Re: [Linux-stm32] [PATCH v16 03/14] counter: Internalize sysfs interface code

[William Breathitt Gray <vilhelm.gray@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 8813 bytes --]

On Tue, Aug 31, 2021 at 03:44:04PM +0200, Fabrice Gasnier wrote:
> On 8/27/21 5:47 AM, William Breathitt Gray wrote:
> > This is a reimplementation of the Generic Counter driver interface.
> > There are no modifications to the Counter subsystem userspace interface,
> > so existing userspace applications should continue to run seamlessly.
> > 
> > The purpose of this patch is to internalize the sysfs interface code
> > among the various counter drivers into a shared module. Counter drivers
> > pass and take data natively (i.e. u8, u64, etc.) and the shared counter
> > module handles the translation between the sysfs interface and the
> > device drivers. This guarantees a standard userspace interface for all
> > counter drivers, and helps generalize the Generic Counter driver ABI in
> > order to support the Generic Counter chrdev interface (introduced in a
> > subsequent patch) without significant changes to the existing counter
> > drivers.
> > 
> > Note, Counter device registration is the same as before: drivers
> > populate a struct counter_device with components and callbacks, then
> > pass the structure to the devm_counter_register function. However,
> > what's different now is how the Counter subsystem code handles this
> > registration internally.
> > 
> > Whereas before callbacks would interact directly with sysfs data, this
> > interaction is now abstracted and instead callbacks interact with native
> > C data types. The counter_comp structure forms the basis for Counter
> > extensions.
> > 
> > The counter-sysfs.c file contains the code to parse through the
> > counter_device structure and register the requested components and
> > extensions. Attributes are created and populated based on type, with
> > respective translation functions to handle the mapping between sysfs and
> > the counter driver callbacks.
> > 
> > The translation performed for each attribute is straightforward: the
> > attribute type and data is parsed from the counter_attribute structure,
> > the respective counter driver read/write callback is called, and sysfs
> > I/O is handled before or after the driver read/write function is called.
> > 
> > Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com>
> > Cc: Patrick Havelange <patrick.havelange@essensium.com>
> > Cc: Kamel Bouhara <kamel.bouhara@bootlin.com>
> > Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
> > Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> > Cc: Alexandre Torgue <alexandre.torgue@st.com>
> > Cc: Dan Carpenter <dan.carpenter@oracle.com>
> > Acked-by: Syed Nayyar Waris <syednwaris@gmail.com>
> > Reviewed-by: David Lechner <david@lechnology.com>
> > Tested-by: David Lechner <david@lechnology.com>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
> > ---
> >  MAINTAINERS                             |    1 -
> >  drivers/counter/104-quad-8.c            |  449 +++----
> >  drivers/counter/Makefile                |    1 +
> >  drivers/counter/counter-core.c          |  142 +++
> >  drivers/counter/counter-sysfs.c         |  849 +++++++++++++
> >  drivers/counter/counter-sysfs.h         |   13 +
> >  drivers/counter/counter.c               | 1496 -----------------------
> >  drivers/counter/ftm-quaddec.c           |   60 +-
> >  drivers/counter/intel-qep.c             |  144 +--
> >  drivers/counter/interrupt-cnt.c         |   62 +-
> >  drivers/counter/microchip-tcb-capture.c |   91 +-
> >  drivers/counter/stm32-lptimer-cnt.c     |  212 ++--
> >  drivers/counter/stm32-timer-cnt.c       |  179 ++-
> >  drivers/counter/ti-eqep.c               |  180 +--
> >  include/linux/counter.h                 |  658 +++++-----
> >  include/linux/counter_enum.h            |   45 -
> >  16 files changed, 1949 insertions(+), 2633 deletions(-)
> >  create mode 100644 drivers/counter/counter-core.c
> >  create mode 100644 drivers/counter/counter-sysfs.c
> >  create mode 100644 drivers/counter/counter-sysfs.h
> >  delete mode 100644 drivers/counter/counter.c
> >  delete mode 100644 include/linux/counter_enum.h
> > 
> 
> Hi William,
> 
> For the STM32 drivers, you can add my:
> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
> 
> Thanks,
> Fabrice

Hello Fabrice,

I noticed the stm32-lptimer-cnt.c function_write() and action_write()
callbacks do not appear to write the desired function/action
configuration to the device. Would you check whether the device actually
supports this functionality or if these callbacks should be removed from
this driver.

