rtc: add MOXA ART RTC driver

Add RTC driver for MOXA ART SoCs.

Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
Reviewed-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 357 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/rtc/moxa,moxart-rtc.txt b/Documentation/devicetree/bindings/rtc/moxa,moxart-rtc.txt
new file mode 100644
index 000000000000..c9d3ac1477fe
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/moxa,moxart-rtc.txt
@@ -0,0 +1,17 @@
+MOXA ART real-time clock
+
+Required properties:
+
+- compatible : Should be "moxa,moxart-rtc"
+- gpio-rtc-sclk : RTC sclk gpio, with zero flags
+- gpio-rtc-data : RTC data gpio, with zero flags
+- gpio-rtc-reset : RTC reset gpio, with zero flags
+
+Example:
+
+        rtc: rtc {
+                compatible = "moxa,moxart-rtc";
+                gpio-rtc-sclk = <&gpio 5 0>;
+                gpio-rtc-data = <&gpio 6 0>;
+                gpio-rtc-reset = <&gpio 7 0>;
+        };
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 9e3498bf302b..9654aa3c05cb 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1249,6 +1249,15 @@ config RTC_DRV_SIRFSOC
           Say "yes" here to support the real time clock on SiRF SOC chips.
           This driver can also be built as a module called rtc-sirfsoc.
 
