linux-kernel - [PATCH v2 04/17] RTC: ds1307: Add DS1341 specific power-saving options

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1466493770-11895-3-git-send-email-andrew.smirnov@gmail.com>
Date:	Tue, 21 Jun 2016 00:22:37 -0700
From:	Andrey Smirnov <andrew.smirnov@...il.com>
To:	rtc-linux@...glegroups.com
Cc:	Andrey Smirnov <andrew.smirnov@...il.com>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	linux-kernel@...r.kernel.org, cphealy@...il.com
Subject: [PATCH v2 04/17] RTC: ds1307: Add DS1341 specific power-saving options

Add DS1341 specific power-saving options that allow to disable certain
functional aspects of the chip in order to minimize its power
consumption.

Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
---
 drivers/rtc/rtc-ds1307.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index c618c22..b21ea5d 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -78,6 +78,7 @@ enum ds_type {
 #define DS1337_REG_CONTROL	0x0e
 #	define DS1337_BIT_nEOSC		0x80
 #	define DS1339_BIT_BBSQI		0x20
+#	define DS1341_BIT_EGFIL		0x20
 #	define DS3231_BIT_BBSQW		0x40 /* same as BBSQI */
 #	define DS1337_BIT_RS2		0x10
 #	define DS1337_BIT_RS1		0x08
@@ -93,7 +94,9 @@ enum ds_type {
 #	define DS1340_BIT_OSF		0x80
 #define DS1337_REG_STATUS	0x0f
 #	define DS1337_BIT_OSF		0x80
+#	define DS1341_BIT_DOSF		0x40
 #	define DS3231_BIT_EN32KHZ	0x08
+#	define DS1341_BIT_ECLK		0x04
 #	define DS1337_BIT_A2I		0x02
 #	define DS1337_BIT_A1I		0x01
 #define DS1339_REG_ALARM1_SECS	0x07
@@ -1319,6 +1322,31 @@ static int ds1307_probe(struct i2c_client *client,
 		if (ds1307->regs[0] & DS1337_BIT_nEOSC)
 			ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
 
+		if (ds1307->type == ds_1341) {
+			/* Make sure we are not generating square wave
+			 * output */
+			ds1307->regs[1] &= ~DS1341_BIT_ECLK;
+
+			if (of_property_read_bool(client->dev.of_node,
+						  "dallas,disable-oscillator-stop-flag"))
+				ds1307->regs[1] |= DS1341_BIT_DOSF;
+			else
+				ds1307->regs[1] &= ~DS1341_BIT_DOSF;
+
+			if (of_property_read_bool(client->dev.of_node,
+						  "dallas,enable-glitch-filter"))
+				ds1307->regs[0] |= DS1341_BIT_EGFIL;
+			else
+				ds1307->regs[0] &= ~DS1341_BIT_EGFIL;
+
+			/*
+			 * Write status register. Control register
+			 * would be set by the code below
+			 */
+			i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
+						  ds1307->regs[1]);
+		}
+
 		/*
 		 * Disable the square wave and both alarms.
 		 * For some variants, be sure alarms can trigger when we're
-- 
2.5.5