Re: [PATCH v6 2/5] rtc: rzn1: Add new RTC driver

[Nobuhiro Iwamatsu <iwamatsu@nigauri.org>]

Hi,

2022年5月13日(金) 20:03 Miquel Raynal <miquel.raynal@bootlin.com>:
>
> From: Michel Pollet <michel.pollet@bp.renesas.com>
>
> Add a basic RTC driver for the RZ/N1.
>
> Signed-off-by: Michel Pollet <michel.pollet@bp.renesas.com>
> Co-developed-by: Miquel Raynal <miquel.raynal@bootlin.com>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
>  drivers/rtc/Kconfig    |   7 ++
>  drivers/rtc/Makefile   |   1 +
>  drivers/rtc/rtc-rzn1.c | 245 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 253 insertions(+)
>  create mode 100644 drivers/rtc/rtc-rzn1.c
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 41c65b4d2baf..a00f901b5c1d 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -1548,6 +1548,13 @@ config RTC_DRV_RS5C313
>         help
>           If you say yes here you get support for the Ricoh RS5C313 RTC chips.
>
> +config RTC_DRV_RZN1
> +       tristate "Renesas RZ/N1 RTC"
> +       depends on ARCH_RZN1 || COMPILE_TEST
> +       depends on OF && HAS_IOMEM
> +       help
> +         If you say yes here you get support for the Renesas RZ/N1 RTC.
> +
>  config RTC_DRV_GENERIC
>         tristate "Generic RTC support"
>         # Please consider writing a new RTC driver instead of using the generic
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 2d827d8261d5..fb04467b652d 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -151,6 +151,7 @@ obj-$(CONFIG_RTC_DRV_RX6110)        += rtc-rx6110.o
>  obj-$(CONFIG_RTC_DRV_RX8010)   += rtc-rx8010.o
>  obj-$(CONFIG_RTC_DRV_RX8025)   += rtc-rx8025.o
>  obj-$(CONFIG_RTC_DRV_RX8581)   += rtc-rx8581.o
> +obj-$(CONFIG_RTC_DRV_RZN1)     += rtc-rzn1.o
>  obj-$(CONFIG_RTC_DRV_S35390A)  += rtc-s35390a.o
>  obj-$(CONFIG_RTC_DRV_S3C)      += rtc-s3c.o
>  obj-$(CONFIG_RTC_DRV_S5M)      += rtc-s5m.o
> diff --git a/drivers/rtc/rtc-rzn1.c b/drivers/rtc/rtc-rzn1.c
> new file mode 100644
> index 000000000000..685cba87cd90
> --- /dev/null
> +++ b/drivers/rtc/rtc-rzn1.c
> @@ -0,0 +1,245 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Renesas RZ/N1 Real Time Clock interface for Linux
> + *
> + * Copyright:
> + * - 2014 Renesas Electronics Europe Limited
> + * - 2022 Schneider Electric
> + *
> + * Authors:
> + * - Michel Pollet <michel.pollet@bp.renesas.com>, <buserror@gmail.com>
> + * - Miquel Raynal <miquel.raynal@bootlin.com>
> + */
> +
> +#include <linux/bcd.h>
> +#include <linux/clk.h>
> +#include <linux/init.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/rtc.h>
> +
> +#define RZN1_RTC_CTL0 0x00
> +#define   RZN1_RTC_CTL0_SLSB_SUBU 0
> +#define   RZN1_RTC_CTL0_SLSB_SCMP BIT(4)
> +#define   RZN1_RTC_CTL0_AMPM BIT(5)
> +#define   RZN1_RTC_CTL0_CE BIT(7)
> +
> +#define RZN1_RTC_CTL1 0x04
> +#define   RZN1_RTC_CTL1_ALME BIT(4)
> +
> +#define RZN1_RTC_CTL2 0x08
> +#define   RZN1_RTC_CTL2_WAIT BIT(0)
> +#define   RZN1_RTC_CTL2_WST BIT(1)
> +#define   RZN1_RTC_CTL2_WUST BIT(5)
> +#define   RZN1_RTC_CTL2_STOPPED (RZN1_RTC_CTL2_WAIT | RZN1_RTC_CTL2_WST)
> +
> +#define RZN1_RTC_SEC 0x14
> +#define RZN1_RTC_MIN 0x18
> +#define RZN1_RTC_HOUR 0x1c
> +#define RZN1_RTC_WEEK 0x20
> +#define RZN1_RTC_DAY 0x24
> +#define RZN1_RTC_MONTH 0x28
> +#define RZN1_RTC_YEAR 0x2c
> +
> +#define RZN1_RTC_SUBU 0x38
> +#define   RZN1_RTC_SUBU_DEV BIT(7)
> +#define   RZN1_RTC_SUBU_DECR BIT(6)
> +
> +#define RZN1_RTC_ALM 0x40
> +#define RZN1_RTC_ALH 0x44
> +#define RZN1_RTC_ALW 0x48
> +
> +#define RZN1_RTC_SECC 0x4c
> +#define RZN1_RTC_MINC 0x50
> +#define RZN1_RTC_HOURC 0x54
> +#define RZN1_RTC_WEEKC 0x58
> +#define RZN1_RTC_DAYC 0x5c
> +#define RZN1_RTC_MONTHC 0x60
> +#define RZN1_RTC_YEARC 0x64
> +
> +struct rzn1_rtc {
> +       struct rtc_device *rtcdev;
> +       void __iomem *base;
> +       struct clk *clk;

