| Message ID | 1515766983-15151-12-git-send-email-claudiu.beznea@microchip.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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. > > 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". > - 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 >
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 >> >
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: - 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 -------------------------
Add documentation for PWM normal and complementary modes. 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(-)