From 832f33366c771855951313a9bab4926f2a0d37a1 Mon Sep 17 00:00:00 2001 From: "Spencer E. Olson" Date: Wed, 19 Sep 2018 10:51:03 -0600 Subject: [PATCH] staging: comedi: add facility to directly query subdevice timing constraints Adds facility to directly query the hardware speed limits of subdevices, in particular for scan_begin and convert signals. This information can be critical for integrating comedi with other hardware modules, and also comedi modules together with software where software requires specific timing capabilities in order to properly coordinate multiple devices. Currently, comedi_command_test almost satisfies this need, but really only for when *_src == TRIG_TIMER. For *_src == TRIG_EXT, comedi_command_test does not help at all. For many subdevices, one might simply use *_src==TRIG_TIMER in command_test in order to determine these limits. For other subdevices, this tactic does not work since *_src == TRIG_TIMER might not be valid. There is also the possibility that the timing limits are different between the TRIG_TIMER and TRIG_EXT modes. Signed-off-by: Spencer E. Olson Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/comedi.h | 5 ++++- drivers/staging/comedi/comedi_fops.c | 4 ++++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/staging/comedi/comedi.h b/drivers/staging/comedi/comedi.h index bb961ac..cf7b2b9 100644 --- a/drivers/staging/comedi/comedi.h +++ b/drivers/staging/comedi/comedi.h @@ -301,6 +301,8 @@ enum comedi_io_direction { * @INSN_CONFIG_PWM_SET_H_BRIDGE: Set PWM H bridge duty cycle and polarity for * a relay simultaneously. * @INSN_CONFIG_PWM_GET_H_BRIDGE: Get PWM H bridge duty cycle and polarity. + * @INSN_CONFIG_GET_CMD_TIMING_CONSTRAINTS: Get the hardware timing restraints, + * regardless of trigger sources. */ enum configuration_ids { INSN_CONFIG_DIO_INPUT = COMEDI_INPUT, @@ -344,7 +346,8 @@ enum configuration_ids { INSN_CONFIG_PWM_GET_PERIOD = 5001, INSN_CONFIG_GET_PWM_STATUS = 5002, INSN_CONFIG_PWM_SET_H_BRIDGE = 5003, - INSN_CONFIG_PWM_GET_H_BRIDGE = 5004 + INSN_CONFIG_PWM_GET_H_BRIDGE = 5004, + INSN_CONFIG_GET_CMD_TIMING_CONSTRAINTS = 5005, }; /** diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index e18b61c..548baa7 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1216,6 +1216,10 @@ static int check_insn_config_length(struct comedi_insn *insn, if (insn->n == 6) return 0; break; + case INSN_CONFIG_GET_CMD_TIMING_CONSTRAINTS: + if (insn->n >= 4) + return 0; + break; /* * by default we allow the insn since we don't have checks for * all possible cases yet -- 2.7.4