iio: proximity: vl53l0x-i2c: claim direct mode for raw readsgrafted

vl53l0x_read_raw() starts a single-shot ranging measurement and reads
back the result. Once the triggered buffer is enabled the sensor runs in
continuous mode and its data-ready interrupt is routed to the trigger,
so a concurrent in_distance_raw read disturbs the streaming setup and
never gets its completion, returning -ETIMEDOUT.

The original submission claimed direct mode here, but it was dropped
during review because the driver had no buffer support at the time [1].
Continuous (buffered) mode was later added without restoring the
claim [2], reintroducing the conflict.

Reject direct reads while buffered capture is active by claiming direct
mode around the measurement, as the vl53l1x sibling already does.

Fixes: 762186c6e7b1 ("iio: proximity: vl53l0x-i2c: Added continuous mode support")
Link: https://lore.kernel.org/linux-iio/20180911160300.GA9212@himanshu-Vostro-3559/ [1]
Link: https://lore.kernel.org/linux-iio/20240909101508.263085-3-abhashkumarjha123@gmail.com/ [2]
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

1 files changed, 169 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/gunze.c b/drivers/input/touchscreen/gunze.c
new file mode 100644
index 000000000..2baeb4f3b
--- /dev/null
+++ b/drivers/input/touchscreen/gunze.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (c) 2000-2001 Vojtech Pavlik
+ */
+
+/*
+ * Gunze AHL-51S touchscreen driver for Linux
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/serio.h>
+
+#define DRIVER_DESC	"Gunze AHL-51S touchscreen driver"
+
+MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+/*
+ * Definitions & global arrays.
+ */
+
+#define	GUNZE_MAX_LENGTH	10
+
+/*
+ * Per-touchscreen data.
+ */
+
+struct gunze {
+	struct input_dev *dev;
+	struct serio *serio;
+	int idx;
+	unsigned char data[GUNZE_MAX_LENGTH];
+	char phys[32];
+};
+
+static void gunze_process_packet(struct gunze *gunze)
+{
+	struct input_dev *dev = gunze->dev;
+
+	if (gunze->idx != GUNZE_MAX_LENGTH || gunze->data[5] != ',' ||
+		(gunze->data[0] != 'T' && gunze->data[0] != 'R')) {
+		printk(KERN_WARNING "gunze.c: bad packet: >%.*s<\n", GUNZE_MAX_LENGTH, gunze->data);
+		return;
+	}
+
+	input_report_abs(dev, ABS_X, simple_strtoul(gunze->data + 1, NULL, 10));
+	input_report_abs(dev, ABS_Y, 1024 - simple_strtoul(gunze->data + 6, NULL, 10));
+	input_report_key(dev, BTN_TOUCH, gunze->data[0] == 'T');
+	input_sync(dev);
+}
+
+static irqreturn_t gunze_interrupt(struct serio *serio,
+		unsigned char data, unsigned int flags)
+{
+	struct gunze *gunze = serio_get_drvdata(serio);
+
+	if (data == '\r') {
+		gunze_process_packet(gunze);
+		gunze->idx = 0;
+	} else {
+		if (gunze->idx < GUNZE_MAX_LENGTH)
+			gunze->data[gunze->idx++] = data;
+	}
+	return IRQ_HANDLED;
+}
+
+/*
+ * gunze_disconnect() is the opposite of gunze_connect()
+ */
+
+static void gunze_disconnect(struct serio *serio)
+{
+	struct gunze *gunze = serio_get_drvdata(serio);
+
+	input_get_device(gunze->dev);
+	input_unregister_device(gunze->dev);
+	serio_close(serio);
+	serio_set_drvdata(serio, NULL);
+	input_put_device(gunze->dev);
+	kfree(gunze);
+}
+
+/*
+ * gunze_connect() is the routine that is called when someone adds a
+ * new serio device that supports Gunze protocol and registers it as
+ * an input device.
+ */
+
+static int gunze_connect(struct serio *serio, struct serio_driver *drv)
+{
+	struct gunze *gunze;
+	struct input_dev *input_dev;
+	int err;
+
+	gunze = kzalloc_obj(*gunze);
+	input_dev = input_allocate_device();
+	if (!gunze || !input_dev) {
+		err = -ENOMEM;
+		goto fail1;
+	}
+
+	gunze->serio = serio;
+	gunze->dev = input_dev;
+	scnprintf(gunze->phys, sizeof(serio->phys), "%s/input0", serio->phys);
+
+	input_dev->name = "Gunze AHL-51S TouchScreen";
+	input_dev->phys = gunze->phys;
+	input_dev->id.bustype = BUS_RS232;
+	input_dev->id.vendor = SERIO_GUNZE;
+	input_dev->id.product = 0x0051;
+	input_dev->id.version = 0x0100;
+	input_dev->dev.parent = &serio->dev;
+	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
+	input_set_abs_params(input_dev, ABS_X, 24, 1000, 0, 0);
+	input_set_abs_params(input_dev, ABS_Y, 24, 1000, 0, 0);
+
+	serio_set_drvdata(serio, gunze);
+
+	err = serio_open(serio, drv);
+	if (err)
+		goto fail2;
+
+	err = input_register_device(gunze->dev);
+	if (err)
+		goto fail3;
+
+	return 0;
+
+ fail3:	serio_close(serio);
+ fail2:	serio_set_drvdata(serio, NULL);
+ fail1:	input_free_device(input_dev);
+	kfree(gunze);
+	return err;
+}
+
+/*
+ * The serio driver structure.
+ */
+
+static const struct serio_device_id gunze_serio_ids[] = {
+	{
+		.type	= SERIO_RS232,
+		.proto	= SERIO_GUNZE,
+		.id	= SERIO_ANY,
+		.extra	= SERIO_ANY,
+	},
+	{ 0 }
+};
+
+MODULE_DEVICE_TABLE(serio, gunze_serio_ids);
+
+static struct serio_driver gunze_drv = {
+	.driver		= {
+		.name	= "gunze",
+	},
+	.description	= DRIVER_DESC,
+	.id_table	= gunze_serio_ids,
+	.interrupt	= gunze_interrupt,
+	.connect	= gunze_connect,
+	.disconnect	= gunze_disconnect,
+};
+
+module_serio_driver(gunze_drv);