clk variables do not seem to be used in this patch series.
If it is not used in the future, I think it can be deleted with
'#Include <linux/clk.h>".

> +};
> +
> +static void rzn1_rtc_get_time_snapshot(struct rzn1_rtc *rtc, struct rtc_time *tm)
> +{
> +       tm->tm_sec = readl(rtc->base + RZN1_RTC_SECC);
> +       tm->tm_min = readl(rtc->base + RZN1_RTC_MINC);
> +       tm->tm_hour = readl(rtc->base + RZN1_RTC_HOURC);
> +       tm->tm_wday = readl(rtc->base + RZN1_RTC_WEEKC);
> +       tm->tm_mday = readl(rtc->base + RZN1_RTC_DAYC);
> +       tm->tm_mon = readl(rtc->base + RZN1_RTC_MONTHC);
> +       tm->tm_year = readl(rtc->base + RZN1_RTC_YEARC);
> +}
> +
> +static unsigned int rzn1_rtc_tm_to_wday(struct rtc_time *tm)
> +{
> +       time64_t time;
> +       unsigned int days;
> +       u32 secs;
> +
> +       time = rtc_tm_to_time64(tm);
> +       days = div_s64_rem(time, 86400, &secs);
> +
> +       /* day of the week, 1970-01-01 was a Thursday */
> +       return (days + 4) % 7;
> +}
> +
> +static int rzn1_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> +       struct rzn1_rtc *rtc = dev_get_drvdata(dev);
> +       u32 val, secs;
> +
> +       /*
> +        * The RTC was not started or is stopped and thus does not carry the
> +        * proper time/date.
> +        */
> +       val = readl(rtc->base + RZN1_RTC_CTL2);
> +       if (val & RZN1_RTC_CTL2_STOPPED)
> +               return -EINVAL;
> +
> +       rzn1_rtc_get_time_snapshot(rtc, tm);
> +       secs = readl(rtc->base + RZN1_RTC_SECC);
> +       if (tm->tm_sec != secs)
> +               rzn1_rtc_get_time_snapshot(rtc, tm);
> +
> +       tm->tm_sec = bcd2bin(tm->tm_sec);
> +       tm->tm_min = bcd2bin(tm->tm_min);
> +       tm->tm_hour = bcd2bin(tm->tm_hour);
> +       tm->tm_wday = bcd2bin(tm->tm_wday);
> +       tm->tm_mday = bcd2bin(tm->tm_mday);
> +       tm->tm_mon = bcd2bin(tm->tm_mon);
> +       tm->tm_year = bcd2bin(tm->tm_year);
> +
> +       return 0;
> +}
> +
> +static int rzn1_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> +       struct rzn1_rtc *rtc = dev_get_drvdata(dev);
> +       u32 val;
> +       int ret;
> +
> +       tm->tm_sec = bin2bcd(tm->tm_sec);
> +       tm->tm_min = bin2bcd(tm->tm_min);
> +       tm->tm_hour = bin2bcd(tm->tm_hour);
> +       tm->tm_wday = bin2bcd(rzn1_rtc_tm_to_wday(tm));
> +       tm->tm_mday = bin2bcd(tm->tm_mday);
> +       tm->tm_mon = bin2bcd(tm->tm_mon);
> +       tm->tm_year = bin2bcd(tm->tm_year);
> +
> +       val = readl(rtc->base + RZN1_RTC_CTL2);
> +       if (!(val & RZN1_RTC_CTL2_STOPPED)) {
> +               /* Hold the counter if it was counting up */
> +               writel(RZN1_RTC_CTL2_WAIT, rtc->base + RZN1_RTC_CTL2);
> +
> +               /* Wait for the counter to stop: two 32k clock cycles */
> +               usleep_range(61, 100);
> +               ret = readl_poll_timeout(rtc->base + RZN1_RTC_CTL2, val,
> +                                        val & RZN1_RTC_CTL2_WST, 0, 100);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       writel(tm->tm_sec, rtc->base + RZN1_RTC_SEC);
> +       writel(tm->tm_min, rtc->base + RZN1_RTC_MIN);
> +       writel(tm->tm_hour, rtc->base + RZN1_RTC_HOUR);
> +       writel(tm->tm_wday, rtc->base + RZN1_RTC_WEEK);
> +       writel(tm->tm_mday, rtc->base + RZN1_RTC_DAY);
> +       writel(tm->tm_mon, rtc->base + RZN1_RTC_MONTH);
> +       writel(tm->tm_year, rtc->base + RZN1_RTC_YEAR);
> +       writel(0, rtc->base + RZN1_RTC_CTL2);
> +
> +       return 0;
> +}
> +
> +static const struct rtc_class_ops rzn1_rtc_ops = {
> +       .read_time = rzn1_rtc_read_time,
> +       .set_time = rzn1_rtc_set_time,
> +};
> +
> +static int rzn1_rtc_probe(struct platform_device *pdev)
> +{
> +       struct rzn1_rtc *rtc;
> +       int ret;
> +
> +       rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
> +       if (!rtc)
> +               return -ENOMEM;
> +
> +       platform_set_drvdata(pdev, rtc);
> +
> +       rtc->base = devm_platform_ioremap_resource(pdev, 0);
> +       if (IS_ERR(rtc->base))
> +               return dev_err_probe(&pdev->dev, PTR_ERR(rtc->base), "Missing reg\n");
> +
> +       rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev);
> +       if (IS_ERR(rtc->rtcdev))
> +               return PTR_ERR(rtc);
> +
> +       rtc->rtcdev->range_min = RTC_TIMESTAMP_BEGIN_2000;
> +       rtc->rtcdev->range_max = RTC_TIMESTAMP_END_2099;
> +       rtc->rtcdev->ops = &rzn1_rtc_ops;
> +       clear_bit(RTC_FEATURE_ALARM, rtc->rtcdev->features);
> +       clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtcdev->features);
> +
> +       devm_pm_runtime_enable(&pdev->dev);
> +       ret = pm_runtime_resume_and_get(&pdev->dev);
> +       if (ret < 0)
> +               return ret;
> +
> +       /*
> +        * Ensure the clock counter is enabled.
> +        * Set 24-hour mode and possible oscillator offset compensation in SUBU mode.
> +        */
> +       writel(RZN1_RTC_CTL0_CE | RZN1_RTC_CTL0_AMPM | RZN1_RTC_CTL0_SLSB_SUBU,
> +              rtc->base + RZN1_RTC_CTL0);
> +
> +       /* Disable all interrupts */
> +       writel(0, rtc->base + RZN1_RTC_CTL1);
> +
> +       ret = devm_rtc_register_device(rtc->rtcdev);
> +       if (ret)
> +               goto dis_runtime_pm;
> +
> +       return 0;
> +
> +dis_runtime_pm:
> +       pm_runtime_put(&pdev->dev);
> +
> +       return ret;
> +}
> +
> +static int rzn1_rtc_remove(struct platform_device *pdev)
> +{
> +       pm_runtime_put(&pdev->dev);
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id rzn1_rtc_of_match[] = {
> +       { .compatible   = "renesas,rzn1-rtc" },
> +       {},
> +};
> +MODULE_DEVICE_TABLE(of, rzn1_rtc_of_match);
> +
> +static struct platform_driver rzn1_rtc_driver = {
> +       .probe = rzn1_rtc_probe,
> +       .remove = rzn1_rtc_remove,
> +       .driver = {
> +               .name   = "rzn1-rtc",
> +               .owner  = THIS_MODULE,
> +               .of_match_table = rzn1_rtc_of_match,
> +       },
> +};
> +module_platform_driver(rzn1_rtc_driver);
> +
> +MODULE_AUTHOR("Michel Pollet <Michel.Pollet@bp.renesas.com");
> +MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com");
> +MODULE_DESCRIPTION("RZ/N1 RTC driver");
> +MODULE_LICENSE("GPL");
> --
> 2.27.0
>

Best regards,
  Nobuhiro


--
Nobuhiro Iwamatsu
   iwamatsu at {nigauri.org / debian.org / kernel.org}
   GPG ID: 40AD1FA6