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// SPDX-License-Identifier: GPL-2.0
/*
* Kunit test for clock fractional divider
*/
#include <linux/clk-provider.h>
#include <kunit/test.h>
#include "clk-fractional-divider.h"
/*
* Test the maximum denominator case for fd clock without flags.
*
* Expect the highest possible denominator to be used in order to get as close as possible to the
* requested rate.
*/
static void clk_fd_test_approximation_max_denominator(struct kunit *test)
{
struct clk_fractional_divider *fd;
unsigned long rate, parent_rate, parent_rate_before, m, n, max_n;
fd = kunit_kzalloc(test, sizeof(*fd), GFP_KERNEL);
KUNIT_ASSERT_NOT_NULL(test, fd);
fd->mwidth = 3;
fd->nwidth = 3;
max_n = 7;
rate = 240000000;
parent_rate = (max_n + 1) * rate; /* so that it exceeds the maximum divisor */
parent_rate_before = parent_rate;
clk_fractional_divider_general_approximation(&fd->hw, rate, &parent_rate, &m, &n);
KUNIT_ASSERT_EQ(test, parent_rate, parent_rate_before);
KUNIT_EXPECT_EQ(test, m, 1);
KUNIT_EXPECT_EQ(test, n, max_n);
}
/*
* Test the maximum numerator case for fd clock without flags.
*
* Expect the highest possible numerator to be used in order to get as close as possible to the
* requested rate.
*/
static void clk_fd_test_approximation_max_numerator(struct kunit *test)
{
struct clk_fractional_divider *fd;
unsigned long rate, parent_rate, parent_rate_before, m, n, max_m;
fd = kunit_kzalloc(test, sizeof(*fd), GFP_KERNEL);
KUNIT_ASSERT_NOT_NULL(test, fd);
fd->mwidth = 3;
max_m = 7;
fd->nwidth = 3;
rate = 240000000;
parent_rate = rate / (max_m + 1); /* so that it exceeds the maximum numerator */
parent_rate_before = parent_rate;
clk_fractional_divider_general_approximation(&fd->hw, rate, &parent_rate, &m, &n);
KUNIT_ASSERT_EQ(test, parent_rate, parent_rate_before);
KUNIT_EXPECT_EQ(test, m, max_m);
KUNIT_EXPECT_EQ(test, n, 1);
}
/*
* Test the maximum denominator case for zero based fd clock.
*
* Expect the highest possible denominator to be used in order to get as close as possible to the
* requested rate.
*/
static void clk_fd_test_approximation_max_denominator_zero_based(struct kunit *test)
{
struct clk_fractional_divider *fd;
unsigned long rate, parent_rate, parent_rate_before, m, n, max_n;
fd = kunit_kzalloc(test, sizeof(*fd), GFP_KERNEL);
KUNIT_ASSERT_NOT_NULL(test, fd);
fd->flags = CLK_FRAC_DIVIDER_ZERO_BASED;
fd->mwidth = 3;
fd->nwidth = 3;
max_n = 8;
rate = 240000000;
parent_rate = (max_n + 1) * rate; /* so that it exceeds the maximum divisor */
parent_rate_before = parent_rate;
clk_fractional_divider_general_approximation(&fd->hw, rate, &parent_rate, &m, &n);
KUNIT_ASSERT_EQ(test, parent_rate, parent_rate_before);
KUNIT_EXPECT_EQ(test, m, 1);
KUNIT_EXPECT_EQ(test, n, max_n);
}
/*
* Test the maximum numerator case for zero based fd clock.
*
* Expect the highest possible numerator to be used in order to get as close as possible to the
* requested rate.
*/
static void clk_fd_test_approximation_max_numerator_zero_based(struct kunit *test)
{
struct clk_fractional_divider *fd;
unsigned long rate, parent_rate, parent_rate_before, m, n, max_m;
fd = kunit_kzalloc(test, sizeof(*fd), GFP_KERNEL);
KUNIT_ASSERT_NOT_NULL(test, fd);
fd->flags = CLK_FRAC_DIVIDER_ZERO_BASED;
fd->mwidth = 3;
max_m = 8;
fd->nwidth = 3;
rate = 240000000;
parent_rate = rate / (max_m + 1); /* so that it exceeds the maximum numerator */
parent_rate_before = parent_rate;
clk_fractional_divider_general_approximation(&fd->hw, rate, &parent_rate, &m, &n);
KUNIT_ASSERT_EQ(test, parent_rate, parent_rate_before);
KUNIT_EXPECT_EQ(test, m, max_m);
KUNIT_EXPECT_EQ(test, n, 1);
}
static struct kunit_case clk_fd_approximation_test_cases[] = {
KUNIT_CASE(clk_fd_test_approximation_max_denominator),
KUNIT_CASE(clk_fd_test_approximation_max_numerator),
KUNIT_CASE(clk_fd_test_approximation_max_denominator_zero_based),
KUNIT_CASE(clk_fd_test_approximation_max_numerator_zero_based),
{}
};
/*
* Test suite for clk_fractional_divider_general_approximation().
*/
static struct kunit_suite clk_fd_approximation_suite = {
.name = "clk-fd-approximation",
.test_cases = clk_fd_approximation_test_cases,
};
kunit_test_suites(
&clk_fd_approximation_suite
);
MODULE_LICENSE("GPL");
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