diff mbox series

[v4,07/11] rtc: isl1208: Add isl1208_set_xtoscb()

Message ID 20230518113643.420806-8-biju.das.jz@bp.renesas.com (mailing list archive)
State Superseded
Delegated to: Geert Uytterhoeven
Headers show
Series Add Renesas PMIC RAA215300 and built-in RTC support | expand

Commit Message

Biju Das May 18, 2023, 11:36 a.m. UTC
As per the HW manual, setting of XTOSCB bit as follws

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 status register
in probe() as it is reused for writing.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v4:
 * New patch.
---
 drivers/rtc/rtc-isl1208.c | 36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

Comments

Geert Uytterhoeven May 19, 2023, 12:48 p.m. UTC | #1
Hi Biju,

On Thu, May 18, 2023 at 1:37 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> As per the HW manual, setting of XTOSCB bit as follws

... 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 status register

the status register

> in probe() as it is reused for writing.
>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v4:
>  * New patch.

Thanks for your patch!

> --- a/drivers/rtc/rtc-isl1208.c
> +++ b/drivers/rtc/rtc-isl1208.c

> @@ -837,6 +852,13 @@ isl1208_probe(struct i2c_client *client)
>                 isl1208->config = (struct isl1208_config *)id->driver_data;
>         }
>
> +       xin = devm_clk_get(&client->dev, "xin");
> +       if (IS_ERR(xin)) {
> +               clkin = devm_clk_get(&client->dev, "clkin");
> +               if (!IS_ERR(clkin))
> +                       int_osc_en = false;
> +       }

devm_clk_get_optional()
(doesn't devm_clk_get() print an error message?)

And check for NULL to find out if a clock is present.
IS_ERR() is a real error condition to be propagated.

Gr{oetje,eeting}s,

                        Geert
Biju Das May 19, 2023, 4:24 p.m. UTC | #2
Hi Geert,

Thanks for the feedback.

> Subject: Re: [PATCH v4 07/11] rtc: isl1208: Add isl1208_set_xtoscb()
> 
> Hi Biju,
> 
> On Thu, May 18, 2023 at 1:37 PM Biju Das <biju.das.jz@bp.renesas.com>
> wrote:
> > As per the HW manual, setting of XTOSCB bit as follws
> 
> ... set the XTOSCB bit as follows:

Oops. Will fix.

> 
> > 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 status register
> 
> the status register

Ok.

> 
> > in probe() as it is reused for writing.
> >
> > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > ---
> > v4:
> >  * New patch.
> 
> Thanks for your patch!
> 
> > --- a/drivers/rtc/rtc-isl1208.c
> > +++ b/drivers/rtc/rtc-isl1208.c
> 
> > @@ -837,6 +852,13 @@ isl1208_probe(struct i2c_client *client)
> >                 isl1208->config = (struct isl1208_config *)id-
> >driver_data;
> >         }
> >
> > +       xin = devm_clk_get(&client->dev, "xin");
> > +       if (IS_ERR(xin)) {
> > +               clkin = devm_clk_get(&client->dev, "clkin");
> > +               if (!IS_ERR(clkin))
> > +                       int_osc_en = false;
> > +       }
> 
> devm_clk_get_optional()

OK, Will use optional variant.

> (doesn't devm_clk_get() print an error message?)
I will double check. If I remember correctly it didn't throw any prtints.

> 
> And check for NULL to find out if a clock is present.

OK.

> IS_ERR() is a real error condition to be propagated.

Agreed.

Cheers,
Biju
diff mbox series

Patch

diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c
index 916e7d44c96f..5f91a3ca5920 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 +176,16 @@  isl1208_i2c_validate_client(struct i2c_client *client)
 	return 0;
 }
 
+static int isl1208_set_xtoscb(struct i2c_client *client, int sr, bool int_osc_en)
+{
+	if (int_osc_en)
+		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)
 {
@@ -808,9 +819,13 @@  static int isl1208_setup_irq(struct i2c_client *client, int irq)
 static int
 isl1208_probe(struct i2c_client *client)
 {
-	int rc = 0;
 	struct isl1208_state *isl1208;
+	bool int_osc_en = true;
 	int evdet_irq = -1;
+	struct clk *clkin;
+	struct clk *xin;
+	int rc = 0;
+	int sr;
 
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 		return -ENODEV;
@@ -837,6 +852,13 @@  isl1208_probe(struct i2c_client *client)
 		isl1208->config = (struct isl1208_config *)id->driver_data;
 	}
 
+	xin = devm_clk_get(&client->dev, "xin");
+	if (IS_ERR(xin)) {
+		clkin = devm_clk_get(&client->dev, "clkin");
+		if (!IS_ERR(clkin))
+			int_osc_en = false;
+	}
+
 	isl1208->rtc = devm_rtc_allocate_device(&client->dev);
 	if (IS_ERR(isl1208->rtc))
 		return PTR_ERR(isl1208->rtc);
@@ -848,13 +870,17 @@  isl1208_probe(struct i2c_client *client)
 	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, int_osc_en);
+	if (rc)
+		return rc;
+
+	if (sr & ISL1208_REG_SR_RTCF)
 		dev_warn(&client->dev, "rtc power failure detected, "
 			 "please set clock.\n");