From: Pavel Modilaynen <pavelmn@xxxxxxxx>
Add support for oscillation adjustment register RS5C372_REG_TRIM
setting that is needed to accommodate for effective crystal
capacitance.
Use optional property ricoh,trim that should contain
raw value to setup this register. According to
datasheets for RS5C372, R2025S/D, RV5C38[67] and R222[13]
the value will be converted to a number of ticks that
is to be subtracted or added when the second digits read
00, 20 or 40 seconds.
Signed-off-by: Pavel Modilaynen <pavelmn@xxxxxxxx>
---
drivers/rtc/rtc-rs5c372.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
index 80980414890c..3a2db0326669 100644
--- a/drivers/rtc/rtc-rs5c372.c
+++ b/drivers/rtc/rtc-rs5c372.c
@@ -13,6 +13,7 @@
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/of_device.h>
+#include <linux/of.h>
/*
* Ricoh has a family of I2C based RTCs, which differ only slightly from
@@ -560,6 +561,8 @@ static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
{
unsigned char buf[2];
int addr, i, ret = 0;
+ struct i2c_client *client = rs5c372->client;
+ u8 trim = 0;
addr = RS5C_ADDR(RS5C_REG_CTRL1);
buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
@@ -599,9 +602,22 @@ static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
break;
}
+ /* optional setup of xtal trimming */
+ if (!of_property_read_u8(client->dev.of_node, "ricoh,trim", &trim)) {
+ if (rs5c372->type != rtc_r2221tl && (trim & ~RS5C372_TRIM_MASK)) {
+ dev_warn(&client->dev, "Erroneous setting for ricoh,trim in devicetree\n");
+ } else {
+ int addr = RS5C_ADDR(RS5C372_REG_TRIM);
+ int ret = i2c_smbus_write_byte_data(client, addr, trim);
+
+ if (unlikely(ret < 0))
+ return ret;
+ }
+ }
+
for (i = 0; i < sizeof(buf); i++) {
addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
- ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
+ ret = i2c_smbus_write_byte_data(client, addr, buf[i]);
if (unlikely(ret < 0))
return ret;
}
--
2.20.1
