The ARR register is cleared unconditionally upon probing, after the maximum
value has been read. This initial condition is rather not intuitive, when
considering the counter child driver. It rather expects the maximum value
by default:
- The counter interface shows a zero value by default for 'ceiling'
attribute.
- Enabling the counter without any prior configuration makes it doesn't
count.
The reset value of ARR register is the maximum. So Choice here
is to backup it, and restore it then, instead of clearing its value.
It also fixes the initial condition seen by the counter driver.
Fixes: d0f949e220 ("mfd: Add STM32 Timers driver")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
dma_request_slave_channel() is a wrapper on top of dma_request_chan()
eating up the error code.
By using dma_request_chan() directly the driver can support deferred
probing against DMA.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
STM32 Timers can support up to 7 DMA requests:
- 4 channels, update, compare and trigger.
Optionally request part, or all DMAs from stm32-timers MFD core.
Also add routine to implement burst reads using DMA from timer registers.
This is exported. So, it can be used by child drivers, PWM capture
for instance (but not limited to).
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Add SPDX identifier
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Use devm_of_platform_populate() instead of of_platform_populate()
and suppress stm32_timers_remove() which become useless.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
STM32 timers register bank size is 0x400. Fix regmap max_register.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Add missing of_platform_depopulate() upon driver removal.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.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>
Fabrice Gasnier