linux-kernel - [PATCH 29/48] Input: wm97xx - switch to using threaded IRQ

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Date:   Tue, 19 Apr 2022 18:37:51 +0200
From:   Arnd Bergmann <arnd@...nel.org>
To:     robert.jarzmik@...e.fr, linux-arm-kernel@...ts.infradead.org
Cc:     Arnd Bergmann <arnd@...db.de>, Daniel Mack <daniel@...que.org>,
        Haojian Zhuang <haojian.zhuang@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Philipp Zabel <philipp.zabel@...il.com>,
        Lubomir Rintel <lkundrak@...sk>,
        Paul Parsons <lost.distance@...oo.com>,
        Tomas Cech <sleep_walker@...e.com>,
        Sergey Lapin <slapin@...fans.org>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Dominik Brodowski <linux@...inikbrodowski.net>,
        Helge Deller <deller@....de>, Mark Brown <broonie@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-kernel@...r.kernel.org, linux-mips@...r.kernel.org,
        linux-ide@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-input@...r.kernel.org,
        patches@...nsource.cirrus.com, linux-leds@...r.kernel.org,
        linux-mmc@...r.kernel.org, linux-mtd@...ts.infradead.org,
        linux-rtc@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        alsa-devel@...a-project.org
Subject: [PATCH 29/48] Input: wm97xx - switch to using threaded IRQ

From: Dmitry Torokhov <dmitry.torokhov@...il.com>

Instead of manually disabling and enabling interrupts and scheduling work
to access the device, let's use threaded oneshot interrupt handler. It
simplifies things.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/input/touchscreen/wm97xx-core.c | 42 +++++--------------------
 include/linux/wm97xx.h                  |  1 -
 2 files changed, 7 insertions(+), 36 deletions(-)

diff --git a/drivers/input/touchscreen/wm97xx-core.c b/drivers/input/touchscreen/wm97xx-core.c
index 1b58611c8084..2757c7768ffe 100644
--- a/drivers/input/touchscreen/wm97xx-core.c
+++ b/drivers/input/touchscreen/wm97xx-core.c
@@ -285,11 +285,12 @@ void wm97xx_set_suspend_mode(struct wm97xx *wm, u16 mode)
 EXPORT_SYMBOL_GPL(wm97xx_set_suspend_mode);
 
 /*
- * Handle a pen down interrupt.
+ * Codec PENDOWN irq handler
+ *
  */
-static void wm97xx_pen_irq_worker(struct work_struct *work)
+static irqreturn_t wm97xx_pen_interrupt(int irq, void *dev_id)
 {
-	struct wm97xx *wm = container_of(work, struct wm97xx, pen_event_work);
+	struct wm97xx *wm = dev_id;
 	int pen_was_down = wm->pen_is_down;
 
 	/* do we need to enable the touch panel reader */
@@ -343,27 +344,6 @@ static void wm97xx_pen_irq_worker(struct work_struct *work)
 	if (!wm->pen_is_down && wm->mach_ops->acc_enabled)
 		wm->mach_ops->acc_pen_up(wm);
 
-	wm->mach_ops->irq_enable(wm, 1);
-}
-
-/*
- * Codec PENDOWN irq handler
- *
- * We have to disable the codec interrupt in the handler because it
- * can take up to 1ms to clear the interrupt source. We schedule a task
- * in a work queue to do the actual interaction with the chip.  The
- * interrupt is then enabled again in the slow handler when the source
- * has been cleared.
- */
-static irqreturn_t wm97xx_pen_interrupt(int irq, void *dev_id)
-{
-	struct wm97xx *wm = dev_id;
-
-	if (!work_pending(&wm->pen_event_work)) {
-		wm->mach_ops->irq_enable(wm, 0);
-		queue_work(wm->ts_workq, &wm->pen_event_work);
-	}
-
 	return IRQ_HANDLED;
 }
 
@@ -374,12 +354,9 @@ static int wm97xx_init_pen_irq(struct wm97xx *wm)
 {
 	u16 reg;
 
-	/* If an interrupt is supplied an IRQ enable operation must also be
-	 * provided. */
-	BUG_ON(!wm->mach_ops->irq_enable);
-
-	if (request_irq(wm->pen_irq, wm97xx_pen_interrupt, IRQF_SHARED,
-			"wm97xx-pen", wm)) {
+	if (request_threaded_irq(wm->pen_irq, NULL, wm97xx_pen_interrupt,
+				 IRQF_SHARED | IRQF_ONESHOT,
+				 "wm97xx-pen", wm)) {
 		dev_err(wm->dev,
 			"Failed to register pen down interrupt, polling");
 		wm->pen_irq = 0;
@@ -509,7 +486,6 @@ static int wm97xx_ts_input_open(struct input_dev *idev)
 	wm->codec->dig_enable(wm, 1);
 
 	INIT_DELAYED_WORK(&wm->ts_reader, wm97xx_ts_reader);
-	INIT_WORK(&wm->pen_event_work, wm97xx_pen_irq_worker);
 
 	wm->ts_reader_min_interval = HZ >= 100 ? HZ / 100 : 1;
 	if (wm->ts_reader_min_interval < 1)
@@ -560,10 +536,6 @@ static void wm97xx_ts_input_close(struct input_dev *idev)
 
 	wm->pen_is_down = 0;
 
-	/* Balance out interrupt disables/enables */
-	if (cancel_work_sync(&wm->pen_event_work))
-		wm->mach_ops->irq_enable(wm, 1);
-
 	/* ts_reader rearms itself so we need to explicitly stop it
 	 * before we destroy the workqueue.
 	 */
diff --git a/include/linux/wm97xx.h b/include/linux/wm97xx.h
index 462854f4f286..85bd8dd3caea 100644
--- a/include/linux/wm97xx.h
+++ b/include/linux/wm97xx.h
@@ -281,7 +281,6 @@ struct wm97xx {
 	unsigned long ts_reader_min_interval; /* Minimum interval */
 	unsigned int pen_irq;		/* Pen IRQ number in use */
 	struct workqueue_struct *ts_workq;
-	struct work_struct pen_event_work;
 	u16 acc_slot;			/* AC97 slot used for acc touch data */
 	u16 acc_rate;			/* acc touch data rate */
 	unsigned pen_is_down:1;		/* Pen is down */
-- 
2.29.2