From: David Lechner <dlechner@baylibre.com>
To: "Romain Gantois" <romain.gantois@bootlin.com>,
"Liam Girdwood" <lgirdwood@gmail.com>,
"Mark Brown" <broonie@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
"Conor Dooley" <conor+dt@kernel.org>,
"Jonathan Cameron" <jic23@kernel.org>,
"Nuno Sá" <nuno.sa@analog.com>,
"Andy Shevchenko" <andy@kernel.org>
Cc: Hans de Goede <hansg@kernel.org>,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
linux-iio@vger.kernel.org
Subject: Re: [PATCH v2 3/5] Add kunit tests for iio_divide_by_value()
Date: Thu, 25 Sep 2025 15:26:38 -0500 [thread overview]
Message-ID: <49b24a0d-a2ac-4620-9a1e-a94e5a2db075@baylibre.com> (raw)
In-Reply-To: <20250925-ltm8054-driver-v2-3-bb61a401a0dc@bootlin.com>
On 9/25/25 7:37 AM, Romain Gantois wrote:
...
> +static void __iio_test_iio_divide_by_integer(struct kunit *test, s64 numerator)
> +{
> + int ret, result, val;
> +
> + val = 42;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_INT, val, 0);
> + KUNIT_EXPECT_EQ(test, ret, IIO_VAL_INT);
> + KUNIT_EXPECT_EQ(test, result, div_s64(numerator, val));
> +
> + val = -23;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_INT, val, 0);
> + KUNIT_EXPECT_EQ(test, ret, IIO_VAL_INT);
> + KUNIT_EXPECT_EQ(test, result, div_s64(numerator, val));
> +
> + val = 0;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_INT, val, 0);
> + KUNIT_EXPECT_EQ(test, ret, -ERANGE);
I would expect EDOM for divide by 0 rather than ERANGE. The function is
undefined at that point.
> +}
> +
> +static void iio_test_iio_divide_by_integer(struct kunit *test)
> +{
> + __iio_test_iio_divide_by_integer(test, 2000);
> + __iio_test_iio_divide_by_integer(test, -2000);
> +}
> +
> +static void __iio_test_iio_divide_by_fixedpoint(struct kunit *test, s64 numerator)
> +{
> + int ret, result, val, val2;
> +
> + /* positive >= 1 (1.5) */
> + val = 1;
> + val2 = 500000;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_INT_PLUS_MICRO, val, val2);
> + KUNIT_EXPECT_EQ(test, ret, IIO_VAL_INT);
> + KUNIT_EXPECT_EQ(test, result, div_s64(numerator * 10, 15));
> +
> + val = 1;
> + val2 = 500000000;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_INT_PLUS_NANO, val, val2);
> + KUNIT_EXPECT_EQ(test, ret, IIO_VAL_INT);
> + KUNIT_EXPECT_EQ(test, result, div_s64(numerator * 10, 15));
> +
> + /* positive < 1 (0.5) */
> + val = 0;
> + val2 = 500000;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_INT_PLUS_MICRO, val, val2);
> + KUNIT_EXPECT_EQ(test, ret, IIO_VAL_INT);
> + KUNIT_EXPECT_EQ(test, result, div_s64(numerator * 10, 5));
> +
> + val = 0;
> + val2 = 500000000;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_INT_PLUS_NANO, val, val2);
> + KUNIT_EXPECT_EQ(test, ret, IIO_VAL_INT);
> + KUNIT_EXPECT_EQ(test, result, div_s64(numerator * 10, 5));
> +
> + /* negative <= -1 (-1.5) */
> + val = -1;
> + val2 = 500000;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_INT_PLUS_MICRO, val, val2);
> + KUNIT_EXPECT_EQ(test, ret, IIO_VAL_INT);
> + KUNIT_EXPECT_EQ(test, result, div_s64(numerator * -10, 15));
> +
> + val = -1;
> + val2 = 500000000;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_INT_PLUS_NANO, val, val2);
> + KUNIT_EXPECT_EQ(test, ret, IIO_VAL_INT);
> + KUNIT_EXPECT_EQ(test, result, div_s64(numerator * -10, 15));
> +
> + /* negative > -1 (-0.5) */
> + val = 0;
> + val2 = -500000;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_INT_PLUS_MICRO, val, val2);
> + KUNIT_EXPECT_EQ(test, ret, IIO_VAL_INT);
> + KUNIT_EXPECT_EQ(test, result, div_s64(numerator * -10, 5));
> +
> + val = 0;
> + val2 = -500000000;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_INT_PLUS_NANO, val, val2);
> + KUNIT_EXPECT_EQ(test, ret, IIO_VAL_INT);
> + KUNIT_EXPECT_EQ(test, result, div_s64(numerator * -10, 5));
> +
> + /* Zero */
> + val = 0;
Odd to break the pattern an not have `val2 = 0;` here.
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_FRACTIONAL_LOG2, val, 0);
> + KUNIT_EXPECT_EQ(test, ret, -ERANGE);
> +}
...
> +static void __iio_test_iio_divide_by_fractional_log2(struct kunit *test, s64 numerator)
> +{
> + int ret, result, val, val2;
> +
> + /* positive < 1 (123/1024) */
> + val = 123;
> + val2 = 10;
> + ret = iio_divide_by_value(&result, numerator, IIO_VAL_FRACTIONAL_LOG2, val, val2);
> + KUNIT_EXPECT_EQ(test, ret, IIO_VAL_INT);
> + KUNIT_EXPECT_EQ(test, result, div_s64((numerator << val2), val));
My instinct would be to write it like this:
div_s64((numerator * 1024), 123)
This follows how it was done in __iio_test_iio_divide_by_fixedpoint() and
makes it easier to see that it matchs exactly the value in the comment.
next prev parent reply other threads:[~2025-09-25 20:26 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-25 12:37 [PATCH v2 0/5] Add support for the LTM8054 voltage regulator Romain Gantois
2025-09-25 12:37 ` [PATCH v2 1/5] regulator: dt-bindings: Add Linear Technology LTM8054 regulator Romain Gantois
2025-09-25 19:27 ` Conor Dooley
2025-09-26 15:59 ` Romain Gantois
2025-09-27 22:31 ` Conor Dooley
2025-10-01 7:11 ` Romain Gantois
2025-10-01 11:18 ` David Lechner
2025-10-01 18:40 ` Conor Dooley
2025-10-02 7:11 ` David Lechner
2025-09-25 12:37 ` [PATCH v2 2/5] iio: add processed write API Romain Gantois
2025-09-25 21:10 ` David Lechner
2025-10-01 7:19 ` Romain Gantois
2025-10-01 10:43 ` David Lechner
[not found] ` <CAMknhBG_o=jTKtHHDyK=bq7wcHMnDM1ZHaYAfX0K2hjHfkX3Bg@mail.gmail.com>
2025-10-03 14:35 ` Romain Gantois
2025-09-28 9:07 ` Jonathan Cameron
2025-09-25 12:37 ` [PATCH v2 3/5] Add kunit tests for iio_divide_by_value() Romain Gantois
2025-09-25 20:26 ` David Lechner [this message]
2025-09-25 12:37 ` [PATCH v2 4/5] regulator: Support the LTM8054 voltage regulator Romain Gantois
2025-10-22 14:44 ` Andy Shevchenko
2025-09-25 12:37 ` [PATCH v2 5/5] regulator: ltm8054: Support output current limit control Romain Gantois
2025-10-22 8:05 ` Romain Gantois
2025-10-22 16:37 ` Andy Shevchenko
2025-10-24 7:55 ` Romain Gantois
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