diff options
Diffstat (limited to 'drivers/rtc/rtc-msc313.c')
| -rw-r--r-- | drivers/rtc/rtc-msc313.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-msc313.c b/drivers/rtc/rtc-msc313.c new file mode 100644 index 0000000000..8d7737e0e2 --- /dev/null +++ b/drivers/rtc/rtc-msc313.c @@ -0,0 +1,249 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Real time clocks driver for MStar/SigmaStar ARMv7 SoCs. + * Based on "Real Time Clock driver for msb252x." that was contained + * in various MStar kernels. + * + * (C) 2019 Daniel Palmer + * (C) 2021 Romain Perier + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> + +/* Registers */ +#define REG_RTC_CTRL 0x00 +#define REG_RTC_FREQ_CW_L 0x04 +#define REG_RTC_FREQ_CW_H 0x08 +#define REG_RTC_LOAD_VAL_L 0x0C +#define REG_RTC_LOAD_VAL_H 0x10 +#define REG_RTC_MATCH_VAL_L 0x14 +#define REG_RTC_MATCH_VAL_H 0x18 +#define REG_RTC_STATUS_INT 0x1C +#define REG_RTC_CNT_VAL_L 0x20 +#define REG_RTC_CNT_VAL_H 0x24 + +/* Control bits for REG_RTC_CTRL */ +#define SOFT_RSTZ_BIT BIT(0) +#define CNT_EN_BIT BIT(1) +#define WRAP_EN_BIT BIT(2) +#define LOAD_EN_BIT BIT(3) +#define READ_EN_BIT BIT(4) +#define INT_MASK_BIT BIT(5) +#define INT_FORCE_BIT BIT(6) +#define INT_CLEAR_BIT BIT(7) + +/* Control bits for REG_RTC_STATUS_INT */ +#define RAW_INT_BIT BIT(0) +#define ALM_INT_BIT BIT(1) + +struct msc313_rtc { + struct rtc_device *rtc_dev; + void __iomem *rtc_base; +}; + +static int msc313_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct msc313_rtc *priv = dev_get_drvdata(dev); + unsigned long seconds; + + seconds = readw(priv->rtc_base + REG_RTC_MATCH_VAL_L) + | ((unsigned long)readw(priv->rtc_base + REG_RTC_MATCH_VAL_H) << 16); + + rtc_time64_to_tm(seconds, &alarm->time); + + if (!(readw(priv->rtc_base + REG_RTC_CTRL) & INT_MASK_BIT)) + alarm->enabled = 1; + + return 0; +} + +static int msc313_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct msc313_rtc *priv = dev_get_drvdata(dev); + u16 reg; + + reg = readw(priv->rtc_base + REG_RTC_CTRL); + if (enabled) + reg &= ~INT_MASK_BIT; + else + reg |= INT_MASK_BIT; + writew(reg, priv->rtc_base + REG_RTC_CTRL); + return 0; +} + +static int msc313_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct msc313_rtc *priv = dev_get_drvdata(dev); + unsigned long seconds; + + seconds = rtc_tm_to_time64(&alarm->time); + writew((seconds & 0xFFFF), priv->rtc_base + REG_RTC_MATCH_VAL_L); + writew((seconds >> 16) & 0xFFFF, priv->rtc_base + REG_RTC_MATCH_VAL_H); + + msc313_rtc_alarm_irq_enable(dev, alarm->enabled); + + return 0; +} + +static bool msc313_rtc_get_enabled(struct msc313_rtc *priv) +{ + return readw(priv->rtc_base + REG_RTC_CTRL) & CNT_EN_BIT; +} + +static void msc313_rtc_set_enabled(struct msc313_rtc *priv) +{ + u16 reg; + + reg = readw(priv->rtc_base + REG_RTC_CTRL); + reg |= CNT_EN_BIT; + writew(reg, priv->rtc_base + REG_RTC_CTRL); +} + +static int msc313_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct msc313_rtc *priv = dev_get_drvdata(dev); + u32 seconds; + u16 reg; + + if (!msc313_rtc_get_enabled(priv)) + return -EINVAL; + + reg = readw(priv->rtc_base + REG_RTC_CTRL); + writew(reg | READ_EN_BIT, priv->rtc_base + REG_RTC_CTRL); + + /* Wait for HW latch done */ + while (readw(priv->rtc_base + REG_RTC_CTRL) & READ_EN_BIT) + udelay(1); + + seconds = readw(priv->rtc_base + REG_RTC_CNT_VAL_L) + | ((unsigned long)readw(priv->rtc_base + REG_RTC_CNT_VAL_H) << 16); + + rtc_time64_to_tm(seconds, tm); + + return 0; +} + +static int msc313_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct msc313_rtc *priv = dev_get_drvdata(dev); + unsigned long seconds; + u16 reg; + + seconds = rtc_tm_to_time64(tm); + writew(seconds & 0xFFFF, priv->rtc_base + REG_RTC_LOAD_VAL_L); + writew((seconds >> 16) & 0xFFFF, priv->rtc_base + REG_RTC_LOAD_VAL_H); + + /* Enable load for loading value into internal RTC counter */ + reg = readw(priv->rtc_base + REG_RTC_CTRL); + writew(reg | LOAD_EN_BIT, priv->rtc_base + REG_RTC_CTRL); + + /* Wait for HW latch done */ + while (readw(priv->rtc_base + REG_RTC_CTRL) & LOAD_EN_BIT) + udelay(1); + msc313_rtc_set_enabled(priv); + return 0; +} + +static const struct rtc_class_ops msc313_rtc_ops = { + .read_time = msc313_rtc_read_time, + .set_time = msc313_rtc_set_time, + .read_alarm = msc313_rtc_read_alarm, + .set_alarm = msc313_rtc_set_alarm, + .alarm_irq_enable = msc313_rtc_alarm_irq_enable, +}; + +static irqreturn_t msc313_rtc_interrupt(s32 irq, void *dev_id) +{ + struct msc313_rtc *priv = dev_get_drvdata(dev_id); + u16 reg; + + reg = readw(priv->rtc_base + REG_RTC_STATUS_INT); + if (!(reg & ALM_INT_BIT)) + return IRQ_NONE; + + reg = readw(priv->rtc_base + REG_RTC_CTRL); + reg |= INT_CLEAR_BIT; + reg &= ~INT_FORCE_BIT; + writew(reg, priv->rtc_base + REG_RTC_CTRL); + + rtc_update_irq(priv->rtc_dev, 1, RTC_IRQF | RTC_AF); + + return IRQ_HANDLED; +} + +static int msc313_rtc_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct msc313_rtc *priv; + unsigned long rate; + struct clk *clk; + int ret; + int irq; + + priv = devm_kzalloc(&pdev->dev, sizeof(struct msc313_rtc), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->rtc_base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(priv->rtc_base)) + return PTR_ERR(priv->rtc_base); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return -EINVAL; + + priv->rtc_dev = devm_rtc_allocate_device(dev); + if (IS_ERR(priv->rtc_dev)) + return PTR_ERR(priv->rtc_dev); + + priv->rtc_dev->ops = &msc313_rtc_ops; + priv->rtc_dev->range_max = U32_MAX; + + ret = devm_request_irq(dev, irq, msc313_rtc_interrupt, IRQF_SHARED, + dev_name(&pdev->dev), &pdev->dev); + if (ret) { + dev_err(dev, "Could not request IRQ\n"); + return ret; + } + + clk = devm_clk_get_enabled(dev, NULL); + if (IS_ERR(clk)) { + dev_err(dev, "No input reference clock\n"); + return PTR_ERR(clk); + } + + rate = clk_get_rate(clk); + writew(rate & 0xFFFF, priv->rtc_base + REG_RTC_FREQ_CW_L); + writew((rate >> 16) & 0xFFFF, priv->rtc_base + REG_RTC_FREQ_CW_H); + + platform_set_drvdata(pdev, priv); + + return devm_rtc_register_device(priv->rtc_dev); +} + +static const struct of_device_id msc313_rtc_of_match_table[] = { + { .compatible = "mstar,msc313-rtc" }, + { } +}; +MODULE_DEVICE_TABLE(of, msc313_rtc_of_match_table); + +static struct platform_driver msc313_rtc_driver = { + .probe = msc313_rtc_probe, + .driver = { + .name = "msc313-rtc", + .of_match_table = msc313_rtc_of_match_table, + }, +}; + +module_platform_driver(msc313_rtc_driver); + +MODULE_AUTHOR("Daniel Palmer <daniel@thingy.jp>"); +MODULE_AUTHOR("Romain Perier <romain.perier@gmail.com>"); +MODULE_DESCRIPTION("MStar RTC Driver"); +MODULE_LICENSE("GPL v2"); |