RE: [PATCH V2 2/4] rtc: add i.MX system controller RTC support
From: Anson Huang
Date: Wed Nov 28 2018 - 04:04:13 EST
Hi, Lothar
Best Regards!
Anson Huang
> -----Original Message-----
> From: Lothar WaÃmann [mailto:LW@xxxxxxxxxxxxxxxxxxx]
> Sent: 2018å11æ28æ 17:01
> To: Anson Huang <anson.huang@xxxxxxx>
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> shawnguo@xxxxxxxxxx; linux-rtc@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
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> dl-linux-imx <linux-imx@xxxxxxx>
> 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@xxxxxxx>
> > ---
> > 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 WaÃmann