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, 172 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/tsc40.c b/drivers/input/touchscreen/tsc40.c
new file mode 100644
index 000000000..2a28a309e
--- /dev/null
+++ b/drivers/input/touchscreen/tsc40.c
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * TSC-40 serial touchscreen driver. It should be compatible with
+ * TSC-10 and 25.
+ *
+ * Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/serio.h>
+
+#define PACKET_LENGTH  5
+struct tsc_ser {
+	struct input_dev *dev;
+	struct serio *serio;
+	u32 idx;
+	unsigned char data[PACKET_LENGTH];
+	char phys[32];
+};
+
+static void tsc_process_data(struct tsc_ser *ptsc)
+{
+	struct input_dev *dev = ptsc->dev;
+	u8 *data = ptsc->data;
+	u32 x;
+	u32 y;
+
+	x = ((data[1] & 0x03) << 8) | data[2];
+	y = ((data[3] & 0x03) << 8) | data[4];
+
+	input_report_abs(dev, ABS_X, x);
+	input_report_abs(dev, ABS_Y, y);
+	input_report_key(dev, BTN_TOUCH, 1);
+
+	input_sync(dev);
+}
+
+static irqreturn_t tsc_interrupt(struct serio *serio,
+		unsigned char data, unsigned int flags)
+{
+	struct tsc_ser *ptsc = serio_get_drvdata(serio);
+	struct input_dev *dev = ptsc->dev;
+
+	ptsc->data[ptsc->idx] = data;
+	switch (ptsc->idx++) {
+	case 0:
+		if (unlikely((data & 0x3e) != 0x10)) {
+			dev_dbg(&serio->dev,
+				"unsynchronized packet start (0x%02x)\n", data);
+			ptsc->idx = 0;
+		} else if (!(data & 0x01)) {
+			input_report_key(dev, BTN_TOUCH, 0);
+			input_sync(dev);
+			ptsc->idx = 0;
+		}
+		break;
+
+	case 1:
+	case 3:
+		if (unlikely(data & 0xfc)) {
+			dev_dbg(&serio->dev,
+				"unsynchronized data 0x%02x at offset %d\n",
+				data, ptsc->idx - 1);
+			ptsc->idx = 0;
+		}
+		break;
+
+	case 4:
+		tsc_process_data(ptsc);
+		ptsc->idx = 0;
+		break;
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int tsc_connect(struct serio *serio, struct serio_driver *drv)
+{
+	struct tsc_ser *ptsc;
+	struct input_dev *input_dev;
+	int error;
+
+	ptsc = kzalloc_obj(*ptsc);
+	input_dev = input_allocate_device();
+	if (!ptsc || !input_dev) {
+		error = -ENOMEM;
+		goto fail1;
+	}
+
+	ptsc->serio = serio;
+	ptsc->dev = input_dev;
+	scnprintf(ptsc->phys, sizeof(ptsc->phys), "%s/input0", serio->phys);
+
+	input_dev->name = "TSC-10/25/40 Serial TouchScreen";
+	input_dev->phys = ptsc->phys;
+	input_dev->id.bustype = BUS_RS232;
+	input_dev->id.vendor = SERIO_TSC40;
+	input_dev->id.product = 40;
+	input_dev->id.version = 0x0001;
+	input_dev->dev.parent = &serio->dev;
+
+	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+	__set_bit(BTN_TOUCH, input_dev->keybit);
+	input_set_abs_params(ptsc->dev, ABS_X, 0, 0x3ff, 0, 0);
+	input_set_abs_params(ptsc->dev, ABS_Y, 0, 0x3ff, 0, 0);
+
+	serio_set_drvdata(serio, ptsc);
+
+	error = serio_open(serio, drv);
+	if (error)
+		goto fail2;
+
+	error = input_register_device(ptsc->dev);
+	if (error)
+		goto fail3;
+
+	return 0;
+
+fail3:
+	serio_close(serio);
+fail2:
+	serio_set_drvdata(serio, NULL);
+fail1:
+	input_free_device(input_dev);
+	kfree(ptsc);
+	return error;
+}
+
+static void tsc_disconnect(struct serio *serio)
+{
+	struct tsc_ser *ptsc = serio_get_drvdata(serio);
+
+	serio_close(serio);
+
+	input_unregister_device(ptsc->dev);
+	kfree(ptsc);
+
+	serio_set_drvdata(serio, NULL);
+}
+
+static const struct serio_device_id tsc_serio_ids[] = {
+	{
+		.type   = SERIO_RS232,
+		.proto  = SERIO_TSC40,
+		.id     = SERIO_ANY,
+		.extra  = SERIO_ANY,
+	},
+	{ 0 }
+};
+MODULE_DEVICE_TABLE(serio, tsc_serio_ids);
+
+#define DRIVER_DESC    "TSC-10/25/40 serial touchscreen driver"
+
+static struct serio_driver tsc_drv = {
+	.driver	= {
+		.name   = "tsc40",
+	},
+	.description    = DRIVER_DESC,
+	.id_table	= tsc_serio_ids,
+	.interrupt      = tsc_interrupt,
+	.connect	= tsc_connect,
+	.disconnect     = tsc_disconnect,
+};
+
+module_serio_driver(tsc_drv);
+
+MODULE_AUTHOR("Sebastian Andrzej Siewior <bigeasy@linutronix.de>");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL v2");