[PATCH V4 0/4] Add i.MX system controller RTC driver

[PATCH V4 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):
  rtc: add i.MX system controller RTC support
  dt-bindings: rtc: add binding doc for i.MX system controller RTC
    driver
  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                           | 104 +++++++++++++++++++++
 6 files changed, 126 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 V4 1/4] dt-bindings: fsl: scu: add rtc binding

[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>
---
ChangeLog:
V3->V4:
  *move rtc binding doc to scu binding doc since it is belonging to SCU.
  *change compatible name to start with "fsl" instead of "nxp" to align with other nodes in dtsi.
 Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
index c20f38e..3f3d697 100644
--- a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
+++ b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
@@ -106,6 +106,12 @@ Required properties for Pinctrl sub nodes:
 [2] Documentation/devicetree/bindings/power/power_domain.txt
 [3] Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt
 
+RTC bindings based on SCU Message Protocol
+------------------------------------------------------------
+
+Required properties:
+- compatible: should be "fsl,imx8qxp-sc-rtc";
+
 Example (imx8qxp):
 -------------
 lsio_mu1: mailbox@5d1c0000 {
@@ -148,6 +154,10 @@ firmware {
 			compatible = "fsl,imx8qxp-scu-pd";
 			#power-domain-cells = <1>;
 		};
+
+		rtc: rtc {
+			compatible = "fsl,imx8qxp-sc-rtc";
+		};
 	};
 };
 
-- 
2.7.4

Re: [PATCH V4 1/4] dt-bindings: fsl: scu: add rtc binding

[Rob Herring]

On Thu, 29 Nov 2018 01:50:04 +0000, Anson Huang wrote:
> 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>
> ---
> ChangeLog:
> V3->V4:
>   *move rtc binding doc to scu binding doc since it is belonging to SCU.
>   *change compatible name to start with "fsl" instead of "nxp" to align with other nodes in dtsi.
>  Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 

Reviewed-by: Rob Herring <robh@kernel.org>

[PATCH V4 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>
---
ChangeLog:
V3->V4:
  *remove unnecessary headfile included;
  *fix potential memory currpution for the message responce;
  *update the compatible string name to start with "fsl" instead of "nxp".
 drivers/rtc/Kconfig      |  6 +++
 drivers/rtc/Makefile     |  1 +
 drivers/rtc/rtc-imx-sc.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 105 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..5976a2e
--- /dev/null
+++ b/drivers/rtc/rtc-imx-sc.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2018 NXP.
+ */
+
+#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
+
+static struct imx_sc_ipc *rtc_ipc_handle;
+static struct rtc_device *imx_sc_rtc;
+
+struct imx_sc_msg_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_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;
+	}
+
+	rtc_time_to_tm(msg.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;
+	}
+
+	imx_sc_rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(imx_sc_rtc)) {
+		ret = PTR_ERR(imx_sc_rtc);
+		return ret;
+	}
+
+	imx_sc_rtc->ops = &imx_sc_rtc_ops;
+	imx_sc_rtc->range_min = 0;
+	imx_sc_rtc->range_max = U32_MAX;
+
+	ret = rtc_register_device(imx_sc_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 = "fsl,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

Re: [PATCH V4 2/4] rtc: add i.MX system controller RTC support

[Alexandre Belloni]

Hello,

On 29/11/2018 01:50:11+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>
> ---
> ChangeLog:
> V3->V4:
>   *remove unnecessary headfile included;
>   *fix potential memory currpution for the message responce;
>   *update the compatible string name to start with "fsl" instead of "nxp".
>  drivers/rtc/Kconfig      |  6 +++
>  drivers/rtc/Makefile     |  1 +
>  drivers/rtc/rtc-imx-sc.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 105 insertions(+)
>  create mode 100644 drivers/rtc/rtc-imx-sc.c
> 

