[PATCH v4 0/6] rtc: ls2x: Add support for the Loongson-2K/LS7A RTC

[PATCH v4 0/6] rtc: ls2x: Add support for the Loongson-2K/LS7A RTC

[WANG Xuerui]

Here is the 4th revision of the series; the review mail got lost in my
inbox so this is a bit late, sorry for the delay!

The previous revision is tested on Loongson-2K by Jiaxun Yang, and this
revision contains no functional changes so should work on 2K too. I compiled
and tested this revision on a Loongson-3A4000 & LS7A system.

This patch series adds support for the RTC module found on various
Loongson systems with the Loongson-2K SoC or the LS7A bridge chip.
The driver is rewritten from an out-of-tree version to meet mainline
standards. I write kernel code as a hobby, though, so there might still
be overlooked issues. Any suggestions are welcome.

This series is based on next-20210628, but should apply cleanly on rtc-next
too.

v4:
- Rebased on top of next-20210628
- Added Jiaxun's Tested-by tag for Loongson-2K
- Addressed all review comments from v3
  - Rewritten field operations with FIELD_GET/FIELD_PREP
  - Removed all error logs
  - Removed unnecessary spinlocking (RTC core already protects against
    concurrent device file operations)

v3:
- Fixed compile error not discovered after rebase (blame sleep
  deprivation)
- Tested on Loongson-3A4000 (still need testing on Loongson-2K)

v2:
- Rebased on top of latest linux-next
- Updated Huacai's e-mail address to the kernel.org one
- Added collected tags
- Added adaptation for newly upstreamed Loongson-2K platforms

WANG Xuerui (6):
  rtc: ls2x: Add support for the Loongson-2K/LS7A RTC
  dt-bindings: rtc: Add bindings for LS2X RTC
  MIPS: Loongson64: DTS: Add RTC support to LS7A
  MIPS: Loongson: Enable LS2X RTC in loongson3_defconfig
  MIPS: Loongson64: DTS: Add RTC support to Loongson-2K
  MIPS: Loongson: Enable LS2X RTC in loongson2k_defconfig

 .../devicetree/bindings/rtc/trivial-rtc.yaml  |   2 +
 .../boot/dts/loongson/loongson64-2k1000.dtsi  |   5 +
 arch/mips/boot/dts/loongson/ls7a-pch.dtsi     |   5 +
 arch/mips/configs/loongson2k_defconfig        |   1 +
 arch/mips/configs/loongson3_defconfig         |   1 +
 drivers/rtc/Kconfig                           |  11 ++
 drivers/rtc/Makefile                          |   1 +
 drivers/rtc/rtc-ls2x.c                        | 184 ++++++++++++++++++
 8 files changed, 210 insertions(+)
 create mode 100644 drivers/rtc/rtc-ls2x.c


base-commit: 3579aa488520feeda433ceca23ef4704bf8cd280
-- 
2.30.1

[PATCH v4 1/6] rtc: ls2x: Add support for the Loongson-2K/LS7A RTC

[WANG Xuerui]

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@kernel.org>
Signed-off-by: WANG Xuerui <git@xen0n.name>
Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com> # loongson2k
Cc: devicetree@vger.kernel.org
Cc: linux-mips@vger.kernel.org
---
 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@loongson.cn>.
+ *
+ * Maintained out-of-tree by Huacai Chen <chenhuacai@kernel.org>.
+ *
+ * Rewritten for mainline by WANG Xuerui <git@xen0n.name>.
+ */
+
+#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, &regs.reg1);
+	if (unlikely(ret))
+		return ret;
+
+	ret = regmap_read(priv->regmap, TOY_READ0_REG, &regs.reg0);
+	if (unlikely(ret))
+		return ret;
+
+	ls2x_rtc_regs_to_time(&regs, 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, &regs);
+
+	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;
+
+	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),
+	},
+};
+
+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

Re: [PATCH v4 1/6] rtc: ls2x: Add support for the Loongson-2K/LS7A RTC

[Nobuhiro Iwamatsu]

