Patchwork rtc: Add MOXA ART RTC driver

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Submitter Jonas Jensen
Date July 10, 2013, 2 p.m.
Message ID <1373464848-28146-1-git-send-email-jonas.jensen@gmail.com>
Download mbox | patch
Permalink /patch/258062/
State New
Headers show

Comments

Jonas Jensen - July 10, 2013, 2 p.m.
Add RTC driver for MOXA ART SoCs.

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
---

Notes:
    Applies to next-20130703

 drivers/rtc/Kconfig      |   9 ++
 drivers/rtc/Makefile     |   1 +
 drivers/rtc/rtc-moxart.c | 335 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 345 insertions(+)
 create mode 100644 drivers/rtc/rtc-moxart.c
Mark Brown - July 10, 2013, 3:47 p.m.
On Wed, Jul 10, 2013 at 04:00:48PM +0200, Jonas Jensen wrote:

> +++ b/drivers/rtc/Makefile
> @@ -77,6 +77,7 @@ obj-$(CONFIG_RTC_DRV_MAX6902)	+= rtc-max6902.o
>  obj-$(CONFIG_RTC_DRV_MAX77686)	+= rtc-max77686.o
>  obj-$(CONFIG_RTC_DRV_MC13XXX)	+= rtc-mc13xxx.o
>  obj-$(CONFIG_RTC_DRV_MSM6242)	+= rtc-msm6242.o
> +obj-$(CONFIG_RTC_DRV_MOXART)	+= rtc-moxart.o
>  obj-$(CONFIG_RTC_DRV_MPC5121)	+= rtc-mpc5121.o

It'd be good to keep this sorted.

> +struct rtc_plat_data {

This is a bit confusing - normally platform data is data passed in by
the platform as part of device registration, not runtime data.

> +	struct rtc_device *rtc;
> +};
> +
> +static spinlock_t rtc_lock;

Why is this global not part of the runtime data?  Not that anyone is
likely to have two RTCs in the one system but still...

> +u8 moxart_rtc_read_byte(void)
> +{
> +	int i;
> +	u8 data = 0;
> +
> +	for (i = 0; i < 8; i++) {
> +		gpio_set_value(GPIO_RTC_SCLK, GPIO_EM1240_LOW);
> +		udelay(GPIO_RTC_DELAY_TIME);
> +		gpio_set_value(GPIO_RTC_SCLK, GPIO_EM1240_HIGH);
> +		if (gpio_get_value(GPIO_RTC_DATA))
> +			data |= (1 << i);
> +		udelay(GPIO_RTC_DELAY_TIME);

This looks wrong, although I expect it's probably fine - you're reading
the value with no delay after setting the GPIO high.  I assume the
hardware actually strobes the data out on the the high to low transition
but in that case I'd expect the get to be before the raise.  Either that
or some delay after the raise just to make sure.

It's also very odd seeing the constants for _LOW and _HIGH, these should
just be booleans.

> +static int moxart_rtc_ioctl(struct device *dev, unsigned int cmd,
> +	unsigned long arg)
> +{
> +	switch (cmd) {
> +	default:
> +		return -ENOIOCTLCMD;
> +	}
> +
> +	return 0;
> +}

Why not just remove this function?

> + out:
> +	if (pdata->rtc)
> +		rtc_device_unregister(pdata->rtc);
> +	devm_kfree(&pdev->dev, pdata);

devm_kfree() isn't needed, the main point of devm_ is to avoid having to
explicitly free things.

> +	gpio_free(GPIO_RTC_DATA);
> +	gpio_free(GPIO_RTC_SCLK);
> +	gpio_free(GPIO_RTC_RESET);

Use devm_gpio_request().

Patch

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index b983813..7035955 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1233,6 +1233,15 @@  config RTC_DRV_SNVS
 	   This driver can also be built as a module, if so, the module
 	   will be called "rtc-snvs".
 
+config RTC_DRV_MOXART
+	tristate "MOXA ART RTC"
+	help
+	   If you say yes here you get support for the MOXA ART
+	   RTC module.
+
+	   This driver can also be built as a module. If so, the module
+	   will be called rtc-moxart
+
 comment "HID Sensor RTC drivers"
 
