linux-kernel - [PATCH v4 0/2] clk: fractional-divider: Improve approximation when zero based and export

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20230617102919.27564-1-frank@oltmanns.dev>
Date:   Sat, 17 Jun 2023 12:29:17 +0200
From:   Frank Oltmanns <frank@...manns.dev>
To:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     Frank Oltmanns <frank@...manns.dev>,
        "A.s. Dong" <aisheng.dong@....com>,
        Abel Vesa <abelvesa@...nel.org>,
        Fabio Estevam <festevam@...il.com>,
        linux-arm-kernel@...ts.infradead.org, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org, NXP Linux Team <linux-imx@....com>,
        Peng Fan <peng.fan@....com>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Shawn Guo <shawnguo@...nel.org>,
        Elaine Zhang <zhangqing@...k-chips.com>
Subject: [PATCH v4 0/2] clk: fractional-divider: Improve approximation when zero based and export

The fractional divider approximation does not utilize the full available
range for clocks that are flagged CLK_FRAC_DIVIDER_ZERO_BASED. This
patchset aims to fix that.

It also adds test cases for the edge cases of fractional divider clocks
with and without the CLK_FRAC_DIVIDER_ZERO_BASED flag to highlight the
changes.

Finally, it also exports clk_fractional_divider_general_approximation so
that the test cases (but also other users like rockchip clk driver) can
be compiled as a module.

Unfortunately, I have no boards to test this patch. So all we have are
the unit tests. It seems the only user of this flag in mainline is
drivers/clk/imx/clk-composite-7ulp.c, therefore I'm cc-ing
get_maintainers.pl --git-blame -f drivers/clk/imx/clk-composite-7ulp.c
in the hopes of a wider audience.

Thank you for considering this contribution,
  Frank

V3: https://lore.kernel.org/all/20230614185521.477924-1-frank@oltmanns.dev/
V2: https://lore.kernel.org/lkml/20230613083626.227476-1-frank@oltmanns.dev/
V1: https://lore.kernel.org/lkml/20230529133433.56215-1-frank@oltmanns.dev/

Changes in V4 (since V3):
 - Export clk_fractional_divider_general_approximation so that users
   (e.g., the testcases) can be compiled as modules.
 - Change test cases so that they test
   clk_fractional_divider_general_approximation again (like in V2)
   instead of clk_fd_round_rate (like in V3), but keeping the structure
   of V3 with separate file and individual test cases for each edge
   case.

Changes in V3 (since V2):
 - Completely reworked the test cases
   - Moved tests to separate file as per Stephen's request
   - Move each edge case into their individual test case as per
     Stephen's request
   - Test clk_fd_round_rate instead of
     clk_fractional_divider_general_approximation as testing the latter
     broke builds

Changes in V2 (since V1):
 - Added test case as requested by Stephen Boyd
 - Fixed commit message as the Cc: was missing a closing bracket, so that the
   original mail unfortunately did not go out to A. s. Dong.

Frank Oltmanns (2):
  clk: fractional-divider: Improve approximation when zero based and
    export
  clk: fractional-divider: tests: Add test suite for edge cases

 drivers/clk/.kunitconfig                  |   1 +
 drivers/clk/Kconfig                       |   7 +
 drivers/clk/Makefile                      |   1 +
 drivers/clk/clk-fractional-divider.c      |  27 +++-
 drivers/clk/clk-fractional-divider_test.c | 161 ++++++++++++++++++++++
 5 files changed, 190 insertions(+), 7 deletions(-)
 create mode 100644 drivers/clk/clk-fractional-divider_test.c

-- 
2.41.0