Add support for TRGO2 trigger that can be found on STM32F7.
Add additional master modes supported by TRGO2.
Register additional "tim[1/8]_trgo2" triggers for timer1 & timer8.
Detect TRGO2 timer capability (master mode selection 2).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

One of the features of STM32 trigger hardware block is a quadrature
encoder that can counts up/down depending of the levels and edges
of the selected external pins.

This patch allow to read/write the counter, get it direction,
set/get quadrature modes and get scale factor.

When counting up preset value is the limit of the counter.
When counting down the counter start from preset value down to 0.
This preset value could be set/get by using
/sys/bus/iio/devices/iio:deviceX/in_count0_preset attribute.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Reviewed-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

This hardware block could at used at same time for PWM generation
and IIO timers.
PWM and IIO timer configuration are mixed in the same registers
so we need a multi fonction driver to be able to share those registers.

version 7:
- rebase on v4.10-rc2

version 6:
- rename files to stm32-timers
- rename functions to stm32_timers_xxx

version 5:
- fix Lee comments about detect function
- add missing dependency on REGMAP_MMIO

version 4:
- add a function to detect Auto Reload Register (ARR) size
- rename the structure shared with other drivers

version 2:
- rename driver "stm32-gptimer" to be align with SoC documentation
- only keep one compatible
- use of_platform_populate() instead of devm_mfd_add_devices()

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>