[PATCH 6.1.y-cip 09/13] rtc: isl1208: Add isl1208_set_xtoscb()

Biju Das
2023-08-16T14:25:29Z

commit 262f72b4656e182eefaab91ab24a7575dda5524f upstream.

As per the HW manual, set the XTOSCB bit as follows:

If using an external clock signal, set the XTOSCB bit as 1 to
disable the crystal oscillator.

If using an external crystal, the XTOSCB bit needs to be set at 0
to enable the crystal oscillator.

Add isl1208_set_xtoscb() to set XTOSCB bit based on the clock-names
property. Fallback is enabling the internal crystal oscillator.

While at it, introduce a variable "sr" for reading the status register
in probe() as it is reused for writing and also remove the unnecessary
blank line.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20230623140948.384762-10-biju.das.jz@bp.renesas.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
drivers/rtc/rtc-isl1208.c | 57 ++++++++++++++++++++++++++++++++++-----
1 file changed, 51 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c
index 80ecb724ae6b..915f23668228 100644
--- a/drivers/rtc/rtc-isl1208.c
+++ b/drivers/rtc/rtc-isl1208.c
@@ -6,6 +6,7 @@
*/

#include <linux/bcd.h>
+#include <linux/clk.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of_device.h>
@@ -175,6 +176,20 @@ isl1208_i2c_validate_client(struct i2c_client *client)
return 0;
}

+static int isl1208_set_xtoscb(struct i2c_client *client, int sr, int xtosb_val)
+{
+ /* Do nothing if bit is already set to desired value */
+ if ((sr & ISL1208_REG_SR_XTOSCB) == xtosb_val)
+ return 0;
+
+ if (xtosb_val)
+ sr |= ISL1208_REG_SR_XTOSCB;
+ else
+ sr &= ~ISL1208_REG_SR_XTOSCB;
+
+ return i2c_smbus_write_byte_data(client, ISL1208_REG_SR, sr);
+}
+
static int
isl1208_i2c_get_sr(struct i2c_client *client)
{
@@ -511,7 +526,6 @@ isl1208_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
return 0;
}

-
static int
isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
@@ -805,12 +819,26 @@ static int isl1208_setup_irq(struct i2c_client *client, int irq)
return rc;
}

+static int
+isl1208_clk_present(struct i2c_client *client, const char *name)
+{
+ struct clk *clk;
+
+ clk = devm_clk_get_optional(&client->dev, name);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ return !!clk;
+}
+
static int
isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
- int rc = 0;
struct isl1208_state *isl1208;
int evdet_irq = -1;
+ int xtosb_val = 0;
+ int rc = 0;
+ int sr;

if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
@@ -835,6 +863,19 @@ isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
isl1208->config = (struct isl1208_config *)id->driver_data;
}

+ rc = isl1208_clk_present(client, "xin");
+ if (rc < 0)
+ return rc;
+
+ if (!rc) {
+ rc = isl1208_clk_present(client, "clkin");
+ if (rc < 0)
+ return rc;
+
+ if (rc)
+ xtosb_val = 1;
+ }
+
isl1208->rtc = devm_rtc_allocate_device(&client->dev);
if (IS_ERR(isl1208->rtc))
return PTR_ERR(isl1208->rtc);
@@ -846,13 +887,17 @@ isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
isl1208->nvmem_config.size = isl1208->config->nvmem_length;
isl1208->nvmem_config.priv = isl1208;

- rc = isl1208_i2c_get_sr(client);
- if (rc < 0) {
+ sr = isl1208_i2c_get_sr(client);
+ if (sr < 0) {
dev_err(&client->dev, "reading status failed\n");
- return rc;
+ return sr;
}

- if (rc & ISL1208_REG_SR_RTCF)
+ rc = isl1208_set_xtoscb(client, sr, xtosb_val);
+ if (rc)
+ return rc;
+
+ if (sr & ISL1208_REG_SR_RTCF)
dev_warn(&client->dev, "rtc power failure detected, "
"please set clock.\n");

--
2.25.1