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Dong" , Abel Vesa , Fabio Estevam , linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, NXP Linux Team , Peng Fan , Pengutronix Kernel Team , Sascha Hauer , Shawn Guo , Elaine Zhang Subject: [PATCH v5 0/2] clk: fractional-divider: Improve approximation when zero based and export Date: Sat, 17 Jun 2023 15:10:39 +0200 Message-ID: <20230617131041.18313-1-frank@oltmanns.dev> MIME-Version: 1.0 X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1768945668763524249?= X-GMAIL-MSGID: =?utf-8?q?1768956581844923442?= 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 P.S.: V4 was short-lived, because it triggered a compiler warning on clang. I'm sorry for the noise. -- Frank V4: https://lore.kernel.org/all/20230617102919.27564-1-frank@oltmanns.dev/ 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 V5 (since V4): - Fix compiler warnings on clang by removing superfluous variable max_m in the test cases for the maximum denominator (n) and max_n in the test cases for max numerator (m). Thank you, Intel, for your kernel test robot! 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 | 157 ++++++++++++++++++++++ 5 files changed, 186 insertions(+), 7 deletions(-) create mode 100644 drivers/clk/clk-fractional-divider_test.c