u-boot/drivers/pwm/Kconfig
Neil Armstrong 2d481b2e3e pwm: Add driver for Amlogic Meson PWM controller
This adds the driver for the PWM controller found in the Amlogic SoCs.

This PWM is only a set of Gates, Dividers and Counters:
PWM output is achieved by calculating a clock that permits calculating
two periods (low and high). The counter then has to be set to switch after
N cycles for the first half period.
The hardware has no "polarity" setting. This driver reverses the period
cycles (the low length is inverted with the high length) for
PWM_POLARITY_INVERSED.

Disabling the PWM stops the output immediately (without waiting for the
current period to complete first).

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
2020-10-05 18:02:16 +02:00

78 lines
2.6 KiB
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config DM_PWM
bool "Enable support for pulse-width modulation devices (PWM)"
depends on DM
help
A pulse-width modulator emits a pulse of varying width and provides
control over the duty cycle (high and low time) of the signal. This
is often used to control a voltage level. The more time the PWM
spends in the 'high' state, the higher the voltage. The PWM's
frequency/period can be controlled along with the proportion of that
time that the signal is high.
config PWM_EXYNOS
bool "Enable support for the Exynos PWM"
depends on DM_PWM
help
This PWM is found on Samsung Exynos 5250 and other Samsung SoCs. It
supports a programmable period and duty cycle. A 32-bit counter is
used. It provides 5 channels which can be independently
programmed. Channel 4 (the last) is normally used as a timer.
config PWM_IMX
bool "Enable support for i.MX27 and later PWM"
help
This PWM is found i.MX27 and later i.MX SoCs.
config PWM_MESON
bool "Enable support for Amlogic Meson SoCs PWM"
depends on DM_PWM
help
This PWM is found on Amlogic Meson SoCs. It supports a
programmable period and duty cycle for 2 independant channels.
config PWM_MTK
bool "Enable support for MediaTek PWM"
depends on DM_PWM
help
This PWM is found on MT7622, MT7623, and MT7629. It supports a
programmable period and duty cycle.
config PWM_ROCKCHIP
bool "Enable support for the Rockchip PWM"
depends on DM_PWM
help
This PWM is found on RK3288 and other Rockchip SoCs. It supports a
programmable period and duty cycle. A 32-bit counter is used.
Various options provided in the hardware (such as capture mode and
continuous/single-shot) are not supported by the driver.
config PWM_SANDBOX
bool "Enable support for the sandbox PWM"
help
This is a sandbox PWM used for testing. It provides 3 channels and
records the settings passed into it, but otherwise does nothing
useful. The PWM can be enabled but is not connected to any outputs
so this is not very useful.
config PWM_SIFIVE
bool "Enable support for SiFive PWM"
depends on DM_PWM
help
This PWM is found SiFive's FU540 and other SoCs.
config PWM_TEGRA
bool "Enable support for the Tegra PWM"
depends on DM_PWM
help
This PWM is found on Tegra 20 and other Nvidia SoCs. It supports
four channels with a programmable period and duty cycle. Only a
32KHz clock is supported by the driver but the duty cycle is
configurable.
config PWM_SUNXI
bool "Enable support for the Allwinner Sunxi PWM"
depends on DM_PWM
help
This PWM is found on H3, A64 and other Allwinner SoCs. It supports a
programmable period and duty cycle. A 16-bit counter is used.