Hi,
2021年6月29日(火) 1:52 WANG Xuerui <git@xxxxxxxxxx>:
>
> This RTC module is integrated into the Loongson-2K SoC and the LS7A
> bridge chip. This version is almost entirely rewritten to make use of
> current kernel API.
>
> Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxx>
> Signed-off-by: WANG Xuerui <git@xxxxxxxxxx>
> Tested-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx> # loongson2k
> Cc: devicetree@xxxxxxxxxxxxxxx
> Cc: linux-mips@xxxxxxxxxxxxxxx
> ---
> drivers/rtc/Kconfig | 11 +++
> drivers/rtc/Makefile | 1 +
> drivers/rtc/rtc-ls2x.c | 184 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 196 insertions(+)
> create mode 100644 drivers/rtc/rtc-ls2x.c
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 12153d5801ce..253b9f22a162 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -1304,6 +1304,17 @@ config RTC_DRV_NTXEC
> embedded controller found in certain e-book readers designed by the
> original design manufacturer Netronix.
>
> +config RTC_DRV_LS2X
> + tristate "Loongson LS2X RTC"
> + depends on MACH_LOONGSON64 || COMPILE_TEST
> + select REGMAP_MMIO
> + help
> + If you say yes here you get support for the RTC on the Loongson-2K
> + SoC and LS7A bridge, which first appeared on the Loongson-2H.
> +
> + This driver can also be built as a module. If so, the module
> + will be called rtc-ls2x.
> +
> comment "on-CPU RTC drivers"
>
> config RTC_DRV_ASM9260
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 2dd0dd956b0e..6042ff1e73b7 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -81,6 +81,7 @@ obj-$(CONFIG_RTC_DRV_LOONGSON1) += rtc-ls1x.o
> obj-$(CONFIG_RTC_DRV_LP8788) += rtc-lp8788.o
> obj-$(CONFIG_RTC_DRV_LPC24XX) += rtc-lpc24xx.o
> obj-$(CONFIG_RTC_DRV_LPC32XX) += rtc-lpc32xx.o
> +obj-$(CONFIG_RTC_DRV_LS2X) += rtc-ls2x.o
> obj-$(CONFIG_RTC_DRV_M41T80) += rtc-m41t80.o
> obj-$(CONFIG_RTC_DRV_M41T93) += rtc-m41t93.o
> obj-$(CONFIG_RTC_DRV_M41T94) += rtc-m41t94.o
> diff --git a/drivers/rtc/rtc-ls2x.c b/drivers/rtc/rtc-ls2x.c
> new file mode 100644
> index 000000000000..1147a6e1591f
> --- /dev/null
> +++ b/drivers/rtc/rtc-ls2x.c
> @@ -0,0 +1,184 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Loongson-2K/7A RTC driver
> + *
> + * Based on the original out-of-tree Loongson-2H RTC driver for Linux 2.6.32,
> + * by Shaozong Liu <liushaozong@xxxxxxxxxxx>.
> + *
> + * Maintained out-of-tree by Huacai Chen <chenhuacai@xxxxxxxxxx>.
> + *
> + * Rewritten for mainline by WANG Xuerui <git@xxxxxxxxxx>.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/rtc.h>
> +
> +#define TOY_TRIM_REG 0x20
> +#define TOY_WRITE0_REG 0x24
> +#define TOY_WRITE1_REG 0x28
> +#define TOY_READ0_REG 0x2c
> +#define TOY_READ1_REG 0x30
> +#define TOY_MATCH0_REG 0x34
> +#define TOY_MATCH1_REG 0x38
> +#define TOY_MATCH2_REG 0x3c
> +#define RTC_CTRL_REG 0x40
> +#define RTC_TRIM_REG 0x60
> +#define RTC_WRITE0_REG 0x64
> +#define RTC_READ0_REG 0x68
> +#define RTC_MATCH0_REG 0x6c
> +#define RTC_MATCH1_REG 0x70
> +#define RTC_MATCH2_REG 0x74
> +
> +#define TOY_MON GENMASK(31, 26)
> +#define TOY_DAY GENMASK(25, 21)
> +#define TOY_HOUR GENMASK(20, 16)
> +#define TOY_MIN GENMASK(15, 10)
> +#define TOY_SEC GENMASK(9, 4)
> +#define TOY_MSEC GENMASK(3, 0)
> +
> +struct ls2x_rtc_priv {
> + struct regmap *regmap;
> +};
> +
> +static const struct regmap_config ls2x_rtc_regmap_config = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> +};
> +
> +struct ls2x_rtc_regs {
> + u32 reg0;
> + u32 reg1;
> +};
> +
> +static inline void ls2x_rtc_regs_to_time(struct ls2x_rtc_regs *regs,
> + struct rtc_time *tm)
> +{
> + tm->tm_year = regs->reg1;
> + tm->tm_sec = FIELD_GET(TOY_SEC, regs->reg0);