Hi,

2021年6月29日(火) 1:52 WANG Xuerui <git@xen0n.name>:
>
> 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@kernel.org>
> Signed-off-by: WANG Xuerui <git@xen0n.name>
> Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com> # loongson2k
> Cc: devicetree@vger.kernel.org
> Cc: linux-mips@vger.kernel.org
> ---
>  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@loongson.cn>.
> + *
> + * Maintained out-of-tree by Huacai Chen <chenhuacai@kernel.org>.
> + *
> + * Rewritten for mainline by WANG Xuerui <git@xen0n.name>.
> + */
> +
> +#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, &regs.reg1);
> +       if (unlikely(ret))
> +               return ret;
> +
> +       ret = regmap_read(priv->regmap, TOY_READ0_REG, &regs.reg0);
> +       if (unlikely(ret))
> +               return ret;
> +
> +       ls2x_rtc_regs_to_time(&regs, 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, &regs);
> +
> +       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

Re: [PATCH v4 1/6] rtc: ls2x: Add support for the Loongson-2K/LS7A RTC

[WANG Xuerui]

Hi Nobuhiro-san,

(sorry for the duplicated reply on your side; I didn't include all recipients correctly in the first mail, hence the resend.)

On 2021/7/2 13:52, Nobuhiro Iwamatsu wrote:
> Hi,
>
> 2021年6月29日(火) 1:52 WANG Xuerui <git@xen0n.name>:
>> 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@kernel.org>
>> Signed-off-by: WANG Xuerui <git@xen0n.name>
>> Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com> # loongson2k
>> Cc: devicetree@vger.kernel.org
>> Cc: linux-mips@vger.kernel.org
>> ---
>>  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@loongson.cn>.
>> + *
>> + * Maintained out-of-tree by Huacai Chen <chenhuacai@kernel.org>.
>> + *
>> + * Rewritten for mainline by WANG Xuerui <git@xen0n.name>.
>> + */
>> +
>> +#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, &regs.reg1);
>> +       if (unlikely(ret))
>> +               return ret;
>> +
>> +       ret = regmap_read(priv->regmap, TOY_READ0_REG, &regs.reg0);
>> +       if (unlikely(ret))
>> +               return ret;
>> +
>> +       ls2x_rtc_regs_to_time(&regs, 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, &regs);
>> +
>> +       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.

Fair point; this is done purely for the two writes to be visually
symmetrical. I'll send v5.

>
>> +
>> +       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.

Actually the forthcoming LoongArch platforms have both ACPI and DT, and
this RTC block would of course be included in these (inside the LS7A
bridge chip). If we remove the of_match_ptr usage now, we would still
have to add back later. However I agree about not doing speculations;
I'll remove that usage in v5.

>> +       },
>> +};
>> +
>> +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
>>
>

[PATCH v4 2/6] dt-bindings: rtc: Add bindings for LS2X RTC

[WANG Xuerui]

Document the binding for the LS2X RTC block found on the Loongson-2K SoC
and the LS7A bridge, originally appearing on the Loongson-2H.

Signed-off-by: WANG Xuerui <git@xen0n.name>
Acked-by: Rob Herring <robh@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
---
 Documentation/devicetree/bindings/rtc/trivial-rtc.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/rtc/trivial-rtc.yaml b/Documentation/devicetree/bindings/rtc/trivial-rtc.yaml
index 7548d8714871..568aa89989fe 100644
--- a/Documentation/devicetree/bindings/rtc/trivial-rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/trivial-rtc.yaml
@@ -42,6 +42,8 @@ properties:
       - isil,isl1218
       # Intersil ISL12022 Real-time Clock
       - isil,isl12022
+      # Loongson LS2X RTC
+      - loongson,ls2x-rtc
       # Real Time Clock Module with I2C-Bus
       - microcrystal,rv3028
       # Real Time Clock Module with I2C-Bus
-- 
2.30.1

[PATCH v4 3/6] MIPS: Loongson64: DTS: Add RTC support to LS7A

[WANG Xuerui]

The LS7A RTC module is now supported, enable it.

