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References: <20221215150214.1109074-1-hugo@hugovil.com> <20221215150214.1109074-8-hugo@hugovil.com>
In-Reply-To: <20221215150214.1109074-8-hugo@hugovil.com>
From:   Bruno Thomsen <bruno.thomsen@gmail.com>
Date:   Sat, 7 Jan 2023 19:15:00 +0100
Message-ID: <CAH+2xPBHTRLpQRBtGe40bJ3k-wWf5LfXjOhHu2x5uuyvCk84Fw@mail.gmail.com>
Subject: Re: [PATCH v3 07/14] rtc: pcf2127: add support for PCF2131 RTC
To:     Hugo Villeneuve <hugo@hugovil.com>
Cc:     a.zummo@towertech.it, alexandre.belloni@bootlin.com,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        linux-rtc@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Hugo Villeneuve <hvilleneuve@dimonoff.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Den tor. 15. dec. 2022 kl. 16.20 skrev Hugo Villeneuve <hugo@hugovil.com>:
>
> From: Hugo Villeneuve <hvilleneuve@dimonoff.com>
>
> This RTC is very similar in functionality to the PCF2127/29.
>
> Basically it:
>   -supports two new control registers at offsets 4 and 5
>   -supports a new reset register (not implemented in this driver)
>   -supports 4 tamper detection functions instead of 1
>   -has no nvmem (like the PCF2129)
>   -has two output interrupt pins
>
> Because of that, most of the register addresses are very different,
> although they still follow the same layout. For example, the tamper
> registers have a different base address, but the offsets are all the same.
>
> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> ---
>  drivers/rtc/Kconfig       |   4 +-
>  drivers/rtc/rtc-pcf2127.c | 234 ++++++++++++++++++++++++++++++++++----
>  2 files changed, 215 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 2bb640d1521d..3d4043ce0057 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -910,9 +910,9 @@ config RTC_DRV_PCF2127
>         select REGMAP_SPI if SPI_MASTER
>         select WATCHDOG_CORE if WATCHDOG
>         help
> -         If you say yes here you get support for the NXP PCF2127/29 RTC
> +         If you say yes here you get support for the NXP PCF2127/29/31 RTC
>           chips with integrated quartz crystal for industrial applications.
> -         Both chips also have watchdog timer and tamper switch detection
> +         These chips also have watchdog timer and tamper switch detection
>           features.
>
>           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
>   *
>   * Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
>   *
>   * Watchdog and tamper functions
>   * Author: Bruno Thomsen <bruno.thomsen@gmail.com>
>   *
> + * PCF2131 support
> + * Author: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> + *
>   * 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
>   */
>
>  #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. */

Replace 0b00100100 with (BIT(2) | BIT(5))

> +#define PCF2131_SR_RESET_RESET_CMD     0x2C /* SR is bit 3. */

Replace 0x2C with (BIT(2) | BIT(3) | BIT(5)) or
(PCF2131_SR_RESET_READ_PATTERN | BIT(3))
and then drop the comment.

>  /* 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.
> +                                             */

I think you should add this rather big comment above
#define PCF2131_REG_TIME_DATE_BASE 0x07

and rename the define to PCF2131_REG_TIME_BASE.

