Hello,
On 16/10/2022 18:29:13+0200, tollsimy wrote:
> RTC Microchip mcp795 patch for 5.19-rc5
>
> Here is the mcp795 patch for the 5.19-rc5 merge window.
> The main modification are the following:
> - fixed wrong driver naming: RTC is a Microchip
> mcp795 and not Maxim mcp795
> - added date/time write sequences: added date/time
> write sequences accordingly to official silicon
> errata document to fix silicon bugs.
> - added support to date/time permanent storage:
> the driver was missing some register bits in order
> to enable the storage of date/time whenever the
> device looses main power.
> - added a check after starting oscillator in order
> to be sure that it is properly working as specified
> in the datasheet
> - renamed OSCON bit to OSCRUN as in the datasheet
> - add debug messages when setting and reading the
> alarm
> - removed wrong offset when retrieving the current
> year from the device
>
> The patch has been successfully tested in the latest
> linux-next releases, and the original problems that I found have
> all been resolved.
>
> Signed-off-by: tollsimy <simonetollardo@xxxxxxxxx>
>
> ---
> .../devicetree/bindings/rtc/maxim,mcp795.txt | 11 -
> .../bindings/rtc/microchip,mcp795.txt | 11 +
> drivers/rtc/rtc-mcp795.c | 359 ++++++++++++++----
> 3 files changed, 296 insertions(+), 85 deletions(-)
> delete mode 100644 Documentation/devicetree/bindings/rtc/maxim,mcp795.txt
> create mode 100644 Documentation/devicetree/bindings/rtc/microchip,mcp795.txt
This needs to be a separate change, also, please convert to yaml.
>
> diff --git a/Documentation/devicetree/bindings/rtc/maxim,mcp795.txt b/Documentation/devicetree/bindings/rtc/maxim,mcp795.txt
> deleted file mode 100644
> index a59fdd8c236d..000000000000
> --- a/Documentation/devicetree/bindings/rtc/maxim,mcp795.txt
> +++ /dev/null
> @@ -1,11 +0,0 @@
> -* Maxim MCP795 SPI Serial Real-Time Clock
> -
> -Required properties:
> -- compatible: Should contain "maxim,mcp795".
> -- reg: SPI address for chip
> -
> -Example:
> - mcp795: rtc@0 {
> - compatible = "maxim,mcp795";
> - reg = <0>;
> - };
> diff --git a/Documentation/devicetree/bindings/rtc/microchip,mcp795.txt b/Documentation/devicetree/bindings/rtc/microchip,mcp795.txt
> new file mode 100644
> index 000000000000..854364c3a173
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rtc/microchip,mcp795.txt
> @@ -0,0 +1,11 @@
> +* Microchip MCP795 SPI Serial Real-Time Clock
> +
> +Required properties:
> +- compatible: Should contain "microchip,mcp795".
> +- reg: SPI address for chip
> +
> +Example:
> + mcp795: rtc@0 {
> + compatible = "microchip,mcp795";
> + reg = <0>;
> + };
> diff --git a/drivers/rtc/rtc-mcp795.c b/drivers/rtc/rtc-mcp795.c
