[PATCH V2 0/4] Add i.MX system controller RTC driver

[PATCH V2 0/4] Add i.MX system controller RTC driver

[Anson Huang]

NXP i.MX8QXP is an ARMv8 SoC with a Cortex-M4 core inside as
system controller, the system controller is in charge of system
power, clock and secure RTC etc. management, Linux kernel
has to communicate with system controller via MU (message unit)
IPC to do RTC operation.

Since the RTC set time MUST to be done in secure EL3 mode (required
by system controller firmware) and ALARM functions needs to be done
with general MU IRQ handle, these are NOT ready NOW, so this patch
ONLY supports RTC read time for now.

Note that this patch set is based on [V4,5/5] defconfig: arm64: add imx8qxp support,
https://patchwork.kernel.org/patch/10677315/

Anson Huang (4):
  dt-bindings: rtc: add binding doc for i.MX system controller RTC
    driver
  rtc: add i.MX system controller RTC support
  defconfig: arm64: add i.MX system controller RTC support
  ARM64: dts: imx: add i.MX8QXP system controller RTC support

 .../devicetree/bindings/rtc/rtc-imx-sc.txt         |  10 ++
 arch/arm64/boot/dts/freescale/imx8qxp.dtsi         |   4 +
 arch/arm64/configs/defconfig                       |   1 +
 drivers/rtc/Kconfig                                |   6 ++
 drivers/rtc/Makefile                               |   1 +
 drivers/rtc/rtc-imx-sc.c                           | 107 +++++++++++++++++++++
 6 files changed, 129 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/rtc-imx-sc.txt
 create mode 100644 drivers/rtc/rtc-imx-sc.c

-- 
2.7.4

[PATCH V2 1/4] dt-bindings: rtc: add binding doc for i.MX system controller RTC driver

[Anson Huang]

NXP i.MX8QXP is an ARMv8 SoC with a Cortex-M4 core inside as
system controller, the system controller is in charge of system
power, clock and secure RTC etc. management, Linux kernel
has to communicate with system controller via MU (message unit)
IPC to do RTC operation, this patch adds binding doc for i.MX
system controller RTC driver.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
	no change since V1.
 Documentation/devicetree/bindings/rtc/rtc-imx-sc.txt | 10 ++++++++++
 1 file changed, 10 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/rtc-imx-sc.txt

diff --git a/Documentation/devicetree/bindings/rtc/rtc-imx-sc.txt b/Documentation/devicetree/bindings/rtc/rtc-imx-sc.txt
new file mode 100644
index 0000000..d6e2353
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/rtc-imx-sc.txt
@@ -0,0 +1,10 @@
+* NXP i.MX System Controller Real Time Clock
+
+Required properties:
+- compatible: should be "nxp,imx8qxp-sc-rtc";
+
+Example:
+
+rtc: rtc {
+	compatible = "nxp,imx8qxp-sc-rtc";
+};
-- 
2.7.4

[PATCH V2 2/4] rtc: add i.MX system controller RTC support

[Anson Huang]

i.MX8QXP is an ARMv8 SoC which has a Cortex-M4 system controller
inside, the system controller is in charge of controlling power,
clock and secure rtc etc..

This patch adds i.MX system controller RTC driver support,
Linux kernel has to communicate with system controller via MU
(message unit) IPC to set/get RTC time and other alarm functions,
since the RTC set time needs to be done in secure EL3 mode (required
by system controller firmware) and alarm functions needs to be done
with general MU IRQ handle, these depend on other components which
are NOT ready, so this patch ONLY enables the RTC time read.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
changes since V1:
	- sort module in Makefile alphabetically;
	- remove boiler plate license text;
	- use devm_rtc_allocate_device and rtc_register_device to register the RTC.
 drivers/rtc/Kconfig      |   6 +++
 drivers/rtc/Makefile     |   1 +
 drivers/rtc/rtc-imx-sc.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 114 insertions(+)
 create mode 100644 drivers/rtc/rtc-imx-sc.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index a819ef0..3b9642e 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1677,6 +1677,12 @@ config RTC_DRV_SNVS
 	   This driver can also be built as a module, if so, the module
 	   will be called "rtc-snvs".
 
