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author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-11 14:06:55 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-11 14:06:55 -0700 |
commit | 7f33e7241d3dbad3c0563fd1fc79fc9380b5c351 (patch) | |
tree | 4f0f72e0954e9a5a60679780a4cdf0bf243d47e1 /Documentation | |
parent | 2dc24b0d0636349d403ae803bbad0c84f6c2ea57 (diff) | |
parent | 39fd3f99aba3f7683fc9b62e916e4c886a1cb6b0 (diff) | |
download | linux-7f33e7241d3dbad3c0563fd1fc79fc9380b5c351.tar.bz2 |
Merge tag 'pwm/for-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm changes from Thierry Reding:
"The majority of these changes are cleanups and fixes across all
drivers. Redundant error messages are removed and more PWM
controllers set the .can_sleep flag to signal that they can't be used
in atomic context.
Support is added for the Broadcom Kona family of SoCs and the Intel
LPSS driver can now probe PCI devices in addition to ACPI devices.
Upon shutdown, the pwm-backlight driver will now power off the
backlight. It also uses the new descriptor-based GPIO API for more
concise GPIO handling.
A large chunk of these changes also converts platforms to use the
lookup mechanism rather than relying on the global number space to
reference PWM devices. This is largely in preparation for more
unification and cleanups in future patches. Eventually it will allow
the legacy PWM API to be removed"
* tag 'pwm/for-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (38 commits)
pwm: fsl-ftm: set pwm_chip can_sleep flag
pwm: ab8500: Fix wrong value shift for disable/enable PWM
pwm: samsung: do not set manual update bit in pwm_samsung_config
pwm: lp3943: Set pwm_chip can_sleep flag
pwm: atmel: set pwm_chip can_sleep flag
pwm: mxs: set pwm_chip can_sleep flag
pwm: tiehrpwm: inline accessor functions
pwm: tiehrpwm: don't build PM related functions when not needed
pwm-backlight: retrieve configured PWM period
leds: leds-pwm: retrieve configured PWM period
ARM: pxa: hx4700: use PWM_LOOKUP to initialize struct pwm_lookup
ARM: shmobile: armadillo: use PWM_LOOKUP to initialize struct pwm_lookup
ARM: OMAP3: Beagle: use PWM_LOOKUP to initialize struct pwm_lookup
pwm: modify PWM_LOOKUP to initialize all struct pwm_lookup members
ARM: pxa: hx4700: initialize all the struct pwm_lookup members
ARM: OMAP3: Beagle: initialize all the struct pwm_lookup members
pwm: renesas-tpu: remove unused struct tpu_pwm_platform_data
ARM: shmobile: armadillo: initialize all struct pwm_lookup members
pwm: add period and polarity to struct pwm_lookup
pwm: twl: Really disable twl6030 PWMs
...
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/devicetree/bindings/pwm/bcm-kona-pwm.txt | 21 | ||||
-rw-r--r-- | Documentation/pwm.txt | 10 |
2 files changed, 30 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/pwm/bcm-kona-pwm.txt b/Documentation/devicetree/bindings/pwm/bcm-kona-pwm.txt new file mode 100644 index 000000000000..8eae9fe7841c --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/bcm-kona-pwm.txt @@ -0,0 +1,21 @@ +Broadcom Kona PWM controller device tree bindings + +This controller has 6 channels. + +Required Properties : +- compatible: should contain "brcm,kona-pwm" +- reg: physical base address and length of the controller's registers +- clocks: phandle + clock specifier pair for the external clock +- #pwm-cells: Should be 3. See pwm.txt in this directory for a + description of the cells format. + +Refer to clocks/clock-bindings.txt for generic clock consumer properties. + +Example: + +pwm: pwm@3e01a000 { + compatible = "brcm,bcm11351-pwm", "brcm,kona-pwm"; + reg = <0x3e01a000 0xc4>; + clocks = <&pwm_clk>; + #pwm-cells = <3>; +}; diff --git a/Documentation/pwm.txt b/Documentation/pwm.txt index 93cb97974986..ca895fd211e4 100644 --- a/Documentation/pwm.txt +++ b/Documentation/pwm.txt @@ -19,7 +19,8 @@ should instead register a static mapping that can be used to match PWM consumers to providers, as given in the following example: static struct pwm_lookup board_pwm_lookup[] = { - PWM_LOOKUP("tegra-pwm", 0, "pwm-backlight", NULL), + PWM_LOOKUP("tegra-pwm", 0, "pwm-backlight", NULL, + 50000, PWM_POLARITY_NORMAL), }; static void __init board_init(void) @@ -97,6 +98,13 @@ pwm_chip as argument which provides a description of the PWM chip, the number of PWM devices provided by the chip and the chip-specific implementation of the supported PWM operations to the framework. +When implementing polarity support in a PWM driver, make sure to respect the +signal conventions in the PWM framework. By definition, normal polarity +characterizes a signal starts high for the duration of the duty cycle and +goes low for the remainder of the period. Conversely, a signal with inversed +polarity starts low for the duration of the duty cycle and goes high for the +remainder of the period. + Locking ------- |