Re: [PATCH v3 07/14] rtc: pcf2127: add support for PCF2131 RTC

From: Alexandre Belloni
Date: Fri Jan 20 2023 - 13:57:16 EST

On 15/12/2022 10:02:08-0500, Hugo Villeneuve wrote:
> PCF2127 has an additional feature of 512 bytes battery backed
> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> index 3265878edc48..4148e135f935 100644
> --- a/drivers/rtc/rtc-pcf2127.c
> +++ b/drivers/rtc/rtc-pcf2127.c
> @@ -1,16 +1,26 @@
> // SPDX-License-Identifier: GPL-2.0-only
> /*
> - * An I2C and SPI driver for the NXP PCF2127/29 RTC
> + * An I2C and SPI driver for the NXP PCF2127/29/31 RTC
> * Copyright 2013 Til-Technologies
> + * Copyright 2021 DimOnOff

For the record, I don't really like that because git will be the
authoritative source for the copyright. This will only end up being
outdated info (as it is already)

> *
> * Author: Renaud Cerrato <r.cerrato@xxxxxxxxxxxxxxxxxxx>
> *
> * Watchdog and tamper functions
> * Author: Bruno Thomsen <bruno.thomsen@xxxxxxxxx>
> *
> + * PCF2131 support
> + * Author: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
> + *
> * based on the other drivers in this same directory.
> *
> - * Datasheet: https://www.nxp.com/docs/en/data-sheet/PCF2127.pdf
> + * Datasheets: https://www.nxp.com/docs/en/data-sheet/PCF2127.pdf
> + * https://www.nxp.com/docs/en/data-sheet/PCF2131DS.pdf
> + */
> +
> +/*
> + * The following features are not yet implemented for the PCF2131:
> + * - support for 1/100th seconds

This will never be added so I would remove that comment

> */
>
> #include <linux/i2c.h>
> @@ -43,8 +53,30 @@
> #define PCF2127_BIT_CTRL3_BLF BIT(2)
> #define PCF2127_BIT_CTRL3_BF BIT(3)
> #define PCF2127_BIT_CTRL3_BTSE BIT(4)
> +/* Control register 4 */
> +#define PCF2131_REG_CTRL4 0x03
> +#define PCF2131_BIT_CTRL4_TSF4 BIT(4)
> +#define PCF2131_BIT_CTRL4_TSF3 BIT(5)
> +#define PCF2131_BIT_CTRL4_TSF2 BIT(6)
> +#define PCF2131_BIT_CTRL4_TSF1 BIT(7)
> +/* Control register 5 */
> +#define PCF2131_REG_CTRL5 0x04
> +#define PCF2131_BIT_CTRL5_TSIE4 BIT(4)
> +#define PCF2131_BIT_CTRL5_TSIE3 BIT(5)
> +#define PCF2131_BIT_CTRL5_TSIE2 BIT(6)
> +#define PCF2131_BIT_CTRL5_TSIE1 BIT(7)
> +/* Software reset register */
> +#define PCF2131_REG_SR_RESET 0x05
> +#define PCF2131_SR_RESET_READ_PATTERN 0b00100100 /* Fixed pattern. */
> +#define PCF2131_SR_RESET_RESET_CMD 0x2C /* SR is bit 3. */
> /* Time and date registers */
> #define PCF2127_REG_TIME_DATE_BASE 0x03
> +#define PCF2131_REG_TIME_DATE_BASE 0x07 /* Register 0x06 is 100th seconds,
> + * but we do not support it. By
> + * using offset 0x07, we can be
> + * compatible with existing
> + * time/date functions.
> + */

Because we will never support 100th of seconds, this comment is not
useful

> /* Time and date registers offsets (starting from base register) */
> #define PCF2127_OFFSET_TD_SC 0
> #define PCF2127_OFFSET_TD_MN 1
> @@ -57,6 +89,7 @@
> #define PCF2127_BIT_SC_OSF BIT(7)
> /* Alarm registers */
> #define PCF2127_REG_ALARM_BASE 0x0A
> +#define PCF2131_REG_ALARM_BASE 0x0E

I'd keep the defines ordered by address, so you could move all the
PCF2131 defines after the PCF2127 ones

