The quartz oscillator load capacitance of the PCF85263 and PCF85363 can
be adjusted to 6 pF, 7 pF (default) and 12.5 pF with the CL[1:0] bits in
the oscillator control register (address 25h).
Signed-off-by: Javier Carrasco <javier.carrasco@xxxxxxxxxxxxxx>
---
v2:
- simple assignment operator instead of |= for the "value" variable.
drivers/rtc/rtc-pcf85363.c | 37 ++++++++++++++++++++++++++++++++++++-
1 file changed, 36 insertions(+), 1 deletion(-)
diff --git a/drivers/rtc/rtc-pcf85363.c b/drivers/rtc/rtc-pcf85363.c
index c05b722f0060..219fbca8c47f 100644
--- a/drivers/rtc/rtc-pcf85363.c
+++ b/drivers/rtc/rtc-pcf85363.c
@@ -101,6 +101,10 @@
#define PIN_IO_INTA_OUT 2
#define PIN_IO_INTA_HIZ 3
+#define OSC_CAP_SEL GENMASK(1, 0)
+#define OSC_CAP_6000 0x01
+#define OSC_CAP_12500 0x02
+
#define STOP_EN_STOP BIT(0)
#define RESET_CPR 0xa4
@@ -117,6 +121,32 @@ struct pcf85x63_config {
unsigned int num_nvram;
};
+static int pcf85363_load_capacitance(struct pcf85363 *pcf85363, struct device_node *node)
+{
+ u32 load = 7000;
+ u8 value = 0;
+
+ of_property_read_u32(node, "quartz-load-femtofarads", &load);
+
+ switch (load) {
+ default:
+ dev_warn(&pcf85363->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 7000",
+ load);
+ fallthrough;
+ case 7000:
+ break;
+ case 6000:
+ value = OSC_CAP_6000;
+ break;
+ case 12500:
+ value = OSC_CAP_12500;
+ break;
+ }
+
+ return regmap_update_bits(pcf85363->regmap, CTRL_OSCILLATOR,
+ OSC_CAP_SEL, value);
+}
+
static int pcf85363_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
@@ -372,7 +402,7 @@ static int pcf85363_probe(struct i2c_client *client)
.reg_write = pcf85363_nvram_write,
},
};
- int ret, i;
+ int ret, i, err;
if (data)
config = data;
@@ -394,6 +424,11 @@ static int pcf85363_probe(struct i2c_client *client)
if (IS_ERR(pcf85363->rtc))
return PTR_ERR(pcf85363->rtc);
+ err = pcf85363_load_capacitance(pcf85363, client->dev.of_node);
+ if (err < 0)
+ dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
+ err);
+
pcf85363->rtc->ops = &rtc_ops;
pcf85363->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
pcf85363->rtc->range_max = RTC_TIMESTAMP_END_2099;
--
2.37.2
