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authorMauro Carvalho Chehab <mchehab@infradead.org>2007-11-04 08:32:42 -0300
committerMauro Carvalho Chehab <mchehab@infradead.org>2008-01-25 19:01:57 -0200
commitd2ba055d3b7ca7694af38a735f00850363ee9417 (patch)
tree3e14d87aa824f397ba87db66c70b97c450338683
parentfad7b958e753e18ff443786360f7846da50a3085 (diff)
V4L/DVB (6546): Add comments for the hint methods
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
-rw-r--r--drivers/media/video/em28xx/em28xx-cards.c29
1 files changed, 24 insertions, 5 deletions
diff --git a/drivers/media/video/em28xx/em28xx-cards.c b/drivers/media/video/em28xx/em28xx-cards.c
index fd7a8a5fba6..e88bf6700e6 100644
--- a/drivers/media/video/em28xx/em28xx-cards.c
+++ b/drivers/media/video/em28xx/em28xx-cards.c
@@ -397,11 +397,13 @@ struct usb_device_id em28xx_id_table [] = {
};
MODULE_DEVICE_TABLE (usb, em28xx_id_table);
-static struct em28xx_hash_table em28xx_hash [] = {
+/* EEPROM hash table for devices with generic USB IDs */
+static struct em28xx_hash_table em28xx_eeprom_hash [] = {
/* P/N: SA 60002070465 Tuner: TVF7533-MF */
{ 0x6ce05a8f, EM2820_BOARD_PROLINK_PLAYTV_USB2, TUNER_YMEC_TVF_5533MF },
};
+/* I2C devicelist hash table for devices with generic USB IDs */
static struct em28xx_hash_table em28xx_i2c_hash[] = {
{ 0xb06a32c3, EM2800_BOARD_TERRATEC_CINERGY_200, TUNER_LG_PAL_NEW_TAPC },
{ 0xf51200e3, EM2800_BOARD_VGEAR_POCKETTV, TUNER_LG_PAL_NEW_TAPC },
@@ -484,10 +486,18 @@ static int em28xx_hint_board(struct em28xx *dev)
{
int i;
- for (i = 0; i < ARRAY_SIZE(em28xx_hash); i++) {
- if (dev->hash == em28xx_hash[i].hash) {
- dev->model = em28xx_hash[i].model;
- dev->tuner_type = em28xx_hash[i].tuner;
+ /* HINT method: EEPROM
+ *
+ * This method works only for boards with eeprom.
+ * Uses a hash of all eeprom bytes. The hash should be
+ * unique for a vendor/tuner pair.
+ * There are a high chance that tuners for different
+ * video standards produce different hashes.
+ */
+ for (i = 0; i < ARRAY_SIZE(em28xx_eeprom_hash); i++) {
+ if (dev->hash == em28xx_eeprom_hash[i].hash) {
+ dev->model = em28xx_eeprom_hash[i].model;
+ dev->tuner_type = em28xx_eeprom_hash[i].tuner;
em28xx_errdev("Your board has no unique USB ID.\n");
em28xx_errdev("A hint were successfully done, "
@@ -504,6 +514,15 @@ static int em28xx_hint_board(struct em28xx *dev)
}
}
+ /* HINT method: I2C attached devices
+ *
+ * This method works for all boards.
+ * Uses a hash of i2c scanned devices.
+ * Devices with the same i2c attached chips will
+ * be considered equal.
+ * This method is less precise than the eeprom one.
+ */
+
/* user did not request i2c scanning => do it now */
if (!dev->i2c_hash)
em28xx_do_i2c_scan(dev);