adi,axi-pwmgen fixes backport #2824
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Fix a shortcoming in the bindings that doesn't allow for a separate external clock. The AXI PWMGEN IP block has a compile option ASYNC_CLK_EN that allows the use of an external clock for the PWM output separate from the AXI clock that runs the peripheral. This was missed in the original bindings and so users were writing dts files where the one and only clock specified would be the external clock, if there was one, incorrectly missing the separate AXI clock. The correct bindings are that the AXI clock is always required and the external clock is optional (must be given only when HDL compile option ASYNC_CLK_EN=1). Fixes: 1edf2c2 ("dt-bindings: pwm: Add AXI PWM generator") Cc: stable@vger.kernel.org Signed-off-by: David Lechner <dlechner@baylibre.com> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Link: https://lore.kernel.org/r/20250529-pwm-axi-pwmgen-add-external-clock-v3-2-5d8809a7da91@baylibre.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> (cherry picked from commit e683131) Signed-off-by: David Lechner <dlechner@baylibre.com>
Add proper support for external clock to the AXI PWM generator driver. In most cases, the HDL for this IP block is compiled with the default ASYNC_CLK_EN=1. With this option, there is a separate external clock that drives the PWM output separate from the peripheral clock. So the driver should be enabling the "axi" clock to power the peripheral and the "ext" clock to drive the PWM output. When ASYNC_CLK_EN=0, the "axi" clock is also used to drive the PWM output and there is no "ext" clock. Previously, if there was a separate external clock, users had to specify only the external clock and (incorrectly) omit the AXI clock in order to get the correct operating frequency for the PWM output. The devicetree bindings are updated to fix this shortcoming and this patch changes the driver to match the new bindings. To preserve compatibility with any existing dtbs that specify only one clock, we don't require the clock name on the first clock. Fixes: 41814fe ("pwm: Add driver for AXI PWM generator") Cc: stable@vger.kernel.org Acked-by: Nuno Sá <nuno.sa@analog.com> Reviewed-by: Trevor Gamblin <tgamblin@baylibre.com> Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://lore.kernel.org/r/20250529-pwm-axi-pwmgen-add-external-clock-v3-3-5d8809a7da91@baylibre.com Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org> (cherry picked from commit a8841dc) Signed-off-by: David Lechner <dlechner@baylibre.com>
After backporting the dt-bindings fix from upstream, update the existing .dts files that use adi,axi-pwmgen-2.00.a to use the corrected clocks binding. In the HDL, ASYNC_CLK_EN=1 by default, so most projects have a separate external clock. The only exceptions are ad7606x, ad7616 and dc2677a, which have ASYNC_CLK_EN=0 and therefore only one clock. In arch/arm/boot/dts/xilinx/zynq-zed-adv7511-ad4134.dts the wrong clock was specified for the old binding so it will have a behavior change to use the correct clock for the PWM clock rate now. In arch/arm/boot/dts/xilinx/zynq-zed-adv7511-ltc2387.dts, we also drop the 0 in the phandle since #clock-cells = <0>; for &ref_clk. Signed-off-by: David Lechner <dlechner@baylibre.com>
This is the same as analogdevicesinc#2823 but has the adi,axi-pwmgen bindings clocks fixed up. We can drop this and add the fixup to the previous patch after the other PR is merged. Signed-off-by: David Lechner <dlechner@baylibre.com>
dlech
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dlech
commented
Jun 18, 2025
| @@ -72,8 +72,8 @@ | |||
| reg = <0x44b00000 0x1000>; | |||
| label = "ad463x_cnv"; | |||
| #pwm-cells = <2>; | |||
| clocks = <&cnv_ext_clk>; | |||
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| clocks = <&clkc 15>, <&spi_clk>; | |||
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Suggested change
| clocks = <&clkc 15>, <&spi_clk>; | |
| clocks = <&clkc 15>, <&cnv_ext_clk>; |
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PR Description
This is backporting a couple of fixes that were recently upstreamed to correct the clocks binding on adi,axi-pwmgen-2.00.a. Plus a patch to update all of the example .dts files that use it. A couple of .dts files had bugs in the clocks bindings as well, so those are fixed.
I intentionally added one more patch that conflicts with #2823 to remind us that it needs to get merged first so that we can fix up that .dts file as well before merging this one.
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