+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 d3b4488f48f2..2dff3d2009b5 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -130,3 +130,4 @@ obj-$(CONFIG_RTC_DRV_WM831X)	+= rtc-wm831x.o
 obj-$(CONFIG_RTC_DRV_WM8350)    += rtc-wm8350.o
 obj-$(CONFIG_RTC_DRV_X1205)     += rtc-x1205.o
 obj-$(CONFIG_RTC_DRV_SIRFSOC)   += rtc-sirfsoc.o
+obj-$(CONFIG_RTC_DRV_MOXART)    += rtc-moxart.o
diff --git a/drivers/rtc/rtc-moxart.c b/drivers/rtc/rtc-moxart.c
new file mode 100644
index 000000000000..c29dee0946e6
--- /dev/null
+++ b/drivers/rtc/rtc-moxart.c
@@ -0,0 +1,330 @@
+/*
+ * 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>
+#include <linux/of_gpio.h>
+
+#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
+
+struct moxart_rtc {
+        struct rtc_device *rtc;
+        spinlock_t rtc_lock;
+        int gpio_data, gpio_sclk, gpio_reset;
+};
+
+static int day_of_year[12] =    { 0, 31, 59, 90, 120, 151, 181,
+                                  212, 243, 273, 304, 334 };
+
+static void moxart_rtc_write_byte(struct device *dev, u8 data)
+{
+        struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
+        int i;
+
+        for (i = 0; i < 8; i++, data >>= 1) {
+                gpio_set_value(moxart_rtc->gpio_sclk, 0);
+                gpio_set_value(moxart_rtc->gpio_data, ((data & 1) == 1));
+                udelay(GPIO_RTC_DELAY_TIME);
+                gpio_set_value(moxart_rtc->gpio_sclk, 1);
+                udelay(GPIO_RTC_DELAY_TIME);
+        }
+}
+
+static u8 moxart_rtc_read_byte(struct device *dev)
+{
+        struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
+        int i;
+        u8 data = 0;
+
+        for (i = 0; i < 8; i++) {
+                gpio_set_value(moxart_rtc->gpio_sclk, 0);
+                udelay(GPIO_RTC_DELAY_TIME);
+                gpio_set_value(moxart_rtc->gpio_sclk, 1);
+                udelay(GPIO_RTC_DELAY_TIME);
+                if (gpio_get_value(moxart_rtc->gpio_data))
+                        data |= (1 << i);
+                udelay(GPIO_RTC_DELAY_TIME);
+        }
+        return data;
+}
+
+static u8 moxart_rtc_read_register(struct device *dev, u8 cmd)
+{
+        struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
+        u8 data;
+        unsigned long flags;
+
+        local_irq_save(flags);
+
+        gpio_direction_output(moxart_rtc->gpio_data, 0);
+        gpio_set_value(moxart_rtc->gpio_reset, 1);
+        udelay(GPIO_RTC_DELAY_TIME);
+        moxart_rtc_write_byte(dev, cmd);
+        gpio_direction_input(moxart_rtc->gpio_data);
+        udelay(GPIO_RTC_DELAY_TIME);
+        data = moxart_rtc_read_byte(dev);
+        gpio_set_value(moxart_rtc->gpio_sclk, 0);
+        gpio_set_value(moxart_rtc->gpio_reset, 0);
+        udelay(GPIO_RTC_DELAY_TIME);
+
+        local_irq_restore(flags);
+
+        return data;
+}
+
+static void moxart_rtc_write_register(struct device *dev, u8 cmd, u8 data)
+{
+        struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
+        unsigned long flags;
+
+        local_irq_save(flags);
+
+        gpio_direction_output(moxart_rtc->gpio_data, 0);
+        gpio_set_value(moxart_rtc->gpio_reset, 1);
+        udelay(GPIO_RTC_DELAY_TIME);
+        moxart_rtc_write_byte(dev, cmd);
+        moxart_rtc_write_byte(dev, data);
+        gpio_set_value(moxart_rtc->gpio_sclk, 0);
+        gpio_set_value(moxart_rtc->gpio_reset, 0);
+        udelay(GPIO_RTC_DELAY_TIME);
+
+        local_irq_restore(flags);
+}
+
+static int moxart_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
+
+        spin_lock_irq(&moxart_rtc->rtc_lock);
+
+        moxart_rtc_write_register(dev, GPIO_RTC_PROTECT_W, 0);
+        moxart_rtc_write_register(dev, GPIO_RTC_YEAR_W,
+                                  (((tm->tm_year - 100) / 10) << 4) |
+                                  ((tm->tm_year - 100) % 10));
+
+        moxart_rtc_write_register(dev, GPIO_RTC_MONTH_W,
+                                  (((tm->tm_mon + 1) / 10) << 4) |
+                                  ((tm->tm_mon + 1) % 10));
+
+        moxart_rtc_write_register(dev, GPIO_RTC_DATE_W,
+                                  ((tm->tm_mday / 10) << 4) |
+                                  (tm->tm_mday % 10));
+
+        moxart_rtc_write_register(dev, GPIO_RTC_HOURS_W,
+                                  ((tm->tm_hour / 10) << 4) |
+                                  (tm->tm_hour % 10));
+
+        moxart_rtc_write_register(dev, GPIO_RTC_MINUTES_W,
+                                  ((tm->tm_min / 10) << 4) |
+                                  (tm->tm_min % 10));
+
+        moxart_rtc_write_register(dev, GPIO_RTC_SECONDS_W,
+                                  ((tm->tm_sec / 10) << 4) |
+                                  (tm->tm_sec % 10));
+
+        moxart_rtc_write_register(dev, GPIO_RTC_PROTECT_W, 0x80);
+
+        spin_unlock_irq(&moxart_rtc->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)
+{
+        struct moxart_rtc *moxart_rtc = dev_get_drvdata(dev);
+        unsigned char v;
+
+        spin_lock_irq(&moxart_rtc->rtc_lock);
+
+        v = moxart_rtc_read_register(dev, GPIO_RTC_SECONDS_R);
+        tm->tm_sec = (((v & 0x70) >> 4) * 10) + (v & 0x0F);
+
+        v = moxart_rtc_read_register(dev, GPIO_RTC_MINUTES_R);
+        tm->tm_min = (((v & 0x70) >> 4) * 10) + (v & 0x0F);
+
+        v = moxart_rtc_read_register(dev, 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(dev, GPIO_RTC_DATE_R);
+        tm->tm_mday = (((v & 0x30) >> 4) * 10) + (v & 0x0F);
+
+        v = moxart_rtc_read_register(dev, GPIO_RTC_MONTH_R);
+        tm->tm_mon = (((v & 0x10) >> 4) * 10) + (v & 0x0F);
+        tm->tm_mon--;
+
+        v = moxart_rtc_read_register(dev, 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(dev, 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(&moxart_rtc->rtc_lock);
+
+        return 0;
+}
+
+static const struct rtc_class_ops moxart_rtc_ops = {
+        .read_time      = moxart_rtc_read_time,
+        .set_time       = moxart_rtc_set_time,
+};
+
+static int moxart_rtc_probe(struct platform_device *pdev)
+{
+        struct moxart_rtc *moxart_rtc;
+        int ret = 0;
+
+        moxart_rtc = devm_kzalloc(&pdev->dev, sizeof(*moxart_rtc), GFP_KERNEL);
+        if (!moxart_rtc) {
+                dev_err(&pdev->dev, "devm_kzalloc failed\n");
+                return -ENOMEM;
+        }
+
+        moxart_rtc->gpio_data = of_get_named_gpio(pdev->dev.of_node,
+                                                  "gpio-rtc-data", 0);
+        if (!gpio_is_valid(moxart_rtc->gpio_data)) {
+                dev_err(&pdev->dev, "invalid gpio (data): %d\n",
+                        moxart_rtc->gpio_data);
+                return moxart_rtc->gpio_data;
+        }
+
+        moxart_rtc->gpio_sclk = of_get_named_gpio(pdev->dev.of_node,
+                                                  "gpio-rtc-sclk", 0);
+        if (!gpio_is_valid(moxart_rtc->gpio_sclk)) {
+                dev_err(&pdev->dev, "invalid gpio (sclk): %d\n",
+                        moxart_rtc->gpio_sclk);
+                return moxart_rtc->gpio_sclk;
+        }
+
+        moxart_rtc->gpio_reset = of_get_named_gpio(pdev->dev.of_node,
+                                                   "gpio-rtc-reset", 0);
+        if (!gpio_is_valid(moxart_rtc->gpio_reset)) {
+                dev_err(&pdev->dev, "invalid gpio (reset): %d\n",
+                        moxart_rtc->gpio_reset);
+                return moxart_rtc->gpio_reset;
+        }
+
+        spin_lock_init(&moxart_rtc->rtc_lock);
+        platform_set_drvdata(pdev, moxart_rtc);
+
+        ret = devm_gpio_request(&pdev->dev, moxart_rtc->gpio_data, "rtc_data");
+        if (ret) {
+                dev_err(&pdev->dev, "can't get rtc_data gpio\n");
+                return ret;
+        }
+
+        ret = devm_gpio_request_one(&pdev->dev, moxart_rtc->gpio_sclk,
+                                    GPIOF_DIR_OUT, "rtc_sclk");
+        if (ret) {
+                dev_err(&pdev->dev, "can't get rtc_sclk gpio\n");
+                return ret;
+        }
+
+        ret = devm_gpio_request_one(&pdev->dev, moxart_rtc->gpio_reset,
+                                    GPIOF_DIR_OUT, "rtc_reset");
+        if (ret) {
+                dev_err(&pdev->dev, "can't get rtc_reset gpio\n");
+                return ret;
+        }
+
+        moxart_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
+                                                   &moxart_rtc_ops,
+                                                   THIS_MODULE);
+        if (IS_ERR(moxart_rtc->rtc)) {
+                dev_err(&pdev->dev, "devm_rtc_device_register failed\n");
+                return PTR_ERR(moxart_rtc->rtc);
+        }
+
+        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,
+        .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>");