From: Claudiu Beznea <Claudiu.Beznea@microchip.com>
To: Rob Herring <robh@kernel.org>
Cc: <thierry.reding@gmail.com>, <mark.rutland@arm.com>,
<linux@armlinux.org.uk>, <daniel@zonque.org>,
<haojian.zhuang@gmail.com>, <robert.jarzmik@free.fr>,
<corbet@lwn.net>, <nicolas.ferre@microchip.com>,
<alexandre.belloni@free-electrons.com>,
<linux-pwm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-amlogic@lists.infradead.org>,
<linux-rockchip@lists.infradead.org>,
<linux-rpi-kernel@lists.infradead.org>,
<devicetree@vger.kernel.org>
Subject: Re: [PATCH v2 11/16] pwm: add documentation for PWM modes
Date: Mon, 22 Jan 2018 10:55:43 +0200 [thread overview]
Message-ID: <158fe004-1202-c27e-1b4b-f87f9d198cf3@microchip.com> (raw)
In-Reply-To: <20180119223908.b3dxdx53nzuhakzw@rob-hp-laptop>
On 20.01.2018 00:39, Rob Herring wrote:
> On Fri, Jan 12, 2018 at 04:22:58PM +0200, Claudiu Beznea wrote:
>> Add documentation for PWM normal and complementary modes.
>
> This and the previous patch can be combined.
OK
>
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
>> ---
>> Documentation/devicetree/bindings/pwm/pwm.txt | 17 ++++++++++++++--
>> Documentation/pwm.txt | 29 +++++++++++++++++++++++++--
>> 2 files changed, 42 insertions(+), 4 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/pwm/pwm.txt b/Documentation/devicetree/bindings/pwm/pwm.txt
>> index 8556263b8502..fdff25bad1db 100644
>> --- a/Documentation/devicetree/bindings/pwm/pwm.txt
>> +++ b/Documentation/devicetree/bindings/pwm/pwm.txt
>> @@ -43,8 +43,8 @@ because the name "backlight" would be used as fallback anyway.
>> pwm-specifier typically encodes the chip-relative PWM number and the PWM
>> period in nanoseconds.
>>
>> -Optionally, the pwm-specifier can encode a number of flags (defined in
>> -<dt-bindings/pwm/pwm.h>) in a third cell:
>> +Optionally, the pwm-specifier can encode:
>> +1. a number of flags (defined in <dt-bindings/pwm/pwm.h>) in a third cell:
>
> Based on the prior patches, "third cell" is probably to restrictive
> here and it should just say "in a flags cell".
OK
Thank you,
Claudiu Beznea
>
>> - PWM_POLARITY_INVERTED: invert the PWM signal polarity
>>
>> Example with optional PWM specifier for inverse polarity
>> @@ -54,6 +54,19 @@ Example with optional PWM specifier for inverse polarity
>> pwm-names = "backlight";
>> };
>>
>> +2. PWM working modes (defined in <dt-bindings/pwm/pwm.h>) in the 4th cell:
>> +- PWM_MODE_NORMAL: for all PWM controllers
>> +- PWM_MODE_COMPLEMENTARY: for PWM controllers with more than one output per
>> +PWM channel
>> +
>> +Example with PWM modes:
>> +
>> + bl: blacklight {
>> + pwms = <&pwm 0 5000000 PWM_POLARITY_INVERTED
>> + PWM_DTMODE_NORMAL | PWM_DTMODE_COMPLEMENTARY>;
>> + pwm-names = "backlight";
>> + };
>> +
>> 2) PWM controller nodes
>> -----------------------
>>
>> diff --git a/Documentation/pwm.txt b/Documentation/pwm.txt
>> index 8fbf0aa3ba2d..58c9bd55f021 100644
>> --- a/Documentation/pwm.txt
>> +++ b/Documentation/pwm.txt
>> @@ -61,8 +61,8 @@ In addition to the PWM state, the PWM API also exposes PWM arguments, which
>> are the reference PWM config one should use on this PWM.
>> PWM arguments are usually platform-specific and allows the PWM user to only
>> care about dutycycle relatively to the full period (like, duty = 50% of the
>> -period). struct pwm_args contains 2 fields (period and polarity) and should
>> -be used to set the initial PWM config (usually done in the probe function
>> +period). struct pwm_args contains 3 fields (period, polarity and mode) and
>> +should be used to set the initial PWM config (usually done in the probe function
>> of the PWM user). PWM arguments are retrieved with pwm_get_args().
>>
>> Using PWMs with the sysfs interface
>> @@ -83,6 +83,9 @@ will find:
>> unexport
>> Unexports a PWM channel from sysfs (write-only).
>>
>> + mode
>> + PWM chip supported modes.
