V4L/DVB (11342): au0828: better document i2c registers

Change the #define entries for the i2c registers to be more meaningful, and
document the valid values for the registers.  Note that this changeset makes
*no* functional changes to the code.

Signed-off-by: Devin Heitmueller <dheitmueller@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

2 files changed, 69 insertions, 28 deletions

diff --git a/drivers/media/video/au0828/au0828-i2c.c b/drivers/media/video/au0828/au0828-i2c.c
index f9a958d0aef1..27dcfc69cd80 100644
--- a/drivers/media/video/au0828/au0828-i2c.c
+++ b/drivers/media/video/au0828/au0828-i2c.c
@@ -39,13 +39,15 @@ MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
 static inline int i2c_slave_did_write_ack(struct i2c_adapter *i2c_adap)
 {
         struct au0828_dev *dev = i2c_adap->algo_data;
-        return au0828_read(dev, REG_201) & 0x08 ? 0 : 1;
+        return au0828_read(dev, AU0828_I2C_STATUS_201) &
+                AU0828_I2C_STATUS_NO_WRITE_ACK ? 0 : 1;
 }
 
 static inline int i2c_slave_did_read_ack(struct i2c_adapter *i2c_adap)
 {
         struct au0828_dev *dev = i2c_adap->algo_data;
-        return au0828_read(dev, REG_201) & 0x02 ? 0 : 1;
+        return au0828_read(dev, AU0828_I2C_STATUS_201) &
+                AU0828_I2C_STATUS_NO_READ_ACK ? 0 : 1;
 }
 
 static int i2c_wait_read_ack(struct i2c_adapter *i2c_adap)
@@ -67,7 +69,8 @@ static int i2c_wait_read_ack(struct i2c_adapter *i2c_adap)
 static inline int i2c_is_read_busy(struct i2c_adapter *i2c_adap)
 {
         struct au0828_dev *dev = i2c_adap->algo_data;
-        return au0828_read(dev, REG_201) & 0x01 ? 0 : 1;
+        return au0828_read(dev, AU0828_I2C_STATUS_201) &
+                AU0828_I2C_STATUS_READ_DONE ? 0 : 1;
 }
 
 static int i2c_wait_read_done(struct i2c_adapter *i2c_adap)
@@ -89,7 +92,8 @@ static int i2c_wait_read_done(struct i2c_adapter *i2c_adap)
 static inline int i2c_is_write_done(struct i2c_adapter *i2c_adap)
 {
         struct au0828_dev *dev = i2c_adap->algo_data;
-        return au0828_read(dev, REG_201) & 0x04 ? 1 : 0;
+        return au0828_read(dev, AU0828_I2C_STATUS_201) &
+                AU0828_I2C_STATUS_WRITE_DONE ? 1 : 0;
 }
 
 static int i2c_wait_write_done(struct i2c_adapter *i2c_adap)
@@ -111,7 +115,8 @@ static int i2c_wait_write_done(struct i2c_adapter *i2c_adap)
 static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
 {
         struct au0828_dev *dev = i2c_adap->algo_data;
-        return au0828_read(dev, REG_201) & 0x10 ? 1 : 0;
+        return au0828_read(dev, AU0828_I2C_STATUS_201) &
+                AU0828_I2C_STATUS_BUSY ? 1 : 0;
 }
 
 static int i2c_wait_done(struct i2c_adapter *i2c_adap)
@@ -139,19 +144,21 @@ static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
 
         dprintk(4, "%s()\n", __func__);
 
-        au0828_write(dev, REG_2FF, 0x01);
+        au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);
 
         /* FIXME: There is a problem with i2c communications with xc5000 that
            requires us to slow down the i2c clock until we have a better
            strategy (such as using the secondary i2c bus to do firmware
            loading */
         if ((msg->addr << 1) == 0xc2)
-                au0828_write(dev, REG_202, 0x40);
+                au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202,
+                             AU0828_I2C_CLK_30KHZ);
         else
-                au0828_write(dev, REG_202, 0x07);
+                au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202,
+                             AU0828_I2C_CLK_250KHZ);
 
         /* Hardware needs 8 bit addresses */
-        au0828_write(dev, REG_203, msg->addr << 1);
+        au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);
 
         dprintk(4, "SEND: %02x\n", msg->addr);
 
@@ -163,7 +170,9 @@ static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
                    actual bytes to the bus, just do a read check.  This is
                    consistent with how I saw i2c device checking done in the
                    USB trace of the Windows driver */
-                au0828_write(dev, REG_200, 0x20);
+                au0828_write(dev, AU0828_I2C_TRIGGER_200,
+                             AU0828_I2C_TRIGGER_READ);
+
                 if (!i2c_wait_done(i2c_adap))
                         return -EIO;
 
@@ -177,7 +186,7 @@ static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
 
                 dprintk(4, " %02x\n", msg->buf[i]);
 
-                au0828_write(dev, REG_205, msg->buf[i]);
+                au0828_write(dev, AU0828_I2C_WRITE_FIFO_205, msg->buf[i]);
 
                 strobe++;
                 i++;
@@ -186,9 +195,12 @@ static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
 
