* [PATCH 1/2] Microchip MCP795xx RTC driver patch
@ 2022-10-15 23:39 tollsimy
2022-10-16 10:35 ` Alexandre Belloni
0 siblings, 1 reply; 3+ messages in thread
From: tollsimy @ 2022-10-15 23:39 UTC (permalink / raw)
To: a.zummo; +Cc: alexandre.belloni, linux-rtc, linux-kernel, tollsimy
---
drivers/rtc/rtc-mcp795.c | 428 +++++++++++++++++++++++++++++----------
1 file changed, 322 insertions(+), 106 deletions(-)
diff --git a/drivers/rtc/rtc-mcp795.c b/drivers/rtc/rtc-mcp795.c
index 0d515b3df571..0e52812a8f85 100644
--- a/drivers/rtc/rtc-mcp795.c
+++ b/drivers/rtc/rtc-mcp795.c
@@ -3,13 +3,18 @@
* SPI Driver for Microchip MCP795 RTC
*
* Copyright (C) Josef Gajdusek <atx@atx.name>
+ * Copyright (C) 2022 Simone Tollardo <simone.tollardo@gmail.com>
*
* 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>
#include <linux/kernel.h>
#include <linux/device.h>
@@ -21,42 +26,164 @@
#include <linux/delay.h>
/* MCP795 Instructions, see datasheet table 3-1 */
-#define MCP795_EEREAD 0x03
-#define MCP795_EEWRITE 0x02
-#define MCP795_EEWRDI 0x04
-#define MCP795_EEWREN 0x06
-#define MCP795_SRREAD 0x05
-#define MCP795_SRWRITE 0x01
-#define MCP795_READ 0x13
-#define MCP795_WRITE 0x12
-#define MCP795_UNLOCK 0x14
-#define MCP795_IDWRITE 0x32
-#define MCP795_IDREAD 0x33
-#define MCP795_CLRWDT 0x44
-#define MCP795_CLRRAM 0x54
+#define MCP795_EEREAD 0x03
+#define MCP795_EEWRITE 0x02
+#define MCP795_EEWRDI 0x04
+#define MCP795_EEWREN 0x06
+#define MCP795_SRREAD 0x05
+#define MCP795_SRWRITE 0x01
+#define MCP795_READ 0x13
+#define MCP795_WRITE 0x12
+#define MCP795_UNLOCK 0x14
+#define MCP795_IDWRITE 0x32
+#define MCP795_IDREAD 0x33
+#define MCP795_CLRRAM 0x54
/* MCP795 RTCC registers, see datasheet table 4-1 */
-#define MCP795_REG_SECONDS 0x01
-#define MCP795_REG_DAY 0x04
-#define MCP795_REG_MONTH 0x06
-#define MCP795_REG_CONTROL 0x08
-#define MCP795_REG_ALM0_SECONDS 0x0C
-#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 SEC_PER_DAY (24 * 60 * 60)
-
+#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_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
+
+
+#define SEC_PER_DAY (24 * 60 * 60)
+
+/* NOTE: count is size in bytes */
static int mcp795_rtcc_read(struct device *dev, u8 addr, u8 *buf, u8 count)
{
struct spi_device *spi = to_spi_device(dev);
@@ -65,11 +192,11 @@ static int mcp795_rtcc_read(struct device *dev, u8 addr, u8 *buf, u8 count)
tx[0] = MCP795_READ;
tx[1] = addr;
+ /* count in bytes */
ret = spi_write_then_read(spi, tx, sizeof(tx), buf, count);
if (ret)
- dev_err(dev, "Failed reading %d bytes from address %x.\n",
- count, addr);
+ dev_err(dev, "Failed reading %d bytes from address %x.\n", count, addr);
return ret;
}
@@ -87,8 +214,7 @@ static int mcp795_rtcc_write(struct device *dev, u8 addr, u8 *data, u8 count)
ret = spi_write(spi, tx, 2 + count);
if (ret)
- dev_err(dev, "Failed to write %d bytes to address %x.\n",
- count, addr);
+ dev_err(dev, "Failed to write %d bytes to address %x.\n", count, addr);
return ret;
}
@@ -124,16 +250,17 @@ static int mcp795_stop_oscillator(struct device *dev, bool *extosc)
return ret;
*extosc = !!(data & MCP795_EXTOSC_BIT);
ret = mcp795_rtcc_set_bits(
- dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, 0);
+ dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, 0);
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))
break;
} while (--retries);
@@ -143,17 +270,33 @@ static int mcp795_stop_oscillator(struct device *dev, bool *extosc)
static int mcp795_start_oscillator(struct device *dev, bool *extosc)
{
- if (extosc) {
- u8 data = *extosc ? MCP795_EXTOSC_BIT : 0;
- int ret;
-
- ret = mcp795_rtcc_set_bits(
- dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, data);
- if (ret)
- return ret;
- }
- return mcp795_rtcc_set_bits(
- dev, MCP795_REG_SECONDS, MCP795_ST_BIT, MCP795_ST_BIT);
+ int ret;
+ int retries = 5;
+ if (extosc) {
+ u8 data = *extosc ? MCP795_EXTOSC_BIT : 0;
+ ret = mcp795_rtcc_set_bits(
+ dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, data);
+ if (ret)
+ return ret;
+ }
+ 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 */
+ do {
+ u8 data = MCP795_OSCRUN_BIT;
+ usleep_range(700, 800);
+ ret = mcp795_rtcc_read(dev, MCP795_REG_DAY, &data, 1);
+ if (ret)
+ break;
+ if ((data & MCP795_OSCRUN_BIT))
+ break;
+
+ } while (--retries);
+
+ return !retries ? -EIO : ret;
}
/* Enable or disable Alarm 0 in RTC */
@@ -164,18 +307,24 @@ 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);
/* 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);
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);
}
return ret;
}
@@ -183,7 +332,7 @@ 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 +341,41 @@ 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));
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[1] & 0x80) | bin2bcd(tim->tm_sec);
+ data[2] = (data[2] & 0x80) | bin2bcd(tim->tm_min);
+ data[3] = (data[3] & 0xC0) | bin2bcd(tim->tm_hour);
+ /* Add one beacause Linux weekday is from 0 to 6 */
+ data[4] = (data[4] & 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 */
+ 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 +387,14 @@ 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 +403,23 @@ 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 +434,17 @@ 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);
+ 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 +471,14 @@ 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 +491,15 @@ 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;
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);
+
return 0;
}
@@ -321,8 +508,7 @@ 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));
if (ret)
return ret;
@@ -336,8 +522,18 @@ 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;
}
@@ -361,7 +557,8 @@ static irqreturn_t mcp795_irq(int irq, void *data)
ret = mcp795_update_alarm(&spi->dev, false);
if (ret)
dev_err(&spi->dev,
- "Failed to disable alarm in IRQ (ret=%d)\n", ret);
+ "Failed to disable alarm in IRQ (ret=%d)\n", ret);
+
rtc_update_irq(rtc, 1, RTC_AF | RTC_IRQF);
rtc_unlock(rtc);
@@ -381,6 +578,7 @@ 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;
@@ -393,38 +591,56 @@ 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);
- if (IS_ERR(rtc))
- return PTR_ERR(rtc);
+ &mcp795_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc)){
+ return PTR_ERR(rtc);}
spi_set_drvdata(spi, rtc);
if (spi->irq > 0) {
dev_dbg(&spi->dev, "Alarm support enabled\n");
-
/* Clear any pending alarm (ALM0IF bit) before requesting
* the interrupt.
*/
mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_ALM0_DAY,
- MCP795_ALM0IF_BIT, 0);
+ 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);
+ mcp795_irq, IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+ dev_name(&rtc->dev), spi);
if (ret)
dev_err(&spi->dev, "Failed to request IRQ: %d: %d\n",
- spi->irq, ret);
+ spi->irq, ret);
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;
+ }
+ /* Set VBAT FLAG TO 1 */
+ ret = mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_DAY, MCP795_VBATEN_BIT,
+ MCP795_VBATEN_BIT);
+ if (ret)
+ return ret;
+
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id mcp795_of_match[] = {
- { .compatible = "maxim,mcp795" },
+ { .compatible = "microchip,mcp795" },
{ }
};
MODULE_DEVICE_TABLE(of, mcp795_of_match);
--
2.37.3
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 1/2] Microchip MCP795xx RTC driver patch
2022-10-15 23:39 [PATCH 1/2] Microchip MCP795xx RTC driver patch tollsimy
@ 2022-10-16 10:35 ` Alexandre Belloni
0 siblings, 0 replies; 3+ messages in thread
From: Alexandre Belloni @ 2022-10-16 10:35 UTC (permalink / raw)
To: tollsimy; +Cc: a.zummo, linux-rtc, linux-kernel
Hello,
On 16/10/2022 01:39:33+0200, tollsimy wrote:
This is missing a message and SoB. Also, you have to pass checkpatch
--strict and remove the useless refactoring.
