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, 304 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-ma35d1.c b/drivers/rtc/rtc-ma35d1.c
new file mode 100644
index 000000000..cfcfc2806
--- /dev/null
+++ b/drivers/rtc/rtc-ma35d1.c
@@ -0,0 +1,304 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RTC driver for Nuvoton MA35D1
+ *
+ * Copyright (C) 2023 Nuvoton Technology Corp.
+ */
+
+#include <linux/bcd.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+/* MA35D1 RTC Control Registers */
+#define MA35_REG_RTC_INIT	0x00
+#define MA35_REG_RTC_SINFASTS	0x04
+#define MA35_REG_RTC_FREQADJ	0x08
+#define MA35_REG_RTC_TIME	0x0c
+#define MA35_REG_RTC_CAL	0x10
+#define MA35_REG_RTC_CLKFMT	0x14
+#define MA35_REG_RTC_WEEKDAY	0x18
+#define MA35_REG_RTC_TALM	0x1c
+#define MA35_REG_RTC_CALM	0x20
+#define MA35_REG_RTC_LEAPYEAR	0x24
+#define MA35_REG_RTC_INTEN	0x28
+#define MA35_REG_RTC_INTSTS	0x2c
+
+/* register MA35_REG_RTC_INIT */
+#define RTC_INIT_ACTIVE		BIT(0)
+#define RTC_INIT_MAGIC_CODE	0xa5eb1357
+
+/* register MA35_REG_RTC_CLKFMT */
+#define RTC_CLKFMT_24HEN	BIT(0)
+#define RTC_CLKFMT_DCOMPEN	BIT(16)
+
+/* register MA35_REG_RTC_INTEN */
+#define RTC_INTEN_ALMIEN	BIT(0)
+#define RTC_INTEN_UIEN		BIT(1)
+#define RTC_INTEN_CLKFIEN	BIT(24)
+#define RTC_INTEN_CLKSTIEN	BIT(25)
+
+/* register MA35_REG_RTC_INTSTS */
+#define RTC_INTSTS_ALMIF	BIT(0)
+#define RTC_INTSTS_UIF		BIT(1)
+#define RTC_INTSTS_CLKFIF	BIT(24)
+#define RTC_INTSTS_CLKSTIF	BIT(25)
+
+#define RTC_INIT_TIMEOUT	250
+
+struct ma35_rtc {
+	int irq_num;
+	void __iomem *rtc_reg;
+	struct rtc_device *rtcdev;
+};
+
+static u32 rtc_reg_read(struct ma35_rtc *p, u32 offset)
+{
+	return __raw_readl(p->rtc_reg + offset);
+}
+
+static inline void rtc_reg_write(struct ma35_rtc *p, u32 offset, u32 value)
+{
+	__raw_writel(value, p->rtc_reg + offset);
+}
+
+static irqreturn_t ma35d1_rtc_interrupt(int irq, void *data)
+{
+	struct ma35_rtc *rtc = (struct ma35_rtc *)data;
+	unsigned long events = 0, rtc_irq;
+
+	rtc_irq = rtc_reg_read(rtc, MA35_REG_RTC_INTSTS);
+
+	if (rtc_irq & RTC_INTSTS_ALMIF) {
+		rtc_reg_write(rtc, MA35_REG_RTC_INTSTS, RTC_INTSTS_ALMIF);
+		events |= RTC_AF | RTC_IRQF;
+	}
+
+	rtc_update_irq(rtc->rtcdev, 1, events);
+
+	return IRQ_HANDLED;
+}
+
+static int ma35d1_rtc_init(struct ma35_rtc *rtc, u32 ms_timeout)
+{
+	const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout);
+
+	do {
+		if (rtc_reg_read(rtc, MA35_REG_RTC_INIT) & RTC_INIT_ACTIVE)
+			return 0;
+
+		rtc_reg_write(rtc, MA35_REG_RTC_INIT, RTC_INIT_MAGIC_CODE);
+
+		mdelay(1);
+
+	} while (time_before(jiffies, timeout));
+
+	return -ETIMEDOUT;
+}
+
+static int ma35d1_alarm_irq_enable(struct device *dev, u32 enabled)