> + tm->tm_min = FIELD_GET(TOY_MIN, regs->reg0);
> + tm->tm_hour = FIELD_GET(TOY_HOUR, regs->reg0);
> + tm->tm_mday = FIELD_GET(TOY_DAY, regs->reg0);
> + tm->tm_mon = FIELD_GET(TOY_MON, regs->reg0) - 1;
> +}
> +
> +static inline void ls2x_rtc_time_to_regs(struct rtc_time *tm,
> + struct ls2x_rtc_regs *regs)
> +{
> + regs->reg0 = FIELD_PREP(TOY_SEC, tm->tm_sec);
> + regs->reg0 |= FIELD_PREP(TOY_MIN, tm->tm_min);
> + regs->reg0 |= FIELD_PREP(TOY_HOUR, tm->tm_hour);
> + regs->reg0 |= FIELD_PREP(TOY_DAY, tm->tm_mday);
> + regs->reg0 |= FIELD_PREP(TOY_MON, tm->tm_mon + 1);
> + regs->reg1 = tm->tm_year;
> +}
> +
> +static int ls2x_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> + struct ls2x_rtc_priv *priv = dev_get_drvdata(dev);
> + struct ls2x_rtc_regs regs;
> + int ret;
> +
> + ret = regmap_read(priv->regmap, TOY_READ1_REG, ®s.reg1);
> + if (unlikely(ret))
> + return ret;
> +
> + ret = regmap_read(priv->regmap, TOY_READ0_REG, ®s.reg0);
> + if (unlikely(ret))
> + return ret;
> +
> + ls2x_rtc_regs_to_time(®s, tm);
> +
> + return 0;
> +}
> +
> +static int ls2x_rtc_set_time(struct device *dev, struct rtc_time *tm)
> +{
> + struct ls2x_rtc_priv *priv = dev_get_drvdata(dev);
> + struct ls2x_rtc_regs regs;
> + int ret;
> +
> + ls2x_rtc_time_to_regs(tm, ®s);
> +
> + ret = regmap_write(priv->regmap, TOY_WRITE0_REG, regs.reg0);
> + if (unlikely(ret))
> + return ret;
> +
> + ret = regmap_write(priv->regmap, TOY_WRITE1_REG, regs.reg1);
> + if (unlikely(ret))
> + return ret;
I think this can be returned directly.
> +
> + return 0;
> +}
> +
> +static struct rtc_class_ops ls2x_rtc_ops = {
> + .read_time = ls2x_rtc_read_time,
> + .set_time = ls2x_rtc_set_time,
> +};
> +
> +static int ls2x_rtc_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct rtc_device *rtc;
> + struct ls2x_rtc_priv *priv;
> + void __iomem *regs;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (unlikely(!priv))
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, priv);
> +
> + regs = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(regs))
> + return PTR_ERR(regs);
> +
> + priv->regmap = devm_regmap_init_mmio(dev, regs,
> + &ls2x_rtc_regmap_config);
> + if (IS_ERR(priv->regmap))
> + return PTR_ERR(priv->regmap);
> +
> + rtc = devm_rtc_allocate_device(dev);
> + if (IS_ERR(rtc))
> + return PTR_ERR(rtc);
> +
> + rtc->ops = &ls2x_rtc_ops;
> +
> + /* Due to hardware erratum, all years multiple of 4 are considered
> + * leap year, so only years 2000 through 2099 are usable.
> + *
> + * Previous out-of-tree versions of this driver wrote tm_year directly
> + * into the year register, so epoch 2000 must be used to preserve
> + * semantics on shipped systems.
> + */
> + rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
> + rtc->range_max = RTC_TIMESTAMP_END_2099;
> +
> + return devm_rtc_register_device(rtc);
> +}
> +
> +static const struct of_device_id ls2x_rtc_of_match[] = {
> + { .compatible = "loongson,ls2x-rtc" },
> + { /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, ls2x_rtc_of_match);
> +
> +static struct platform_driver ls2x_rtc_driver = {
> + .probe = ls2x_rtc_probe,
> + .driver = {
> + .name = "ls2x-rtc",
> + .of_match_table = of_match_ptr(ls2x_rtc_of_match),
If my understanding is correct, this architecture is a DT-only platform.
Therefore, of_match_ptr() macro is unnecessary.
> + },
> +};
> +
> +module_platform_driver(ls2x_rtc_driver);
> +
> +MODULE_DESCRIPTION("LS2X RTC driver");
> +MODULE_AUTHOR("WANG Xuerui");
> +MODULE_AUTHOR("Huacai Chen");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:ls2x-rtc");
> --
> 2.30.1
>
--
Nobuhiro Iwamatsu
iwamatsu at {nigauri.org / debian.org / kernel.org}
GPG ID: 40AD1FA6