> ---
> drivers/rtc/rtc-mcp795.c | 428 +++++++++++++++++++++++++++++----------
> 1 file changed, 322 insertions(+), 106 deletions(-)
>
> diff --git a/drivers/rtc/rtc-mcp795.c b/drivers/rtc/rtc-mcp795.c
> index 0d515b3df571..0e52812a8f85 100644
> --- a/drivers/rtc/rtc-mcp795.c
> +++ b/drivers/rtc/rtc-mcp795.c
> @@ -3,13 +3,18 @@
> * SPI Driver for Microchip MCP795 RTC
> *
> * Copyright (C) Josef Gajdusek <atx@atx.name>
> + * Copyright (C) 2022 Simone Tollardo <simone.tollardo@gmail.com>
> *
> * 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>
> #include <linux/kernel.h>
> #include <linux/device.h>
> @@ -21,42 +26,164 @@
> #include <linux/delay.h>
>
> /* MCP795 Instructions, see datasheet table 3-1 */
> -#define MCP795_EEREAD 0x03
> -#define MCP795_EEWRITE 0x02
> -#define MCP795_EEWRDI 0x04
> -#define MCP795_EEWREN 0x06
> -#define MCP795_SRREAD 0x05
> -#define MCP795_SRWRITE 0x01
> -#define MCP795_READ 0x13
> -#define MCP795_WRITE 0x12
> -#define MCP795_UNLOCK 0x14
> -#define MCP795_IDWRITE 0x32
> -#define MCP795_IDREAD 0x33
> -#define MCP795_CLRWDT 0x44
> -#define MCP795_CLRRAM 0x54
> +#define MCP795_EEREAD 0x03
> +#define MCP795_EEWRITE 0x02
> +#define MCP795_EEWRDI 0x04
> +#define MCP795_EEWREN 0x06
> +#define MCP795_SRREAD 0x05
> +#define MCP795_SRWRITE 0x01
> +#define MCP795_READ 0x13
> +#define MCP795_WRITE 0x12
> +#define MCP795_UNLOCK 0x14
> +#define MCP795_IDWRITE 0x32
> +#define MCP795_IDREAD 0x33
> +#define MCP795_CLRRAM 0x54
>
> /* MCP795 RTCC registers, see datasheet table 4-1 */
> -#define MCP795_REG_SECONDS 0x01
> -#define MCP795_REG_DAY 0x04
> -#define MCP795_REG_MONTH 0x06
> -#define MCP795_REG_CONTROL 0x08
> -#define MCP795_REG_ALM0_SECONDS 0x0C
> -#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 SEC_PER_DAY (24 * 60 * 60)
> -
> +#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_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
> +
> +
> +#define SEC_PER_DAY (24 * 60 * 60)
> +
> +/* NOTE: count is size in bytes */
> static int mcp795_rtcc_read(struct device *dev, u8 addr, u8 *buf, u8 count)
> {
> struct spi_device *spi = to_spi_device(dev);
> @@ -65,11 +192,11 @@ static int mcp795_rtcc_read(struct device *dev, u8 addr, u8 *buf, u8 count)
>
> tx[0] = MCP795_READ;
> tx[1] = addr;
> + /* count in bytes */
> ret = spi_write_then_read(spi, tx, sizeof(tx), buf, count);
>
> if (ret)
> - dev_err(dev, "Failed reading %d bytes from address %x.\n",
> - count, addr);
> + dev_err(dev, "Failed reading %d bytes from address %x.\n", count, addr);
>
> return ret;
> }
> @@ -87,8 +214,7 @@ static int mcp795_rtcc_write(struct device *dev, u8 addr, u8 *data, u8 count)
> ret = spi_write(spi, tx, 2 + count);
>
> if (ret)
> - dev_err(dev, "Failed to write %d bytes to address %x.\n",
> - count, addr);
> + dev_err(dev, "Failed to write %d bytes to address %x.\n", count, addr);
>
> return ret;
> }
> @@ -124,16 +250,17 @@ static int mcp795_stop_oscillator(struct device *dev, bool *extosc)
> return ret;
> *extosc = !!(data & MCP795_EXTOSC_BIT);
> ret = mcp795_rtcc_set_bits(
> - dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, 0);
> + dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, 0);
> 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))
> break;
>
> } while (--retries);
> @@ -143,17 +270,33 @@ static int mcp795_stop_oscillator(struct device *dev, bool *extosc)
>
> static int mcp795_start_oscillator(struct device *dev, bool *extosc)
> {
> - if (extosc) {
> - u8 data = *extosc ? MCP795_EXTOSC_BIT : 0;
> - int ret;
> -
> - ret = mcp795_rtcc_set_bits(
> - dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, data);
> - if (ret)
> - return ret;
> - }
> - return mcp795_rtcc_set_bits(
> - dev, MCP795_REG_SECONDS, MCP795_ST_BIT, MCP795_ST_BIT);
> + int ret;
> + int retries = 5;
> + if (extosc) {
> + u8 data = *extosc ? MCP795_EXTOSC_BIT : 0;
> + ret = mcp795_rtcc_set_bits(
> + dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, data);
> + if (ret)
> + return ret;
> + }
> + 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 */
> + do {
> + u8 data = MCP795_OSCRUN_BIT;
> + usleep_range(700, 800);
> + ret = mcp795_rtcc_read(dev, MCP795_REG_DAY, &data, 1);
> + if (ret)
> + break;
> + if ((data & MCP795_OSCRUN_BIT))
> + break;
> +
> + } while (--retries);
> +
> + return !retries ? -EIO : ret;
> }
>
> /* Enable or disable Alarm 0 in RTC */
> @@ -164,18 +307,24 @@ 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);
> /* 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);
> 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);
> }
> return ret;
> }
> @@ -183,7 +332,7 @@ 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 +341,41 @@ 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));
> 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[1] & 0x80) | bin2bcd(tim->tm_sec);
> + data[2] = (data[2] & 0x80) | bin2bcd(tim->tm_min);
> + data[3] = (data[3] & 0xC0) | bin2bcd(tim->tm_hour);
> + /* Add one beacause Linux weekday is from 0 to 6 */
> + data[4] = (data[4] & 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 */
> + 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 +387,14 @@ 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 +403,23 @@ 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 +434,17 @@ 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);
> + 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 +471,14 @@ 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 +491,15 @@ 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;
> 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);
> +
> return 0;
> }
>
> @@ -321,8 +508,7 @@ 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));
> if (ret)
> return ret;
>
> @@ -336,8 +522,18 @@ 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;
> }
>
> @@ -361,7 +557,8 @@ static irqreturn_t mcp795_irq(int irq, void *data)
> ret = mcp795_update_alarm(&spi->dev, false);
> if (ret)
> dev_err(&spi->dev,
> - "Failed to disable alarm in IRQ (ret=%d)\n", ret);
> + "Failed to disable alarm in IRQ (ret=%d)\n", ret);
> +
> rtc_update_irq(rtc, 1, RTC_AF | RTC_IRQF);
>
> rtc_unlock(rtc);
> @@ -381,6 +578,7 @@ 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;
> @@ -393,38 +591,56 @@ 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);
> - if (IS_ERR(rtc))
> - return PTR_ERR(rtc);
> + &mcp795_rtc_ops, THIS_MODULE);
> + if (IS_ERR(rtc)){
> + return PTR_ERR(rtc);}
>
> spi_set_drvdata(spi, rtc);
>
> if (spi->irq > 0) {
> dev_dbg(&spi->dev, "Alarm support enabled\n");
> -
> /* Clear any pending alarm (ALM0IF bit) before requesting
> * the interrupt.
