From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pa0-x22e.google.com ([2607:f8b0:400e:c03::22e]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1amszG-0007O9-2Q for barebox@lists.infradead.org; Mon, 04 Apr 2016 01:07:27 +0000 Received: by mail-pa0-x22e.google.com with SMTP id td3so131890530pab.2 for ; Sun, 03 Apr 2016 18:07:05 -0700 (PDT) From: Andrey Smirnov Date: Sun, 3 Apr 2016 18:06:33 -0700 Message-Id: <1459731993-14807-3-git-send-email-andrew.smirnov@gmail.com> In-Reply-To: <1459731993-14807-1-git-send-email-andrew.smirnov@gmail.com> References: <1459731993-14807-1-git-send-email-andrew.smirnov@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 3/3] ds1307: Configure ds1341 for lowest power mode To: barebox@lists.infradead.org Cc: Andrey Smirnov Empirical observations show that configuring INTCN=1, ECLK=0, EGFIL=0, DOSF=1 on DS1341 put the chip in the mode where it draws the least amount fo current. Add code to configure DS1341 in such a way in case Barebox is the last code that runs on the processor before being shut down. Signed-off-by: Andrey Smirnov --- drivers/rtc/rtc-ds1307.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c index a1cfed6..4720964 100644 --- a/drivers/rtc/rtc-ds1307.c +++ b/drivers/rtc/rtc-ds1307.c @@ -68,6 +68,7 @@ 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 @@ -83,6 +84,7 @@ enum ds_type { # define DS1340_BIT_OSF 0x80 #define DS1337_REG_STATUS 0x0f # define DS1337_BIT_OSF 0x80 +# define DS1341_BIT_DOSF 0x40 # define DS1341_BIT_ECLK 0x04 # define DS1337_BIT_A2I 0x02 # define DS1337_BIT_A1I 0x01 @@ -333,12 +335,22 @@ static int ds1307_probe(struct device_d *dev) i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ds1307->regs[0]); - /* - For the above to be true, DS1341 also has to have - ECLK bit set to 0 - */ if (ds1307->type == ds_1341) { + /* + For the above to be true, DS1341 also has to have + ECLK bit set to 0 + */ ds1307->regs[1] &= ~DS1341_BIT_ECLK; + + /* + * Let's set additionale RTC bits to + * facilitate maximum power saving. + */ + ds1307->regs[0] |= DS1341_BIT_DOSF; + ds1307->regs[0] &= ~DS1341_BIT_EGFIL; + + i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, + ds1307->regs[0]); i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, ds1307->regs[1]); } -- 2.5.5 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox