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[2003:f1:33dd:a400:428d:5cff:feb9:9db8]) by smtp.googlemail.com with ESMTPSA id f10sm1026745wrg.24.2019.06.12.12.59.28 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 12 Jun 2019 12:59:28 -0700 (PDT) From: Martin Blumenstingl To: linux-amlogic@lists.infradead.org, linux-pwm@vger.kernel.org, thierry.reding@gmail.com Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, u.kleine-koenig@pengutronix.de, narmstrong@baylibre.com, Martin Blumenstingl Subject: [PATCH v3 00/14] pwm-meson: cleanups and improvements Date: Wed, 12 Jun 2019 21:58:57 +0200 Message-Id: <20190612195911.4442-1-martin.blumenstingl@googlemail.com> X-Mailer: git-send-email 2.22.0 MIME-Version: 1.0 Sender: linux-pwm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pwm@vger.kernel.org This series consists of various cleanups and improvements for the pwm-meson driver. Patches 1 to 6 are small code cleanups with the goal of making the code easier to read. Patches 7 to 9 are reworking the way the per-channel settings are accessed. This is a first preparation step for adding full support to meson_pwm_get_state() in the pwm-meson driver. Patch 7 makes struct meson_pwm_channel accessible from struct meson_pwm because meson_pwm_get_state() cannot use pwm_get_chip_data(). Patch 8 removes redundant switch/case statements and ensures that we don't have to add another redundant one for the upcoming full meson_pwm_get_state() implementation. Patch 9 gets rid of meson_pwm_add_channels() and moves the pwm_set_chip_data() call to meson_pwm_request() (like all other PWM drivers do - except two). Patch 10 is based on a suggestion by Uwe to simplify the calculation of the values which the PWM IP requires. The nice benefit of this is that we have an easier calculation which we can do "in reverse" for the meson_pwm_get_state() (which calculates nanoseconds from the hardware values). Patch 11 implements reading the period and duty cycle in the meson_pwm_get_state() callback. Patch 12 removes some internal caching which we don't need anymore now meson_pwm_get_state() is fully implemented. The PWM core now takes care of not calling pwm_ops.apply() if "nothing has changed". Patch 13 adds support for PWM_POLARITY_INVERSED when disabling the output as suggested by Uwe. Patch 14 completes this series by adding some documentation to the driver. Thanks to Neil for summarizing how the hardware works internally. Due to the changed PWM calculation in patch 10 I have verified that we don't break any existing boards. The patch itself contains two examples which show that the new calculation improves precision. I made screenshots of the measurements in pulseview [0] for the second case ("PWM LED on Khadas VIM"): - old algorithm: [1] - old algorithm: [2] Dependencies: This series applies on top of Neil's patch "pwm: pwm-meson: update with SPDX Licence identifier" [3] Changes since v1 at [4]: - fixed MESON_NUM_PWM vs MESON_NUM_PWMS typo in patch #7 - add another example to patch #10 where the pre_div has changed with the new calculation. the generated PWM signal is still the same as measuring shows - added Neil's Reviewed-by's and Uwe's Acked-by (thank you!) Changes since v2 at [5]: - fix the SoC name in the documentation patch (#14). The link points to the S912 datasheet so we shouldn't call it the "S922X datasheet". Spotted by Chris Moore (thank you!) - add the link to the S922X datasheet in the documentation patch (#14) because that SoC generation contains an updated version of the IP block with hardware support for "inversion" and "constant mode" - put my Signed-off-by after all Reviewed-by/Acked-by to indicate that I was the one who put the R-b/A-b there (spotted by Uwe - thank you) - added Uwe's Reviewed-by to three patches (thank you!) [0] https://sigrok.org/wiki/PulseView [1] https://abload.de/img/old-algormjs9.png [2] https://abload.de/img/new-algo4ckjo.png [3] https://patchwork.kernel.org/patch/10951319/ [4] https://patchwork.kernel.org/cover/10961073/ [5] https://patchwork.kernel.org/cover/10983279/ Martin Blumenstingl (14): pwm: meson: unify the parameter list of meson_pwm_{enable,disable} pwm: meson: use devm_clk_get_optional() to get the input clock pwm: meson: use GENMASK and FIELD_PREP for the lo and hi values pwm: meson: change MISC_CLK_SEL_WIDTH to MISC_CLK_SEL_MASK pwm: meson: don't duplicate the polarity internally pwm: meson: pass struct pwm_device to meson_pwm_calc() pwm: meson: add the meson_pwm_channel data to struct meson_pwm pwm: meson: add the per-channel register offsets and bits in a struct pwm: meson: move pwm_set_chip_data() to meson_pwm_request() pwm: meson: simplify the calculation of the pre-divider and count pwm: meson: read the full hardware state in meson_pwm_get_state() pwm: meson: don't cache struct pwm_state internally pwm: meson: add support PWM_POLARITY_INVERSED when disabling pwm: meson: add documentation to the driver drivers/pwm/pwm-meson.c | 327 +++++++++++++++++++++------------------- 1 file changed, 173 insertions(+), 154 deletions(-)