I applied it on my test branch and this makes sparc64-allyesconfig fail
with:

   drivers/rtc/rtc-imx-sc.o: In function `imx_sc_rtc_read_time':
   rtc-imx-sc.c:(.text+0x34): undefined reference to `imx_scu_call_rpc'
   drivers/rtc/rtc-imx-sc.o: In function `imx_sc_rtc_probe':
   rtc-imx-sc.c:(.text+0x90): undefined reference to `imx_scu_get_handle'



-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

RE: [PATCH V4 2/4] rtc: add i.MX system controller RTC support

[Anson Huang]

Hi, Alexandre

Best Regards!
Anson Huang

> -----Original Message-----
> From: Alexandre Belloni [mailto:alexandre.belloni@bootlin.com]
> Sent: 2018年12月19日 16:54
> To: Anson Huang <anson.huang@nxp.com>
> Cc: a.zummo@towertech.it; 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;
> LW@KARO-electronics.de; 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 V4 2/4] rtc: add i.MX system controller RTC support
> 
> Hello,
> 
> On 29/11/2018 01:50:11+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>
> > ---
> > ChangeLog:
> > V3->V4:
> >   *remove unnecessary headfile included;
> >   *fix potential memory currpution for the message responce;
> >   *update the compatible string name to start with "fsl" instead of "nxp".
> >  drivers/rtc/Kconfig      |  6 +++
> >  drivers/rtc/Makefile     |  1 +
> >  drivers/rtc/rtc-imx-sc.c | 98
> > ++++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 105 insertions(+)
> >  create mode 100644 drivers/rtc/rtc-imx-sc.c
> >
> 
> I applied it on my test branch and this makes sparc64-allyesconfig fail
> with:
> 
>    drivers/rtc/rtc-imx-sc.o: In function `imx_sc_rtc_read_time':
>    rtc-imx-sc.c:(.text+0x34): undefined reference to `imx_scu_call_rpc'
>    drivers/rtc/rtc-imx-sc.o: In function `imx_sc_rtc_probe':
>    rtc-imx-sc.c:(.text+0x90): undefined reference to `imx_scu_get_handle'

Maybe there are some changes on basic support of imx scu driver, I will resend
a patch set later, thanks.

Anson.

> 
> 
> 
> --
> Alexandre Belloni, Bootlin
> Embedded Linux and Kernel engineering
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbootl
> in.com&amp;data=02%7C01%7Canson.huang%40nxp.com%7C72b147643a3f
> 44c258c208d6658f9cce%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0
> %7C636808064818797711&amp;sdata=%2Bl5jGXX6wBYbOg5Zalg4CyxyZKjUe
> uzRSQEKO9TJnRI%3D&amp;reserved=0

RE: [PATCH V4 2/4] rtc: add i.MX system controller RTC support

[Aisheng Dong]

[...]
> >
> > I applied it on my test branch and this makes sparc64-allyesconfig
> > fail
> > with:
> >
> >    drivers/rtc/rtc-imx-sc.o: In function `imx_sc_rtc_read_time':
> >    rtc-imx-sc.c:(.text+0x34): undefined reference to `imx_scu_call_rpc'
> >    drivers/rtc/rtc-imx-sc.o: In function `imx_sc_rtc_probe':
> >    rtc-imx-sc.c:(.text+0x90): undefined reference to `imx_scu_get_handle'
> 
> Maybe there are some changes on basic support of imx scu driver, I will resend
> a patch set later, thanks.
> 

This driver should depend on IMX_SCU which seems not got compiled.

Regards
Dong Aisheng

> Anson.
> 
> >
> >
> >
> > --
> > Alexandre Belloni, Bootlin
> > Embedded Linux and Kernel engineering
> > https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fboo
> > tl
> in.com&data=02%7C01%7Canson.huang%40nxp.com%7C72b147643a3f
> >
> 44c258c208d6658f9cce%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0
> > %7C636808064818797711&sdata=%2Bl5jGXX6wBYbOg5Zalg4CyxyZKj
> Ue
> > uzRSQEKO9TJnRI%3D&reserved=0

Re: [PATCH V4 2/4] rtc: add i.MX system controller RTC support

[Alexandre Belloni]