+config RTC_DRV_IMX_SC
+	tristate "NXP i.MX System Controller RTC support"
+	help
+	   If you say yes here you get support for the NXP i.MX System
+	   Controller RTC module.
+
 config RTC_DRV_SIRFSOC
 	tristate "SiRFSOC RTC"
 	depends on ARCH_SIRF
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 290c173..f97c05e 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -75,6 +75,7 @@ obj-$(CONFIG_RTC_DRV_GOLDFISH)	+= rtc-goldfish.o
 obj-$(CONFIG_RTC_DRV_HID_SENSOR_TIME) += rtc-hid-sensor-time.o
 obj-$(CONFIG_RTC_DRV_HYM8563)	+= rtc-hym8563.o
 obj-$(CONFIG_RTC_DRV_IMXDI)	+= rtc-imxdi.o
+obj-$(CONFIG_RTC_DRV_IMX_SC)	+= rtc-imx-sc.o
 obj-$(CONFIG_RTC_DRV_ISL12022)	+= rtc-isl12022.o
 obj-$(CONFIG_RTC_DRV_ISL12026)	+= rtc-isl12026.o
 obj-$(CONFIG_RTC_DRV_ISL1208)	+= rtc-isl1208.o
diff --git a/drivers/rtc/rtc-imx-sc.c b/drivers/rtc/rtc-imx-sc.c
new file mode 100644
index 0000000..7212e38
--- /dev/null
+++ b/drivers/rtc/rtc-imx-sc.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2018 NXP.
+ */
+
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/firmware/imx/sci.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+#define IMX_SC_TIMER_FUNC_GET_RTC_SEC1970	9
+#define IMX_SC_TIMER_FUNC_SET_RTC_TIME		6
+
+struct imx_sc_ipc *rtc_ipc_handle;
+struct rtc_device *rtc;
+
+struct imx_sc_msg_req_timer_get_rtc_time {
+	struct imx_sc_rpc_msg hdr;
+} __packed;
+
+struct imx_sc_msg_resp_timer_get_rtc_time {
+	struct imx_sc_rpc_msg hdr;
+	u32 time;
+} __packed;
+
+static int imx_sc_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct imx_sc_msg_resp_timer_get_rtc_time *resp;
+	struct imx_sc_msg_req_timer_get_rtc_time msg;
+	struct imx_sc_rpc_msg *hdr = &msg.hdr;
+	int ret;
+
+	hdr->ver = IMX_SC_RPC_VERSION;
+	hdr->svc = IMX_SC_RPC_SVC_TIMER;
+	hdr->func = IMX_SC_TIMER_FUNC_GET_RTC_SEC1970;
+	hdr->size = 1;
+
+	ret = imx_scu_call_rpc(rtc_ipc_handle, &msg, true);
+	if (ret) {
+		pr_err("read rtc time failed, ret %d\n", ret);
+		return ret;
+	}
+
+	resp = (struct imx_sc_msg_resp_timer_get_rtc_time *)&msg;
+	rtc_time_to_tm(resp->time, tm);
+
+	return 0;
+}
+
+static const struct rtc_class_ops imx_sc_rtc_ops = {
+	.read_time = imx_sc_rtc_read_time,
+};
+
+static int imx_sc_rtc_probe(struct platform_device *pdev)
+{
+	int ret;
+
+	ret = imx_scu_get_handle(&rtc_ipc_handle);
+	if (ret) {
+		if (ret == -EPROBE_DEFER)
+			return ret;
+
+		dev_err(&pdev->dev, "failed to get ipc handle: %d!\n", ret);
+		return ret;
+	}
+
+	rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtc)) {
+		ret = PTR_ERR(rtc);
+		return ret;
+	}
+
+	rtc->ops = &imx_sc_rtc_ops;
+	rtc->range_min = 0;
+	rtc->range_max = U32_MAX;
+
+	ret = rtc_register_device(rtc);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register rtc: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id imx_sc_dt_ids[] = {
+	{ .compatible = "nxp,imx8qxp-sc-rtc", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, imx_sc_dt_ids);
+
+static struct platform_driver imx_sc_rtc_driver = {
+	.driver = {
+		.name	= "imx-sc-rtc",
+		.of_match_table = imx_sc_dt_ids,
+	},
+	.probe		= imx_sc_rtc_probe,
+};
+module_platform_driver(imx_sc_rtc_driver);
+
+MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
+MODULE_DESCRIPTION("NXP i.MX System Controller RTC Driver");
+MODULE_LICENSE("GPL");
-- 
2.7.4