> index 0d515b3df571..292a440b62dd 100644
> --- a/drivers/rtc/rtc-mcp795.c
> +++ b/drivers/rtc/rtc-mcp795.c
> @@ -3,11 +3,15 @@
> * SPI Driver for Microchip MCP795 RTC
> *
> * Copyright (C) Josef Gajdusek <atx@xxxxxxxx>
> + * Copyright (C) 2022 Simone Tollardo <simone.tollardo@xxxxxxxxx>
> *
> * based on other Linux RTC drivers
> *
> * Device datasheet:
> - * https://ww1.microchip.com/downloads/en/DeviceDoc/22280A.pdf
> + * https://ww1.microchip.com/downloads/en/DeviceDoc/MCP7951X-MCP7952X-Battery-Backed-SPI-RTCC-20002300C.pdf
> + *
> + * Device errata:
> + * http://ww1.microchip.com/downloads/en/DeviceDoc/MCP795XX-Family-Silicon-Errata-80000680D.pdf
> */
>
> #include <linux/module.h>
> @@ -32,28 +36,148 @@
> #define MCP795_UNLOCK 0x14
> #define MCP795_IDWRITE 0x32
> #define MCP795_IDREAD 0x33
> -#define MCP795_CLRWDT 0x44
> #define MCP795_CLRRAM 0x54
>
> /* MCP795 RTCC registers, see datasheet table 4-1 */
> +#define MCP795_REG_TMSECONDS 0x00 /* Tenths of ms (=centi-seconds) */
> #define MCP795_REG_SECONDS 0x01
> +#define MCP795_REG_MINUTES 0x02
> +#define MCP795_REG_HOURS 0x03
> #define MCP795_REG_DAY 0x04
> +#define MCP795_REG_DATE 0x05
> #define MCP795_REG_MONTH 0x06
> +#define MCP795_REG_YEAR 0x07
> #define MCP795_REG_CONTROL 0x08
> +#define MCP795_REG_OSC_TRIM 0x09
> +/* Alarm 0 */
> #define MCP795_REG_ALM0_SECONDS 0x0C
> +#define MCP795_REG_ALM0_MINUTES 0x0D
> +#define MCP795_REG_ALM0_HOURS 0x0E
> #define MCP795_REG_ALM0_DAY 0x0F
> -
> -#define MCP795_ST_BIT BIT(7)
> -#define MCP795_24_BIT BIT(6)
> -#define MCP795_LP_BIT BIT(5)
> -#define MCP795_EXTOSC_BIT BIT(3)
> -#define MCP795_OSCON_BIT BIT(5)
> -#define MCP795_ALM0_BIT BIT(4)
> -#define MCP795_ALM1_BIT BIT(5)
> -#define MCP795_ALM0IF_BIT BIT(3)
> -#define MCP795_ALM0C0_BIT BIT(4)
> -#define MCP795_ALM0C1_BIT BIT(5)
> -#define MCP795_ALM0C2_BIT BIT(6)
> +#define MCP795_REG_ALM0_DATE 0x10
> +#define MCP795_REG_ALM0_MONTH 0x11 /* Month only for alarm 0 */
> +/* Alarm 1 */
> +#define MCP795_REG_ALM1_TMSECONDS 0x12 /* Centi-seconds only for alarm 1 */
> +#define MCP795_REG_ALM1_SECONDS 0x13
> +#define MCP795_REG_ALM1_MINUTES 0x14
> +#define MCP795_REG_ALM1_HOURS 0x15
> +#define MCP795_REG_ALM1_DAY 0x16
> +#define MCP795_REG_ALM1_DATE 0x17
> +
> +/* Power-Fail Timestamp */
> +/* Power-Down Timetsamp */
> +#define MCP795_REG_PWD_MINUTES 0x18
> +#define MCP795_REG_PWD_HOURS 0x19
> +#define MCP795_REG_PWD_DATE 0x1A
> +#define MCP795_REG_PWD_MONTH 0x1B
> +/* Power-Up Timestamp */
> +#define MCP795_REG_PUP_MINUTES 0x1C
> +#define MCP795_REG_PUP_HOURS 0x1D
> +#define MCP795_REG_PUP_DATE 0x1E
> +#define MCP795_REG_PUP_MONTH 0x1F
> +
> +/* MCP795_REG_CONTROL bits */
