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Message-ID: <CAH+2xPAP1zk+SWLvKHm=sXNfmBtPogS8GMCdmoCvxTEXyJjPSA@mail.gmail.com>
Date: Sat, 7 Jan 2023 18:58:25 +0100
From: Bruno Thomsen <bruno.thomsen@...il.com>
To: Hugo Villeneuve <hugo@...ovil.com>
Cc: a.zummo@...ertech.it, alexandre.belloni@...tlin.com,
robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
linux-rtc@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org,
Hugo Villeneuve <hvilleneuve@...onoff.com>
Subject: Re: [PATCH v3 06/14] rtc: pcf2127: add support for multiple TS functions
Den tor. 15. dec. 2022 kl. 16.48 skrev Hugo Villeneuve <hugo@...ovil.com>:
>
> From: Hugo Villeneuve <hvilleneuve@...onoff.com>
>
> This will simplify the implementation of new variants into this driver.
>
> Signed-off-by: Hugo Villeneuve <hvilleneuve@...onoff.com>
> ---
> drivers/rtc/rtc-pcf2127.c | 303 +++++++++++++++++++++++++++-----------
> 1 file changed, 215 insertions(+), 88 deletions(-)
>
> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> index 38816ad065eb..3265878edc48 100644
> --- a/drivers/rtc/rtc-pcf2127.c
> +++ b/drivers/rtc/rtc-pcf2127.c
> @@ -75,16 +75,19 @@
> #define PCF2127_BIT_WD_CTL_CD0 BIT(6)
> #define PCF2127_BIT_WD_CTL_CD1 BIT(7)
> #define PCF2127_REG_WD_VAL 0x11
> -/* Tamper timestamp registers */
> -#define PCF2127_REG_TS_CTRL 0x12
> +/* Tamper timestamp1 registers */
> +#define PCF2127_REG_TS1_BASE 0x12
> +/* Tamper timestamp registers common offsets (starting from base register) */
> +#define PCF2127_OFFSET_TS_CTL 0
> +#define PCF2127_OFFSET_TS_SC 1
> +#define PCF2127_OFFSET_TS_MN 2
> +#define PCF2127_OFFSET_TS_HR 3
> +#define PCF2127_OFFSET_TS_DM 4
> +#define PCF2127_OFFSET_TS_MO 5
> +#define PCF2127_OFFSET_TS_YR 6
> +/* Tamper timestamp registers common bits */
> #define PCF2127_BIT_TS_CTRL_TSOFF BIT(6)
> #define PCF2127_BIT_TS_CTRL_TSM BIT(7)
> -#define PCF2127_REG_TS_SC 0x13
> -#define PCF2127_REG_TS_MN 0x14
> -#define PCF2127_REG_TS_HR 0x15
> -#define PCF2127_REG_TS_DM 0x16
> -#define PCF2127_REG_TS_MO 0x17
> -#define PCF2127_REG_TS_YR 0x18
> /*
> * RAM registers
> * PCF2127 has 512 bytes general-purpose static RAM (SRAM) that is
> @@ -108,6 +111,20 @@
> PCF2127_BIT_CTRL2_WDTF | \
> PCF2127_BIT_CTRL2_TSF2)
>
> +struct pcf21xx_ts_config {
> + u8 regs_base; /* Base register to read timestamp values. */
reg_base as there is only one.
> + /* TS input pin driven to GND detection (supported by all variants): */
> + u8 low_reg; /* Interrupt control register. */
> + u8 low_bit; /* Interrupt flag in low_reg control register. */
> + /* TS input pin driven to intermediate level between GND and supply
> + * detection (optional feature depending on variant):
> + */
> + u8 inter_reg; /* Interrupt control register. */
> + u8 inter_bit; /* Interrupt flag in inter_reg control register. */
I had to read this a couple of times to understand it :)
Maybe rename variables to low_ctl_reg, low_ctl_bit,
inter_ctl_reg and inter_ctl_bit.
> + u8 ie_reg; /* Interrupt enable control register. */
> + u8 ie_bit; /* Interrupt enable bit. */
> +};
> +
> struct pcf21xx_config {
> int max_register;
> unsigned int has_nvmem:1;
> @@ -117,6 +134,9 @@ struct pcf21xx_config {
> u8 reg_wd_ctl; /* Watchdog control register. */
> u8 reg_wd_val; /* Watchdog value register. */
> u8 reg_clkout; /* Clkout register. */
> + unsigned int ts_count;
> + struct pcf21xx_ts_config ts[4];
You should create a driver constant with the maximum number
of supported timestamps, something like:
#define PCF2127_MAX_TS_SUPPORTED 1
and raise it to 4 when pcf2131 support is added.
