7c460f2c0d23..5ca4fa4fd246 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 997bded2949f..524ee49fbacb 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 5bb6e760aa61..2925df3ce78a 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