On 02/12/16 10:17, Benjamin Gaignard wrote: > version 3: > - no change on mfd and pwm divers patches > - add cross reference between bindings > - change compatible to "st,stm32-timer-trigger" > - fix attributes access rights > - use string instead of int for master_mode and slave_mode > - document device attributes in sysfs-bus-iio-timer-stm32 > - udpate DT with the new compatible > > version 2: > - keep only one compatible per driver > - use DT parameters to describe hardware block configuration: > - pwm channels, complementary output, counter size, break input > - triggers accepted and create by IIO timers > - change DT to limite use of reference to the node > - interrupt is now in IIO timer driver > - rename stm32-mfd-timer to stm32-gptimer (for general purpose timer) > > The following patches enable pwm and IIO Timer features for stm32 platforms. > > Those two features are mixed into the registers of the same hardware block > (named general purpose timer) which lead to introduce a multifunctions driver > on the top of them to be able to share the registers. > > In stm32 14 instances of timer hardware block exist, even if they all have > the same register mapping they could have a different number of pwm channels > and/or different triggers capabilities. We use various parameters in DT to > describe the differences between hardware blocks > > The MFD (stm32-gptimer.c) takes care of clock and register mapping > by using regmap. stm32_gptimer_dev structure is provided to its sub-node to > share those information. > > PWM driver is implemented into pwm-stm32.c. Depending of the instance we may > have up to 4 channels, sometime with complementary outputs or 32 bits counter > instead of 16 bits. Some hardware blocks may also have a break input function > which allows to stop pwm depending of a level, defined in devicetree, on an > external pin. > > IIO timer driver (stm32-iio-timer.c and stm32-iio-timers.h) define a list of > hardware triggers usable by hardware blocks like ADC, DAC or other timers. > > The matrix of possible connections between blocks is quite complex so we use > trigger names and is_stm32_iio_timer_trigger() function to be sure that > triggers are valid and configure the IPs. > Possible triggers ar listed in include/dt-bindings/iio/timer/st,stm32-iio-timer.h > > At run time IIO timer hardware blocks can configure (through "master_mode" > IIO device attribute) which internal signal (counter enable, reset, > comparison block, etc...) is used to generate the trigger. > > By using "slave_mode" IIO device attribute timer can also configure on which > event (level, rising edge) of the block is enabled. > > Since we can use trigger from one hardware to control an other block, we can > use a pwm to control an other one. The following example shows how to configure > pwm1 and pwm3 to make pwm3 generate pulse only when pwm1 pulse level is high. > > /sys/bus/iio/devices # ls > iio:device0 iio:device1 trigger0 trigger1 > > configure timer1 to use pwm1 channel 0 as output trigger > /sys/bus/iio/devices # echo 'OC1REF' > iio\:device0/master_mode > configure timer3 to enable only when input is high > /sys/bus/iio/devices # echo 'gated' > iio\:device1/slave_mode > /sys/bus/iio/devices # cat trigger0/name > tim1_trgo > configure timer2 to use timer1 trigger is input > /sys/bus/iio/devices # echo "tim1_trgo" > iio\:device1/trigger/current_trigger > > configure pwm3 channel 0 to generate a signal with a period of 100ms and a > duty cycle of 50% > /sys/devices/platform/soc/40000400.gptimer3/40000400.gptimer3:pwm3@0/pwm/pwmchip4 # echo 0 > export > /sys/devices/platform/soc/40000400.gptimer3/40000400.gptimer3:pwm3@0/pwm/pwmchip4 # echo 100000000 > pwm0/period > /sys/devices/platform/soc/40000400.gptimer3/40000400.gptimer3:pwm3@0/pwm/pwmchip4 # echo 50000000 > pwm0/duty_cycle > /sys/devices/platform/soc/40000400.gptimer3/40000400.gptimer3:pwm3@0/pwm/pwmchip4# echo 1 > pwm0/enable > here pwm3 channel 0, as expected, doesn't start because has to be triggered by > pwm1 channel 0 > > configure pwm1 channel 0 to generate a signal with a period of 1s and a > duty cycle of 50% > /sys/devices/platform/soc/40010000.gptimer1/40010000.gptimer1:pwm1@0/pwm/pwmchip0 # echo 0 > export > /sys/devices/platform/soc/40010000.gptimer1/40010000.gptimer1:pwm1@0/pwm/pwmchip0 # echo 1000000000 > pwm0/period > /sys/devices/platform/soc/40010000.gptimer1/40010000.gptimer1:pwm1@0/pwm/pwmchip0 # echo 500000000 > pwm0/duty_cycle > /sys/devices/platform/soc/40010000.gptimer1/40010000.gptimer1:pwm1@0/pwm/pwmchip0 # echo 1 > pwm0/enable > finally pwm1 starts and pwm3 only generates pulse when pwm1 signal is high > > An other example to use a timer as source of clock for another device. > Here timer1 is used a source clock for pwm3: > > /sys/bus/iio/devices # echo 100000 > trigger0/sampling_frequency > /sys/bus/iio/devices # echo tim1_trgo > iio\:device1/trigger/current_trigger > /sys/bus/iio/devices # echo 'external_clock' > iio\:device1/slave_mode > /sys/devices/platform/soc/40000400.gptimer3/40000400.gptimer3:pwm3@0/pwm/pwmchip4 # echo 0 > export > /sys/devices/platform/soc/40000400.gptimer3/40000400.gptimer3:pwm3@0/pwm/pwmchip4 # echo 1000000 > pwm0/period > /sys/devices/platform/soc/40000400.gptimer3/40000400.gptimer3:pwm3@0/pwm/pwmchip4 # echo 500000 > pwm0/duty_cycle > /sys/devices/platform/soc/40000400.gptimer3/40000400.gptimer3:pwm3@0/pwm/pwmchip4 # echo 1 > pwm0/enable This is good thorough documentation. Could we have an additional patch adding just this documentation to the tree (probably under Documentation/mfd?). Documentation in general is a bit in flux at the moment so we'll may want to sphixify it afterwards but plain text is fine for now. Jonathan > > Benjamin Gaignard (7): > MFD: add bindings for stm32 general purpose timer driver > MFD: add stm32 general purpose timer driver > PWM: add pwm-stm32 DT bindings > PWM: add pwm driver for stm32 plaftorm > IIO: add bindings for stm32 timer trigger driver > IIO: add STM32 timer trigger driver > ARM: dts: stm32: add stm32 general purpose timer driver in DT > > .../ABI/testing/sysfs-bus-iio-timer-stm32 | 47 ++ > .../bindings/iio/timer/stm32-timer-trigger.txt | 39 ++ > .../bindings/mfd/stm32-general-purpose-timer.txt | 47 ++ > .../devicetree/bindings/pwm/pwm-stm32.txt | 38 ++ > arch/arm/boot/dts/stm32f429.dtsi | 333 +++++++++++++- > arch/arm/boot/dts/stm32f469-disco.dts | 28 ++ > drivers/iio/Kconfig | 2 +- > drivers/iio/Makefile | 1 + > drivers/iio/timer/Kconfig | 15 + > drivers/iio/timer/Makefile | 1 + > drivers/iio/timer/stm32-timer-trigger.c | 477 +++++++++++++++++++++ > drivers/iio/trigger/Kconfig | 1 - > drivers/mfd/Kconfig | 10 + > drivers/mfd/Makefile | 2 + > drivers/mfd/stm32-gptimer.c | 73 ++++ > drivers/pwm/Kconfig | 8 + > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-stm32.c | 285 ++++++++++++ > .../iio/timer/st,stm32-timer-triggers.h | 60 +++ > include/linux/iio/timer/stm32-timer-trigger.h | 16 + > include/linux/mfd/stm32-gptimer.h | 62 +++ > 21 files changed, 1543 insertions(+), 3 deletions(-) > create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-timer-stm32 > create mode 100644 Documentation/devicetree/bindings/iio/timer/stm32-timer-trigger.txt > create mode 100644 Documentation/devicetree/bindings/mfd/stm32-general-purpose-timer.txt > create mode 100644 Documentation/devicetree/bindings/pwm/pwm-stm32.txt > create mode 100644 drivers/iio/timer/Kconfig > create mode 100644 drivers/iio/timer/Makefile > create mode 100644 drivers/iio/timer/stm32-timer-trigger.c > create mode 100644 drivers/mfd/stm32-gptimer.c > create mode 100644 drivers/pwm/pwm-stm32.c > create mode 100644 include/dt-bindings/iio/timer/st,stm32-timer-triggers.h > create mode 100644 include/linux/iio/timer/stm32-timer-trigger.h > create mode 100644 include/linux/mfd/stm32-gptimer.h > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
