Commit 10365dd4 authored by David Lechner's avatar David Lechner Committed by William Breathitt Gray
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counter: ti-eqep: implement over/underflow events 



This adds support to the TI eQEP counter driver for subscribing to
overflow and underflow events using the counter chrdev interface.

Signed-off-by: default avatarDavid Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240609-counter-ti-eqep-over-under-events-v1-1-74fe1632f5ab@baylibre.com


Signed-off-by: default avatarWilliam Breathitt Gray <wbg@kernel.org>
parent 5f81aa76

drivers/counter/ti-eqep.c

+105 −1
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include <linux/bitops.h>

#include <linux/clk.h>

#include <linux/counter.h>

#include <linux/interrupt.h>

#include <linux/kernel.h>

#include <linux/mod_devicetable.h>

#include <linux/module.h>
@@ -68,6 +69,44 @@ 
#define QEPCTL_UTE		BIT(1)

#define QEPCTL_WDE		BIT(0)



#define QEINT_UTO		BIT(11)

#define QEINT_IEL		BIT(10)

#define QEINT_SEL		BIT(9)

#define QEINT_PCM		BIT(8)

#define QEINT_PCR		BIT(7)

#define QEINT_PCO		BIT(6)

#define QEINT_PCU		BIT(5)

#define QEINT_WTO		BIT(4)

#define QEINT_QDC		BIT(3)

#define QEINT_PHE		BIT(2)

#define QEINT_PCE		BIT(1)



#define QFLG_UTO		BIT(11)

#define QFLG_IEL		BIT(10)

#define QFLG_SEL		BIT(9)

#define QFLG_PCM		BIT(8)

#define QFLG_PCR		BIT(7)

#define QFLG_PCO		BIT(6)

#define QFLG_PCU		BIT(5)

#define QFLG_WTO		BIT(4)

#define QFLG_QDC		BIT(3)

#define QFLG_PHE		BIT(2)

#define QFLG_PCE		BIT(1)

#define QFLG_INT		BIT(0)



#define QCLR_UTO		BIT(11)

#define QCLR_IEL		BIT(10)

#define QCLR_SEL		BIT(9)

#define QCLR_PCM		BIT(8)

#define QCLR_PCR		BIT(7)

#define QCLR_PCO		BIT(6)

#define QCLR_PCU		BIT(5)

#define QCLR_WTO		BIT(4)

#define QCLR_QDC		BIT(3)

#define QCLR_PHE		BIT(2)

#define QCLR_PCE		BIT(1)

#define QCLR_INT		BIT(0)



/* EQEP Inputs */

enum {

	TI_EQEP_SIGNAL_QEPA,	/* QEPA/XCLK */
@@ -239,12 +278,49 @@ static int ti_eqep_action_read(struct counter_device *counter, 
	}

}



static int ti_eqep_events_configure(struct counter_device *counter)

{

	struct ti_eqep_cnt *priv = counter_priv(counter);

	struct counter_event_node *event_node;

	u32 qeint = 0;



	list_for_each_entry(event_node, &counter->events_list, l) {

		switch (event_node->event) {

		case COUNTER_EVENT_OVERFLOW:

			qeint |= QEINT_PCO;

			break;

		case COUNTER_EVENT_UNDERFLOW:

			qeint |= QEINT_PCU;

			break;

		}

	}



	return regmap_write(priv->regmap16, QEINT, qeint);

}



static int ti_eqep_watch_validate(struct counter_device *counter,

				  const struct counter_watch *watch)

{

	switch (watch->event) {

	case COUNTER_EVENT_OVERFLOW:

	case COUNTER_EVENT_UNDERFLOW:

		if (watch->channel != 0)

			return -EINVAL;



		return 0;

	default:

		return -EINVAL;

	}

}



static const struct counter_ops ti_eqep_counter_ops = {

	.count_read	= ti_eqep_count_read,

	.count_write	= ti_eqep_count_write,

	.function_read	= ti_eqep_function_read,

	.function_write	= ti_eqep_function_write,

	.action_read	= ti_eqep_action_read,

	.events_configure = ti_eqep_events_configure,

	.watch_validate	= ti_eqep_watch_validate,

};



static int ti_eqep_position_ceiling_read(struct counter_device *counter,
@@ -355,6 +431,25 @@ static struct counter_count ti_eqep_counts[] = { 
	},

};



static irqreturn_t ti_eqep_irq_handler(int irq, void *dev_id)

{

	struct counter_device *counter = dev_id;

	struct ti_eqep_cnt *priv = counter_priv(counter);

	u32 qflg;



	regmap_read(priv->regmap16, QFLG, &qflg);



	if (qflg & QFLG_PCO)

		counter_push_event(counter, COUNTER_EVENT_OVERFLOW, 0);



	if (qflg & QFLG_PCU)

		counter_push_event(counter, COUNTER_EVENT_UNDERFLOW, 0);



	regmap_write(priv->regmap16, QCLR, qflg);



	return IRQ_HANDLED;

}



static const struct regmap_config ti_eqep_regmap32_config = {

	.name = "32-bit",

	.reg_bits = 32,
@@ -378,7 +473,7 @@ static int ti_eqep_probe(struct platform_device *pdev) 
	struct ti_eqep_cnt *priv;

	void __iomem *base;

	struct clk *clk;

	int err;

	int err, irq;



	counter = devm_counter_alloc(dev, sizeof(*priv));

	if (!counter)
@@ -399,6 +494,15 @@ static int ti_eqep_probe(struct platform_device *pdev) 
	if (IS_ERR(priv->regmap16))

		return PTR_ERR(priv->regmap16);



	irq = platform_get_irq(pdev, 0);

	if (irq < 0)

		return irq;



	err = devm_request_threaded_irq(dev, irq, NULL, ti_eqep_irq_handler,

					IRQF_ONESHOT, dev_name(dev), counter);

	if (err < 0)

		return dev_err_probe(dev, err, "failed to request IRQ\n");



	counter->name = dev_name(dev);

	counter->parent = dev;

	counter->ops = &ti_eqep_counter_ops;