                         /* Strobe the byte into the bus */
                         if (i < msg->len)
-                                au0828_write(dev, REG_200, 0x41);
+                                au0828_write(dev, AU0828_I2C_TRIGGER_200,
+                                             AU0828_I2C_TRIGGER_WRITE |
+                                             AU0828_I2C_TRIGGER_HOLD);
                         else
-                                au0828_write(dev, REG_200, 0x01);
+                                au0828_write(dev, AU0828_I2C_TRIGGER_200,
+                                             AU0828_I2C_TRIGGER_WRITE);
 
                         /* Reset strobe trigger */
                         strobe = 0;
@@ -216,25 +228,29 @@ static int i2c_readbytes(struct i2c_adapter *i2c_adap,
 
         dprintk(4, "%s()\n", __func__);
 
-        au0828_write(dev, REG_2FF, 0x01);
+        au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);
 
         /* FIXME: There is a problem with i2c communications with xc5000 that
            requires us to slow down the i2c clock until we have a better
            strategy (such as using the secondary i2c bus to do firmware
            loading */
         if ((msg->addr << 1) == 0xc2)
-                au0828_write(dev, REG_202, 0x40);
+                au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202,
+                             AU0828_I2C_CLK_30KHZ);
         else
-                au0828_write(dev, REG_202, 0x07);
+                au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202,
+                             AU0828_I2C_CLK_250KHZ);
 
         /* Hardware needs 8 bit addresses */
-        au0828_write(dev, REG_203, msg->addr << 1);
+        au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);
 
         dprintk(4, " RECV:\n");
 
         /* Deal with i2c_scan */
         if (msg->len == 0) {
-                au0828_write(dev, REG_200, 0x20);
+                au0828_write(dev, AU0828_I2C_TRIGGER_200,
+                             AU0828_I2C_TRIGGER_READ);
+
                 if (i2c_wait_read_ack(i2c_adap))
                         return -EIO;
                 return 0;
@@ -245,14 +261,18 @@ static int i2c_readbytes(struct i2c_adapter *i2c_adap,
                 i++;
 
                 if (i < msg->len)
-                        au0828_write(dev, REG_200, 0x60);
+                        au0828_write(dev, AU0828_I2C_TRIGGER_200,
+                                     AU0828_I2C_TRIGGER_READ |
+                                     AU0828_I2C_TRIGGER_HOLD);
                 else
-                        au0828_write(dev, REG_200, 0x20);
+                        au0828_write(dev, AU0828_I2C_TRIGGER_200,
+                                     AU0828_I2C_TRIGGER_READ);
 
                 if (!i2c_wait_read_done(i2c_adap))
                         return -EIO;
 
-                msg->buf[i-1] = au0828_read(dev, REG_209) & 0xff;
+                msg->buf[i-1] = au0828_read(dev, AU0828_I2C_READ_FIFO_209) &
+                        0xff;
 
                 dprintk(4, " %02x\n", msg->buf[i-1]);
         }
diff --git a/drivers/media/video/au0828/au0828-reg.h b/drivers/media/video/au0828/au0828-reg.h
index b15e4a3b6fc0..c39f3d2b721e 100644
--- a/drivers/media/video/au0828/au0828-reg.h
+++ b/drivers/media/video/au0828/au0828-reg.h
@@ -30,15 +30,36 @@
 #define AU0828_SENSORCTRL_100 0x100
 #define AU0828_SENSORCTRL_VBI_103 0x103
 
-#define REG_200 0x200
-#define REG_201 0x201
-#define REG_202 0x202
-#define REG_203 0x203
-#define REG_205 0x205
-#define REG_209 0x209
-#define REG_2FF 0x2ff
+/* I2C registers */
+#define AU0828_I2C_TRIGGER_200          0x200
+#define AU0828_I2C_STATUS_201           0x201
+#define AU0828_I2C_CLK_DIVIDER_202      0x202
+#define AU0828_I2C_DEST_ADDR_203        0x203
+#define AU0828_I2C_WRITE_FIFO_205       0x205
+#define AU0828_I2C_READ_FIFO_209        0x209
+#define AU0828_I2C_MULTIBYTE_MODE_2FF   0x2ff
 
 /* Audio registers */
 #define AU0828_AUDIOCTRL_50C 0x50C
 
 #define REG_600 0x600
+
+/*********************************************************************/
+/* Here are constants for values associated with the above registers */
+
+/* I2C Trigger (Reg 0x200) */
+#define AU0828_I2C_TRIGGER_WRITE        0x01
+#define AU0828_I2C_TRIGGER_READ         0x20
+#define AU0828_I2C_TRIGGER_HOLD         0x40
+
+/* I2C Status (Reg 0x201) */
+#define AU0828_I2C_STATUS_READ_DONE     0x01
+#define AU0828_I2C_STATUS_NO_READ_ACK   0x02
+#define AU0828_I2C_STATUS_WRITE_DONE    0x04
+#define AU0828_I2C_STATUS_NO_WRITE_ACK  0x08
+#define AU0828_I2C_STATUS_BUSY          0x10
+
+/* I2C Clock Divider (Reg 0x202) */
+#define AU0828_I2C_CLK_250KHZ 0x07
+#define AU0828_I2C_CLK_100KHZ 0x14
+#define AU0828_I2C_CLK_30KHZ  0x40