On 19/12/2018 09:48:25+0000, Aisheng Dong wrote:
> [...]
> > >
> > > I applied it on my test branch and this makes sparc64-allyesconfig
> > > fail
> > > with:
> > >
> > >    drivers/rtc/rtc-imx-sc.o: In function `imx_sc_rtc_read_time':
> > >    rtc-imx-sc.c:(.text+0x34): undefined reference to `imx_scu_call_rpc'
> > >    drivers/rtc/rtc-imx-sc.o: In function `imx_sc_rtc_probe':
> > >    rtc-imx-sc.c:(.text+0x90): undefined reference to `imx_scu_get_handle'
> > 
> > Maybe there are some changes on basic support of imx scu driver, I will resend
> > a patch set later, thanks.
> > 
> 
> This driver should depend on IMX_SCU which seems not got compiled.
> 

Yes, this seems to be the straightforward solution.

> Regards
> Dong Aisheng
> 
> > Anson.
> > 
> > >
> > >
> > >
> > > --
> > > Alexandre Belloni, Bootlin
> > > Embedded Linux and Kernel engineering
> > > https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fboo
> > > tl
> > in.com&data=02%7C01%7Canson.huang%40nxp.com%7C72b147643a3f
> > >
> > 44c258c208d6658f9cce%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0
> > > %7C636808064818797711&sdata=%2Bl5jGXX6wBYbOg5Zalg4CyxyZKj
> > Ue
> > > uzRSQEKO9TJnRI%3D&reserved=0

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

RE: [PATCH V4 2/4] rtc: add i.MX system controller RTC support

[Aisheng Dong]

> -----Original Message-----
> From: Anson Huang
> Sent: Thursday, November 29, 2018 9:50 AM
[...]
> 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>
> ---
> ChangeLog:
> V3->V4:
>   *remove unnecessary headfile included;
>   *fix potential memory currpution for the message responce;
>   *update the compatible string name to start with "fsl" instead of "nxp".
>  drivers/rtc/Kconfig      |  6 +++
>  drivers/rtc/Makefile     |  1 +
>  drivers/rtc/rtc-imx-sc.c | 98
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 105 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"

This should depend on IMX_SCU

> +	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..5976a2e
> --- /dev/null
> +++ b/drivers/rtc/rtc-imx-sc.c
> @@ -0,0 +1,98 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2018 NXP.
> + */
> +
> +#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
> +
> +static struct imx_sc_ipc *rtc_ipc_handle; static struct rtc_device
> +*imx_sc_rtc;
> +
> +struct imx_sc_msg_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_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);

Nitpick: 
better to use dev_err?

> +		return ret;
> +	}
> +
> +	rtc_time_to_tm(msg.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;
> +	}

You don't have to handle different error cases as API has already enclosed it.

> +
> +	imx_sc_rtc = devm_rtc_allocate_device(&pdev->dev);
> +	if (IS_ERR(imx_sc_rtc)) {
> +		ret = PTR_ERR(imx_sc_rtc);
> +		return ret;

Return PTR_ERR(imx_sc_rtc)

Regards
Dong Aisheng

> +	}
> +
> +	imx_sc_rtc->ops = &imx_sc_rtc_ops;
> +	imx_sc_rtc->range_min = 0;
> +	imx_sc_rtc->range_max = U32_MAX;
> +
> +	ret = rtc_register_device(imx_sc_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 = "fsl,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 V4 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 10fade8..9f12324 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 V4 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>
---
ChangeLog:
V3->V4:
  *move sc rtc to inside of SCU node.
 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..b38730a 100644
--- a/arch/arm64/boot/dts/freescale/imx8qxp.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8qxp.dtsi
@@ -84,6 +84,10 @@
 			compatible = "fsl,imx8qxp-scu-pd";
 			#power-domain-cells = <1>;
 		};
+
+		rtc: rtc {
+			compatible = "fsl,imx8qxp-sc-rtc";
+		};
 	};
 
 	tsens: thermal-sensor {
-- 
2.7.4