linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Chris Packham <chris.packham@alliedtelesis.co.nz>
To: a.zummo@towertech.it, alexandre.belloni@bootlin.com
Cc: linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org,
	Chris Packham <chris.packham@alliedtelesis.co.nz>
Subject: [PATCH v1 2/2] rtc: ds1307: add support for watchdog timer on ds1388
Date: Fri,  7 Feb 2020 16:18:12 +1300	[thread overview]
Message-ID: <20200207031812.14424-3-chris.packham@alliedtelesis.co.nz> (raw)
In-Reply-To: <20200207031812.14424-1-chris.packham@alliedtelesis.co.nz>

The DS1388 variant has watchdog timer capabilities. When using a DS1388
and having enabled CONFIG_WATCHDOG_CORE register a watchdog device for
the DS1388.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---
 drivers/rtc/rtc-ds1307.c | 105 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 31a38d468378..e83d9e52aae5 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -22,6 +22,7 @@
 #include <linux/hwmon-sysfs.h>
 #include <linux/clk-provider.h>
 #include <linux/regmap.h>
+#include <linux/watchdog.h>
 
 /*
  * We can't determine type by probing, but if we expect pre-Linux code
@@ -144,8 +145,15 @@ enum ds_type {
 #	define M41TXX_BIT_CALIB_SIGN	BIT(5)
 #	define M41TXX_M_CALIBRATION	GENMASK(4, 0)
 
+#define DS1388_REG_WDOG_HUN_SECS	0x08
+#define DS1388_REG_WDOG_SECS		0x09
 #define DS1388_REG_FLAG			0x0b
+#	define DS1388_BIT_WF		BIT(6)
 #	define DS1388_BIT_OSF		BIT(7)
+#define DS1388_REG_CONTROL		0x0c
+#	define DS1388_BIT_RST		BIT(0)
+#	define DS1388_BIT_WDE		BIT(1)
+
 /* negative offset step is -2.034ppm */
 #define M41TXX_NEG_OFFSET_STEP_PPB	2034
 /* positive offset step is +4.068ppm */
@@ -166,6 +174,9 @@ struct ds1307 {
 #ifdef CONFIG_COMMON_CLK
 	struct clk_hw		clks[2];
 #endif
+#ifdef CONFIG_WATCHDOG_CORE
+	struct watchdog_device	wdt;
+#endif
 };
 
 struct chip_desc {
@@ -854,6 +865,58 @@ static int m41txx_rtc_set_offset(struct device *dev, long offset)
 				  ctrl_reg);
 }
 
+#ifdef CONFIG_WATCHDOG_CORE
+static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
+{
+	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
+	u8 regs[2];
+	int ret;
+
+	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
+			DS1388_BIT_WF, 0);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
+				 DS1388_BIT_WDE|DS1388_BIT_RST, 0);
+	if (ret)
+		return ret;
+
+	/*
+	 * watchdog timeouts are measured in seconds so max out hundreths of
+	 * seconds field.
+	 */
+	regs[0] = 0x99;
+	regs[1] = bin2bcd(wdt_dev->timeout);
+
+	ret = regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
+			sizeof(regs));
+	if (ret)
+		return ret;
+
+	return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
+				  DS1388_BIT_WDE|DS1388_BIT_RST,
+				  DS1388_BIT_WDE|DS1388_BIT_RST);
+}
+
+static int ds1388_wdt_stop(struct watchdog_device *wdt_dev)
+{
+	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
+
+	return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
+				  DS1388_BIT_WDE|DS1388_BIT_RST, 0);
+}
+
+static int ds1388_wdt_ping(struct watchdog_device *wdt_dev)
+{
+	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
+	u8 regs[2];
+
+	return regmap_bulk_read(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
+				sizeof(regs));
+}
+#endif
+
 static const struct rtc_class_ops rx8130_rtc_ops = {
 	.read_time      = ds1307_get_time,
 	.set_time       = ds1307_set_time,
@@ -880,6 +943,20 @@ static const struct rtc_class_ops m41txx_rtc_ops = {
 	.set_offset	= m41txx_rtc_set_offset,
 };
 
+#ifdef CONFIG_WATCHDOG_CORE
+static const struct watchdog_info ds1388_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "DS1388 watchdog",
+};
+
+static const struct watchdog_ops ds1388_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = ds1388_wdt_start,
+	.stop = ds1388_wdt_stop,
+	.ping = ds1388_wdt_ping,
+};
+#endif
+
 static const struct chip_desc chips[last_ds_type] = {
 	[ds_1307] = {
 		.nvram_offset	= 8,
@@ -1576,6 +1653,33 @@ static void ds1307_clks_register(struct ds1307 *ds1307)
 
 #endif /* CONFIG_COMMON_CLK */
 
+#ifdef CONFIG_WATCHDOG_CORE
+static void ds1307_wdt_register(struct ds1307 *ds1307)
+{
+	int ret;
+
+	if (ds1307->type != ds_1388)
+		return;
+
+	ds1307->wdt.info = &ds1388_wdt_info;
+	ds1307->wdt.ops = &ds1388_wdt_ops;
+	ds1307->wdt.max_timeout = 99;
+	ds1307->wdt.min_timeout = 1;
+
+	watchdog_init_timeout(&ds1307->wdt, 99, ds1307->dev);
+	watchdog_set_drvdata(&ds1307->wdt, ds1307);
+	ret = watchdog_register_device(&ds1307->wdt);
+	if (ret) {
+		dev_warn(ds1307->dev, "unable to register watchdog device %d\n",
+			 ret);
+	}
+}
+#else
+static void ds1307_wdt_register(struct ds1307 *ds1307)
+{
+}
+#endif /* CONFIG_WATCHDOG_CORE */
+
 static const struct regmap_config regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
@@ -1865,6 +1969,7 @@ static int ds1307_probe(struct i2c_client *client,
 
 	ds1307_hwmon_register(ds1307);
 	ds1307_clks_register(ds1307);
+	ds1307_wdt_register(ds1307);
 
 	return 0;
 
-- 
2.25.0


  parent reply	other threads:[~2020-02-07  3:18 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-07  3:18 [PATCH v1 0/2] rtc: update ds1388 support Chris Packham
2020-02-07  3:18 ` [PATCH v1 1/2] rtc: ds1307: handle oscillator failure flags for ds1388 variant Chris Packham
2020-03-22 20:40   ` Alexandre Belloni
2020-02-07  3:18 ` Chris Packham [this message]
2020-03-22 21:05   ` [PATCH v1 2/2] rtc: ds1307: add support for watchdog timer on ds1388 Alexandre Belloni
2020-03-10 23:56 ` [PATCH v1 0/2] rtc: update ds1388 support Chris Packham

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=20200207031812.14424-3-chris.packham@alliedtelesis.co.nz \
    --to=chris.packham@alliedtelesis.co.nz \
    --cc=a.zummo@towertech.it \
    --cc=alexandre.belloni@bootlin.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rtc@vger.kernel.org \
    /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).