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counter: ti-eqep: implement over/underflow events

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

Signed-off-by: David 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: William Breathitt Gray <wbg@kernel.org>
This commit is contained in:
David Lechner 2024-06-09 16:49:33 -05:00 committed by William Breathitt Gray
parent 5f81aa7677
commit 10365dd4c1
1 changed files with 105 additions and 1 deletions
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106
drivers/counter/ti-eqep.c
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@ -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;