[PATCH V2 3/4] defconfig: arm64: add i.MX system controller RTC support

[Anson Huang]

This patch enables CONFIG_RTC_DRV_IMX_SC as module by default.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
 arch/arm64/configs/defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index 6d224f7..e3df5dd 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -573,6 +573,7 @@ CONFIG_RTC_DRV_PL031=y
 CONFIG_RTC_DRV_SUN6I=y
 CONFIG_RTC_DRV_ARMADA38X=y
 CONFIG_RTC_DRV_TEGRA=y
+CONFIG_RTC_DRV_IMX_SC=m
 CONFIG_RTC_DRV_XGENE=y
 CONFIG_DMADEVICES=y
 CONFIG_DMA_BCM2835=m
-- 
2.7.4

[PATCH V2 4/4] ARM64: dts: imx: add i.MX8QXP system controller RTC support

[Anson Huang]

Add i.MX8QXP system controller RTC support.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
---
 arch/arm64/boot/dts/freescale/imx8qxp.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8qxp.dtsi b/arch/arm64/boot/dts/freescale/imx8qxp.dtsi
index 9155d45..ef57db6 100644
--- a/arch/arm64/boot/dts/freescale/imx8qxp.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8qxp.dtsi
@@ -433,4 +433,8 @@
 		#size-cells = <1>;
 		ranges = <0x5f000000 0x0 0x5f000000 0x1000000>;
 	};
+
+	rtc: rtc {
+		compatible = "nxp,imx8qxp-sc-rtc";
+	};
 };
-- 
2.7.4

Re: [PATCH V2 2/4] rtc: add i.MX system controller RTC support

[Lothar Waßmann]

Hi,

On Wed, 28 Nov 2018 05:21:11 +0000 Anson Huang wrote:
> i.MX8QXP is an ARMv8 SoC which has a Cortex-M4 system controller
> inside, the system controller is in charge of controlling power,
> clock and secure rtc etc..
> 
> This patch adds i.MX system controller RTC driver support,
> Linux kernel has to communicate with system controller via MU
> (message unit) IPC to set/get RTC time and other alarm functions,
> since the RTC set time needs to be done in secure EL3 mode (required
> by system controller firmware) and alarm functions needs to be done
> with general MU IRQ handle, these depend on other components which
> are NOT ready, so this patch ONLY enables the RTC time read.
> 
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> ---
> changes since V1:
> 	- sort module in Makefile alphabetically;
> 	- remove boiler plate license text;
> 	- use devm_rtc_allocate_device and rtc_register_device to register the RTC.
>  drivers/rtc/Kconfig      |   6 +++
>  drivers/rtc/Makefile     |   1 +
>  drivers/rtc/rtc-imx-sc.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 114 insertions(+)
>  create mode 100644 drivers/rtc/rtc-imx-sc.c
> 
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index a819ef0..3b9642e 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -1677,6 +1677,12 @@ config RTC_DRV_SNVS
>  	   This driver can also be built as a module, if so, the module
>  	   will be called "rtc-snvs".
>  
> +config RTC_DRV_IMX_SC
> +	tristate "NXP i.MX System Controller RTC support"
> +	help
> +	   If you say yes here you get support for the NXP i.MX System
> +	   Controller RTC module.
> +
>  config RTC_DRV_SIRFSOC
>  	tristate "SiRFSOC RTC"
>  	depends on ARCH_SIRF
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index 290c173..f97c05e 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -75,6 +75,7 @@ obj-$(CONFIG_RTC_DRV_GOLDFISH)	+= rtc-goldfish.o
>  obj-$(CONFIG_RTC_DRV_HID_SENSOR_TIME) += rtc-hid-sensor-time.o
>  obj-$(CONFIG_RTC_DRV_HYM8563)	+= rtc-hym8563.o
>  obj-$(CONFIG_RTC_DRV_IMXDI)	+= rtc-imxdi.o
> +obj-$(CONFIG_RTC_DRV_IMX_SC)	+= rtc-imx-sc.o
>  obj-$(CONFIG_RTC_DRV_ISL12022)	+= rtc-isl12022.o
>  obj-$(CONFIG_RTC_DRV_ISL12026)	+= rtc-isl12026.o
>  obj-$(CONFIG_RTC_DRV_ISL1208)	+= rtc-isl1208.o
> diff --git a/drivers/rtc/rtc-imx-sc.c b/drivers/rtc/rtc-imx-sc.c
> new file mode 100644
> index 0000000..7212e38
> --- /dev/null
> +++ b/drivers/rtc/rtc-imx-sc.c
> @@ -0,0 +1,107 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2018 NXP.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/firmware/imx/sci.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/rtc.h>
> +
> +#define IMX_SC_TIMER_FUNC_GET_RTC_SEC1970	9
> +#define IMX_SC_TIMER_FUNC_SET_RTC_TIME		6
> +
> +struct imx_sc_ipc *rtc_ipc_handle;
> +struct rtc_device *rtc;
> +
Shouldn't these be static?
A generic name like 'rtc' as a global variable name is definitely a very
bad idea.