> + struct attribute_group attribute_group;
> };
>
> struct pcf2127 {
> @@ -124,9 +144,9 @@ struct pcf2127 {
> struct watchdog_device wdd;
> struct regmap *regmap;
> const struct pcf21xx_config *cfg;
> - time64_t ts;
> - bool ts_valid;
> bool irq_enabled;
> + time64_t ts[4]; /* Timestamp values. */
> + bool ts_valid[4]; /* Timestamp valid indication. */
> };
>
> /*
> @@ -469,38 +489,39 @@ static int pcf2127_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> }
>
> /*
> - * This function reads ctrl2 register, caller is responsible for calling
> - * pcf2127_wdt_active_ping()
> + * This function reads one timestamp function data, caller is responsible for
> + * calling pcf2127_wdt_active_ping()
> */
> -static int pcf2127_rtc_ts_read(struct device *dev, time64_t *ts)
> +static int pcf2127_rtc_ts_read(struct device *dev, time64_t *ts,
> + int ts_id)
> {
> struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> struct rtc_time tm;
> int ret;
> - unsigned char data[25];
> + unsigned char data[7]; /* To store result of reading 7 consecutive
> + * timestamp registers.
> + */
Remove comment about data variable.
>
> - ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL1, data,
> - sizeof(data));
> + ret = regmap_bulk_read(pcf2127->regmap, pcf2127->cfg->ts[ts_id].regs_base,
> + data, sizeof(data));
> if (ret) {
> - dev_err(dev, "%s: read error ret=%d\n", __func__, ret);
> + dev_err(dev, "%s: bulk read error ret=%d\n", __func__, ret);
> return ret;
> }
>
> dev_dbg(dev,
> - "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, ts_sc=%02x, ts_mn=%02x, ts_hr=%02x, ts_dm=%02x, ts_mo=%02x, ts_yr=%02x\n",
> - __func__, data[PCF2127_REG_CTRL1], data[PCF2127_REG_CTRL2],
> - data[PCF2127_REG_CTRL3], data[PCF2127_REG_TS_SC],
> - data[PCF2127_REG_TS_MN], data[PCF2127_REG_TS_HR],
> - data[PCF2127_REG_TS_DM], data[PCF2127_REG_TS_MO],
> - data[PCF2127_REG_TS_YR]);
> -
> - tm.tm_sec = bcd2bin(data[PCF2127_REG_TS_SC] & 0x7F);
> - tm.tm_min = bcd2bin(data[PCF2127_REG_TS_MN] & 0x7F);
> - tm.tm_hour = bcd2bin(data[PCF2127_REG_TS_HR] & 0x3F);
> - tm.tm_mday = bcd2bin(data[PCF2127_REG_TS_DM] & 0x3F);
> + "%s: raw data is ts_sc=%02x, ts_mn=%02x, ts_hr=%02x, ts_dm=%02x, ts_mo=%02x, ts_yr=%02x\n",
> + __func__, data[PCF2127_OFFSET_TS_SC], data[PCF2127_OFFSET_TS_MN],
> + data[PCF2127_OFFSET_TS_HR], data[PCF2127_OFFSET_TS_DM],
> + data[PCF2127_OFFSET_TS_MO], data[PCF2127_OFFSET_TS_YR]);
> +
> + tm.tm_sec = bcd2bin(data[PCF2127_OFFSET_TS_SC] & 0x7F);
> + tm.tm_min = bcd2bin(data[PCF2127_OFFSET_TS_MN] & 0x7F);
> + tm.tm_hour = bcd2bin(data[PCF2127_OFFSET_TS_HR] & 0x3F);
> + tm.tm_mday = bcd2bin(data[PCF2127_OFFSET_TS_DM] & 0x3F);
> /* TS_MO register (month) value range: 1-12 */
> - tm.tm_mon = bcd2bin(data[PCF2127_REG_TS_MO] & 0x1F) - 1;
> - tm.tm_year = bcd2bin(data[PCF2127_REG_TS_YR]);
> + tm.tm_mon = bcd2bin(data[PCF2127_OFFSET_TS_MO] & 0x1F) - 1;
> + tm.tm_year = bcd2bin(data[PCF2127_OFFSET_TS_YR]);
> if (tm.tm_year < 70)
> tm.tm_year += 100; /* assume we are in 1970...2069 */
>
> @@ -514,18 +535,21 @@ static int pcf2127_rtc_ts_read(struct device *dev, time64_t *ts)
> return 0;
> };
>
> -static void pcf2127_rtc_ts_snapshot(struct device *dev)
> +static void pcf2127_rtc_ts_snapshot(struct device *dev, int ts_id)
> {
> struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> int ret;
>
> + if (ts_id >= pcf2127->cfg->ts_count)
> + return;
> +
> /* Let userspace read the first timestamp */
> - if (pcf2127->ts_valid)
> + if (pcf2127->ts_valid[ts_id])
> return;
>
> - ret = pcf2127_rtc_ts_read(dev, &pcf2127->ts);
> + ret = pcf2127_rtc_ts_read(dev, &pcf2127->ts[ts_id], ts_id);
> if (!ret)
> - pcf2127->ts_valid = true;
> + pcf2127->ts_valid[ts_id] = true;
> }
>
> static irqreturn_t pcf2127_rtc_irq(int irq, void *dev)
> @@ -546,7 +570,7 @@ static irqreturn_t pcf2127_rtc_irq(int irq, void *dev)
> return IRQ_NONE;
>
> if (ctrl1 & PCF2127_BIT_CTRL1_TSF1 || ctrl2 & PCF2127_BIT_CTRL2_TSF2)
> - pcf2127_rtc_ts_snapshot(dev);
> + pcf2127_rtc_ts_snapshot(dev, 0);
>
> if (ctrl1 & PCF2127_CTRL1_IRQ_MASK)
> regmap_write(pcf2127->regmap, PCF2127_REG_CTRL1,
> @@ -575,28 +599,40 @@ static const struct rtc_class_ops pcf2127_rtc_ops = {
>
> /* sysfs interface */
>
> -static ssize_t timestamp0_store(struct device *dev,
> - struct device_attribute *attr,
> - const char *buf, size_t count)
> +static ssize_t timestamp_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count, int ts_id)
> {
> struct pcf2127 *pcf2127 = dev_get_drvdata(dev->parent);
> int ret;
>
> + if (ts_id >= pcf2127->cfg->ts_count)
> + return 0;
> +
> if (pcf2127->irq_enabled) {
> - pcf2127->ts_valid = false;
> + pcf2127->ts_valid[ts_id] = false;
> } else {
> - ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL1,
> - PCF2127_BIT_CTRL1_TSF1, 0);
> + /* Always clear LOW interrupt bit. */
> + ret = regmap_update_bits(pcf2127->regmap,
> + pcf2127->cfg->ts[ts_id].low_reg,
> + pcf2127->cfg->ts[ts_id].low_bit,
> + 0);
> +
> if (ret) {
> - dev_err(dev, "%s: update ctrl1 ret=%d\n", __func__, ret);
> + dev_err(dev, "%s: update TS low ret=%d\n", __func__, ret);
> return ret;
> }
>
> - ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
> - PCF2127_BIT_CTRL2_TSF2, 0);
> - if (ret) {
> - dev_err(dev, "%s: update ctrl2 ret=%d\n", __func__, ret);
> - return ret;
> + if (pcf2127->cfg->ts[ts_id].inter_bit) {
> + /* Clear INTERMEDIATE interrupt bit if supported. */
> + ret = regmap_update_bits(pcf2127->regmap,
> + pcf2127->cfg->ts[ts_id].inter_reg,
> + pcf2127->cfg->ts[ts_id].inter_bit,
> + 0);
> + if (ret) {
> + dev_err(dev, "%s: update TS intermediate ret=%d\n", __func__, ret);
> + return ret;
> + }
> }
>
> ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
> @@ -605,34 +641,63 @@ static ssize_t timestamp0_store(struct device *dev,
> }
>
> return count;
> +}
> +
> +static ssize_t timestamp0_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + return timestamp_store(dev, attr, buf, count, 0);
> };
>
> -static ssize_t timestamp0_show(struct device *dev,
> - struct device_attribute *attr, char *buf)
> +static ssize_t timestamp_show(struct device *dev,
> + struct device_attribute *attr, char *buf,
> + int ts_id)
> {
> struct pcf2127 *pcf2127 = dev_get_drvdata(dev->parent);
> - unsigned int ctrl1, ctrl2;
> int ret;
> time64_t ts;
>
> + if (ts_id >= pcf2127->cfg->ts_count)
> + return 0;
> +
> if (pcf2127->irq_enabled) {
> - if (!pcf2127->ts_valid)
> + if (!pcf2127->ts_valid[ts_id])
> return 0;
> - ts = pcf2127->ts;
> + ts = pcf2127->ts[ts_id];
> } else {
> - ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL1, &ctrl1);
> - if (ret)
> - return 0;
> + u8 valid_low = 0;
> + u8 valid_inter = 0;
> + unsigned int ctrl;
>
> - ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL2, &ctrl2);
> + /* Check if TS input pin is driven to GND, supported by all
> + * variants.
