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pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 09:40:40 +01:00
menuconfig PWM
pwm: Improve Kconfig help text The Kconfig help text should help the user understand what functionality is provided by an option. This is especially true for new subsystems. An improved help text is provided by this commit in the hopes of clarifying the usefulness of the PWM framework. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Acked-by: Borislav Petkov <bp@alien8.de>
2012-08-16 08:01:21 +02:00
bool "Pulse-Width Modulation (PWM) Support"
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 09:40:40 +01:00
help
pwm: Improve Kconfig help text The Kconfig help text should help the user understand what functionality is provided by an option. This is especially true for new subsystems. An improved help text is provided by this commit in the hopes of clarifying the usefulness of the PWM framework. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Acked-by: Borislav Petkov <bp@alien8.de>
2012-08-16 08:01:21 +02:00
Generic Pulse-Width Modulation (PWM) support.
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 09:40:40 +01:00
pwm: Improve Kconfig help text The Kconfig help text should help the user understand what functionality is provided by an option. This is especially true for new subsystems. An improved help text is provided by this commit in the hopes of clarifying the usefulness of the PWM framework. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Acked-by: Borislav Petkov <bp@alien8.de>
2012-08-16 08:01:21 +02:00
In Pulse-Width Modulation, a variation of the width of pulses
in a rectangular pulse signal is used as a means to alter the
average power of the signal. Applications include efficient
power delivery and voltage regulation. In computer systems,
PWMs are commonly used to control fans or the brightness of
display backlights.
This framework provides a generic interface to PWM devices
within the Linux kernel. On the driver side it provides an API
to register and unregister a PWM chip, an abstraction of a PWM
controller, that supports one or more PWM devices. Client
drivers can request PWM devices and use the generic framework
to configure as well as enable and disable them.
This generic framework replaces the legacy PWM framework which
allows only a single driver implementing the required API. Not
all legacy implementations have been ported to the framework
yet. The framework provides an API that is backward compatible
with the legacy framework so that existing client drivers
continue to work as expected.
If unsure, say no.
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 09:40:40 +01:00
if PWM
pwm: Move AB8500 PWM driver to PWM framework This commit moves the driver to drivers/pwm and converts it to the new PWM framework. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Arun Murthy <arun.murthy@stericsson.com>
2012-08-31 11:46:24 +02:00
config PWM_AB8500
tristate "AB8500 PWM support"
depends on AB8500_CORE && ARCH_U8500
help
Generic PWM framework driver for Analog Baseband AB8500.
To compile this driver as a module, choose M here: the module
will be called pwm-ab8500.
pwm: Move Blackfin PWM driver to PWM framework This commit moves the Blackfin PWM driver to the drivers/pwm sub- directory and converts it to register with the new PWM framework. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-01-02 20:53:50 +01:00
config PWM_BFIN
tristate "Blackfin PWM support"
depends on BFIN_GPTIMERS
help
Generic PWM framework driver for Blackfin.
To compile this driver as a module, choose M here: the module
will be called pwm-bfin.
ARM i.MX: Move i.MX pwm driver to pwm framework Move the driver to drivers/pwm/ and convert it to use the framework. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> [eric@eukrea.com: set chip.dev to prevent probe failure] [eric@eukrea.com: fix pwmchip_add return code test] Signed-off-by: Eric Bénard <eric@eukrea.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-03-15 10:04:35 +01:00
config PWM_IMX
tristate "i.MX pwm support"
depends on ARCH_MXC
help
Generic PWM framework driver for i.MX.
To compile this driver as a module, choose M here: the module
will be called pwm-imx.
pwm: Add Ingenic JZ4740 support This commit moves the driver to drivers/pwm and converts it to the new PWM framework. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Acked-by: Lars-Peter Clausen <lars@metafoo.de> Tested-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Ralf Baechle <ralf@linux-mips.org>
2012-08-22 10:01:24 +02:00
config PWM_JZ4740
tristate "Ingenic JZ4740 PWM support"
depends on MACH_JZ4740
help
Generic PWM framework driver for Ingenic JZ4740 based
machines.
