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;a=summary
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@xxxxxxxxxxxxxxx> know about it.
>From 05a03bf260e0480bfc0db91b1fdbc2115e3f193b Mon Sep 17 00:00:00 2001
From: Troy Kisky <troy.kisky@xxxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxx>
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.html
Signed-off-by: Troy Kisky <troy.kisky@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Fritz <chf.fritz@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxxxxxxxxxxx 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