 config RTC_DRV_HID_SENSOR_TIME
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index c33f86f..c0381fd 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -77,6 +77,7 @@  obj-$(CONFIG_RTC_DRV_MAX6902)	+= rtc-max6902.o
 obj-$(CONFIG_RTC_DRV_MAX77686)	+= rtc-max77686.o
 obj-$(CONFIG_RTC_DRV_MC13XXX)	+= rtc-mc13xxx.o
 obj-$(CONFIG_RTC_DRV_MSM6242)	+= rtc-msm6242.o
+obj-$(CONFIG_RTC_DRV_MOXART)	+= rtc-moxart.o
 obj-$(CONFIG_RTC_DRV_MPC5121)	+= rtc-mpc5121.o
 obj-$(CONFIG_RTC_DRV_MV)	+= rtc-mv.o
 obj-$(CONFIG_RTC_DRV_NUC900)	+= rtc-nuc900.o
diff --git a/drivers/rtc/rtc-moxart.c b/drivers/rtc/rtc-moxart.c
new file mode 100644
index 0000000..cfdbedc
--- /dev/null
+++ b/drivers/rtc/rtc-moxart.c
@@ -0,0 +1,335 @@ 
+/*
+ * MOXA ART RTC driver.
+ *
+ * Copyright (C) 2013 Jonas Jensen
+ *
+ * Jonas Jensen <jonas.jensen@gmail.com>
+ *
+ * Based on code from
+ * Moxa Technology Co., Ltd. <www.moxa.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/gpio.h>
+
+#define GPIO_EM1240_HIGH			1
+#define GPIO_EM1240_LOW				0
+#define GPIO_EM1240_OUTPUT			1
+#define GPIO_EM1240_INPUT			0
+
+#define GPIO_RTC_SCLK				(5)
+#define GPIO_RTC_DATA				(6)
+#define GPIO_RTC_RESET				(7)
+
+#define GPIO_RTC_RESERVED			0x0C
+#define GPIO_RTC_DATA_SET			0x10
+#define GPIO_RTC_DATA_CLEAR			0x14
+#define GPIO_RTC_PIN_PULL_ENABLE		0x18
+#define GPIO_RTC_PIN_PULL_TYPE			0x1C
+#define GPIO_RTC_INT_ENABLE			0x20
+#define GPIO_RTC_INT_RAW_STATE			0x24
+#define GPIO_RTC_INT_MASKED_STATE		0x28
+#define GPIO_RTC_INT_MASK			0x2C
+#define GPIO_RTC_INT_CLEAR			0x30
+#define GPIO_RTC_INT_TRIGGER			0x34
+#define GPIO_RTC_INT_BOTH			0x38
+#define GPIO_RTC_INT_RISE_NEG			0x3C
+#define GPIO_RTC_BOUNCE_ENABLE			0x40
+#define GPIO_RTC_BOUNCE_PRE_SCALE		0x44
+
+#define GPIO_RTC_PROTECT_W			0x8E
+#define GPIO_RTC_PROTECT_R			0x8F
+#define GPIO_RTC_YEAR_W				0x8C
+#define GPIO_RTC_YEAR_R				0x8D
+#define GPIO_RTC_DAY_W				0x8A
+#define GPIO_RTC_DAY_R				0x8B
+#define GPIO_RTC_MONTH_W			0x88
+#define GPIO_RTC_MONTH_R			0x89
+#define GPIO_RTC_DATE_W				0x86
+#define GPIO_RTC_DATE_R				0x87
+#define GPIO_RTC_HOURS_W			0x84
+#define GPIO_RTC_HOURS_R			0x85
+#define GPIO_RTC_MINUTES_W			0x82
+#define GPIO_RTC_MINUTES_R			0x83
+#define GPIO_RTC_SECONDS_W			0x80
+#define GPIO_RTC_SECONDS_R			0x81
+#define GPIO_RTC_DELAY_TIME			8	/* 8 usecond */
+#define GPIO_RTC_IS_OPEN			0x01	/* /dev/rtc in use */
+#define GPIO_PIO(x)				(1 << x)
+
+struct rtc_plat_data {
+	struct rtc_device *rtc;
+};
+
+static spinlock_t rtc_lock;
+static int day_of_year[12] =	{ 0, 31, 59, 90, 120, 151, 181,
+				  212, 243, 273, 304, 334 };
+
+void moxart_rtc_write_byte(u8 data)
+{
+	int i;
+
+	for (i = 0; i < 8; i++, data >>= 1) {
+		gpio_set_value(GPIO_RTC_SCLK, GPIO_EM1240_LOW);
+		gpio_set_value(GPIO_RTC_DATA, ((data & 1) == 1));
+		udelay(GPIO_RTC_DELAY_TIME);
+		gpio_set_value(GPIO_RTC_SCLK, GPIO_EM1240_HIGH);
+		udelay(GPIO_RTC_DELAY_TIME);
+	}
+}
+
+u8 moxart_rtc_read_byte(void)
+{
+	int i;