+{
+	struct ma35_rtc *rtc = dev_get_drvdata(dev);
+	u32 reg_ien;
+
+	reg_ien = rtc_reg_read(rtc, MA35_REG_RTC_INTEN);
+
+	if (enabled)
+		rtc_reg_write(rtc, MA35_REG_RTC_INTEN, reg_ien | RTC_INTEN_ALMIEN);
+	else
+		rtc_reg_write(rtc, MA35_REG_RTC_INTEN, reg_ien & ~RTC_INTEN_ALMIEN);
+
+	return 0;
+}
+
+static int ma35d1_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct ma35_rtc *rtc = dev_get_drvdata(dev);
+	u32 time, cal, wday;
+
+	do {
+		time = rtc_reg_read(rtc, MA35_REG_RTC_TIME);
+		cal  = rtc_reg_read(rtc, MA35_REG_RTC_CAL);
+		wday = rtc_reg_read(rtc, MA35_REG_RTC_WEEKDAY);
+	} while (time != rtc_reg_read(rtc, MA35_REG_RTC_TIME) ||
+		 cal != rtc_reg_read(rtc, MA35_REG_RTC_CAL));
+
+	tm->tm_mday = bcd2bin(cal >> 0);
+	tm->tm_wday = wday;
+	tm->tm_mon = bcd2bin(cal >> 8);
+	tm->tm_mon = tm->tm_mon - 1;
+	tm->tm_year = bcd2bin(cal >> 16) + 100;
+
+	tm->tm_sec = bcd2bin(time >> 0);
+	tm->tm_min = bcd2bin(time >> 8);
+	tm->tm_hour = bcd2bin(time >> 16);
+
+	return rtc_valid_tm(tm);
+}
+
+static int ma35d1_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct ma35_rtc *rtc = dev_get_drvdata(dev);
+	u32 val;
+
+	val = bin2bcd(tm->tm_mday) << 0 | bin2bcd(tm->tm_mon + 1) << 8 |
+	      bin2bcd(tm->tm_year - 100) << 16;
+	rtc_reg_write(rtc, MA35_REG_RTC_CAL, val);
+
+	val = bin2bcd(tm->tm_sec) << 0 | bin2bcd(tm->tm_min) << 8 |
+	      bin2bcd(tm->tm_hour) << 16;
+	rtc_reg_write(rtc, MA35_REG_RTC_TIME, val);
+
+	val = tm->tm_wday;
+	rtc_reg_write(rtc, MA35_REG_RTC_WEEKDAY, val);
+
+	return 0;
+}
+
+static int ma35d1_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct ma35_rtc *rtc = dev_get_drvdata(dev);
+	u32 talm, calm;
+
+	talm = rtc_reg_read(rtc, MA35_REG_RTC_TALM);
+	calm = rtc_reg_read(rtc, MA35_REG_RTC_CALM);
+
+	alrm->time.tm_mday = bcd2bin(calm >> 0);
+	alrm->time.tm_mon = bcd2bin(calm >> 8);
+	alrm->time.tm_mon = alrm->time.tm_mon - 1;
+
+	alrm->time.tm_year = bcd2bin(calm >> 16) + 100;
+
+	alrm->time.tm_sec = bcd2bin(talm >> 0);
+	alrm->time.tm_min = bcd2bin(talm >> 8);
+	alrm->time.tm_hour = bcd2bin(talm >> 16);
+
+	return rtc_valid_tm(&alrm->time);
+}
+
+static int ma35d1_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct ma35_rtc *rtc = dev_get_drvdata(dev);
+	unsigned long val;
+
+	val = bin2bcd(alrm->time.tm_mday) << 0 | bin2bcd(alrm->time.tm_mon + 1) << 8 |
+	      bin2bcd(alrm->time.tm_year - 100) << 16;
+	rtc_reg_write(rtc, MA35_REG_RTC_CALM, val);
+
+	val = bin2bcd(alrm->time.tm_sec) << 0 | bin2bcd(alrm->time.tm_min) << 8 |
+	      bin2bcd(alrm->time.tm_hour) << 16;
+	rtc_reg_write(rtc, MA35_REG_RTC_TALM, val);
+
+	ma35d1_alarm_irq_enable(dev, alrm->enabled);
+
+	return 0;
+}
+
+static const struct rtc_class_ops ma35d1_rtc_ops = {
