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Date: Sun, 9 Jun 2024 16:49:33 -0500
From: David Lechner <dlechner@...libre.com>
To: William Breathitt Gray <wbg@...nel.org>
Cc: David Lechner <dlechner@...libre.com>,
Judith Mendez <jm@...com>,
linux-iio@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH] 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: David Lechner <dlechner@...libre.com>
---
This is split out from a series that was sent a few years back [1] that
I never finished, so I'm calling it v2. This was tested on a BeagleBone
Blue using LEGO MINDSTORMS EV3 motors and this script[2].
[1]: https://lore.kernel.org/linux-iio/20211017013343.3385923-2-david@lechnology.com/
[2]: https://github.com/dlech/linux-counter-ti-eqep-python/blob/3745b0840736248d8e60cc675a0f43558fcbb2af/test.py
v2 changes:
* Only clear interrupts that were handled.
* Don't set default QPOSMAX value.
* Don't error when setting QPOSMAX to 0.
* Use regmap_write() when appropriate.
* Validate watch channel.
* Use counter_priv().
---
drivers/counter/ti-eqep.c | 106 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 105 insertions(+), 1 deletion(-)
diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
index 072b11fd6b32..9f4ca219385c 100644
--- a/drivers/counter/ti-eqep.c
+++ b/drivers/counter/ti-eqep.c
@@ -7,6 +7,7 @@
#include <linux/bitops.h>
#include <linux/counter.h>
+#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
@@ -67,6 +68,44 @@
#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 */
@@ -238,12 +277,49 @@ 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,
@@ -354,6 +430,25 @@ 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,
@@ -376,7 +471,7 @@ static int ti_eqep_probe(struct platform_device *pdev)
struct counter_device *counter;
struct ti_eqep_cnt *priv;
void __iomem *base;
- int err;
+ int err, irq;
counter = devm_counter_alloc(dev, sizeof(*priv));
if (!counter)
@@ -397,6 +492,15 @@ 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;
---
base-commit: bb3f1c5fc434b0b177449f7f73ea9b112b397dd1
change-id: 20240609-counter-ti-eqep-over-under-events-8e7ace53d35a
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