> +struct imx_sc_msg_req_timer_get_rtc_time {
> +	struct imx_sc_rpc_msg hdr;
> +} __packed;
> +
> +struct imx_sc_msg_resp_timer_get_rtc_time {
> +	struct imx_sc_rpc_msg hdr;
> +	u32 time;
> +} __packed;
> +
> +static int imx_sc_rtc_read_time(struct device *dev, struct rtc_time *tm)
> +{
> +	struct imx_sc_msg_resp_timer_get_rtc_time *resp;
> +	struct imx_sc_msg_req_timer_get_rtc_time msg;
> +	struct imx_sc_rpc_msg *hdr = &msg.hdr;
> +	int ret;
> +
> +	hdr->ver = IMX_SC_RPC_VERSION;
> +	hdr->svc = IMX_SC_RPC_SVC_TIMER;
> +	hdr->func = IMX_SC_TIMER_FUNC_GET_RTC_SEC1970;
> +	hdr->size = 1;
> +
> +	ret = imx_scu_call_rpc(rtc_ipc_handle, &msg, true);
> +	if (ret) {
> +		pr_err("read rtc time failed, ret %d\n", ret);
> +		return ret;
> +	}
> +
> +	resp = (struct imx_sc_msg_resp_timer_get_rtc_time *)&msg;
> +	rtc_time_to_tm(resp->time, tm);
> +
> +	return 0;
> +}
> +
> +static const struct rtc_class_ops imx_sc_rtc_ops = {
> +	.read_time = imx_sc_rtc_read_time,
> +};
> +
> +static int imx_sc_rtc_probe(struct platform_device *pdev)
> +{
> +	int ret;
> +
> +	ret = imx_scu_get_handle(&rtc_ipc_handle);
> +	if (ret) {
> +		if (ret == -EPROBE_DEFER)
> +			return ret;
> +
> +		dev_err(&pdev->dev, "failed to get ipc handle: %d!\n", ret);
> +		return ret;
> +	}
> +
> +	rtc = devm_rtc_allocate_device(&pdev->dev);
> +	if (IS_ERR(rtc)) {
> +		ret = PTR_ERR(rtc);
> +		return ret;
> +	}
> +
> +	rtc->ops = &imx_sc_rtc_ops;
> +	rtc->range_min = 0;
> +	rtc->range_max = U32_MAX;
> +
> +	ret = rtc_register_device(rtc);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to register rtc: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id imx_sc_dt_ids[] = {
> +	{ .compatible = "nxp,imx8qxp-sc-rtc", },
> +	{},
s/{},/{}/
The trailing comma is usually added to make patches that add more
entries to the array simpler and help avoid patch conflicts.
Since the empty entry MUST be the LAST entry in this array the comma
should NOT be added here. Without the comma, adding new entries after
the EOL marker will generate a compile error.