> /* Alarm registers offsets (starting from base register) */
> #define PCF2127_OFFSET_ALARM_SC 0
> #define PCF2127_OFFSET_ALARM_MN 1
> @@ -67,16 +100,26 @@
> #define PCF2127_BIT_ALARM_AE BIT(7)
> /* CLKOUT control register */
> #define PCF2127_REG_CLKOUT 0x0f
> +#define PCF2131_REG_CLKOUT 0x13
> #define PCF2127_BIT_CLKOUT_OTPR BIT(5)
> /* Watchdog registers */
> #define PCF2127_REG_WD_CTL 0x10
> +#define PCF2131_REG_WD_CTL 0x35
> #define PCF2127_BIT_WD_CTL_TF0 BIT(0)
> #define PCF2127_BIT_WD_CTL_TF1 BIT(1)
> #define PCF2127_BIT_WD_CTL_CD0 BIT(6)
> #define PCF2127_BIT_WD_CTL_CD1 BIT(7)
> #define PCF2127_REG_WD_VAL 0x11
> +#define PCF2131_REG_WD_VAL 0x36
> /* Tamper timestamp1 registers */
> #define PCF2127_REG_TS1_BASE 0x12
> +#define PCF2131_REG_TS1_BASE 0x14
> +/* Tamper timestamp2 registers */
> +#define PCF2131_REG_TS2_BASE 0x1B
> +/* Tamper timestamp3 registers */
> +#define PCF2131_REG_TS3_BASE 0x22
> +/* Tamper timestamp4 registers */
> +#define PCF2131_REG_TS4_BASE 0x29
> /* Tamper timestamp registers common offsets (starting from base register) */
> #define PCF2127_OFFSET_TS_CTL 0
> #define PCF2127_OFFSET_TS_SC 1
> @@ -92,11 +135,22 @@
> * RAM registers
> * PCF2127 has 512 bytes general-purpose static RAM (SRAM) that is
> * battery backed and can survive a power outage.
> - * PCF2129 doesn't have this feature.
> + * PCF2129/31 doesn't have this feature.
> */
> #define PCF2127_REG_RAM_ADDR_MSB 0x1A
> #define PCF2127_REG_RAM_WRT_CMD 0x1C
> #define PCF2127_REG_RAM_RD_CMD 0x1D
> +/* Interrupt mask registers */
> +#define PCF2131_REG_INT_A_MASK1 0x31
> +#define PCF2131_REG_INT_A_MASK2 0x32
> +#define PCF2131_REG_INT_B_MASK1 0x33
> +#define PCF2131_REG_INT_B_MASK2 0x34
> +#define PCF2131_BIT_INT_BLIE BIT(0)
> +#define PCF2131_BIT_INT_BIE BIT(1)
> +#define PCF2131_BIT_INT_AIE BIT(2)
> +#define PCF2131_BIT_INT_WD_CD BIT(3)
> +#define PCF2131_BIT_INT_SI BIT(4)
> +#define PCF2131_BIT_INT_MI BIT(5)
>
> /* Watchdog timer value constants */
> #define PCF2127_WD_VAL_STOP 0
> @@ -110,6 +164,14 @@
> PCF2127_BIT_CTRL2_AF | \
> PCF2127_BIT_CTRL2_WDTF | \
> PCF2127_BIT_CTRL2_TSF2)
> +#define PCF2131_CTRL2_IRQ_MASK ( \
> + PCF2127_BIT_CTRL2_AF | \
> + PCF2127_BIT_CTRL2_WDTF)
> +#define PCF2131_CTRL4_IRQ_MASK ( \
> + PCF2131_BIT_CTRL4_TSF4 | \
> + PCF2131_BIT_CTRL4_TSF3 | \
> + PCF2131_BIT_CTRL4_TSF2 | \
> + PCF2131_BIT_CTRL4_TSF1)
>
> struct pcf21xx_ts_config {
> u8 regs_base; /* Base register to read timestamp values. */
> @@ -370,7 +432,7 @@ static int pcf2127_wdt_set_timeout(struct watchdog_device *wdd,
> }
>
> static const struct watchdog_info pcf2127_wdt_info = {
> - .identity = "NXP PCF2127/PCF2129 Watchdog",
> + .identity = "NXP PCF2127/29/31 Watchdog",

This change may break userspace tools as this is exposed to userspace


--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com