Signed-off-by: WANG Xuerui <git@xen0n.name>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: linux-mips@vger.kernel.org
---
 arch/mips/boot/dts/loongson/ls7a-pch.dtsi | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/mips/boot/dts/loongson/ls7a-pch.dtsi b/arch/mips/boot/dts/loongson/ls7a-pch.dtsi
index 2f45fce2cdc4..82035de4774f 100644
--- a/arch/mips/boot/dts/loongson/ls7a-pch.dtsi
+++ b/arch/mips/boot/dts/loongson/ls7a-pch.dtsi
@@ -19,6 +19,11 @@ pic: interrupt-controller@10000000 {
 			#interrupt-cells = <2>;
 		};
 
+		rtc0: rtc@100d0100 {
+			compatible = "loongson,ls2x-rtc";
+			reg = <0 0x100d0100 0 0x78>;
+		};
+
 		ls7a_uart0: serial@10080000 {
 			compatible = "ns16550a";
 			reg = <0 0x10080000 0 0x100>;
-- 
2.30.1

Re: [PATCH v4 3/6] MIPS: Loongson64: DTS: Add RTC support to LS7A

[Jiaxun Yang]

在 2021/6/29 上午12:45, WANG Xuerui 写道:
> The LS7A RTC module is now supported, enable it.
>
> Signed-off-by: WANG Xuerui <git@xen0n.name>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: devicetree@vger.kernel.org
> Cc: linux-mips@vger.kernel.org
Acked-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> ---
>   arch/mips/boot/dts/loongson/ls7a-pch.dtsi | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/arch/mips/boot/dts/loongson/ls7a-pch.dtsi b/arch/mips/boot/dts/loongson/ls7a-pch.dtsi
> index 2f45fce2cdc4..82035de4774f 100644
> --- a/arch/mips/boot/dts/loongson/ls7a-pch.dtsi
> +++ b/arch/mips/boot/dts/loongson/ls7a-pch.dtsi
> @@ -19,6 +19,11 @@ pic: interrupt-controller@10000000 {
>   			#interrupt-cells = <2>;
>   		};
>   
> +		rtc0: rtc@100d0100 {
> +			compatible = "loongson,ls2x-rtc";
> +			reg = <0 0x100d0100 0 0x78>;
> +		};
> +
>   		ls7a_uart0: serial@10080000 {
>   			compatible = "ns16550a";
>   			reg = <0 0x10080000 0 0x100>;

[PATCH v4 5/6] MIPS: Loongson64: DTS: Add RTC support to Loongson-2K

[WANG Xuerui]

The Loongson-2K RTC module is now supported, enable it.

The MMIO address is unclear from the Loongson 2K1000 user manual, I took
it from Loongson's out-of-tree fork of Linux 4.19.

Signed-off-by: WANG Xuerui <git@xen0n.name>
Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com> # loongson2k
Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: linux-mips@vger.kernel.org
---
 arch/mips/boot/dts/loongson/loongson64-2k1000.dtsi | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/mips/boot/dts/loongson/loongson64-2k1000.dtsi b/arch/mips/boot/dts/loongson/loongson64-2k1000.dtsi
index bfc3d3243ee7..4a04e1dc5fda 100644
--- a/arch/mips/boot/dts/loongson/loongson64-2k1000.dtsi
+++ b/arch/mips/boot/dts/loongson/loongson64-2k1000.dtsi
@@ -52,6 +52,11 @@ package0: bus@10000000 {
 			0 0x40000000 0 0x40000000 0 0x40000000
 			0xfe 0x00000000 0xfe 0x00000000 0 0x40000000>;
 
+		rtc0: rtc@1fe07800 {
+			compatible = "loongson,ls2x-rtc";
+			reg = <0 0x1fe07800 0 0x78>;
+		};
+
 		liointc0: interrupt-controller@1fe11400 {
 			compatible = "loongson,liointc-2.0";
 			reg = <0 0x1fe11400 0 0x40>,
-- 
2.30.1