>  /* 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
>  /* 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",
>         .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
>  };
>
> @@ -555,30 +617,64 @@ static void pcf2127_rtc_ts_snapshot(struct device *dev, int ts_id)
>  static irqreturn_t pcf2127_rtc_irq(int irq, void *dev)
>  {
>         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> -       unsigned int ctrl1, ctrl2;
> +       unsigned int ctrl2;
>         int ret = 0;
>
> -       ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL1, &ctrl1);
> -       if (ret)
> -               return IRQ_NONE;
> -
>         ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL2, &ctrl2);
>         if (ret)
>                 return IRQ_NONE;
>
> -       if (!(ctrl1 & PCF2127_CTRL1_IRQ_MASK || ctrl2 & PCF2127_CTRL2_IRQ_MASK))
> -               return IRQ_NONE;
> +       if (pcf2127->cfg->ts_count == 1) {
> +               /* PCF2127/29 */
> +               unsigned int ctrl1;
> +
> +               ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL1, &ctrl1);
> +               if (ret)
> +                       return IRQ_NONE;
> +
> +               if (!(ctrl1 & PCF2127_CTRL1_IRQ_MASK || ctrl2 & PCF2127_CTRL2_IRQ_MASK))
> +                       return IRQ_NONE;
>
> -       if (ctrl1 & PCF2127_BIT_CTRL1_TSF1 || ctrl2 & PCF2127_BIT_CTRL2_TSF2)
> -               pcf2127_rtc_ts_snapshot(dev, 0);
> +               if (ctrl1 & PCF2127_BIT_CTRL1_TSF1 || ctrl2 & PCF2127_BIT_CTRL2_TSF2)
> +                       pcf2127_rtc_ts_snapshot(dev, 0);
>
> -       if (ctrl1 & PCF2127_CTRL1_IRQ_MASK)
> -               regmap_write(pcf2127->regmap, PCF2127_REG_CTRL1,
> -                       ctrl1 & ~PCF2127_CTRL1_IRQ_MASK);
> +               if (ctrl1 & PCF2127_CTRL1_IRQ_MASK)
> +                       regmap_write(pcf2127->regmap, PCF2127_REG_CTRL1,
> +                                    ctrl1 & ~PCF2127_CTRL1_IRQ_MASK);
> +
> +               if (ctrl2 & PCF2127_CTRL2_IRQ_MASK)
> +                       regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
> +                                    ctrl2 & ~PCF2127_CTRL2_IRQ_MASK);
> +       } else {
> +               /* PCF2131. */
> +               unsigned int ctrl4;
> +
> +               ret = regmap_read(pcf2127->regmap, PCF2131_REG_CTRL4, &ctrl4);
> +               if (ret)
> +                       return IRQ_NONE;
>
> -       if (ctrl2 & PCF2127_CTRL2_IRQ_MASK)
> -               regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
> -                       ctrl2 & ~PCF2127_CTRL2_IRQ_MASK);
> +               if (!(ctrl4 & PCF2131_CTRL4_IRQ_MASK || ctrl2 & PCF2131_CTRL2_IRQ_MASK))
> +                       return IRQ_NONE;
> +
> +               if (ctrl4 & PCF2131_CTRL4_IRQ_MASK) {
> +                       int i;
> +                       int tsf_bit = PCF2131_BIT_CTRL4_TSF1; /* Start at bit 7. */
> +
> +                       for (i = 0; i < pcf2127->cfg->ts_count; i++) {
> +                               if (ctrl4 & tsf_bit)
> +                                       pcf2127_rtc_ts_snapshot(dev, i);
> +
> +                               tsf_bit = tsf_bit >> 1;
> +                       }
> +
> +                       regmap_write(pcf2127->regmap, PCF2131_REG_CTRL4,
> +                                    ctrl4 & ~PCF2131_CTRL4_IRQ_MASK);
> +               }
> +
> +               if (ctrl2 & PCF2131_CTRL2_IRQ_MASK)
> +                       regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
> +                                    ctrl2 & ~PCF2131_CTRL2_IRQ_MASK);
> +       }
>
>         if (ctrl2 & PCF2127_BIT_CTRL2_AF)
>                 rtc_update_irq(pcf2127->rtc, 1, RTC_IRQF | RTC_AF);
> @@ -650,6 +746,27 @@ static ssize_t timestamp0_store(struct device *dev,
>         return timestamp_store(dev, attr, buf, count, 0);
>  };
>
> +static ssize_t timestamp1_store(struct device *dev,
> +                               struct device_attribute *attr,
> +                               const char *buf, size_t count)
> +{
> +       return timestamp_store(dev, attr, buf, count, 1);
> +};
> +
> +static ssize_t timestamp2_store(struct device *dev,
> +                               struct device_attribute *attr,
> +                               const char *buf, size_t count)
> +{
> +       return timestamp_store(dev, attr, buf, count, 2);
> +};
> +
> +static ssize_t timestamp3_store(struct device *dev,
> +                               struct device_attribute *attr,
> +                               const char *buf, size_t count)
> +{
> +       return timestamp_store(dev, attr, buf, count, 3);
> +};
> +
>  static ssize_t timestamp_show(struct device *dev,
>                               struct device_attribute *attr, char *buf,
>                               int ts_id)
> @@ -714,16 +831,46 @@ static ssize_t timestamp0_show(struct device *dev,
>         return timestamp_show(dev, attr, buf, 0);
>  };
>
> +static ssize_t timestamp1_show(struct device *dev,
> +                              struct device_attribute *attr, char *buf)
> +{
> +       return timestamp_show(dev, attr, buf, 1);
> +};
> +
> +static ssize_t timestamp2_show(struct device *dev,
> +                              struct device_attribute *attr, char *buf)
> +{
> +       return timestamp_show(dev, attr, buf, 2);
> +};
> +
> +static ssize_t timestamp3_show(struct device *dev,
> +                              struct device_attribute *attr, char *buf)
> +{
> +       return timestamp_show(dev, attr, buf, 3);
> +};
> +
>  static DEVICE_ATTR_RW(timestamp0);
> +static DEVICE_ATTR_RW(timestamp1);
> +static DEVICE_ATTR_RW(timestamp2);
> +static DEVICE_ATTR_RW(timestamp3);
>
>  static struct attribute *pcf2127_attrs[] = {
>         &dev_attr_timestamp0.attr,
>         NULL
>  };
>
> +static struct attribute *pcf2131_attrs[] = {
> +       &dev_attr_timestamp0.attr,
> +       &dev_attr_timestamp1.attr,
> +       &dev_attr_timestamp2.attr,
> +       &dev_attr_timestamp3.attr,
> +       NULL
> +};
> +
>  enum pcf21xx_type {
>         PCF2127,
>         PCF2129,
> +       PCF2131,
>         PCF21XX_LAST_ID
>  };
>
> @@ -774,6 +921,48 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
>                         .attrs  = pcf2127_attrs,
>                 },
>         },
> +       [PCF2131] = {
> +               .max_register = 0x36,
> +               .has_nvmem = 0,
> +               .has_bit_wd_ctl_cd0 = 0,
> +               .regs_td_base = PCF2131_REG_TIME_DATE_BASE,
> +               .regs_alarm_base = PCF2131_REG_ALARM_BASE,
> +               .reg_wd_ctl = PCF2131_REG_WD_CTL,
> +               .reg_wd_val = PCF2131_REG_WD_VAL,
> +               .reg_clkout = PCF2131_REG_CLKOUT,
> +               .ts_count = 4,
> +               .ts[0] = {
> +                       .regs_base = PCF2131_REG_TS1_BASE,
> +                       .low_reg   = PCF2131_REG_CTRL4,
> +                       .low_bit   = PCF2131_BIT_CTRL4_TSF1,

