This is a note to let you know that I've just added the patch titled

rtc: m41t80: remove unneeded checks from m41t80_sqw_set_rate

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: rtc-m41t80-remove-unneeded-checks-from-m41t80_sqw_set_rate.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 05a03bf260e0480bfc0db91b1fdbc2115e3f193b Mon Sep 17 00:00:00 2001

From: Troy Kisky troy.kisky@boundarydevices.com Date: Thu, 2 Nov 2017 18:58:16 -0700 Subject: rtc: m41t80: remove unneeded checks from m41t80_sqw_set_rate

From: Troy Kisky troy.kisky@boundarydevices.com

commit 05a03bf260e0480bfc0db91b1fdbc2115e3f193b upstream.

m41t80_sqw_set_rate will be called with the result from m41t80_sqw_round_rate, so might as well make m41t80_sqw_set_rate(n) same as m41t80_sqw_set_rate(m41t80_sqw_round_rate(n))

As Russell King wrote[1], "clk_round_rate() is supposed to tell you what you end up with if you ask clk_set_rate() to set the exact same value you passed in - but clk_round_rate() won't modify the hardware."

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2012-January/080175.ht...

Signed-off-by: Troy Kisky troy.kisky@boundarydevices.com Signed-off-by: Alexandre Belloni alexandre.belloni@free-electrons.com Cc: Christoph Fritz chf.fritz@googlemail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/rtc/rtc-m41t80.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-)

--- a/drivers/rtc/rtc-m41t80.c +++ b/drivers/rtc/rtc-m41t80.c @@ -490,17 +490,12 @@ static int m41t80_sqw_set_rate(struct cl M41T80_REG_WDAY : M41T80_REG_SQW; int reg, ret, val = 0;

- if (rate) { - if (!is_power_of_2(rate)) - return -EINVAL; - val = ilog2(rate); - if (val == ilog2(M41T80_SQW_MAX_FREQ)) - val = 1; - else if (val < (ilog2(M41T80_SQW_MAX_FREQ) - 1)) - val = ilog2(M41T80_SQW_MAX_FREQ) - val; - else - return -EINVAL; - } + if (rate >= M41T80_SQW_MAX_FREQ) + val = 1; + else if (rate >= M41T80_SQW_MAX_FREQ / 4) + val = 2; + else if (rate) + val = 15 - ilog2(rate);

reg = i2c_smbus_read_byte_data(client, reg_sqw); if (reg < 0)

Patches currently in stable-queue which might be from troy.kisky@boundarydevices.com are

queue-4.14/rtc-m41t80-m41t80_sqw_set_rate-should-return-0-on-success.patch queue-4.14/rtc-m41t80-avoid-i2c-read-in-m41t80_sqw_is_prepared.patch queue-4.14/rtc-m41t80-avoid-i2c-read-in-m41t80_sqw_recalc_rate.patch queue-4.14/rtc-m41t80-remove-unneeded-checks-from-m41t80_sqw_set_rate.patch queue-4.14/rtc-m41t80-fix-m41t80_sqw_round_rate-return-value.patch