> */
> mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_ALM0_DAY,
> - MCP795_ALM0IF_BIT, 0);
> + 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);
> + mcp795_irq, IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> + dev_name(&rtc->dev), spi);
> if (ret)
> dev_err(&spi->dev, "Failed to request IRQ: %d: %d\n",
> - spi->irq, ret);
> + spi->irq, ret);
> 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;
> + }
> + /* Set VBAT FLAG TO 1 */
> + ret = mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_DAY, MCP795_VBATEN_BIT,
> + MCP795_VBATEN_BIT);
> + if (ret)
> + return ret;
> +
> return 0;
> }
>
> #ifdef CONFIG_OF
> static const struct of_device_id mcp795_of_match[] = {
> - { .compatible = "maxim,mcp795" },
> + { .compatible = "microchip,mcp795" },
> { }
> };
> MODULE_DEVICE_TABLE(of, mcp795_of_match);
> --
> 2.37.3
>
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 1/2] Microchip MCP795xx RTC driver patch
@ 2022-10-16 16:27 tollsimy
0 siblings, 0 replies; 3+ messages in thread
From: tollsimy @ 2022-10-16 16:27 UTC (permalink / raw)
To: a.zummo; +Cc: alexandre.belloni, linux-rtc, linux-kernel, tollsimy
---
drivers/rtc/rtc-mcp795.c | 428 +++++++++++++++++++++++++++++----------
1 file changed, 322 insertions(+), 106 deletions(-)
diff --git a/drivers/rtc/rtc-mcp795.c b/drivers/rtc/rtc-mcp795.c
index 0d515b3df571..0e52812a8f85 100644
--- a/drivers/rtc/rtc-mcp795.c
+++ b/drivers/rtc/rtc-mcp795.c
@@ -3,13 +3,18 @@
* SPI Driver for Microchip MCP795 RTC
*
* Copyright (C) Josef Gajdusek <atx@atx.name>
+ * Copyright (C) 2022 Simone Tollardo <simone.tollardo@gmail.com>
*
* 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>
#include <linux/kernel.h>
#include <linux/device.h>
@@ -21,42 +26,164 @@
#include <linux/delay.h>
/* MCP795 Instructions, see datasheet table 3-1 */
-#define MCP795_EEREAD 0x03
-#define MCP795_EEWRITE 0x02
-#define MCP795_EEWRDI 0x04
-#define MCP795_EEWREN 0x06
-#define MCP795_SRREAD 0x05
-#define MCP795_SRWRITE 0x01
-#define MCP795_READ 0x13
-#define MCP795_WRITE 0x12
-#define MCP795_UNLOCK 0x14
-#define MCP795_IDWRITE 0x32
-#define MCP795_IDREAD 0x33
-#define MCP795_CLRWDT 0x44
-#define MCP795_CLRRAM 0x54
+#define MCP795_EEREAD 0x03
+#define MCP795_EEWRITE 0x02
+#define MCP795_EEWRDI 0x04
+#define MCP795_EEWREN 0x06
+#define MCP795_SRREAD 0x05
+#define MCP795_SRWRITE 0x01
+#define MCP795_READ 0x13
+#define MCP795_WRITE 0x12
+#define MCP795_UNLOCK 0x14
+#define MCP795_IDWRITE 0x32
+#define MCP795_IDREAD 0x33
+#define MCP795_CLRRAM 0x54
/* MCP795 RTCC registers, see datasheet table 4-1 */
-#define MCP795_REG_SECONDS 0x01
-#define MCP795_REG_DAY 0x04
-#define MCP795_REG_MONTH 0x06
-#define MCP795_REG_CONTROL 0x08
-#define MCP795_REG_ALM0_SECONDS 0x0C
-#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 SEC_PER_DAY (24 * 60 * 60)
-
+#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_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
+
+
+#define SEC_PER_DAY (24 * 60 * 60)
+
+/* NOTE: count is size in bytes */
static int mcp795_rtcc_read(struct device *dev, u8 addr, u8 *buf, u8 count)
{
struct spi_device *spi = to_spi_device(dev);
@@ -65,11 +192,11 @@ static int mcp795_rtcc_read(struct device *dev, u8 addr, u8 *buf, u8 count)
tx[0] = MCP795_READ;
tx[1] = addr;
+ /* count in bytes */
ret = spi_write_then_read(spi, tx, sizeof(tx), buf, count);
if (ret)
- dev_err(dev, "Failed reading %d bytes from address %x.\n",
- count, addr);
+ dev_err(dev, "Failed reading %d bytes from address %x.\n", count, addr);
return ret;
}
@@ -87,8 +214,7 @@ static int mcp795_rtcc_write(struct device *dev, u8 addr, u8 *data, u8 count)
ret = spi_write(spi, tx, 2 + count);
if (ret)
- dev_err(dev, "Failed to write %d bytes to address %x.\n",
- count, addr);
+ dev_err(dev, "Failed to write %d bytes to address %x.\n", count, addr);
return ret;
}
@@ -124,16 +250,17 @@ static int mcp795_stop_oscillator(struct device *dev, bool *extosc)
return ret;
*extosc = !!(data & MCP795_EXTOSC_BIT);
ret = mcp795_rtcc_set_bits(
- dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, 0);
+ dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, 0);
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))
