Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1948370AbdDYOp5 (ORCPT ); Tue, 25 Apr 2017 10:45:57 -0400 Received: from mail-wr0-f169.google.com ([209.85.128.169]:34000 "EHLO mail-wr0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1948322AbdDYOp2 (ORCPT ); Tue, 25 Apr 2017 10:45:28 -0400 From: Gary Bisson To: rtc-linux@googlegroups.com Cc: linux-kernel@vger.kernel.org, alexandre.belloni@free-electrons.com, a.zummo@towertech.it, Gary Bisson Subject: [PATCH 2/4] rtc: m41t80: fix SQW dividers override when setting a date Date: Tue, 25 Apr 2017 16:45:15 +0200 Message-Id: <20170425144517.15962-3-gary.bisson@boundarydevices.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170425144517.15962-1-gary.bisson@boundarydevices.com> References: <20170425144517.15962-1-gary.bisson@boundarydevices.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1482 Lines: 44 This patch is only relevant for RTC with the SQ_ALT feature which means the clock output frequency divider is stored in the weekday register. Current implementation discards the previous dividers value and clear them as soon as the time is set. Signed-off-by: Gary Bisson --- drivers/rtc/rtc-m41t80.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/rtc/rtc-m41t80.c b/drivers/rtc/rtc-m41t80.c index 93684ab293f2..0c142653c309 100644 --- a/drivers/rtc/rtc-m41t80.c +++ b/drivers/rtc/rtc-m41t80.c @@ -168,6 +168,7 @@ static int m41t80_get_datetime(struct i2c_client *client, /* Sets the given date and time to the real time clock. */ static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) { + struct m41t80_data *clientdata = i2c_get_clientdata(client); unsigned char buf[8]; int err, flags; @@ -183,6 +184,17 @@ static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100); buf[M41T80_REG_WDAY] = tm->tm_wday; + /* If the square wave output is controlled in the weekday register */ + if (clientdata->features & M41T80_FEATURE_SQ_ALT) { + int val; + + val = i2c_smbus_read_byte_data(client, M41T80_REG_WDAY); + if (val < 0) + return val; + + buf[M41T80_REG_WDAY] |= (val & 0xf0); + } + err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC, sizeof(buf), buf); if (err < 0) { -- 2.11.0