> + */
> + ret = regmap_read(pcf2127->regmap,
> + pcf2127->cfg->ts[ts_id].low_reg,
> + &ctrl);
> if (ret)
> return 0;
>
> - if (!(ctrl1 & PCF2127_BIT_CTRL1_TSF1) &&
> - !(ctrl2 & PCF2127_BIT_CTRL2_TSF2))
> + valid_low = ctrl & pcf2127->cfg->ts[ts_id].low_bit;
> +
> + if (pcf2127->cfg->ts[ts_id].inter_bit) {
> + /* Check if TS input pin is driven to intermediate level
> + * between GND and supply, if supported by variant.
> + */
> + ret = regmap_read(pcf2127->regmap,
> + pcf2127->cfg->ts[ts_id].inter_reg,
> + &ctrl);
> + if (ret)
> + return 0;
> +
> + valid_inter = ctrl & pcf2127->cfg->ts[ts_id].inter_bit;
> + }
> +
> + if (!valid_low && !valid_inter)
> return 0;
>
> - ret = pcf2127_rtc_ts_read(dev->parent, &ts);
> + ret = pcf2127_rtc_ts_read(dev->parent, &ts, ts_id);
> if (ret)
> return 0;
>
> @@ -641,6 +706,12 @@ static ssize_t timestamp0_show(struct device *dev,
> return ret;
> }
> return sprintf(buf, "%llu\n", (unsigned long long)ts);
> +}
> +
> +static ssize_t timestamp0_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + return timestamp_show(dev, attr, buf, 0);
> };
>
> static DEVICE_ATTR_RW(timestamp0);
> @@ -650,10 +721,6 @@ static struct attribute *pcf2127_attrs[] = {
> NULL
> };
>
> -static const struct attribute_group pcf2127_attr_group = {
> - .attrs = pcf2127_attrs,
> -};
> -
> enum pcf21xx_type {
> PCF2127,
> PCF2129,
> @@ -670,6 +737,19 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
> .reg_wd_ctl = PCF2127_REG_WD_CTL,
> .reg_wd_val = PCF2127_REG_WD_VAL,
> .reg_clkout = PCF2127_REG_CLKOUT,
> + .ts_count = 1,
> + .ts[0] = {
> + .regs_base = PCF2127_REG_TS1_BASE,
> + .low_reg = PCF2127_REG_CTRL1,
> + .low_bit = PCF2127_BIT_CTRL1_TSF1,
> + .inter_reg = PCF2127_REG_CTRL2,
> + .inter_bit = PCF2127_BIT_CTRL2_TSF2,
> + .ie_reg = PCF2127_REG_CTRL2,
> + .ie_bit = PCF2127_BIT_CTRL2_TSIE,
> + },
> + .attribute_group = {
> + .attrs = pcf2127_attrs,
> + },
> },
> [PCF2129] = {
> .max_register = 0x19,
> @@ -680,15 +760,81 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
> .reg_wd_ctl = PCF2127_REG_WD_CTL,
> .reg_wd_val = PCF2127_REG_WD_VAL,
> .reg_clkout = PCF2127_REG_CLKOUT,
> + .ts_count = 1,
> + .ts[0] = {
> + .regs_base = PCF2127_REG_TS1_BASE,
> + .low_reg = PCF2127_REG_CTRL1,
> + .low_bit = PCF2127_BIT_CTRL1_TSF1,
> + .inter_reg = PCF2127_REG_CTRL2,
> + .inter_bit = PCF2127_BIT_CTRL2_TSF2,
> + .ie_reg = PCF2127_REG_CTRL2,
> + .ie_bit = PCF2127_BIT_CTRL2_TSIE,
> + },
> + .attribute_group = {
> + .attrs = pcf2127_attrs,
> + },
> },
> };
>
> +/*
> + * Enable timestamp function and corresponding interrupt(s).