To compile this driver as a module, choose M here: the module
will be called pwm-jz4740.
pwm: add lpc32xx PWM support Add lpc32xx SOC PWM driver. Signed-off-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com> Acked-by: Roland Stigge <stigge@antcom.de> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-07-10 11:38:10 -03:00
config PWM_LPC32XX
tristate "LPC32XX PWM support"
depends on ARCH_LPC32XX
help
Generic PWM framework driver for LPC32XX. The LPC32XX SOC has two
PWM controllers.
To compile this driver as a module, choose M here: the module
will be called pwm-lpc32xx.
pwm: add pwm-mxs support Add generic PWM framework driver (DT only) for Freescale MXS. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-04-04 10:50:52 +08:00
config PWM_MXS
tristate "Freescale MXS PWM support"
depends on ARCH_MXS && OF
pwm: pwm-mxs: use global reset function stmp_reset_block Use global reset function stmp_reset_block instead of mxs_reset_block to remove <mach/common.h> inclusion. Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-06-26 16:58:09 +08:00
select STMP_DEVICE
pwm: add pwm-mxs support Add generic PWM framework driver (DT only) for Freescale MXS. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-04-04 10:50:52 +08:00
help
Generic PWM framework driver for Freescale MXS.
To compile this driver as a module, choose M here: the module
will be called pwm-mxs.
pwm: Move PUV3 PWM driver to PWM framework This commit moves the driver to drivers/pwm and converts it to the new PWM framework. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Tested-by: Qin Rui <qinrui@mprc.pku.edu.cn> Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
2012-08-31 08:29:24 +02:00
config PWM_PUV3
tristate "PKUnity NetBook-0916 PWM support"
depends on ARCH_PUV3
help
Generic PWM framework driver for PKUnity NetBook-0916.
To compile this driver as a module, choose M here: the module
will be called pwm-puv3.
pwm: Move PXA PWM driver to PWM framework This commit moves the PXA PWM driver to the drivers/pwm subdirectory and converts it to use the new PWM framework. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-01-02 21:22:38 +01:00
config PWM_PXA
tristate "PXA PWM support"
depends on ARCH_PXA
help
Generic PWM framework driver for PXA.
To compile this driver as a module, choose M here: the module
will be called pwm-pxa.
ARM Samsung: Move s3c pwm driver to pwm framework Move the driver to drivers/pwm/ and convert it to use the framework. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Cc: Ben Dooks <ben-linux@fluff.org> Cc: Kukjin Kim <kgene.kim@samsung.com> [eric@eukrea.com: fix pwmchip_add return code test] Signed-off-by: Eric Bénard <eric@eukrea.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-03-15 10:04:36 +01:00
config PWM_SAMSUNG
tristate "Samsung pwm support"
depends on PLAT_SAMSUNG
help
Generic PWM framework driver for Samsung.
To compile this driver as a module, choose M here: the module
will be called pwm-samsung.
pwm: Add SPEAr PWM chip driver support Add support for PWM chips present on SPEAr platforms. These PWM chips support 4 channel output with programmable duty cycle and frequency. More details on these PWM chips can be obtained from relevant chapter of reference manual, present at following[1] location. 1. http://www.st.com/internet/mcu/product/251211.jsp Cc: Thierry Reding <thierry.reding@avionic-design.de> Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Vipin Kumar <vipin.kumar@st.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-10-25 09:39:13 +05:30
config PWM_SPEAR
tristate "STMicroelectronics SPEAr PWM support"
depends on PLAT_SPEAR
depends on OF
help
Generic PWM framework driver for the PWM controller on ST
SPEAr SoCs.
To compile this driver as a module, choose M here: the module
will be called pwm-spear.
pwm: Add NVIDIA Tegra SoC support This commit adds a generic PWM framework driver for the PWFM controller found on NVIDIA Tegra SoCs. The driver is based on code from the Chromium kernel tree and was originally written by Gary King (NVIDIA) and later modified by Simon Que (Chromium). Acked-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-12-21 07:47:07 +01:00
config PWM_TEGRA
tristate "NVIDIA Tegra PWM support"
depends on ARCH_TEGRA
help
Generic PWM framework driver for the PWFM controller found on NVIDIA
Tegra SoCs.