+	u8 data = 0;
+
+	for (i = 0; i < 8; i++) {
+		gpio_set_value(GPIO_RTC_SCLK, GPIO_EM1240_LOW);
+		udelay(GPIO_RTC_DELAY_TIME);
+		gpio_set_value(GPIO_RTC_SCLK, GPIO_EM1240_HIGH);
+		if (gpio_get_value(GPIO_RTC_DATA))
+			data |= (1 << i);
+		udelay(GPIO_RTC_DELAY_TIME);
+	}
+	return data;
+}
+
+static u8 moxart_rtc_read_register(u8 cmd)
+{
+	u8 data;
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	gpio_direction_output(GPIO_RTC_DATA, 0);
+	gpio_set_value(GPIO_RTC_RESET, GPIO_EM1240_HIGH);
+	udelay(GPIO_RTC_DELAY_TIME);
+	moxart_rtc_write_byte(cmd);
+	gpio_direction_input(GPIO_RTC_DATA);
+	udelay(GPIO_RTC_DELAY_TIME);
+	data = moxart_rtc_read_byte();
+	gpio_set_value(GPIO_RTC_SCLK, GPIO_EM1240_LOW);
+	gpio_set_value(GPIO_RTC_RESET, GPIO_EM1240_LOW);
+	udelay(GPIO_RTC_DELAY_TIME);
+
+	local_irq_restore(flags);
+
+	return data;
+}
+
+static void moxart_rtc_write_register(u8 cmd, u8 data)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	gpio_direction_output(GPIO_RTC_DATA, 0);
+	gpio_set_value(GPIO_RTC_RESET, GPIO_EM1240_HIGH);
+	udelay(GPIO_RTC_DELAY_TIME);
+	moxart_rtc_write_byte(cmd);
+	moxart_rtc_write_byte(data);
+	gpio_set_value(GPIO_RTC_SCLK, GPIO_EM1240_LOW);
+	gpio_set_value(GPIO_RTC_RESET, GPIO_EM1240_LOW);
+	udelay(GPIO_RTC_DELAY_TIME);
+
+	local_irq_restore(flags);
+}
+
+static int moxart_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	spin_lock_irq(&rtc_lock);
+
+	moxart_rtc_write_register(GPIO_RTC_PROTECT_W, 0);
+	moxart_rtc_write_register(GPIO_RTC_YEAR_W,
+				  (((tm->tm_year - 100) / 10) << 4) |
+				  ((tm->tm_year - 100) % 10));
+
+	moxart_rtc_write_register(GPIO_RTC_MONTH_W,
+				  (((tm->tm_mon + 1) / 10) << 4) |
+				  ((tm->tm_mon + 1) % 10));
+
+	moxart_rtc_write_register(GPIO_RTC_DATE_W,
+				  ((tm->tm_mday / 10) << 4) |
+				  (tm->tm_mday % 10));
+
+	moxart_rtc_write_register(GPIO_RTC_HOURS_W,
+				  ((tm->tm_hour / 10) << 4) |
+				  (tm->tm_hour % 10));
+
+	moxart_rtc_write_register(GPIO_RTC_MINUTES_W,
+				  ((tm->tm_min / 10) << 4) |
+				  (tm->tm_min % 10));
+
+	moxart_rtc_write_register(GPIO_RTC_SECONDS_W,
+				  ((tm->tm_sec / 10) << 4) |
+				  (tm->tm_sec % 10));
+
+	moxart_rtc_write_register(GPIO_RTC_PROTECT_W, 0x80);
+
+	spin_unlock_irq(&rtc_lock);
+
+	dev_dbg(dev, "%s: success tm_year=%d tm_mon=%d\n"
+		"tm_mday=%d tm_hour=%d tm_min=%d tm_sec=%d\n",
+		__func__, tm->tm_year, tm->tm_mon, tm->tm_mday,
+		tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+	return 0;
+}
+
+static int moxart_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	unsigned char v;
+
+	spin_lock_irq(&rtc_lock);
+
+	v = moxart_rtc_read_register(GPIO_RTC_SECONDS_R);
+	tm->tm_sec = (((v & 0x70) >> 4) * 10) + (v & 0x0F);
+
+	v = moxart_rtc_read_register(GPIO_RTC_MINUTES_R);
+	tm->tm_min = (((v & 0x70) >> 4) * 10) + (v & 0x0F);
+
+	v = moxart_rtc_read_register(GPIO_RTC_HOURS_R);
+	if (v & 0x80) { /* 12-hour mode */
+		tm->tm_hour = (((v & 0x10) >> 4) * 10) + (v & 0x0F);
