diff options
| author | Bastian Krause <bst@pengutronix.de> | 2020-09-17 20:32:42 +0200 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2020-09-24 09:56:03 +0200 |
| commit | 462eb736db3db76899022e4e4db788a7b6efbe09 (patch) | |
| tree | 5518cd7bed833ffbf08e24959809cf404e9c87c0 /drivers/rtc/rtc-ds1307.c | |
| parent | 40d58c9742286ef95ef8dc5885d4043224490c82 (diff) | |
| download | linux-462eb736db3db76899022e4e4db788a7b6efbe09.tar.gz | |
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.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c index 8f4ddbaa20522..82f75a7987056 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); |