> +
> +/* MISC */
> +#define MCP795_ST_BIT BIT(7) /* Status bit */
> +#define MCP795_24_BIT BIT(6) /* 12/24 hour mode */
> +#define MCP795_LP_BIT BIT(5) /* Leap Year */
> +#define MCP795_OSCRUN_BIT BIT(5) /* Oscillator Run */
> +#define MCP795_PWRFAIL_BIT BIT(4) /* Power Fail */
> +#define MCP795_VBATEN_BIT BIT(3) /* VBAT Enable */
> +
> +/* RTCC 0x08 register bits */
> +#define MCP795_SQWEN_BIT BIT(6) /* Square Wave Enable (MFP pin) */
> +#define MCP795_ALM1_EN_BIT BIT(5) /* Alarm 1 Enable */
> +#define MCP795_ALM0_EN_BIT BIT(4) /* Alarm 0 Enable */
> +#define MCP795_EXTOSC_BIT BIT(3) /* External Oscillator */
> +#define MCP795_CRSTRIM_BIT BIT(2) /* Crystal Trim */
> +#define MCP795_SQWFS_BIT_H BIT(1) /* Square Wave Frequency Select H */
> +#define MCP795_SQWFS_BIT_L BIT(0) /* Square Wave Frequency Select L */
> +
> +/* Alarms (0 and 1) */
> +
> +/* Centi-seconds - ALARM 1 ONLY */
> +/* Alarms BCD Decimal Values of Centi-Second's Tens Digit (=deci-seconds) */
> +#define MCP795_ALM1_CSEC_T_C0_BIT BIT(4)
> +#define MCP795_ALM1_CSEC_T_C1_BIT BIT(5)
> +#define MCP795_ALM1_CSEC_T_C2_BIT BIT(6)
> +#define MCP795_ALM1_CSEC_T_C3_BIT BIT(6)
> +/* Alarms BCD Decimal Values of Centi-Second's Ones Digit (=centi-seconds) */
> +#define MCP795_ALM1_CSEC_O_C0_BIT BIT(0)
> +#define MCP795_ALM1_CSEC_O_C1_BIT BIT(1)
> +#define MCP795_ALM1_CSEC_O_C2_BIT BIT(2)
> +#define MCP795_ALM1_CSEC_O_C3_BIT BIT(3)
> +
> +/* Seconds */
> +/* Alarms BCD Decimal Values of Second's Tens Digit */
> +#define MCP795_ALM_SEC_T_C0_BIT BIT(4)
> +#define MCP795_ALM_SEC_T_C1_BIT BIT(5)
> +#define MCP795_ALM_SEC_T_C2_BIT BIT(6)
> +/* Alarms BCD Decimal Values of Second's Ones Digit */
> +#define MCP795_ALM_SEC_O_C0_BIT BIT(0)
> +#define MCP795_ALM_SEC_O_C1_BIT BIT(1)
> +#define MCP795_ALM_SEC_O_C2_BIT BIT(2)
> +#define MCP795_ALM_SEC_O_C3_BIT BIT(3)
> +
> +/* Minutes */
> +/* Alarms BCD Decimal Values of Minute's Tens Digit */
> +#define MCP795_ALM_MIN_T_C0_BIT BIT(4)
> +#define MCP795_ALM_MIN_T_C1_BIT BIT(5)
> +#define MCP795_ALM_MIN_T_C2_BIT BIT(6)
> +/* Alarms BCD Decimal Values of Minute's Ones Digit */
> +#define MCP795_ALM_MIN_O_C0_BIT BIT(0)
> +#define MCP795_ALM_MIN_O_C1_BIT BIT(1)
> +#define MCP795_ALM_MIN_O_C2_BIT BIT(2)
> +#define MCP795_ALM_MIN_O_C3_BIT BIT(3)
> +
> +/* Hours */
> +/* Alarms BCD Decimal Values of Hour's Tens Digit */
> +#define MCP795_ALM_HOUR_T_C0_BIT BIT(4)
> +/* Alarms BCD Decimal Values of Hour's Ones Digit */
> +#define MCP795_ALM_HOUR_O_C0_BIT BIT(0)
> +#define MCP795_ALM_HOUR_O_C1_BIT BIT(1)
> +#define MCP795_ALM_HOUR_O_C2_BIT BIT(2)
> +#define MCP795_ALM_HOUR_O_C3_BIT BIT(3)
> +
> +/* Days */
> +/* Alarms Interrupt Flag */
