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From: Brian Masney <masneyb@onstation.org>
To: Stephen Boyd <sboyd@kernel.org>
Cc: dmitry.torokhov@gmail.com, robh+dt@kernel.org,
	mark.rutland@arm.com, agross@kernel.org,
	bjorn.andersson@linaro.org, mturquette@baylibre.com,
	linux-input@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-clk@vger.kernel.org
Subject: Re: [PATCH 4/7] dt-bindings: Input: introduce new clock vibrator bindings
Date: Tue, 7 Jan 2020 18:18:20 -0500	[thread overview]
Message-ID: <20200107231820.GA13416@onstation.org> (raw)
In-Reply-To: <20200107175222.6B5052073D@mail.kernel.org>

On Tue, Jan 07, 2020 at 09:52:21AM -0800, Stephen Boyd wrote:
> Quoting Brian Masney (2020-01-07 04:03:17)
> > On Sun, Jan 05, 2020 at 12:35:33AM -0800, Stephen Boyd wrote:
> > > Quoting Brian Masney (2019-12-04 16:25:00)
> > > > +examples:
> > > > +  - |
> > > > +    #include <dt-bindings/clock/qcom,mmcc-msm8974.h>
> > > > +    #include <dt-bindings/gpio/gpio.h>
> > > > +
> > > > +    vibrator {
> > > > +        compatible = "clk-vibrator";
> > > > +
> > > > +        vcc-supply = <&pm8941_l19>;
> > > > +
> > > > +        clocks = <&mmcc CAMSS_GP1_CLK>;
> > > > +        clock-names = "core";
> > > > +        clock-frequency = <24000>;
> > > > +
> > > > +        enable-gpios = <&msmgpio 60 GPIO_ACTIVE_HIGH>;
> > > > +
> > > > +        pinctrl-names = "default";
> > > > +        pinctrl-0 = <&vibrator_pin>;
> > > 
> > > I'm still trying to wrap my head around this. I think we can have a pwm
> > > provider in a clk controller node (so imagine &mmcc has #pwm-cells) and
> > > then this 'clk-vibrator' binding wouldn't exist? Instead we would have
> > > some sort of binding for a device that expects a pwm and whatever else
> > > is required, like the enable gpio and power supply. Is there an actual
> > > hardware block that is this way? Does it have a real product id and is
> > > made by some company? Right now this looks a little too generic to not
> > > just be a catch-all for something that buzzes.
> > 
> > So have some of the Qualcomm clocks like this one register with both the
> > clk and the pwm frameworks? I feel that approach would better represent
> > the hardware in device tree.
> 
> That is one option. Or another option would be to have another node that
> "adapts" a clk signal to a pwm provider. Similar to how we adapt a gpio
> to make a clk gate or mux. Something like:
> 
> 	gcc: clock-controller@f00d {
> 		reg = <0xf00d 0xd00d>;
> 		#clock-cells = <1>;
> 	};
> 
> 
> 	pwm {
> 		compatible = "pwm-clk";
> 		#pwm-cells = <0>;
> 		clocks = <&gcc 45>;
> 		assigned-clocks = <&gcc 45>;
> 		assigned-clock-rates = <1400000>;
> 	};
> 
> And then the pwm-clk driver would adjust the duty cycle to generate a
> pwm.

OK, that makes sense.

I'll pick this up after someone from Qualcomm posts a patch that
implements the clock duty cycle. I'm willing to do that work if someone
explains the relationship between the m, n, and d values on these clocks.

Brian

  reply	other threads:[~2020-01-07 23:18 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-05  0:24 [PATCH 0/7] qcom: add clk-vibrator driver Brian Masney
2019-12-05  0:24 ` [PATCH 1/7] clk: qcom: add support for setting the duty cycle Brian Masney
2019-12-10  4:47   ` Taniya Das
2020-02-12 23:23     ` Stephen Boyd
     [not found]   ` <0101016eee224b50-8a5545e2-837f-41c2-9574-b385e111a6b3-000000@us-west-2.amazonses.com>
2019-12-10 11:51     ` Brian Masney
2019-12-13 13:56       ` Linus Walleij
2019-12-05  0:24 ` [PATCH 2/7] dt-bindings: Input: drop msm-vibrator in favor of clk-vibrator Brian Masney
2019-12-17 14:11   ` Rob Herring
2019-12-05  0:24 ` [PATCH 3/7] Input: drop msm-vibrator in favor of clk-vibrator driver Brian Masney
2020-02-11 12:18   ` Brian Masney
2019-12-05  0:25 ` [PATCH 4/7] dt-bindings: Input: introduce new clock vibrator bindings Brian Masney
2019-12-05 13:56   ` Rob Herring
2019-12-09  0:54     ` Brian Masney
2019-12-09 16:16       ` Rob Herring
2019-12-09 16:55         ` Brian Masney
2020-01-05  8:35   ` Stephen Boyd
2020-01-07 12:03     ` Brian Masney
2020-01-07 17:52       ` Stephen Boyd
2020-01-07 23:18         ` Brian Masney [this message]
2019-12-05  0:25 ` [PATCH 5/7] Input: introduce new clock vibrator driver Brian Masney
2019-12-05  0:25 ` [PATCH 6/7] ARM: qcom_defconfig: drop msm-vibrator in favor of clk-vibrator driver Brian Masney
2019-12-05  0:25 ` [PATCH 7/7] ARM: dts: qcom: msm8974-hammerhead: add support for vibrator Brian Masney

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