Lothar Waßmann

RE: [PATCH V2 2/4] rtc: add i.MX system controller RTC support

[Anson Huang]

Hi, Lothar

Best Regards!
Anson Huang

> -----Original Message-----
> From: Lothar Waßmann [mailto:LW@KARO-electronics.de]
> Sent: 2018年11月28日 17:01
> To: Anson Huang <anson.huang@nxp.com>
> Cc: a.zummo@towertech.it; alexandre.belloni@bootlin.com;
> robh+dt@kernel.org; mark.rutland@arm.com; catalin.marinas@arm.com;
> will.deacon@arm.com; Aisheng DONG <aisheng.dong@nxp.com>; Andy Gross
> <andy.gross@linaro.org>; arnd@arndb.de; horms+renesas@verge.net.au;
> heiko@sntech.de; bjorn.andersson@linaro.org; enric.balletbo@collabora.com;
> amit.kucheria@linaro.org; ezequiel@collabora.com; olof@lixom.net;
> shawnguo@kernel.org; linux-rtc@vger.kernel.org; devicetree@vger.kernel.org;
> linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> dl-linux-imx <linux-imx@nxp.com>
> Subject: Re: [PATCH V2 2/4] rtc: add i.MX system controller RTC support
> 
> Hi,
> 
> On Wed, 28 Nov 2018 05:21:11 +0000 Anson Huang wrote:
> > i.MX8QXP is an ARMv8 SoC which has a Cortex-M4 system controller
> > inside, the system controller is in charge of controlling power, clock
> > and secure rtc etc..
> >
> > This patch adds i.MX system controller RTC driver support, Linux
> > kernel has to communicate with system controller via MU (message unit)
> > IPC to set/get RTC time and other alarm functions, since the RTC set
> > time needs to be done in secure EL3 mode (required by system
> > controller firmware) and alarm functions needs to be done with general
> > MU IRQ handle, these depend on other components which are NOT ready,
> > so this patch ONLY enables the RTC time read.
> >
> > Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> > ---
> > changes since V1:
> > 	- sort module in Makefile alphabetically;
> > 	- remove boiler plate license text;
> > 	- use devm_rtc_allocate_device and rtc_register_device to register the
> RTC.
> >  drivers/rtc/Kconfig      |   6 +++
> >  drivers/rtc/Makefile     |   1 +
> >  drivers/rtc/rtc-imx-sc.c | 107
> > +++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 114 insertions(+)
> >  create mode 100644 drivers/rtc/rtc-imx-sc.c
> >
> > diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index
> > a819ef0..3b9642e 100644
> > --- a/drivers/rtc/Kconfig
> > +++ b/drivers/rtc/Kconfig
> > @@ -1677,6 +1677,12 @@ config RTC_DRV_SNVS
> >  	   This driver can also be built as a module, if so, the module
> >  	   will be called "rtc-snvs".
> >
> > +config RTC_DRV_IMX_SC
> > +	tristate "NXP i.MX System Controller RTC support"
> > +	help
> > +	   If you say yes here you get support for the NXP i.MX System
> > +	   Controller RTC module.
> > +
> >  config RTC_DRV_SIRFSOC
> >  	tristate "SiRFSOC RTC"
> >  	depends on ARCH_SIRF
> > diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index
> > 290c173..f97c05e 100644
> > --- a/drivers/rtc/Makefile
> > +++ b/drivers/rtc/Makefile
> > @@ -75,6 +75,7 @@ obj-$(CONFIG_RTC_DRV_GOLDFISH)	+=
> rtc-goldfish.o
> >  obj-$(CONFIG_RTC_DRV_HID_SENSOR_TIME) += rtc-hid-sensor-time.o
> >  obj-$(CONFIG_RTC_DRV_HYM8563)	+= rtc-hym8563.o
> >  obj-$(CONFIG_RTC_DRV_IMXDI)	+= rtc-imxdi.o
> > +obj-$(CONFIG_RTC_DRV_IMX_SC)	+= rtc-imx-sc.o
> >  obj-$(CONFIG_RTC_DRV_ISL12022)	+= rtc-isl12022.o
> >  obj-$(CONFIG_RTC_DRV_ISL12026)	+= rtc-isl12026.o
> >  obj-$(CONFIG_RTC_DRV_ISL1208)	+= rtc-isl1208.o
> > diff --git a/drivers/rtc/rtc-imx-sc.c b/drivers/rtc/rtc-imx-sc.c new
> > file mode 100644 index 0000000..7212e38
> > --- /dev/null
> > +++ b/drivers/rtc/rtc-imx-sc.c
> > @@ -0,0 +1,107 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright 2018 NXP.
> > + */
> > +
> > +#include <linux/init.h>
> > +#include <linux/io.h>
> > +#include <linux/kernel.h>
> > +#include <linux/firmware/imx/sci.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/rtc.h>
> > +
> > +#define IMX_SC_TIMER_FUNC_GET_RTC_SEC1970	9
> > +#define IMX_SC_TIMER_FUNC_SET_RTC_TIME		6
> > +
> > +struct imx_sc_ipc *rtc_ipc_handle;
> > +struct rtc_device *rtc;
> > +
> Shouldn't these be static?
> A generic name like 'rtc' as a global variable name is definitely a very bad idea.