break;
} while (--retries);
@@ -143,17 +270,33 @@ static int mcp795_stop_oscillator(struct device *dev, bool *extosc)
static int mcp795_start_oscillator(struct device *dev, bool *extosc)
{
- if (extosc) {
- u8 data = *extosc ? MCP795_EXTOSC_BIT : 0;
- int ret;
-
- ret = mcp795_rtcc_set_bits(
- dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, data);
- if (ret)
- return ret;
- }
- return mcp795_rtcc_set_bits(
- dev, MCP795_REG_SECONDS, MCP795_ST_BIT, MCP795_ST_BIT);
+ int ret;
+ int retries = 5;
+ if (extosc) {
+ u8 data = *extosc ? MCP795_EXTOSC_BIT : 0;
+ ret = mcp795_rtcc_set_bits(
+ dev, MCP795_REG_CONTROL, MCP795_EXTOSC_BIT, data);
+ if (ret)
+ return ret;
+ }
+ 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 */
+ do {
+ u8 data = MCP795_OSCRUN_BIT;
+ usleep_range(700, 800);
+ ret = mcp795_rtcc_read(dev, MCP795_REG_DAY, &data, 1);
+ if (ret)
+ break;
+ if ((data & MCP795_OSCRUN_BIT))
+ break;
+
+ } while (--retries);
+
+ return !retries ? -EIO : ret;
}
/* Enable or disable Alarm 0 in RTC */
@@ -164,18 +307,24 @@ 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);
/* 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);
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);
}
return ret;
}
@@ -183,7 +332,7 @@ 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 +341,41 @@ 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));
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[1] & 0x80) | bin2bcd(tim->tm_sec);
+ data[2] = (data[2] & 0x80) | bin2bcd(tim->tm_min);
+ data[3] = (data[3] & 0xC0) | bin2bcd(tim->tm_hour);
+ /* Add one beacause Linux weekday is from 0 to 6 */
+ data[4] = (data[4] & 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 */
+ 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 +387,14 @@ 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 +403,23 @@ 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 +434,17 @@ 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);
+ 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 +471,14 @@ 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 +491,15 @@ 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;
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);
+
return 0;
}
@@ -321,8 +508,7 @@ 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));
if (ret)
return ret;
@@ -336,8 +522,18 @@ 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;
}
@@ -361,7 +557,8 @@ static irqreturn_t mcp795_irq(int irq, void *data)
ret = mcp795_update_alarm(&spi->dev, false);
if (ret)
dev_err(&spi->dev,
- "Failed to disable alarm in IRQ (ret=%d)\n", ret);
+ "Failed to disable alarm in IRQ (ret=%d)\n", ret);
+
rtc_update_irq(rtc, 1, RTC_AF | RTC_IRQF);
rtc_unlock(rtc);
@@ -381,6 +578,7 @@ 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;
@@ -393,38 +591,56 @@ 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);
- if (IS_ERR(rtc))
- return PTR_ERR(rtc);
+ &mcp795_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc)){
+ return PTR_ERR(rtc);}
spi_set_drvdata(spi, rtc);
if (spi->irq > 0) {
dev_dbg(&spi->dev, "Alarm support enabled\n");
-
/* Clear any pending alarm (ALM0IF bit) before requesting
* the interrupt.
*/
mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_ALM0_DAY,
- MCP795_ALM0IF_BIT, 0);
+ 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);
+ mcp795_irq, IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+ dev_name(&rtc->dev), spi);
if (ret)
dev_err(&spi->dev, "Failed to request IRQ: %d: %d\n",
- spi->irq, ret);
+ spi->irq, ret);
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;
+ }
+ /* Set VBAT FLAG TO 1 */
+ ret = mcp795_rtcc_set_bits(&spi->dev, MCP795_REG_DAY, MCP795_VBATEN_BIT,
+ MCP795_VBATEN_BIT);
+ if (ret)
+ return ret;
+
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id mcp795_of_match[] = {
- { .compatible = "maxim,mcp795" },
+ { .compatible = "microchip,mcp795" },
{ }
};
MODULE_DEVICE_TABLE(of, mcp795_of_match);
--
2.37.3
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2022-10-15 23:39 [PATCH 1/2] Microchip MCP795xx RTC driver patch tollsimy
2022-10-16 10:35 ` Alexandre Belloni
2022-10-16 16:27 tollsimy
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