diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.4/950-0944-rtc-rv3028-Write-BSM-and-TCE-TCR-to-EEPROM.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.4/950-0944-rtc-rv3028-Write-BSM-and-TCE-TCR-to-EEPROM.patch | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.4/950-0944-rtc-rv3028-Write-BSM-and-TCE-TCR-to-EEPROM.patch b/target/linux/bcm27xx/patches-5.4/950-0944-rtc-rv3028-Write-BSM-and-TCE-TCR-to-EEPROM.patch new file mode 100644 index 0000000000..54f3f4f367 --- /dev/null +++ b/target/linux/bcm27xx/patches-5.4/950-0944-rtc-rv3028-Write-BSM-and-TCE-TCR-to-EEPROM.patch @@ -0,0 +1,120 @@ +From ffc137a8949cd7859bdf139fa7a56b9dbdb4b2ce Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.com> +Date: Fri, 15 May 2020 16:28:32 +0100 +Subject: [PATCH] rtc: rv3028: Write BSM and TCE/TCR to EEPROM + +Periodically the RV3028 refreshes registers from the EEPROM. When this +happens, some settings that have only been committed to registers are +lost. Change the handling of backup-switchover-mode and +trickle-resistor-ohms to write the EEPROM instead (if something has +changed), on the understanding that registers will be refreshed +afterwards. + +See: https://github.com/raspberrypi/linux/issues/2912 + +Signed-off-by: Phil Elwell <phil@raspberrypi.com> +--- + drivers/rtc/rtc-rv3028.c | 60 ++++++++++++++++++++++++++++------------ + 1 file changed, 43 insertions(+), 17 deletions(-) + +--- a/drivers/rtc/rtc-rv3028.c ++++ b/drivers/rtc/rtc-rv3028.c +@@ -18,6 +18,7 @@ + #include <linux/of_device.h> + #include <linux/regmap.h> + #include <linux/rtc.h> ++//#include "rtc-core.h" + + #define RV3028_SEC 0x00 + #define RV3028_MIN 0x01 +@@ -73,7 +74,7 @@ + + #define RV3028_BACKUP_TCE BIT(5) + #define RV3028_BACKUP_TCR_MASK GENMASK(1,0) +-#define RV3028_BACKUP_BSM_MASK 0x0C ++#define RV3028_BACKUP_BSM_MASK GENMASK(3,2) + + #define OFFSET_STEP_PPT 953674 + +@@ -601,7 +602,8 @@ static int rv3028_probe(struct i2c_clien + struct rv3028_data *rv3028; + int ret, status; + u32 ohms; +- u8 bsm; ++ u32 bsm; ++ u8 backup, backup_bits, backup_mask; + struct nvmem_config nvmem_cfg = { + .name = "rv3028_nvram", + .word_size = 1, +@@ -673,16 +675,17 @@ static int rv3028_probe(struct i2c_clien + if (ret) + return ret; + ++ backup_bits = 0; ++ backup_mask = 0; ++ + /* setup backup switchover mode */ +- if (!device_property_read_u8(&client->dev, "backup-switchover-mode", +- &bsm)) { ++ dev_dbg(&client->dev, "Checking RTC backup switchover-mode\n"); ++ if (!device_property_read_u32(&client->dev, ++ "backup-switchover-mode", ++ &bsm)) { + if (bsm <= 3) { +- ret = regmap_update_bits(rv3028->regmap, RV3028_BACKUP, +- RV3028_BACKUP_BSM_MASK, +- (bsm & 0x03) << 2); +- +- if (ret) +- return ret; ++ backup_bits |= (u8)(bsm << 2); ++ backup_mask |= RV3028_BACKUP_BSM_MASK; + } else { + dev_warn(&client->dev, "invalid backup switchover mode value\n"); + } +@@ -698,15 +701,38 @@ static int rv3028_probe(struct i2c_clien + break; + + if (i < ARRAY_SIZE(rv3028_trickle_resistors)) { +- ret = regmap_update_bits(rv3028->regmap, RV3028_BACKUP, +- RV3028_BACKUP_TCE | +- RV3028_BACKUP_TCR_MASK, +- RV3028_BACKUP_TCE | i); +- if (ret) +- return ret; ++ backup_bits |= RV3028_BACKUP_TCE | i; ++ backup_mask |= RV3028_BACKUP_TCE | ++ RV3028_BACKUP_TCR_MASK; + } else { +- dev_warn(&client->dev, "invalid trickle resistor value\n"); ++ dev_warn(&client->dev, ++ "invalid trickle resistor value\n"); ++ } ++ } ++ ++ if (backup_mask) { ++ ret = rv3028_eeprom_read((void *)(rv3028->regmap), ++ RV3028_BACKUP, ++ (void *)&backup, 1); ++ if (!ret) { ++ /* Write EEPROM only if needed */ ++ if ((backup & backup_mask) != backup_bits) { ++ backup = (backup & ~backup_mask) | backup_bits; ++ dev_dbg(&client->dev, ++ "Backup register doesn't match: EEPROM write required\n"); ++ ret = rv3028_eeprom_write( ++ (void *)(rv3028->regmap), ++ RV3028_BACKUP, (void *)&backup, 1); ++ } + } ++ ++ /* In the event of an EEPROM failure, update the register ++ instead. */ ++ if (ret) ++ ret = regmap_update_bits(rv3028->regmap, RV3028_BACKUP, ++ backup_mask, backup_bits); ++ if (ret) ++ return ret; + } + + ret = rtc_add_group(rv3028->rtc, &rv3028_attr_group); |