+	.read_time = ma35d1_rtc_read_time,
+	.set_time = ma35d1_rtc_set_time,
+	.read_alarm = ma35d1_rtc_read_alarm,
+	.set_alarm = ma35d1_rtc_set_alarm,
+	.alarm_irq_enable = ma35d1_alarm_irq_enable,
+};
+
+static int ma35d1_rtc_probe(struct platform_device *pdev)
+{
+	struct ma35_rtc *rtc;
+	struct clk *clk;
+	int ret;
+
+	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	rtc->rtc_reg = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(rtc->rtc_reg))
+		return PTR_ERR(rtc->rtc_reg);
+
+	clk = of_clk_get(pdev->dev.of_node, 0);
+	if (IS_ERR(clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(clk), "failed to find rtc clock\n");
+
+	ret = clk_prepare_enable(clk);
+	if (ret)
+		return ret;
+
+	if (!(rtc_reg_read(rtc, MA35_REG_RTC_INIT) & RTC_INIT_ACTIVE)) {
+		ret = ma35d1_rtc_init(rtc, RTC_INIT_TIMEOUT);
+		if (ret)
+			return dev_err_probe(&pdev->dev, ret, "rtc init failed\n");
+	}
+
+	rtc->irq_num = platform_get_irq(pdev, 0);
+
+	ret = devm_request_irq(&pdev->dev, rtc->irq_num, ma35d1_rtc_interrupt,
+			       IRQF_NO_SUSPEND, "ma35d1rtc", rtc);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "Failed to request rtc irq\n");
+
+	platform_set_drvdata(pdev, rtc);
+
+	device_init_wakeup(&pdev->dev, true);
+
+	rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtc->rtcdev))
+		return PTR_ERR(rtc->rtcdev);
+
+	rtc->rtcdev->ops = &ma35d1_rtc_ops;
+	rtc->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
+	rtc->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
+
+	ret = devm_rtc_register_device(rtc->rtcdev);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "Failed to register rtc device\n");
+
+	return 0;
+}
+
+static int ma35d1_rtc_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct ma35_rtc *rtc = platform_get_drvdata(pdev);
+
+	if (device_may_wakeup(&pdev->dev))
+		enable_irq_wake(rtc->irq_num);
+
+	return 0;
+}
+
+static int ma35d1_rtc_resume(struct platform_device *pdev)
+{
+	struct ma35_rtc *rtc = platform_get_drvdata(pdev);
+
+	if (device_may_wakeup(&pdev->dev))
+		disable_irq_wake(rtc->irq_num);
+
+	return 0;
+}
+
+static const struct of_device_id ma35d1_rtc_of_match[] = {
+	{ .compatible = "nuvoton,ma35d1-rtc", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ma35d1_rtc_of_match);
+
+static struct platform_driver ma35d1_rtc_driver = {
+	.suspend    = ma35d1_rtc_suspend,
+	.resume     = ma35d1_rtc_resume,
+	.probe      = ma35d1_rtc_probe,
+	.driver		= {
+		.name	= "rtc-ma35d1",
+		.of_match_table = ma35d1_rtc_of_match,
+	},
+};
+
+module_platform_driver(ma35d1_rtc_driver);
+
+MODULE_AUTHOR("Ming-Jen Chen <mjchen@nuvoton.com>");
+MODULE_DESCRIPTION("MA35D1 RTC driver");
+MODULE_LICENSE("GPL");