> +#define MCP795_ALM_IF_BIT BIT(3)
> +/* Alarms BCD Decimal Values of Day's Ones Digit */
> +#define MCP795_ALM_DAY_O_C0_BIT BIT(0)
> +#define MCP795_ALM_DAY_O_C1_BIT BIT(1)
> +#define MCP795_ALM_DAY_O_C2_BIT BIT(2)
> +
> +/* Date */
> +/* Alarms BCD Decimal Values of Date's Tens Digit */
> +#define MCP795_ALM_DATE_T_C0_BIT BIT(4)
> +#define MCP795_ALM_DATE_T_C1_BIT BIT(5)
> +/* Alarms BCD Decimal Values of Date's Ones Digit */
> +#define MCP795_ALM_DATE_O_C0_BIT BIT(0)
> +#define MCP795_ALM_DATE_O_C1_BIT BIT(1)
> +#define MCP795_ALM_DATE_O_C2_BIT BIT(2)
> +#define MCP795_ALM_DATE_O_C3_BIT BIT(3)
> +
> +/* Months */
> +/* Alarms BCD Decimal Values of Month's Tens Digit */
> +#define MCP795_ALM0_MONTH_T_C0_BIT BIT(3)
> +/* Alarms BCD Decimal Values of Month's Ones Digit */
> +#define MCP795_ALM0_MONTH_O_C0_BIT BIT(0)
> +#define MCP795_ALM0_MONTH_O_C1_BIT BIT(1)
> +#define MCP795_ALM0_MONTH_O_C2_BIT BIT(2)
> +#define MCP795_ALM0_MONTH_O_C3_BIT BIT(3)
> +
> +/* Alarms Masks */
> +#define MCP795_ALM_MASKS_BIT BIT(4)
> +
> +/* BCD mask values for alarm matching - need BCD conversion */
> +#define MCP795_ALM_MASK_SEC 0x00
> +#define MCP795_ALM_MASK_MIN 0x01
> +#define MCP795_ALM_MASK_HOUR 0x02
> +#define MCP795_ALM_MASK_DAY 0x03
> +#define MCP795_ALM_MASK_DATE 0x04
> +#define MCP795_ALM_MASK_CSEC 0x05
> +#define MCP795_ALM_MASK_ALL 0x07
You have a bunch of unused defines, please remove them
>
> #define SEC_PER_DAY (24 * 60 * 60)
>
> @@ -69,7 +193,7 @@ static int mcp795_rtcc_read(struct device *dev, u8 addr, u8 *buf, u8 count)
>
> if (ret)
> dev_err(dev, "Failed reading %d bytes from address %x.\n",
> - count, addr);
> + count, addr);
Unnecessary change
>
> return ret;
> }
> @@ -88,7 +212,7 @@ static int mcp795_rtcc_write(struct device *dev, u8 addr, u8 *data, u8 count)
>
> if (ret)
> dev_err(dev, "Failed to write %d bytes to address %x.\n",
> - count, addr);
> + count, addr);
>
Unnecessary change
> return ret;
> }
> @@ -123,17 +247,16 @@ static int mcp795_stop_oscillator(struct device *dev, bool *extosc)
> if (ret)
> return ret;
> *extosc = !!(data & MCP795_EXTOSC_BIT);
> - ret = mcp795_rtcc_set_bits(
> - dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, 0);
> + ret = mcp795_rtcc_set_bits(dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, 0);
ditto
> if (ret)
> return ret;
> - /* wait for the OSCON bit to clear */
> + /* wait for the OSCRUN bit to clear */
> do {
> usleep_range(700, 800);
> ret = mcp795_rtcc_read(dev, MCP795_REG_DAY, &data, 1);
> if (ret)
> break;
> - if (!(data & MCP795_OSCON_BIT))
> + if (!(data & MCP795_OSCRUN_BIT))
I'm not really in favour of changing a define name but do so in a
separate patch.