To compile this driver as a module, choose M here: the module
will be called pwm-tegra.
pwm: pwm-tiecap: PWM driver support for ECAP APWM ECAP hardware on AM33XX SOC supports auxiliary PWM (APWM) feature. This commit adds PWM driver support for ECAP hardware on AM33XX SOC. In the ECAP hardware, each PWM pin can also be configured to be in capture mode. Current implementation only supports PWM mode of operation. Also, hardware supports sync between multiple PWM pins but the driver supports simple independent PWM functionality. Reviewed-by: Vaibhav Bedia <vaibhav.bedia@ti.com> Signed-off-by: Philip, Avinash <avinashphilip@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-07-25 16:58:18 +05:30
config PWM_TIECAP
tristate "ECAP PWM support"
depends on SOC_AM33XX
pwm: Add TI PWM subsystem driver In some platforms (like am33xx), PWM sub modules (ECAP, EHRPWM, EQEP) are integrated to PWM subsystem. These PWM submodules has resources shared and only one register bit-field is provided to control module/clock enable/disable, makes it difficult to handle common resources from independent PWMSS submodule drivers. So the solution here implemented in this patch is, to create driver for PWMSS and take the role of parent driver for PWM submodules. PWMSS parent driver enumerates all the child nodes under PWMSS module. Also symbol "pwmss_submodule_state_change" exported to enable clock gating for individual PWMSS submodules, and submodule drivers has to enable clock gating from their drivers. As this is only supported during DT boot, the parent/child relationship is created and populated in DT execution flow. The only required change is inside DTS file, making EHRPWM & ECAP as a child to PWMSS node. Signed-off-by: Philip, Avinash <avinashphilip@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-11-27 14:18:06 +05:30
select PWM_TIPWMSS
pwm: pwm-tiecap: PWM driver support for ECAP APWM ECAP hardware on AM33XX SOC supports auxiliary PWM (APWM) feature. This commit adds PWM driver support for ECAP hardware on AM33XX SOC. In the ECAP hardware, each PWM pin can also be configured to be in capture mode. Current implementation only supports PWM mode of operation. Also, hardware supports sync between multiple PWM pins but the driver supports simple independent PWM functionality. Reviewed-by: Vaibhav Bedia <vaibhav.bedia@ti.com> Signed-off-by: Philip, Avinash <avinashphilip@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-07-25 16:58:18 +05:30
help
PWM driver support for the ECAP APWM controller found on AM33XX
TI SOC
To compile this driver as a module, choose M here: the module
will be called pwm-tiecap.
pwm: pwm-tiehrpwm: PWM driver support for EHRPWM Enhanced high resolution PWM module (EHRPWM) hardware can be used to generate PWM output over 2 channels. This commit adds PWM driver support for EHRPWM device present on AM33XX SOC. Current implementation supports simple PWM functionality. Reviewed-by: Vaibhav Bedia <vaibhav.bedia@ti.com> Signed-off-by: Philip, Avinash <avinashphilip@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-07-25 16:58:19 +05:30
config PWM_TIEHRPWM
tristate "EHRPWM PWM support"
depends on SOC_AM33XX
pwm: Add TI PWM subsystem driver In some platforms (like am33xx), PWM sub modules (ECAP, EHRPWM, EQEP) are integrated to PWM subsystem. These PWM submodules has resources shared and only one register bit-field is provided to control module/clock enable/disable, makes it difficult to handle common resources from independent PWMSS submodule drivers. So the solution here implemented in this patch is, to create driver for PWMSS and take the role of parent driver for PWM submodules. PWMSS parent driver enumerates all the child nodes under PWMSS module. Also symbol "pwmss_submodule_state_change" exported to enable clock gating for individual PWMSS submodules, and submodule drivers has to enable clock gating from their drivers. As this is only supported during DT boot, the parent/child relationship is created and populated in DT execution flow. The only required change is inside DTS file, making EHRPWM & ECAP as a child to PWMSS node. Signed-off-by: Philip, Avinash <avinashphilip@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-11-27 14:18:06 +05:30
select PWM_TIPWMSS
pwm: pwm-tiehrpwm: PWM driver support for EHRPWM Enhanced high resolution PWM module (EHRPWM) hardware can be used to generate PWM output over 2 channels. This commit adds PWM driver support for EHRPWM device present on AM33XX SOC. Current implementation supports simple PWM functionality. Reviewed-by: Vaibhav Bedia <vaibhav.bedia@ti.com> Signed-off-by: Philip, Avinash <avinashphilip@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-07-25 16:58:19 +05:30
help
PWM driver support for the EHRPWM controller found on AM33XX
TI SOC
To compile this driver as a module, choose M here: the module
will be called pwm-tiehrpwm.