>> +
>> The PWM channels are numbered using a per-chip index from 0 to npwm-1.
>>
>> When a PWM channel is exported a pwmX directory will be created in the
>> @@ -110,6 +113,28 @@ channel that was exported. The following properties will then be available:
>> - 0 - disabled
>> - 1 - enabled
>>
>> + mode
>> + Set PWM channel working mode (normal and complementary). PWM chip with
>> + complementary mode could also work in normal mode by using only one physical
>> + output.
>> +
>> + Normal mode - for PWM chips with one output per PWM channel; output
>> + waveforms looks like this:
>> + __ __ __ __
>> + PWM __| |__| |__| |__| |__
>> + <--T-->
>> +
>> + Complementary mode - for PWM chips with more than one output per PWM
>> + channel; output waveforms for a PWM controller with 2 outputs per PWM
>> + channel looks line this:
>> + __ __ __ __
>> + PWMH1 __| |__| |__| |__| |__
>> + __ __ __ __ __
>> + PWML1 |__| |__| |__| |__|
>> + <--T-->
>> +
>> + Where T is the signal period.
>> +
>> Implementing a PWM driver
>> -------------------------
>>
>> --
>> 2.7.4
>>
>
next prev parent reply other threads:[~2018-01-22 8:55 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-12 14:22 [PATCH v2 00/16] extend PWM framework to support PWM modes Claudiu Beznea
2018-01-12 14:22 ` [PATCH v2 01/16] drivers: pwm: core: use a single of xlate function Claudiu Beznea
2018-01-12 18:35 ` Brian Norris
2018-01-15 8:41 ` Claudiu Beznea
2018-01-15 12:43 ` Claudiu Beznea
2018-01-15 20:27 ` Andy Shevchenko
2018-01-16 8:24 ` Claudiu Beznea
2018-01-17 23:14 ` Brian Norris
2018-01-18 9:11 ` Claudiu Beznea
2018-01-16 9:07 ` Neil Armstrong
2018-01-16 9:33 ` Claudiu Beznea
2018-01-12 14:22 ` [PATCH v2 02/16] pwm: pxa: update documentation regarding pwm-cells Claudiu Beznea
2018-01-19 22:30 ` Rob Herring
2018-01-22 8:47 ` Claudiu Beznea
2018-01-12 14:22 ` [PATCH v2 03/16] pwm: cros-ec: " Claudiu Beznea
2018-01-12 18:31 ` Brian Norris
2018-01-15 9:01 ` Claudiu Beznea
2018-01-17 8:29 ` Claudiu Beznea
2018-01-17 23:10 ` Brian Norris
2018-01-18 9:18 ` Claudiu Beznea
2018-01-12 14:22 ` [PATCH v2 04/16] pwm: clps711x: " Claudiu Beznea
2018-01-12 14:22 ` [PATCH v2 05/16] ARM: dts: clps711x: update pwm-cells Claudiu Beznea
2018-01-12 14:22 ` [PATCH v2 06/16] ARM: dts: pxa: " Claudiu Beznea
2018-01-12 14:22 ` [PATCH v2 07/16] arm64: dts: rockchip: " Claudiu Beznea
2018-01-12 14:22 ` [PATCH v2 08/16] drivers: pwm: core: extend PWM framework with PWM modes Claudiu Beznea
2018-01-12 14:22 ` [PATCH v2 09/16] drivers: pwm: core: add PWM mode to pwm_config() Claudiu Beznea
2018-01-12 14:22 ` [PATCH v2 10/16] pwm: Add PWM modes Claudiu Beznea
2018-01-19 22:34 ` Rob Herring
2018-01-22 8:54 ` Claudiu Beznea
2018-01-22 18:12 ` Rob Herring
2018-01-23 10:40 ` Claudiu Beznea
2018-01-23 15:21 ` Rob Herring
2018-01-23 16:55 ` Claudiu Beznea
2018-01-12 14:22 ` [PATCH v2 11/16] pwm: add documentation for " Claudiu Beznea
2018-01-19 22:39 ` Rob Herring
2018-01-22 8:55 ` Claudiu Beznea [this message]
2018-01-12 14:22 ` [PATCH v2 12/16] pwm: atmel: add pwm capabilities Claudiu Beznea
2018-01-12 14:23 ` [PATCH v2 13/16] drivers: pwm: core: add push-pull mode support Claudiu Beznea
2018-01-12 14:23 ` [PATCH v2 14/16] pwm: add push-pull mode Claudiu Beznea
2018-01-12 14:23 ` [PATCH v2 15/16] pwm: add documentation for pwm " Claudiu Beznea
2018-01-19 22:41 ` Rob Herring
2018-01-12 14:23 ` [PATCH v2 16/16] pwm: atmel: add push-pull mode support Claudiu Beznea
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