> break;
>
> } while (--retries);
> @@ -143,17 +266,34 @@ static int mcp795_stop_oscillator(struct device *dev, bool *extosc)
>
> static int mcp795_start_oscillator(struct device *dev, bool *extosc)
> {
> + int ret;
> + int retries = 5;
> +
> if (extosc) {
> u8 data = *extosc ? MCP795_EXTOSC_BIT : 0;
> - int ret;
>
> - ret = mcp795_rtcc_set_bits(
> - dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, data);
> + ret = mcp795_rtcc_set_bits(dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, data);
Unnecessary change
> if (ret)
> return ret;
> }
> - return mcp795_rtcc_set_bits(
> - dev, MCP795_REG_SECONDS, MCP795_ST_BIT, MCP795_ST_BIT);
> + ret = mcp795_rtcc_set_bits(dev, MCP795_REG_SECONDS, MCP795_ST_BIT, MCP795_ST_BIT);
> + if (ret)
> + return ret;
> +
> + /* wait for the OSCRUN bit to set */
This comment is not really useful
> + do {
> + u8 data = MCP795_OSCRUN_BIT;
> +
> + usleep_range(700, 800);
but this needs to be documented
> + ret = mcp795_rtcc_read(dev, MCP795_REG_DAY, &data, 1);
> + if (ret)
> + break;
> + if ((data & MCP795_OSCRUN_BIT))
> + break;
> +
> + } while (--retries);
Then number of retires too. Maybe it would better to have a timeout
instead?
> +
> + return !retries ? -EIO : ret;
> }
>
> /* Enable or disable Alarm 0 in RTC */
> @@ -164,18 +304,24 @@ static int mcp795_update_alarm(struct device *dev, bool enable)
> dev_dbg(dev, "%s alarm\n", enable ? "Enable" : "Disable");
>
> if (enable) {
> + /* Disable Square Wave Function to enable Alarm output */
> + ret = mcp795_rtcc_set_bits(dev, MCP795_REG_CONTROL,
> + MCP795_SQWEN_BIT, 0);
ret is not checked here?
Also, the SQW may be useful to calibrate the oscillator, this
unconditionally breaks that feature
> /* clear ALM0IF (Alarm 0 Interrupt Flag) bit */
> ret = mcp795_rtcc_set_bits(dev, MCP795_REG_ALM0_DAY,
> - MCP795_ALM0IF_BIT, 0);
> + MCP795_ALM_IF_BIT, 0);
This renaming also seems unnecessary and makes reading the patch more
complicated
> if (ret)
> return ret;
> /* enable alarm 0 */
> ret = mcp795_rtcc_set_bits(dev, MCP795_REG_CONTROL,
> - MCP795_ALM0_BIT, MCP795_ALM0_BIT);
> + MCP795_ALM0_EN_BIT, MCP795_ALM0_EN_BIT);
> } else {
> /* disable alarm 0 and alarm 1 */
> ret = mcp795_rtcc_set_bits(dev, MCP795_REG_CONTROL,
> - MCP795_ALM0_BIT | MCP795_ALM1_BIT, 0);
> + MCP795_ALM0_EN_BIT | MCP795_ALM1_EN_BIT, 0);
> + /* Disable Alarm output to let enable Square Wave Function */
> + ret = mcp795_rtcc_set_bits(dev, MCP795_REG_CONTROL,
> + MCP795_SQWEN_BIT, 0);
The code doesn't do what the comment says and so the comment is useless
> }
> return ret;
> }
> @@ -183,7 +329,7 @@ static int mcp795_update_alarm(struct device *dev, bool enable)
> static int mcp795_set_time(struct device *dev, struct rtc_time *tim)
> {
> int ret;
> - u8 data[7];
> + u8 data[8];
> bool extosc;
>
> /* Stop RTC and store current value of EXTOSC bit */
> @@ -192,32 +338,42 @@ static int mcp795_set_time(struct device *dev, struct rtc_time *tim)
> return ret;
>
> /* Read first, so we can leave config bits untouched */
> - ret = mcp795_rtcc_read(dev, MCP795_REG_SECONDS, data, sizeof(data));
> + ret = mcp795_rtcc_read(dev, MCP795_REG_TMSECONDS, data, sizeof(data));
Why do you read centiseconds here?
>
> if (ret)
> return ret;
>
> - data[0] = (data[0] & 0x80) | bin2bcd(tim->tm_sec);
> - data[1] = (data[1] & 0x80) | bin2bcd(tim->tm_min);
> - data[2] = bin2bcd(tim->tm_hour);
> - data[3] = (data[3] & 0xF8) | bin2bcd(tim->tm_wday + 1);
> - data[4] = bin2bcd(tim->tm_mday);
> - data[5] = (data[5] & MCP795_LP_BIT) | bin2bcd(tim->tm_mon + 1);
> -
> - if (tim->tm_year > 100)
> - tim->tm_year -= 100;
> -
> - data[6] = bin2bcd(tim->tm_year);
> -
> - /* Always write the date and month using a separate Write command.