> + */
> +static int pcf2127_enable_ts(struct device *dev, int ts_id)
> +{
> + struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> + int ret;
> +
> + if (ts_id >= pcf2127->cfg->ts_count) {
> + dev_err(dev, "%s: invalid tamper detection ID (%d)\n",
> + __func__, ts_id);
> + return -EINVAL;
> + }
> +
> + /* Enable timestamp function. */
> + ret = regmap_update_bits(pcf2127->regmap,
> + pcf2127->cfg->ts[ts_id].regs_base,
> + PCF2127_BIT_TS_CTRL_TSOFF |
> + PCF2127_BIT_TS_CTRL_TSM,
> + PCF2127_BIT_TS_CTRL_TSM);
> + if (ret) {
> + dev_err(dev, "%s: tamper detection config (ts%d_ctrl) failed\n",
> + __func__, ts_id);
> + return ret;
> + }
> +
> + /* TS input pin driven to GND detection is supported by all variants.
> + * Make sure that low_bit is defined.
> + */
> + if (pcf2127->cfg->ts[ts_id].low_bit == 0) {
> + dev_err(dev, "%s: tamper detection LOW configuration invalid\n",
> + __func__);
> + return ret;
> + }
> +
> + /*
> + * Enable interrupt generation when TSF timestamp flag is set.
> + * Interrupt signals are open-drain outputs and can be left floating if
> + * unused.
> + */
> + ret = regmap_update_bits(pcf2127->regmap, pcf2127->cfg->ts[ts_id].ie_reg,
> + pcf2127->cfg->ts[ts_id].ie_bit,
> + pcf2127->cfg->ts[ts_id].ie_bit);
> + if (ret) {
> + dev_err(dev, "%s: tamper detection TSIE%d config failed\n",
> + __func__, ts_id);
> + return ret;
> + }
> +
> + return ret;
> +}
> +
> static int pcf2127_probe(struct device *dev, struct regmap *regmap,
> int alarm_irq, const char *name, const struct pcf21xx_config *config)
> {
> struct pcf2127 *pcf2127;
> int ret = 0;
> unsigned int val;
> + int i;
>
> dev_dbg(dev, "%s\n", __func__);
>
> @@ -813,34 +959,15 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
> }
>
> /*
> - * Enable timestamp function and store timestamp of first trigger
> - * event until TSF1 and TSF2 interrupt flags are cleared.
> + * Enable timestamp functions 1 to 4.
> */
> - ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_TS_CTRL,
> - PCF2127_BIT_TS_CTRL_TSOFF |
> - PCF2127_BIT_TS_CTRL_TSM,
> - PCF2127_BIT_TS_CTRL_TSM);
> - if (ret) {
> - dev_err(dev, "%s: tamper detection config (ts_ctrl) failed\n",
> - __func__);
> - return ret;
> - }
> -
> - /*
> - * Enable interrupt generation when TSF1 or TSF2 timestamp flags
> - * are set. Interrupt signal is an open-drain output and can be
> - * left floating if unused.
> - */
> - ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
> - PCF2127_BIT_CTRL2_TSIE,
> - PCF2127_BIT_CTRL2_TSIE);
> - if (ret) {
> - dev_err(dev, "%s: tamper detection config (ctrl2) failed\n",
> - __func__);
> - return ret;
> + for (i = 0; i < pcf2127->cfg->ts_count; i++) {
Just define the loop counter variable inline.
for (int i = 0; i < pcf2127->cfg->ts_count; i++) {
> + ret = pcf2127_enable_ts(dev, i);
> + if (ret)
> + return ret;
> }
>
> - ret = rtc_add_group(pcf2127->rtc, &pcf2127_attr_group);
> + ret = rtc_add_group(pcf2127->rtc, &pcf2127->cfg->attribute_group);
> if (ret) {
> dev_err(dev, "%s: tamper sysfs registering failed\n",
> __func__);
> --
> 2.30.2
>
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