Thanks,

William Breathitt Gray

> > diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> > index 7367f46c6f91..5168833b1fdf 100644
> > --- a/drivers/counter/stm32-lptimer-cnt.c
> > +++ b/drivers/counter/stm32-lptimer-cnt.c
> > @@ -170,28 +154,28 @@ static int stm32_lptim_cnt_read(struct counter_device *counter,
> >  	return 0;
> >  }
> >  
> > -static int stm32_lptim_cnt_function_get(struct counter_device *counter,
> > -					struct counter_count *count,
> > -					size_t *function)
> > +static int stm32_lptim_cnt_function_read(struct counter_device *counter,
> > +					 struct counter_count *count,
> > +					 enum counter_function *function)
> >  {
> >  	struct stm32_lptim_cnt *const priv = counter->priv;
> >  
> >  	if (!priv->quadrature_mode) {
> > -		*function = STM32_LPTIM_COUNTER_INCREASE;
> > +		*function = COUNTER_FUNCTION_INCREASE;
> >  		return 0;
> >  	}
> >  
> > -	if (priv->polarity == STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES) {
> > -		*function = STM32_LPTIM_ENCODER_BOTH_EDGE;
> > +	if (priv->polarity == STM32_LPTIM_CKPOL_BOTH_EDGES) {
> > +		*function = COUNTER_FUNCTION_QUADRATURE_X4;
> >  		return 0;
> >  	}
> >  
> >  	return -EINVAL;
> >  }
> >  
> > -static int stm32_lptim_cnt_function_set(struct counter_device *counter,
> > -					struct counter_count *count,
> > -					size_t function)
> > +static int stm32_lptim_cnt_function_write(struct counter_device *counter,
> > +					  struct counter_count *count,
> > +					  enum counter_function function)
> >  {
> >  	struct stm32_lptim_cnt *const priv = counter->priv;
> >  
> > @@ -199,12 +183,12 @@ static int stm32_lptim_cnt_function_set(struct counter_device *counter,
> >  		return -EBUSY;
> >  
> >  	switch (function) {
> > -	case STM32_LPTIM_COUNTER_INCREASE:
> > +	case COUNTER_FUNCTION_INCREASE:
> >  		priv->quadrature_mode = 0;
> >  		return 0;
> > -	case STM32_LPTIM_ENCODER_BOTH_EDGE:
> > +	case COUNTER_FUNCTION_QUADRATURE_X4:
> >  		priv->quadrature_mode = 1;
> > -		priv->polarity = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES;
> > +		priv->polarity = STM32_LPTIM_CKPOL_BOTH_EDGES;
> >  		return 0;
> >  	default:
> >  		/* should never reach this path */
> > @@ -333,43 +316,48 @@ static int stm32_lptim_cnt_action_get(struct counter_device *counter,
> >  	}
> >  }
> >  
> > -static int stm32_lptim_cnt_action_set(struct counter_device *counter,
> > -				      struct counter_count *count,
> > -				      struct counter_synapse *synapse,
> > -				      size_t action)
> > +static int stm32_lptim_cnt_action_write(struct counter_device *counter,
> > +					struct counter_count *count,
> > +					struct counter_synapse *synapse,
> > +					enum counter_synapse_action action)
> >  {
> >  	struct stm32_lptim_cnt *const priv = counter->priv;
> > -	size_t function;
> > +	enum counter_function function;
> >  	int err;
> >  
> >  	if (stm32_lptim_is_enabled(priv))
> >  		return -EBUSY;
> >  
> > -	err = stm32_lptim_cnt_function_get(counter, count, &function);
> > +	err = stm32_lptim_cnt_function_read(counter, count, &function);
> >  	if (err)
> >  		return err;
> >  
> >  	/* only set polarity when in counter mode (on input 1) */
> > -	if (function == STM32_LPTIM_COUNTER_INCREASE
> > -	    && synapse->signal->id == count->synapses[0].signal->id) {
> > -		switch (action) {
> > -		case STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE:
> > -		case STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE:
> > -		case STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES:
> > -			priv->polarity = action;
> > -			return 0;
> > -		}
> > -	}
> > +	if (function != COUNTER_FUNCTION_INCREASE
> > +	    || synapse->signal->id != count->synapses[0].signal->id)
> > +		return -EINVAL;
> >  
> > -	return -EINVAL;
> > +	switch (action) {
> > +	case COUNTER_SYNAPSE_ACTION_RISING_EDGE:
> > +		priv->polarity = STM32_LPTIM_CKPOL_RISING_EDGE;
> > +		return 0;
> > +	case COUNTER_SYNAPSE_ACTION_FALLING_EDGE:
> > +		priv->polarity = STM32_LPTIM_CKPOL_FALLING_EDGE;
> > +		return 0;
> > +	case COUNTER_SYNAPSE_ACTION_BOTH_EDGES:
> > +		priv->polarity = STM32_LPTIM_CKPOL_BOTH_EDGES;
> > +		return 0;
> > +	default:
> > +		return -EINVAL;
> > +	}
> >  }

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]