> - * This is a workaround for a know silicon issue that some combinations
> - * of date and month values may result in the date being reset to 1.
> - */
> - ret = mcp795_rtcc_write(dev, MCP795_REG_SECONDS, data, 5);
> + data[0] = 0x00; //centiseconds not implemented
> + data[1] = (data[0] & 0x80) | bin2bcd(tim->tm_sec);
I think one of the index is not correct
> + data[2] = (data[1] & 0x80) | bin2bcd(tim->tm_min);
ditto
> + data[3] = (data[3] & 0xC0) | bin2bcd(tim->tm_hour);
> + /* Add one beacause Linux weekday is from 0 to 6 */
I don't think this comment is useful
> + data[4] = (data[3] & 0xF8) | bin2bcd(tim->tm_wday + 1);
> + data[5] = (data[5] & 0xC0) | bin2bcd(tim->tm_mday);
> + /* Add one because Linux month is from 0 to 11 */
ditto
> + data[6] = (data[6] & 0xC0) | ((data[6] & MCP795_LP_BIT)
> + | bin2bcd(tim->tm_mon + 1));
> + data[7] = bin2bcd(tim->tm_year);
> +
> + /* Set time sequence needed to avoid common device problems, see errata */
> + /* Write month */
> + ret = mcp795_rtcc_write(dev, MCP795_REG_MONTH, &data[6], 1);
> if (ret)
> return ret;
> -
> - ret = mcp795_rtcc_write(dev, MCP795_REG_MONTH, &data[5], 2);
> + /* Write data (month day) */
> + ret = mcp795_rtcc_write(dev, MCP795_REG_DATE, &data[5], 1);
> + if (ret)
> + return ret;
> + /* Write month again */
> + ret = mcp795_rtcc_write(dev, MCP795_REG_MONTH, &data[6], 1);
> + if (ret)
> + return ret;
> + /* Send the rest apart from year and dayweek */
> + ret = mcp795_rtcc_write(dev, MCP795_REG_TMSECONDS, data, 4);
> + if (ret)
> + return ret;
> + /* Send the year */
> + ret = mcp795_rtcc_write(dev, MCP795_REG_YEAR, &data[7], 1);
> if (ret)
> return ret;
>
> @@ -229,6 +385,14 @@ static int mcp795_set_time(struct device *dev, struct rtc_time *tim)
> if (ret)
> return ret;
>
> + /* Always set the weekday using a separate Write command and when
> + * oscillator is running.
> + * This is a workaround for a know silicon issue.
> + */
> + ret = mcp795_rtcc_write(dev, MCP795_REG_DAY, &data[4], 1);
> + if (ret)
> + return ret;
> +
> dev_dbg(dev, "Set mcp795: %ptR\n", tim);
>
> return 0;
> @@ -237,20 +401,23 @@ static int mcp795_set_time(struct device *dev, struct rtc_time *tim)
> static int mcp795_read_time(struct device *dev, struct rtc_time *tim)
> {
> int ret;
> - u8 data[7];
> + u8 data[8];
> + int tm_c_sec;
>
> - ret = mcp795_rtcc_read(dev, MCP795_REG_SECONDS, data, sizeof(data));
> + ret = mcp795_rtcc_read(dev, MCP795_REG_TMSECONDS, data, sizeof(data));
>
> if (ret)
> return ret;
>
> - tim->tm_sec = bcd2bin(data[0] & 0x7F);
> - tim->tm_min = bcd2bin(data[1] & 0x7F);
> - tim->tm_hour = bcd2bin(data[2] & 0x3F);
> - tim->tm_wday = bcd2bin(data[3] & 0x07) - 1;
> - tim->tm_mday = bcd2bin(data[4] & 0x3F);
> - tim->tm_mon = bcd2bin(data[5] & 0x1F) - 1;
> - tim->tm_year = bcd2bin(data[6]) + 100; /* Assume we are in 20xx */