pwm: Add TI PWM subsystem driver In some platforms (like am33xx), PWM sub modules (ECAP, EHRPWM, EQEP) are integrated to PWM subsystem. These PWM submodules has resources shared and only one register bit-field is provided to control module/clock enable/disable, makes it difficult to handle common resources from independent PWMSS submodule drivers. So the solution here implemented in this patch is, to create driver for PWMSS and take the role of parent driver for PWM submodules. PWMSS parent driver enumerates all the child nodes under PWMSS module. Also symbol "pwmss_submodule_state_change" exported to enable clock gating for individual PWMSS submodules, and submodule drivers has to enable clock gating from their drivers. As this is only supported during DT boot, the parent/child relationship is created and populated in DT execution flow. The only required change is inside DTS file, making EHRPWM & ECAP as a child to PWMSS node. Signed-off-by: Philip, Avinash <avinashphilip@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-11-27 14:18:06 +05:30
config PWM_TIPWMSS
bool
depends on SOC_AM33XX && (PWM_TIEHRPWM || PWM_TIECAP)
help
PWM Subsystem driver support for AM33xx SOC.
PWM submodules require PWM config space access from submodule
drivers and require common parent driver support.
pwm: New driver to support PWMs on TWL4030/6030 series of PMICs The driver supports the following PWM outputs: TWL4030 PWM0 and PWM1 TWL6030 PWM1 and PWM2 On TWL4030 the PWM signals are muxed. Upon requesting the PWM the driver will select the correct mux so the PWM can be used. When the PWM has been freed the original configuration is going to be restored. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-11-27 11:09:57 +01:00
config PWM_TWL
tristate "TWL4030/6030 PWM support"
depends on TWL4030_CORE
help
Generic PWM framework driver for TWL4030/6030.
To compile this driver as a module, choose M here: the module
will be called pwm-twl.
pwm: New driver to support PWM driven LEDs on TWL4030/6030 series of PMICs The driver supports the following LED outputs as generic PWM driver: TWL4030 LEDA and LEDB (PWMA and PWMB) TWL6030 Charging indicator LED (PWM LED) On TWL6030 when the PWM requested LED is configured to be controlled by SW. In this case the user can enable/disable and set the duty period freely. When the PWM has been freed, the LED driver is put back to HW control. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-11-27 11:09:58 +01:00
config PWM_TWL_LED
tristate "TWL4030/6030 PWM support for LED drivers"
depends on TWL4030_CORE
help
Generic PWM framework driver for TWL4030/6030 LED terminals.
To compile this driver as a module, choose M here: the module
will be called pwm-twl-led.
ARM vt8500: Move vt8500 pwm driver to pwm framework Move the driver to drivers/pwm/ and convert it to use the framework. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Cc: Alexey Charkov <alchark@gmail.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2012-03-15 10:04:37 +01:00
config PWM_VT8500
tristate "vt8500 pwm support"
depends on ARCH_VT8500
help
Generic PWM framework driver for vt8500.
To compile this driver as a module, choose M here: the module
will be called pwm-vt8500.
pwm: Add PWM framework support This patch adds framework support for PWM (pulse width modulation) devices. The is a barebone PWM API already in the kernel under include/linux/pwm.h, but it does not allow for multiple drivers as each of them implements the pwm_*() functions. There are other PWM framework patches around from Bill Gatliff. Unlike his framework this one does not change the existing API for PWMs so that this framework can act as a drop in replacement for the existing API. Why another framework? Several people argue that there should not be another framework for PWMs but they should be integrated into one of the existing frameworks like led or hwmon. Unlike these frameworks the PWM framework is agnostic to the purpose of the PWM. In fact, a PWM can drive a LED, but this makes the LED framework a user of a PWM, like already done in leds-pwm.c. The gpio framework also is not suitable for PWMs. Every gpio could be turned into a PWM using timer based toggling, but on the other hand not every PWM hardware device can be turned into a gpio due to the lack of hardware capabilities. This patch does not try to improve the PWM API yet, this could be done in subsequent patches. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Matthias Kaehlcke <matthias@kaehlcke.net> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> [thierry.reding@avionic-design.de: fixup typos, kerneldoc comments] Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
2011-01-28 09:40:40 +01:00
endif
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