Set .inter_bit to 0 as it's used/read in timestamp_store() to
control flow in if-condition.

> +                       .ie_reg    = PCF2131_REG_CTRL5,
> +                       .ie_bit    = PCF2131_BIT_CTRL5_TSIE1,
> +               },
> +               .ts[1] = {
> +                       .regs_base = PCF2131_REG_TS2_BASE,
> +                       .low_reg   = PCF2131_REG_CTRL4,
> +                       .low_bit   = PCF2131_BIT_CTRL4_TSF2,
> +                       .ie_reg    = PCF2131_REG_CTRL5,
> +                       .ie_bit    = PCF2131_BIT_CTRL5_TSIE2,
> +               },
> +               .ts[2] = {
> +                       .regs_base = PCF2131_REG_TS3_BASE,
> +                       .low_reg   = PCF2131_REG_CTRL4,
> +                       .low_bit   = PCF2131_BIT_CTRL4_TSF3,
> +                       .ie_reg    = PCF2131_REG_CTRL5,
> +                       .ie_bit    = PCF2131_BIT_CTRL5_TSIE3,
> +               },
> +               .ts[3] = {
> +                       .regs_base = PCF2131_REG_TS4_BASE,
> +                       .low_reg   = PCF2131_REG_CTRL4,
> +                       .low_bit   = PCF2131_BIT_CTRL4_TSF4,
> +                       .ie_reg    = PCF2131_REG_CTRL5,
> +                       .ie_bit    = PCF2131_BIT_CTRL5_TSIE4,
> +               },
> +               .attribute_group = {
> +                       .attrs  = pcf2131_attrs,
> +               },
> +       },
>  };
>
>  /*
> @@ -922,7 +1111,7 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
>          * Watchdog timer enabled and reset pin /RST activated when timed out.
>          * Select 1Hz clock source for watchdog timer.
>          * Note: Countdown timer disabled and not available.
> -        * For pca2129, pcf2129, only bit[7] is for Symbol WD_CD
> +        * For pca2129, pcf2129 and pcf2131, only bit[7] is for Symbol WD_CD
>          * of register watchdg_tim_ctl. The bit[6] is labeled
>          * as T. Bits labeled as T must always be written with
>          * logic 0.
> @@ -982,6 +1171,7 @@ static const struct of_device_id pcf2127_of_match[] = {
>         { .compatible = "nxp,pcf2127", .data = &pcf21xx_cfg[PCF2127] },
>         { .compatible = "nxp,pcf2129", .data = &pcf21xx_cfg[PCF2129] },
>         { .compatible = "nxp,pca2129", .data = &pcf21xx_cfg[PCF2129] },
> +       { .compatible = "nxp,pcf2131", .data = &pcf21xx_cfg[PCF2131] },
>         {}
>  };
>  MODULE_DEVICE_TABLE(of, pcf2127_of_match);
> @@ -1069,6 +1259,7 @@ static const struct i2c_device_id pcf2127_i2c_id[] = {
>         { "pcf2127", PCF2127 },
>         { "pcf2129", PCF2129 },
>         { "pca2129", PCF2129 },
> +       { "pcf2131", PCF2131 },
>         { }
>  };
>  MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
> @@ -1190,6 +1381,7 @@ static const struct spi_device_id pcf2127_spi_id[] = {
>         { "pcf2127", PCF2127 },
>         { "pcf2129", PCF2129 },
>         { "pca2129", PCF2129 },
> +       { "pcf2131", PCF2131 },
>         { }
>  };
>  MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
> @@ -1254,5 +1446,5 @@ static void __exit pcf2127_exit(void)
>  module_exit(pcf2127_exit)
>
>  MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
> -MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
> +MODULE_DESCRIPTION("NXP PCF2127/29/31 RTC driver");
>  MODULE_LICENSE("GPL v2");
> --
> 2.30.2
>