On Wed, 21 Jun 2023 10:14:29 -0400 Hugo Villeneuve <hugo@xxxxxxxxxxx> wrote: > On Fri, 20 Jan 2023 20:05:07 +0100 > Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> wrote: > > > Hello, > > > > I know I've been holding off on the review of this series for a while > > and I'm sorry for that. > > > > One of the main issue that is remaining is that the driver ends up being > > 53% bigger and generaly less efficient for no added functionality for > > the existing RTCs. > > > > I know performance is not a concern however, having more code in the > > set/read time and irq paths means that it is more difficult to set an > > get the time precisely. > > Hi Alexandre, > one way to keep rtc_read_time() as efficient as before, and even more > efficient by reading 7 instead of 10 registers, would be to drop reading > the CTRL3 register, which is only used to detect and display an info > message for the low battery condition. This low battery check could be > moved to an ioctl call, like it is done in the PCF8523 driver. > > Hugo. Hi, in fact it is already part of the ioctl, so it is even simpler... Hugo. > > > > I guess I'll take it as a merged driver but I took a different decision > > for other RTCs. > > > > On 15/12/2022 10:02:01-0500, Hugo Villeneuve wrote: > > > From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> > > > > > > Hello, > > > this patch series adds the driver for the PCF2131 real-time clock. > > > > > > This RTC is very similar in functionality to the PCF2127/29 with the > > > following differences: > > > -supports two new control registers at offsets 4 and 5 > > > -supports a new reset register > > > -supports 4 tamper detection functions instead of 1 > > > -has no nvmem (like the PCF2129) > > > -has two output interrupt pins instead of one > > > -has 1/100th seconds capabilities (not supported in this driver) > > > -pcf2127 has watchdog clock sources: 1/60, 1, 64 and 4096Hz > > > pcf2131 has watchdog clock sources: 1/64, 1/4, 4 and 64Hz > > > -watchdog value register cannot be read after being set > > > > > > Most of the register addresses are very different, although they still > > > follow the same layout. For example, the time/date and tamper registers > > > have a different base address, but the offsets are all the same. > > > Consequently, the source code of the PCF2127 driver can be easily adapted > > > to support this new device. > > > > > > Patches 1 to 6 modify the existing pcf2127 driver to make it more generic > > > and able to support multiple variants, like the PCF2131. This is done > > > mostly by using offsets instead of absolute hardcoded register addresses. > > > > > > Patch 7 add actual support for the PCF2131. > > > > > > Patch 8 configures all interrupt sources to go through the INT A pin. > > > > > > Patch 9 changes the PWRMNG bits to be the same with the PCF2131 as they > > > are with the PCF2127/29 (different default values). > > > > > > Patch 10 allow to confirm PCF2131 device presence by reading the reset > > > register fixed pattern. > > > > > > Patch 11 adapt the time/date registers write sequence for PCF2131 (STOP and > > > CPR bits). > > > > > > Patch 12 add support for generic watchdog timing configuration. > > > > > > Patch 13 add a new flag to identify if device has read support for reading > > > watchdog register value. > > > Since the watchdog value register cannot be read on the PCF2131 after > > > being set, it seems that we cannot detect if watchdog timer was > > > started by bootloader. I am not sure what is the best way to handle > > > this situation, suggestions are welcomed. > > > > > > Patch 14 add the dt-bindings for the PCF2131. > > > > > > I have tested the driver using a PCF2131-ARD evaluation board connected to > > > an NXP imx8mp evaluation board: > > > - Time get/set ok; > > > - Alarms get/set ok > > > - Timestamp 1 to 4 ok > > > - IRQ alarm ok > > > - Watchdog ok > > > - Also tested successfully with "RTC Driver Test Example" from > > > Documentation/rtc.txt > > > > > > I have also tested the driver on a custom PCF2129 adapter board connected to a > > > beaglebone black. > > > > > > Thank you. > > > > > > Link: [v1] https://patchwork.ozlabs.org/project/rtc-linux/patch/20220125200009.900660-2-hugo@xxxxxxxxxxx/ > > > Link: [v2] https://patchwork.ozlabs.org/project/rtc-linux/list/?series=285734 > > > > > > Changes for V3: > > > - Rebased for kernel v6.1 > > > > > > Changes for V2: > > > - In general, fix and improvements after I have tested on real hardware > > > - Fix alarm interrupt A/B mask setting for PCF2131: > > > PCF2131_BIT_INT_AIE must be cleared, not set, to enable interrupt. > > > - Remove low_reg validation: only check if TS interrupt flag is > > > defined, as low_reg is defined at address 0 for PCF2127/29. > > > - Change PWRMNG value for PCF2131: default is different than PCF2127/29. > > > - Adapt time/date registers write sequence for PCF2131 (STOP and CPR bits). > > > - Map all interrupt sources to INT A pin > > > - Read and validate PCF2131 device presence from RESET register > > > - Adapt watchdog configuration for PCF2131 > > > > > > Hugo Villeneuve (14): > > > rtc: pcf2127: add variant-specific configuration structure > > > rtc: pcf2127: adapt for time/date registers at any offset > > > rtc: pcf2127: adapt for alarm registers at any offset > > > rtc: pcf2127: adapt for WD registers at any offset > > > rtc: pcf2127: adapt for CLKOUT register at any offset > > > rtc: pcf2127: add support for multiple TS functions > > > rtc: pcf2127: add support for PCF2131 RTC > > > rtc: pcf2127: add support for PCF2131 interrupts on output INT_A > > > rtc: pcf2127: set PWRMNG value for PCF2131 > > > rtc: pcf2127: read and validate PCF2131 device signature > > > rtc: pcf2127: adapt time/date registers write sequence for PCF2131 > > > rtc: pcf2127: support generic watchdog timing configuration > > > rtc: pcf2127: add flag for watchdog register value read support > > > dt-bindings: rtc: pcf2127: add PCF2131 > > > > > > .../devicetree/bindings/rtc/nxp,pcf2127.yaml | 4 +- > > > drivers/rtc/Kconfig | 4 +- > > > drivers/rtc/rtc-pcf2127.c | 939 ++++++++++++++---- > > > 3 files changed, 752 insertions(+), 195 deletions(-) > > > > > > -- > > > 2.30.2 > > > > > > > -- > > Alexandre Belloni, co-owner and COO, Bootlin > > Embedded Linux and Kernel engineering > > https://bootlin.com > >