+		if (v & 0x20) { /* PM mode */
+			tm->tm_hour += 12;
+			if (tm->tm_hour >= 24)
+				tm->tm_hour = 0;
+		}
+	} else { /* 24-hour mode */
+		tm->tm_hour = (((v & 0x30) >> 4) * 10) + (v & 0x0F);
+	}
+
+	v = moxart_rtc_read_register(GPIO_RTC_DATE_R);
+	tm->tm_mday = (((v & 0x30) >> 4) * 10) + (v & 0x0F);
+
+	v = moxart_rtc_read_register(GPIO_RTC_MONTH_R);
+	tm->tm_mon = (((v & 0x10) >> 4) * 10) + (v & 0x0F);
+	tm->tm_mon--;
+
+	v = moxart_rtc_read_register(GPIO_RTC_YEAR_R);
+	tm->tm_year = (((v & 0xF0) >> 4) * 10) + (v & 0x0F);
+	tm->tm_year += 100;
+	if (tm->tm_year <= 69)
+		tm->tm_year += 100;
+
+	v = moxart_rtc_read_register(GPIO_RTC_DAY_R);
+	tm->tm_wday = (v & 0x0f) - 1;
+	tm->tm_yday = day_of_year[tm->tm_mon];
+	tm->tm_yday += (tm->tm_mday - 1);
+	if (tm->tm_mon >= 2) {
+		if (!(tm->tm_year % 4) && (tm->tm_year % 100))
+			tm->tm_yday++;
+	}
+
+	tm->tm_isdst = 0;
+
+	spin_unlock_irq(&rtc_lock);
+
+	return 0;
+}
+
+static int moxart_rtc_ioctl(struct device *dev, unsigned int cmd,
+	unsigned long arg)
+{
+	switch (cmd) {
+	default:
+		return -ENOIOCTLCMD;
+	}
+
+	return 0;
+}
+
+static const struct rtc_class_ops moxart_rtc_ops = {
+	.read_time	= moxart_rtc_read_time,
+	.set_time	= moxart_rtc_set_time,
+	.ioctl		= moxart_rtc_ioctl,
+};
+
+static int moxart_rtc_probe(struct platform_device *pdev)
+{
+	struct rtc_device *rtc;
+	struct rtc_plat_data *pdata = NULL;
+	int ret = 0;
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata) {
+		dev_err(&pdev->dev, "devm_kzalloc failed\n");
+		return -ENOMEM;
+	}
+
+	spin_lock_init(&rtc_lock);
+
+	gpio_request(GPIO_RTC_DATA, "rtc_data");
+	gpio_request(GPIO_RTC_SCLK, "rtc_sclk");
+	gpio_request(GPIO_RTC_RESET, "rtc_reset");
+
+	gpio_direction_output(GPIO_RTC_RESET, 0);
+	gpio_direction_output(GPIO_RTC_SCLK, 0);
+
+	rtc = rtc_device_register(pdev->name, &pdev->dev,
+		&moxart_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc)) {
+		ret = PTR_ERR(rtc);
+		goto out;
+	}
+
+	pdata->rtc = rtc;
+	platform_set_drvdata(pdev, pdata);
+
+	dev_dbg(&pdev->dev, "%s\n", __func__);
+
+	if (ret)
+		goto out;
+
+	return 0;
+
+ out:
+	if (pdata->rtc)
+		rtc_device_unregister(pdata->rtc);
+	devm_kfree(&pdev->dev, pdata);
+	return ret;
+}
+
+static int moxart_rtc_remove(struct platform_device *pdev)
+{
+	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
+
+	gpio_free(GPIO_RTC_DATA);
+	gpio_free(GPIO_RTC_SCLK);
+	gpio_free(GPIO_RTC_RESET);
+
+	rtc_device_unregister(pdata->rtc);
+	devm_kfree(&pdev->dev, pdata);
+
+	return 0;
+}
+
+static const struct of_device_id moxart_rtc_match[] = {
+	{ .compatible = "moxa,moxart-rtc" },
+	{ },
+};
+
+static struct platform_driver moxart_rtc_driver = {
+	.probe	= moxart_rtc_probe,
+	.remove	= moxart_rtc_remove,
+	.driver	= {
+		.name		= "moxart-rtc",
+		.owner		= THIS_MODULE,
+		.of_match_table	= moxart_rtc_match,
+	},
+};
+module_platform_driver(moxart_rtc_driver);
+
+MODULE_DESCRIPTION("MOXART RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");