From: Sam Ravnborg <sam@ravnborg.org>
To: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: "Alessandro Zummo" <a.zummo@towertech.it>,
"Andrew Jeffery" <andrew@aj.id.au>,
"Fabio Estevam" <fabio.estevam@nxp.com>,
"Joel Stanley" <joel@jms.id.au>,
"Mark Rutland" <mark.rutland@arm.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Russell King" <linux@armlinux.org.uk>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Urs Fässler" <urs.fassler@bbv.ch>,
"Shawn Guo" <shawnguo@kernel.org>,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-rtc@vger.kernel.org, "Sam Ravnborg" <sam@ravnborg.org>
Subject: [PATCH v3 6/6] rtc: pcf85063: set xtal load capacitance from DT
Date: Sat, 19 Jan 2019 10:00:31 +0100 [thread overview]
Message-ID: <20190119090031.29147-7-sam@ravnborg.org> (raw)
In-Reply-To: <20190119090031.29147-1-sam@ravnborg.org>
Add support for specifying the xtal load capacitance in the DT node.
The pcf85063 supports xtal load capacitance of 7pF or 12.5pF.
If the rtc has the wrong configuration the time will
drift several hours/week.
The driver use the default value 7pF.
The DT may specify either 7000fF or 12500fF.
(The DT uses femto Farad to avoid decimal numbers).
Other values are warned and the driver uses the default value.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Urs Fässler <urs.fassler@bbv.ch>
---
drivers/rtc/rtc-pcf85063.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
index 283c2335b01b..b79af6e96292 100644
--- a/drivers/rtc/rtc-pcf85063.c
+++ b/drivers/rtc/rtc-pcf85063.c
@@ -27,6 +27,7 @@
*/
#define PCF85063_REG_CTRL1 0x00 /* status */
+#define PCF85063_REG_CTRL1_CAP_SEL BIT(0)
#define PCF85063_REG_CTRL1_STOP BIT(5)
#define PCF85063_REG_CTRL2 0x01
@@ -180,6 +181,39 @@ static const struct rtc_class_ops pcf85063_rtc_ops = {
.set_time = pcf85063_rtc_set_time
};
+static int pcf85063_load_capacitance(struct i2c_client *client)
+{
+ u32 load;
+ int rc;
+ u8 reg;
+
+ rc = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
+ if (rc < 0)
+ return rc;
+
+ reg = rc;
+ load = 7000;
+ of_property_read_u32(client->dev.of_node, "quartz-load-femtofarads",
+ &load);
+
+ switch (load) {
+ default:
+ dev_warn(&client->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 7000",
+ load);
+ /* fall through */
+ case 7000:
+ reg &= ~PCF85063_REG_CTRL1_CAP_SEL;
+ break;
+ case 12500:
+ reg |= PCF85063_REG_CTRL1_CAP_SEL;
+ break;
+ }
+
+ rc = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, reg);
+
+ return rc;
+}
+
static int pcf85063_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -197,6 +231,11 @@ static int pcf85063_probe(struct i2c_client *client,
return err;
}
+ err = pcf85063_load_capacitance(client);
+ if (err < 0)
+ dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
+ err);
+
rtc = devm_rtc_device_register(&client->dev,
pcf85063_driver.driver.name,
&pcf85063_rtc_ops, THIS_MODULE);
--
2.12.0
next prev parent reply other threads:[~2019-01-19 9:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-19 9:00 [PATCH v3 0/6] add quartz load support to NXP rtc drivers Sam Ravnborg
2019-01-19 9:00 ` [PATCH v3 1/6] devicetree: property-units: Add femtofarads unit Sam Ravnborg
2019-01-19 9:00 ` [PATCH v3 2/6] dt-bindings: rtc: Add quartz-load-femtofarads property Sam Ravnborg
2019-01-21 15:24 ` Rob Herring
2019-01-19 9:00 ` [PATCH v3 3/6] dt-binding: pcf8523: add xtal load capacitance Sam Ravnborg
2019-01-19 9:00 ` [PATCH v3 4/6] dt-binding: pcf85063: " Sam Ravnborg
2019-01-21 15:25 ` Rob Herring
2019-01-19 9:00 ` [PATCH v3 5/6] rtc: pcf8523: set xtal load capacitance from DT Sam Ravnborg
2019-01-19 9:00 ` Sam Ravnborg [this message]
2019-01-22 17:57 ` [PATCH v3 0/6] add quartz load support to NXP rtc drivers Alexandre Belloni
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190119090031.29147-7-sam@ravnborg.org \
--to=sam@ravnborg.org \
--cc=a.zummo@towertech.it \
--cc=alexandre.belloni@bootlin.com \
--cc=andrew@aj.id.au \
--cc=devicetree@vger.kernel.org \
--cc=fabio.estevam@nxp.com \
--cc=joel@jms.id.au \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rtc@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=mark.rutland@arm.com \
--cc=robh+dt@kernel.org \
--cc=s.hauer@pengutronix.de \
--cc=shawnguo@kernel.org \
--cc=urs.fassler@bbv.ch \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).