From ecb4a353d3afd45b9bb30c85d03ee113a0589079 Mon Sep 17 00:00:00 2001 From: Baruch Siach Date: Wed, 5 Dec 2018 17:00:09 +0200 Subject: rtc: pcf8523: don't return invalid date when battery is low MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The RTC_VL_READ ioctl reports the low battery condition. Still, pcf8523_rtc_read_time() happily returns invalid dates in this case. Check the battery health on pcf8523_rtc_read_time() to avoid that. Reported-by: Erik Čuk Signed-off-by: Baruch Siach Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-pcf8523.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) (limited to 'drivers/rtc/rtc-pcf8523.c') diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c index 453615f8ac9a..3fcd2cbafc84 100644 --- a/drivers/rtc/rtc-pcf8523.c +++ b/drivers/rtc/rtc-pcf8523.c @@ -85,6 +85,18 @@ static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value) return 0; } +static int pcf8523_voltage_low(struct i2c_client *client) +{ + u8 value; + int err; + + err = pcf8523_read(client, REG_CONTROL3, &value); + if (err < 0) + return err; + + return !!(value & REG_CONTROL3_BLF); +} + static int pcf8523_select_capacitance(struct i2c_client *client, bool high) { u8 value; @@ -167,6 +179,14 @@ static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm) struct i2c_msg msgs[2]; int err; + err = pcf8523_voltage_low(client); + if (err < 0) { + return err; + } else if (err > 0) { + dev_err(dev, "low voltage detected, time is unreliable\n"); + return -EINVAL; + } + msgs[0].addr = client->addr; msgs[0].flags = 0; msgs[0].len = 1; @@ -251,17 +271,13 @@ static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) { struct i2c_client *client = to_i2c_client(dev); - u8 value; - int ret = 0, err; + int ret; switch (cmd) { case RTC_VL_READ: - err = pcf8523_read(client, REG_CONTROL3, &value); - if (err < 0) - return err; - - if (value & REG_CONTROL3_BLF) - ret = 1; + ret = pcf8523_voltage_low(client); + if (ret < 0) + return ret; if (copy_to_user((void __user *)arg, &ret, sizeof(int))) return -EFAULT; -- cgit From 7c617e0c5f37d2f681b3a568c3642115a32b7427 Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Tue, 18 Dec 2018 22:52:12 +0100 Subject: rtc: pcf8523: Add rv8523 compatible The Microcrystal RV-8523 is compatible with the PCF8523. Signed-off-by: Alexandre Belloni --- Documentation/devicetree/bindings/rtc/rtc.txt | 1 + drivers/rtc/rtc-pcf8523.c | 1 + 2 files changed, 2 insertions(+) (limited to 'drivers/rtc/rtc-pcf8523.c') diff --git a/Documentation/devicetree/bindings/rtc/rtc.txt b/Documentation/devicetree/bindings/rtc/rtc.txt index e46edab31403..b79a4794a928 100644 --- a/Documentation/devicetree/bindings/rtc/rtc.txt +++ b/Documentation/devicetree/bindings/rtc/rtc.txt @@ -49,6 +49,7 @@ isil,isl1208 Intersil ISL1208 Low Power RTC with Battery Backed SRAM isil,isl1218 Intersil ISL1218 Low Power RTC with Battery Backed SRAM isil,isl12022 Intersil ISL12022 Real-time Clock microcrystal,rv3029 Real Time Clock Module with I2C-Bus +microcrystal,rv8523 Real Time Clock nxp,pcf2127 Real-time clock nxp,pcf2129 Real-time clock nxp,pcf8523 Real-time Clock diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c index 3fcd2cbafc84..fb13933f4006 100644 --- a/drivers/rtc/rtc-pcf8523.c +++ b/drivers/rtc/rtc-pcf8523.c @@ -374,6 +374,7 @@ MODULE_DEVICE_TABLE(i2c, pcf8523_id); #ifdef CONFIG_OF static const struct of_device_id pcf8523_of_match[] = { { .compatible = "nxp,pcf8523" }, + { .compatible = "microcrystal,rv8523" }, { } }; MODULE_DEVICE_TABLE(of, pcf8523_of_match); -- cgit From 189927e719e36ceefbb8037f23d3849e47833aef Mon Sep 17 00:00:00 2001 From: Sam Ravnborg Date: Sat, 19 Jan 2019 10:00:30 +0100 Subject: rtc: pcf8523: set xtal load capacitance from DT Add support for specifying the xtal load capacitance in the DT node. The pcf8523 supports xtal load capacitance of 7pF or 12.5pF. If the rtc has the wrong configuration the time will drift several hours/week. The driver use the default value 12.5pF. The DT may specify either 7000fF or 12500fF. (The DT uses femto Farad to avoid decimal numbers). Other values are warned and the driver uses the default value. Signed-off-by: Sam Ravnborg Cc: Alessandro Zummo Cc: Alexandre Belloni Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-pcf8523.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-) (limited to 'drivers/rtc/rtc-pcf8523.c') diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c index fb13933f4006..b5c61a70b5df 100644 --- a/drivers/rtc/rtc-pcf8523.c +++ b/drivers/rtc/rtc-pcf8523.c @@ -97,8 +97,9 @@ static int pcf8523_voltage_low(struct i2c_client *client) return !!(value & REG_CONTROL3_BLF); } -static int pcf8523_select_capacitance(struct i2c_client *client, bool high) +static int pcf8523_load_capacitance(struct i2c_client *client) { + u32 load; u8 value; int err; @@ -106,14 +107,24 @@ static int pcf8523_select_capacitance(struct i2c_client *client, bool high) if (err < 0) return err; - if (!high) - value &= ~REG_CONTROL1_CAP_SEL; - else + load = 12500; + of_property_read_u32(client->dev.of_node, "quartz-load-femtofarads", + &load); + + switch (load) { + default: + dev_warn(&client->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500", + load); + /* fall through */ + case 12500: value |= REG_CONTROL1_CAP_SEL; + break; + case 7000: + value &= ~REG_CONTROL1_CAP_SEL; + break; + } err = pcf8523_write(client, REG_CONTROL1, value); - if (err < 0) - return err; return err; } @@ -347,9 +358,10 @@ static int pcf8523_probe(struct i2c_client *client, if (!pcf) return -ENOMEM; - err = pcf8523_select_capacitance(client, true); + err = pcf8523_load_capacitance(client); if (err < 0) - return err; + dev_warn(&client->dev, "failed to set xtal load capacitance: %d", + err); err = pcf8523_set_pm(client, 0); if (err < 0) -- cgit