From: Luis de Bethencourt <luisbg@osg.samsung.com>
To: linux-kernel@vger.kernel.org
Cc: gregkh@linuxfoundation.org, lars@metafoo.de,
Michael.Hennerich@analog.com, jic23@kernel.org, knaack.h@gmx.de,
pmeerw@pmeerw.net, linux-iio@vger.kernel.org,
devel@driverdev.osuosl.org,
Luis de Bethencourt <luisbg@osg.samsung.com>
Subject: [PATCH] staging: iio: ad5933: fix handling of settling time cycles
Date: Wed, 1 Jun 2016 16:55:25 +0100 [thread overview]
Message-ID: <1464796525-9030-1-git-send-email-luisbg@osg.samsung.com> (raw)
Correctly handle the settling time cycles value. The else branch was an
impossible condition (> 1022 in the else branch of > 511) and the handling
of the values was dividing by 2 and 4, with a left shift, instead of
multiplying.
Based on the Table 13 at the bottom of Page 25 of the Data Sheet:
http://www.analog.com/media/en/technical-documentation/data-sheets/AD5933.pdf
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
---
Hi,
I decided to use the hexadecimal values instead of (1 << 10) and (1 << 9), for
briefness, I could resend using those instead if it is prefered.
I also decided to use multiplications instead of right-shifts for readability.
I could use change that as well.
Thanks,
Luis
drivers/staging/iio/impedance-analyzer/ad5933.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
index 9f43976..3a2cf8f3 100644
--- a/drivers/staging/iio/impedance-analyzer/ad5933.c
+++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
@@ -444,10 +444,13 @@ static ssize_t ad5933_store(struct device *dev,
st->settling_cycles = val;
/* 2x, 4x handling, see datasheet */
- if (val > 511)
- val = (val >> 1) | (1 << 9);
- else if (val > 1022)
- val = (val >> 2) | (3 << 9);
+ if (val & 0x400 && val & 0x200) {
+ val &= 0x1ff;
+ val *= 4;
+ } else if (val & 0x200) {
+ val &= 0x1ff;
+ val *= 2;
+ }
dat = cpu_to_be16(val);
ret = ad5933_i2c_write(st->client,
--
2.5.1
next reply other threads:[~2016-06-01 15:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-01 15:55 Luis de Bethencourt [this message]
2016-06-01 16:22 ` [PATCH] staging: iio: ad5933: fix handling of settling time cycles Lars-Peter Clausen
2016-06-01 18:15 ` Luis de Bethencourt
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