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FROMLIST: pwm: gpio: Add a generic gpio based PWM driver

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This patch adds a bit-banging gpio PWM driver. It makes
use of hrtimers, to allow nano-second resolution, though
it obviously strongly depends on the switching speed of
the gpio pins, hrtimer and system load.

Each pwm node can have 1 or more "pwm-gpio" entries,
which will be treated as pwm's as part of a pwm chip.

Link: https://patchwork.ozlabs.org/project/linux-pwm/patch/1445895161-2317-8-git-send-email-o.schinagl@ultimaker.com/
Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
Change-Id: Ibdb28eca3239a3a8503c947667117a9b0e9427b9
This commit is contained in:
Damon Ding
2022-01-04 18:48:18 +08:00
committed by Tao Huang
parent b5dccad7be
commit 31e2803cc9
3 changed files with 16 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/pwm/Kconfig
+15
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@@ -181,6 +181,21 @@ config PWM_FSL_FTM
To compile this driver as a module, choose M here: the module
will be called pwm-fsl-ftm.
config PWM_GPIO
tristate "Generic GPIO bit-banged PWM driver"
depends on OF
depends on GPIOLIB
help
Some platforms do not offer any hardware PWM capabilities but do have
General Purpose Input Output (GPIO) pins available. Using the kernels
High-Resolution Timer API this driver tries to toggle GPIO using the
generic kernel PWM framework. The maximum frequency and/or accuracy
is dependent on several factors such as system load and the maximum
speed a pin can be toggled at the hardware.
To compile this driver as a module, choose M here: the module
will be called pwm-gpio.
config PWM_HIBVT
tristate "HiSilicon BVT PWM support"
depends on ARCH_HISI || COMPILE_TEST
drivers/pwm/Makefile
+1
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@@ -15,6 +15,7 @@ obj-$(CONFIG_PWM_CRC) += pwm-crc.o
obj-$(CONFIG_PWM_CROS_EC) += pwm-cros-ec.o
obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o
obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o
obj-$(CONFIG_PWM_GPIO) += pwm-gpio.o
obj-$(CONFIG_PWM_HIBVT) += pwm-hibvt.o
obj-$(CONFIG_PWM_IMG) += pwm-img.o
obj-$(CONFIG_PWM_IMX1) += pwm-imx1.o
drivers/pwm/pwm-gpio.c
-1
View File
@@ -157,7 +157,6 @@ static int gpio_pwm_probe(struct platform_device *pdev)
pc->chip.npwm = 1;
pc->chip.of_xlate = of_pwm_xlate_with_flags;
pc->chip.of_pwm_n_cells = 3;
pc->chip.can_sleep = true;
pc->gpiod = devm_gpiod_get(&pdev->dev, "pwm", GPIOD_OUT_LOW);