iio: proximity: isl29501: Fix return type of isl29501_register_writegrafted

isl29501_register_write() was returning a u32 instead of an int.
Since the function returns negative error codes (such as -ERANGE or
return values from i2c_smbus_write_byte_data()), returning an unsigned
integer type prevents callers from correctly checking for negative error
conditions.

Fix this by changing the function return type from u32 to int.

This was found through manual code review.

Fixes: 1c28799257bc ("iio: light: isl29501: Add support for the ISL29501 ToF sensor.")
Signed-off-by: Salah Triki <salah.triki@gmail.com>
Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>

1 files changed, 119 insertions, 0 deletions

diff --git a/drivers/pps/kc.c b/drivers/pps/kc.c
new file mode 100644
index 000000000..4f8fffa7e
--- /dev/null
+++ b/drivers/pps/kc.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PPS kernel consumer API
+ *
+ * Copyright (C) 2009-2010   Alexander Gordeev <lasaine@lvk.cs.msu.su>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/pps_kernel.h>
+
+#include "kc.h"
+
+/*
+ * Global variables
+ */
+
+/* state variables to bind kernel consumer */
+static DEFINE_SPINLOCK(pps_kc_hardpps_lock);
+/* PPS API (RFC 2783): current source and mode for kernel consumer */
+static struct pps_device *pps_kc_hardpps_dev;	/* unique pointer to device */
+static int pps_kc_hardpps_mode;		/* mode bits for kernel consumer */
+
+/* pps_kc_bind - control PPS kernel consumer binding
+ * @pps: the PPS source
+ * @bind_args: kernel consumer bind parameters
+ *
+ * This function is used to bind or unbind PPS kernel consumer according to
+ * supplied parameters. Should not be called in interrupt context.
+ */
+int pps_kc_bind(struct pps_device *pps, struct pps_bind_args *bind_args)
+{
+	/* Check if another consumer is already bound */
+	spin_lock_irq(&pps_kc_hardpps_lock);
+
+	/*
+	 * Don't allow PPS_KC_BIND on a removed device.
+	 */
+	if (pps->kc_removed) {
+		spin_unlock_irq(&pps_kc_hardpps_lock);
+		return -ENODEV;
+	}
+
+	if (bind_args->edge == 0)
+		if (pps_kc_hardpps_dev == pps) {
+			pps_kc_hardpps_mode = 0;
+			pps_kc_hardpps_dev = NULL;
+			spin_unlock_irq(&pps_kc_hardpps_lock);
+			dev_info(&pps->dev, "unbound kernel"
+					" consumer\n");
+		} else {
+			spin_unlock_irq(&pps_kc_hardpps_lock);
+			dev_err(&pps->dev, "selected kernel consumer"
+					" is not bound\n");
+			return -EINVAL;
+		}
+	else
+		if (pps_kc_hardpps_dev == NULL ||
+				pps_kc_hardpps_dev == pps) {
+			pps_kc_hardpps_mode = bind_args->edge;
+			pps_kc_hardpps_dev = pps;
+			spin_unlock_irq(&pps_kc_hardpps_lock);
+			dev_info(&pps->dev, "bound kernel consumer: "
+				"edge=0x%x\n", bind_args->edge);
+		} else {
+			spin_unlock_irq(&pps_kc_hardpps_lock);
+			dev_err(&pps->dev, "another kernel consumer"
+					" is already bound\n");
+			return -EINVAL;
+		}
+
+	return 0;
+}
+
+/* pps_kc_remove - unbind kernel consumer on PPS source removal
+ * @pps: the PPS source
+ *
+ * This function is used to disable kernel consumer on PPS source removal
+ * if this source was bound to PPS kernel consumer. Can be called on any
+ * source safely. Should not be called in interrupt context.
+ */
+void pps_kc_remove(struct pps_device *pps)
+{
+	spin_lock_irq(&pps_kc_hardpps_lock);
+
+	pps->kc_removed = true;
+	if (pps == pps_kc_hardpps_dev) {
+		pps_kc_hardpps_mode = 0;
+		pps_kc_hardpps_dev = NULL;
+		spin_unlock_irq(&pps_kc_hardpps_lock);
+		dev_info(&pps->dev, "unbound kernel consumer"
+				" on device removal\n");
+	} else
+		spin_unlock_irq(&pps_kc_hardpps_lock);
+}
+
+/* pps_kc_event - call hardpps() on PPS event
+ * @pps: the PPS source
+ * @ts: PPS event timestamp
+ * @event: PPS event edge
+ *
+ * This function calls hardpps() when an event from bound PPS source occurs.
+ */
+void pps_kc_event(struct pps_device *pps, struct pps_event_time *ts,
+		int event)
+{
+	unsigned long flags;
+
+	/* Pass some events to kernel consumer if activated */
+	spin_lock_irqsave(&pps_kc_hardpps_lock, flags);
+	if (pps == pps_kc_hardpps_dev && event & pps_kc_hardpps_mode)
+		hardpps(&ts->ts_real, &ts->ts_raw);
+	spin_unlock_irqrestore(&pps_kc_hardpps_lock, flags);
+}