> + tm_c_sec = bcd2bin(data[0] & 0xFF);
> + tim->tm_sec = bcd2bin(data[1] & 0x7F);
> + tim->tm_min = bcd2bin(data[2] & 0x7F);
> + /* This is only for 24h mode, see datasheet for 12h mode */
> + tim->tm_hour = bcd2bin(data[3] & 0x3F);
> + tim->tm_wday = bcd2bin(data[4] & 0x07) - 1;
> + tim->tm_mday = bcd2bin(data[5] & 0x3F);
> + tim->tm_mon = bcd2bin(data[6] & 0x1F) - 1;
> + tim->tm_year = bcd2bin(data[7]);
>
> dev_dbg(dev, "Read from mcp795: %ptR\n", tim);
>
> @@ -265,6 +432,17 @@ static int mcp795_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
> u8 tmp[6];
> int ret;
>
> + /* Set Alarm 0 Mask to match all */
> + /* Read first, so we can leave other bits untouched */
> + ret = mcp795_rtcc_read(dev, MCP795_REG_ALM0_DAY, tmp, 1);
> + if (ret)
> + return ret;
> + /* Set Alarm 0 Mask to match all */
> + tmp[0] = (tmp[0] & 0x8F) | (bin2bcd(MCP795_ALM_MASK_ALL) << 4);
If possible, I wouldn't match all and simply drop weekday, there is no
guarantee that userspace will provide a valid weekday and you could then
drop the previous workaround while setting weekday.
> + ret = mcp795_rtcc_write(dev, MCP795_REG_ALM0_DAY, tmp, 1);
> + if (ret)
> + return ret;
> +
> /* Read current time from RTC hardware */
> ret = mcp795_read_time(dev, &now_tm);
> if (ret)
> @@ -291,12 +469,14 @@ static int mcp795_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
> alm->time.tm_isdst = -1;
> alm->time.tm_yday = -1;
>
> + /* set alarm match: seconds, minutes, hour, day, date and month */
> tmp[0] = (tmp[0] & 0x80) | bin2bcd(alm->time.tm_sec);
> tmp[1] = (tmp[1] & 0x80) | bin2bcd(alm->time.tm_min);
> tmp[2] = (tmp[2] & 0xE0) | bin2bcd(alm->time.tm_hour);
> tmp[3] = (tmp[3] & 0x80) | bin2bcd(alm->time.tm_wday + 1);
> - /* set alarm match: seconds, minutes, hour, day, date and month */
> - tmp[3] |= (MCP795_ALM0C2_BIT | MCP795_ALM0C1_BIT | MCP795_ALM0C0_BIT);
> + /* ALMxIF cleared in the update function */
> + tmp[3] |= (MCP795_ALM_SEC_T_C2_BIT | MCP795_ALM_SEC_T_C1_BIT
> + | MCP795_ALM_SEC_T_C0_BIT);
> tmp[4] = (tmp[4] & 0xC0) | bin2bcd(alm->time.tm_mday);
> tmp[5] = (tmp[5] & 0xE0) | bin2bcd(alm->time.tm_mon + 1);
>
> @@ -309,10 +489,14 @@ static int mcp795_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
> ret = mcp795_update_alarm(dev, true);
> if (ret)
> return ret;
> + alm->pending = 1;
Why is that needed?
> dev_dbg(dev, "Alarm IRQ armed\n");
> }
> - dev_dbg(dev, "Set alarm: %ptRdr(%d) %ptRt\n",
> - &alm->time, alm->time.tm_wday, &alm->time);
> +
> + /* do not print year, it's not implemented in the RTC hardware */
> + dev_dbg(dev, "Set alarm: %02d-%02dT%02d:%02d:%02d\n", alm->time.tm_mon + 1,
> + alm->time.tm_mday, alm->time.tm_hour, alm->time.tm_min, alm->time.tm_sec);
> +
This is a debug print, I don't think it is an issue to print year
anyway.
