#include <linux/err.h>
#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/mod_devicetable.h>
#include <linux/gpio/consumer.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;
struct gpio_desc *gpio_data;
struct gpio_desc *gpio_sclk;
struct gpio_desc *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) {
gpiod_set_value(moxart_rtc->gpio_sclk, 0);
gpiod_set_value(moxart_rtc->gpio_data, ((data & 1) == 1));
udelay(GPIO_RTC_DELAY_TIME);
gpiod_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++) {
gpiod_set_value(moxart_rtc->gpio_sclk, 0);
udelay(GPIO_RTC_DELAY_TIME);
gpiod_set_value(moxart_rtc->gpio_sclk, 1);
udelay(GPIO_RTC_DELAY_TIME);
if (gpiod_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);
gpiod_direction_output(moxart_rtc->gpio_data, 0);
gpiod_set_value(moxart_rtc->gpio_reset, 1);
udelay(GPIO_RTC_DELAY_TIME);
moxart_rtc_write_byte(dev, cmd);
gpiod_direction_input(moxart_rtc->gpio_data);
udelay(GPIO_RTC_DELAY_TIME);
data = moxart_rtc_read_byte(dev);
gpiod_set_value(moxart_rtc->gpio_sclk, 0);
gpiod_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);
gpiod_direction_output(moxart_rtc->gpio_data, 0);
gpiod_set_value(moxart_rtc->gpio_reset, 1);
udelay(GPIO_RTC_DELAY_TIME);
moxart_rtc_write_byte(dev, cmd);
moxart_rtc_write_byte(dev, data);
gpiod_set_value(moxart_rtc->gpio_sclk, 0);
gpiod_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) {
tm->tm_hour = (((v & 0x10) >> 4) * 10) + (v & 0x0F);
if (v & 0x20) {
tm->tm_hour += 12;
if (tm->tm_hour >= 24)
tm->tm_hour = 0;
}
} else {
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)
return -ENOMEM;
moxart_rtc->gpio_data = devm_gpiod_get(&pdev->dev, "rtc-data",
GPIOD_IN);
ret = PTR_ERR_OR_ZERO(moxart_rtc->gpio_data);
if (ret) {
dev_err(&pdev->dev, "can't get rtc data gpio: %d\n", ret);
return ret;
}
moxart_rtc->gpio_sclk = devm_gpiod_get(&pdev->dev, "rtc-sclk",
GPIOD_ASIS);
ret = PTR_ERR_OR_ZERO(moxart_rtc->gpio_sclk);
if (ret) {
dev_err(&pdev->dev, "can't get rtc sclk gpio: %d\n", ret);
return ret;
}
moxart_rtc->gpio_reset = devm_gpiod_get(&pdev->dev, "rtc-reset",
GPIOD_ASIS);
ret = PTR_ERR_OR_ZERO(moxart_rtc->gpio_reset);
if (ret) {
dev_err(&pdev->dev, "can't get rtc reset gpio: %d\n", ret);
return ret;
}
spin_lock_init(&moxart_rtc->rtc_lock);
platform_set_drvdata(pdev, moxart_rtc);
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" },
{ },
};
MODULE_DEVICE_TABLE(of, moxart_rtc_match);
static struct platform_driver moxart_rtc_driver = {
.probe = moxart_rtc_probe,
.driver = {
.name = "moxart-rtc",
.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>");
