[PATCH 1/2] rtc: rs5c372: Add support for trim configuration
From: Pavel Modilaynen <hidden>
Date: 2021-10-30 22:51:15
Also in:
linux-devicetree, lkml
Subsystem:
real time clock (rtc) subsystem, the rest · Maintainers:
Alexandre Belloni, Linus Torvalds
From: Pavel Modilaynen <redacted> 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 <redacted> --- 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