| Message ID | 20230517144144.365631-1-romain.perier@gmail.com |
|---|---|
| Headers | show |
| Series | Add RTC for MStar SSD20xD SoCs | expand |
Hello, On 17/05/2023 16:41:42+0200, Romain Perier wrote: > Newer SigmaStar SSD20xD SoCs contain a really low power RTC (300uA claimed), The low power RTCs are more on the side of a few tenth of nA. RV3028 consumes 40nA, including the crystal. AB1805 consumes 14nA with an RC oscillator. It is funny how SoC vendors think they are low power ;) > +static int ssd20xd_rtc_isoctrl(struct ssd20xd_rtc *priv) > +{ > + static const unsigned int sequence[] = { 0x0, 0x1, 0x3, 0x7, 0x5, 0x1, 0x0 }; > + unsigned int val; > + struct device *dev = &priv->rtc_dev->dev; > + int i, ret; > + > + /* > + * This gates iso_en by writing a special sequence of bytes to iso_ctrl > + * and ensuring that it has been correctly applied by reading iso_ctrl_ack > + */ > + for (i = 0; i < ARRAY_SIZE(sequence); i++) { > + writeb(sequence[i] & ISO_CTRL_MASK, priv->base + REG_ISO_CTRL); > + > + ret = read_poll_timeout(read_iso_ctrl_ack, val, val == (i % 2), 100, > + 20 * 100, true, priv->base); > + if (ret) { > + dev_err(dev, "Timeout waiting for ack byte %i (%x) of sequence\n", i, > + sequence[i]); This is a user visible message but there is no action for the user to take apart from retrying. You should drop this. > + return ret; > + } > + } > + > + /* > + * At this point iso_en should be raised for 1ms > + */ > + ret = read_poll_timeout(read_iso_en, val, val, 100, 22 * 100, true, priv->base); > + if (ret) > + dev_err(dev, "Timeout waiting for iso_en\n"); Ditto. > + mdelay(2); > + return 0; > +} > +
Hi Alexandre, On Tue, 30 May 2023 at 07:40, Alexandre Belloni <alexandre.belloni@bootlin.com> wrote: > > Hello, > > On 17/05/2023 16:41:42+0200, Romain Perier wrote: > > Newer SigmaStar SSD20xD SoCs contain a really low power RTC (300uA claimed), > > The low power RTCs are more on the side of a few tenth of nA. RV3028 > consumes 40nA, including the crystal. AB1805 consumes 14nA with an RC > oscillator. It is funny how SoC vendors think they are low power ;) To be fair to them I think the 300uA claim is for the whole SoC in RTC-only deep sleep. Whatever logic is powered on alongside the RTC to trigger wake up will be part of that number I guess. Cheers, Daniel
This patches series adds a new driver for the RTC found in the Mstar SSD20xD SoCs. It adds a basic rtc driver, the corresponding devicetree bindings and its documentation. The rtctest (from selftests) has been passed on this driver, with the following output: # rtctest TAP version 13 1..8 # Starting 8 tests from 1 test cases. # RUN rtc.date_read ... # rtctest.c:52:date_read:Current RTC date/time is 17/05/2023 15:58:12. # OK rtc.date_read ok 1 rtc.date_read # RUN rtc.date_read_loop ... # rtctest.c:95:date_read_loop:Continuously reading RTC time for 30s (with 11ms breaks after every read). # rtctest.c:122:date_read_loop:Performed 888 RTC time reads. # OK rtc.date_read_loop ok 2 rtc.date_read_loop # RUN rtc.uie_read ... # rtctest.c:137:uie_read:skip update IRQs not supported. # OK rtc.uie_read ok 3 rtc.uie_read # RUN rtc.uie_select ... # rtctest.c:166:uie_select:skip update IRQs not supported. # OK rtc.uie_select ok 4 rtc.uie_select # RUN rtc.alarm_alm_set ... # rtctest.c:214:alarm_alm_set:skip alarms are not supported. # OK rtc.alarm_alm_set ok 5 rtc.alarm_alm_set # RUN rtc.alarm_wkalm_set ... # rtctest.c:274:alarm_wkalm_set:skip alarms are not supported. # OK rtc.alarm_wkalm_set ok 6 rtc.alarm_wkalm_set # RUN rtc.alarm_alm_set_minute ... # rtctest.c:324:alarm_alm_set_minute:skip alarms are not supported. # OK rtc.alarm_alm_set_minute ok 7 rtc.alarm_alm_set_minute # RUN rtc.alarm_wkalm_set_minute ... # rtctest.c:384:alarm_wkalm_set_minute:skip alarms are not supported. # OK rtc.alarm_wkalm_set_minute ok 8 rtc.alarm_wkalm_set_minute # PASSED: 8 / 8 tests passed. # Totals: pass:8 fail:0 xfail:0 xpass:0 skip:0 error:0 Romain Perier (3): rtc: Add support for the SSD20xD RTC dt-bindings: rtc: Add Mstar SSD20xD RTC devicetree bindings documentation ARM: dts: mstar: Enable rtc for SSD20xD .../bindings/rtc/mstar,ssd20xd-rtc.yaml | 37 +++ arch/arm/boot/dts/mstar-infinity2m.dtsi | 5 + drivers/rtc/Kconfig | 11 + drivers/rtc/Makefile | 1 + drivers/rtc/rtc-ssd20xd.c | 249 ++++++++++++++++++ 5 files changed, 303 insertions(+) create mode 100644 Documentation/devicetree/bindings/rtc/mstar,ssd20xd-rtc.yaml create mode 100644 drivers/rtc/rtc-ssd20xd.c