> return 0;
> }
>
> @@ -321,8 +505,7 @@ static int mcp795_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
> u8 data[6];
> int ret;
>
> - ret = mcp795_rtcc_read(
> - dev, MCP795_REG_ALM0_SECONDS, data, sizeof(data));
> + ret = mcp795_rtcc_read(dev, MCP795_REG_ALM0_SECONDS, data, sizeof(data));
Unnecessary change
> if (ret)
> return ret;
>
> @@ -336,8 +519,17 @@ static int mcp795_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
> alm->time.tm_isdst = -1;
> alm->time.tm_yday = -1;
>
> - dev_dbg(dev, "Read alarm: %ptRdr(%d) %ptRt\n",
> - &alm->time, alm->time.tm_wday, &alm->time);
> + alm->pending = !!(data[3] & MCP795_ALM_IF_BIT);
> +
> + ret = mcp795_rtcc_read(dev, MCP795_REG_CONTROL, data, 1);
> + if (ret)
> + return ret;
> + alm->enabled = !!(data[0] & MCP795_ALM0_EN_BIT);
> +
> + /* Do not print year, it's not implemented in the RTC hardware */
> + dev_dbg(dev, "Read alarm: %02d-%02dT%02d:%02d:%02d\n", alm->time.tm_mon + 1,
> + alm->time.tm_mday, alm->time.tm_hour, alm->time.tm_min, alm->time.tm_sec);
> +
> return 0;
> }
>
> @@ -381,6 +573,7 @@ static int mcp795_probe(struct spi_device *spi)
> {
> struct rtc_device *rtc;
> int ret;
> + u8 data;
>
> spi->mode = SPI_MODE_0;
> spi->bits_per_word = 8;
> @@ -393,10 +586,10 @@ static int mcp795_probe(struct spi_device *spi)
> /* Start the oscillator but don't set the value of EXTOSC bit */
> mcp795_start_oscillator(&spi->dev, NULL);
> /* Clear the 12 hour mode flag*/
> - mcp795_rtcc_set_bits(&spi->dev, 0x03, MCP795_24_BIT, 0);
> + mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_HOURS, MCP795_24_BIT, 0);
>
> rtc = devm_rtc_device_register(&spi->dev, "rtc-mcp795",
> - &mcp795_rtc_ops, THIS_MODULE);
> + &mcp795_rtc_ops, THIS_MODULE);
ditto
> if (IS_ERR(rtc))
> return PTR_ERR(rtc);
>
> @@ -409,22 +602,40 @@ static int mcp795_probe(struct spi_device *spi)
> * the interrupt.
> */
> mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_ALM0_DAY,
> - MCP795_ALM0IF_BIT, 0);
> - ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
> - mcp795_irq, IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> - dev_name(&rtc->dev), spi);
> + MCP795_ALM_IF_BIT, 0);
> + ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL, mcp795_irq,
> + IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> + dev_name(&rtc->dev), spi);
ditto
> if (ret)
> dev_err(&spi->dev, "Failed to request IRQ: %d: %d\n",
> - spi->irq, ret);
> + spi->irq, ret);
ditto
> else
> device_init_wakeup(&spi->dev, true);
> }
> +
> + /* If PWRFAIL BIT is set, it must be cleared */
> + ret = mcp795_rtcc_read(&spi->dev, MCP795_REG_DAY, &data, 1);
> + if (ret)
> + return ret;
> +
> + if (!!(data & MCP795_PWRFAIL_BIT)) {
> + ret = mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_DAY,
> + MCP795_PWRFAIL_BIT, 0);
> + if (ret)
> + return ret;
If this indicates that the time/date is invalid, then it must not be
cleared in the probe and instead in set_time also this information has
to be used in read_time
> + }
> + /* Set VBAT flag to 1 */
> + ret = mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_DAY, MCP795_VBATEN_BIT,
> + MCP795_VBATEN_BIT);
There is a proper interface to set the backup mode, please use it
> + if (ret)
> + return ret;
> +
> return 0;
> }
>
> #ifdef CONFIG_OF
> static const struct of_device_id mcp795_of_match[] = {
> - { .compatible = "maxim,mcp795" },
> + { .compatible = "microchip,mcp795" },
> { }
You should really slice this up in separate changes to make reviewing
easier.
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