Agreed, will improve them in V3 patch set.

> 
> > +struct imx_sc_msg_req_timer_get_rtc_time {
> > +	struct imx_sc_rpc_msg hdr;
> > +} __packed;
> > +
> > +struct imx_sc_msg_resp_timer_get_rtc_time {
> > +	struct imx_sc_rpc_msg hdr;
> > +	u32 time;
> > +} __packed;
> > +
> > +static int imx_sc_rtc_read_time(struct device *dev, struct rtc_time
> > +*tm) {
> > +	struct imx_sc_msg_resp_timer_get_rtc_time *resp;
> > +	struct imx_sc_msg_req_timer_get_rtc_time msg;
> > +	struct imx_sc_rpc_msg *hdr = &msg.hdr;
> > +	int ret;
> > +
> > +	hdr->ver = IMX_SC_RPC_VERSION;
> > +	hdr->svc = IMX_SC_RPC_SVC_TIMER;
> > +	hdr->func = IMX_SC_TIMER_FUNC_GET_RTC_SEC1970;
> > +	hdr->size = 1;
> > +
> > +	ret = imx_scu_call_rpc(rtc_ipc_handle, &msg, true);
> > +	if (ret) {
> > +		pr_err("read rtc time failed, ret %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	resp = (struct imx_sc_msg_resp_timer_get_rtc_time *)&msg;
> > +	rtc_time_to_tm(resp->time, tm);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct rtc_class_ops imx_sc_rtc_ops = {
> > +	.read_time = imx_sc_rtc_read_time,
> > +};
> > +
> > +static int imx_sc_rtc_probe(struct platform_device *pdev) {
> > +	int ret;
> > +
> > +	ret = imx_scu_get_handle(&rtc_ipc_handle);
> > +	if (ret) {
> > +		if (ret == -EPROBE_DEFER)
> > +			return ret;
> > +
> > +		dev_err(&pdev->dev, "failed to get ipc handle: %d!\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	rtc = devm_rtc_allocate_device(&pdev->dev);
> > +	if (IS_ERR(rtc)) {
> > +		ret = PTR_ERR(rtc);
> > +		return ret;
> > +	}
> > +
> > +	rtc->ops = &imx_sc_rtc_ops;
> > +	rtc->range_min = 0;
> > +	rtc->range_max = U32_MAX;
> > +
> > +	ret = rtc_register_device(rtc);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "failed to register rtc: %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id imx_sc_dt_ids[] = {
> > +	{ .compatible = "nxp,imx8qxp-sc-rtc", },
> > +	{},
> s/{},/{}/
> The trailing comma is usually added to make patches that add more entries to
> the array simpler and help avoid patch conflicts.
> Since the empty entry MUST be the LAST entry in this array the comma should
> NOT be added here. Without the comma, adding new entries after the EOL
> marker will generate a compile error.

Thanks for review, will improve it in V3 patch set.

Anson.

> 
> 
> Lothar Waßmann