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authorBastian Krause <bst@pengutronix.de>2020-09-17 20:32:42 +0200
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2020-09-24 09:56:03 +0200
commit462eb736db3db76899022e4e4db788a7b6efbe09 (patch)
tree5518cd7bed833ffbf08e24959809cf404e9c87c0 /drivers/rtc/rtc-ds1307.c
parent40d58c9742286ef95ef8dc5885d4043224490c82 (diff)
rtc: ds1307: apply DS13XX_TRICKLE_CHARGER_MAGIC only conditionally
DS13XX_TRICKLE_CHARGER_MAGIC sets the trickle-charge select (TCS) bits (7..4). The datasheet of Maxim Integrated's DS1339 [1] for instance reads: "To prevent accidental enabling, only a pattern on 1010 enables the trickle charger. All other patterns disable the trickle charger." Since not all RTCs connected to a backup battery or supercap use these bits DS13XX_TRICKLE_CHARGER_MAGIC should not get applied for all charger setups unconditionally. Epson's RX8130 is such an example: Instead of TCS bits "SMPTSEL1", "SMPTSEL0", "CHGEN" and "INIEN" are expected as bit 7..4. DS1339 and DS1340 are currently the only RTCs in the ds1307 driver that apply DS13XX_TRICKLE_CHARGER_MAGIC to their setup register value. So apply DS13XX_TRICKLE_CHARGER_MAGIC in do_trickle_setup_ds1339() which is used by both RTCs. [1] https://datasheets.maximintegrated.com/en/ds/DS1339-DS1339U.pdf [2] https://support.epson.biz/td/api/doc_check.php?dl=app_RX8130CE Signed-off-by: Bastian Krause <bst@pengutronix.de> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20200917183246.19446-5-bst@pengutronix.de
Diffstat (limited to 'drivers/rtc/rtc-ds1307.c')
-rw-r--r--drivers/rtc/rtc-ds1307.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 8f4ddbaa2052..82f75a798705 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -512,6 +512,8 @@ static u8 do_trickle_setup_ds1339(struct ds1307 *ds1307, u32 ohms, bool diode)
u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
DS1307_TRICKLE_CHARGER_NO_DIODE;
+ setup |= DS13XX_TRICKLE_CHARGER_MAGIC;
+
switch (ohms) {
case 250:
setup |= DS1307_TRICKLE_CHARGER_250_OHM;
@@ -1763,7 +1765,6 @@ static int ds1307_probe(struct i2c_client *client,
trickle_charger_setup = pdata->trickle_charger_setup;
if (trickle_charger_setup && chip->trickle_charger_reg) {
- trickle_charger_setup |= DS13XX_TRICKLE_CHARGER_MAGIC;
dev_dbg(ds1307->dev,
"writing trickle charger info 0x%x to 0x%x\n",
trickle_charger_setup, chip->trickle_charger_reg);