RE: [PATCH V5 2/4] thermal: imx_sc: add i.MX system controller thermal support

[Anson Huang]

Hi, Eduardo

Best Regards!
Anson Huang

> -----Original Message-----
> From: Eduardo Valentin [mailto:edubezval@xxxxxxxxx]
> Sent: 2018年12月26日 6:44
> To: Anson Huang <anson.huang@xxxxxxx>
> Cc: robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx; catalin.marinas@xxxxxxx;
> will.deacon@xxxxxxx; rui.zhang@xxxxxxxxx; daniel.lezcano@xxxxxxxxxx;
> Aisheng Dong <aisheng.dong@xxxxxxx>; s.hauer@xxxxxxxxxxxxxx;
> shawnguo@xxxxxxxxxx; Andy Gross <andy.gross@xxxxxxxxxx>; arnd@xxxxxxxx;
> horms+renesas@xxxxxxxxxxxx; heiko@xxxxxxxxx; bjorn.andersson@xxxxxxxxxx;
> enric.balletbo@xxxxxxxxxxxxx; amit.kucheria@xxxxxxxxxx;
> ezequiel@xxxxxxxxxxxxx; olof@xxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-pm@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>
> Subject: Re: [PATCH V5 2/4] thermal: imx_sc: add i.MX system controller
> thermal support
> 
> On Thu, Dec 20, 2018 at 09:08:32AM +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 thermal sensors etc..
> >
> > This patch adds i.MX system controller thermal driver support, Linux
> > kernel has to communicate with system controller via MU (message unit)
> > IPC to get each thermal sensor's temperature, it supports multiple
> > sensors which are passed from device tree, please see the binding doc
> > for details.
> >
> > Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
> > ---
> > ChangeLog since V4:
> >     - Add driver dependency on IMX_SCU to avoid compile error when
> IMX_SCU is NOT selected;
> >     - Remove unnecessary of different errors handle for
> imx_scu_get_handle, already included in API.
> > ---
> >  drivers/thermal/Kconfig          |  11 +++
> >  drivers/thermal/Makefile         |   1 +
> >  drivers/thermal/imx_sc_thermal.c | 200
> > +++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 212 insertions(+)
> >  create mode 100644 drivers/thermal/imx_sc_thermal.c
> >
> > diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index
> > 0e69edc..8d4601d 100644
> > --- a/drivers/thermal/Kconfig
> > +++ b/drivers/thermal/Kconfig
> > @@ -222,6 +222,17 @@ config IMX_THERMAL
> >  	  cpufreq is used as the cooling device to throttle CPUs when the
> >  	  passive trip is crossed.
> >
> > +config IMX_SC_THERMAL
> > +	tristate "Temperature sensor driver for NXP i.MX SoCs with System
> Controller"
> > +	depends on (ARCH_MXC && IMX_SCU) || COMPILE_TEST
> > +	depends on OF
> > +	help
> > +	  Support for Temperature Monitor (TEMPMON) found on NXP i.MX SoCs
> with
> > +	  system controller inside, Linux kernel has to communicate with system
> > +	  controller via MU (message unit) IPC to get temperature from thermal
> > +	  sensor. It supports one critical trip point and one
> > +	  passive trip point for each thermal sensor.
> > +
> >  config MAX77620_THERMAL
> >  	tristate "Temperature sensor driver for Maxim MAX77620 PMIC"
> >  	depends on MFD_MAX77620
> > diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile index
> > 610344e..1b13f6a 100644
> > --- a/drivers/thermal/Makefile
> > +++ b/drivers/thermal/Makefile
> > @@ -41,6 +41,7 @@ obj-$(CONFIG_DB8500_THERMAL)	+=
> db8500_thermal.o
> >  obj-$(CONFIG_ARMADA_THERMAL)	+= armada_thermal.o
> >  obj-$(CONFIG_TANGO_THERMAL)	+= tango_thermal.o
> >  obj-$(CONFIG_IMX_THERMAL)	+= imx_thermal.o
> > +obj-$(CONFIG_IMX_SC_THERMAL)	+= imx_sc_thermal.o
> >  obj-$(CONFIG_MAX77620_THERMAL)	+= max77620_thermal.o
> >  obj-$(CONFIG_QORIQ_THERMAL)	+= qoriq_thermal.o
> >  obj-$(CONFIG_DA9062_THERMAL)	+= da9062-thermal.o
> > diff --git a/drivers/thermal/imx_sc_thermal.c
> > b/drivers/thermal/imx_sc_thermal.c
> > new file mode 100644
> > index 0000000..1030a31
> > --- /dev/null
> > +++ b/drivers/thermal/imx_sc_thermal.c
> > @@ -0,0 +1,200 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright 2018 NXP.
> > + */
> > +
> > +#include <linux/err.h>
> > +#include <linux/firmware/imx/sci.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +#include <linux/thermal.h>
> > +
> > +#include "thermal_core.h"
> > +
> > +#define IMX_SC_MISC_FUNC_GET_TEMP	13
> > +#define IMX_SC_C_TEMP			0
> > +
> > +static struct imx_sc_ipc *thermal_ipc_handle;
> > +
> > +struct imx_sc_sensor {
> > +	struct thermal_zone_device *tzd;
> > +	u32 resource_id;
> > +};
> > +
> > +struct imx_sc_thermal_data {
> > +	struct imx_sc_sensor *sensor;
> > +};
> > +
> > +struct req_get_temp {
> > +	u16 resource_id;
> > +	u8 type;
> > +} __packed;
> > +
> > +struct resp_get_temp {
> > +	u16 celsius;
> > +	u8 tenths;
> > +} __packed;
> > +
> > +struct imx_sc_msg_misc_get_temp {
> > +	struct imx_sc_rpc_msg hdr;
> > +	union {
> > +		struct req_get_temp req;
> > +		struct resp_get_temp resp;
> > +	} data;
> > +} __packed;
> > +
> > +static int imx_sc_thermal_get_temp(void *data, int *temp) {
> > +	struct imx_sc_msg_misc_get_temp msg;
> > +	struct imx_sc_rpc_msg *hdr = &msg.hdr;
> > +	struct imx_sc_sensor *sensor = data;
> > +	int ret;
> > +
> > +	msg.data.req.resource_id = sensor->resource_id;
> > +	msg.data.req.type = IMX_SC_C_TEMP;
> > +
> > +	hdr->ver = IMX_SC_RPC_VERSION;
> > +	hdr->svc = IMX_SC_RPC_SVC_MISC;
> > +	hdr->func = IMX_SC_MISC_FUNC_GET_TEMP;
> > +	hdr->size = 2;
> > +
> > +	ret = imx_scu_call_rpc(thermal_ipc_handle, &msg, true);
> > +	if (ret) {
> > +		pr_err("read temp sensor %d failed, ret %d\n",
> > +			sensor->resource_id, ret);
> > +		return ret;
> > +	}
> > +
> > +	*temp = msg.data.resp.celsius * 1000 + msg.data.resp.tenths * 100;
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct thermal_zone_of_device_ops imx_sc_thermal_ops = {
> > +	.get_temp = imx_sc_thermal_get_temp, };
> > +
> > +static int imx_sc_thermal_register_sensor(struct platform_device *pdev,
> > +					  struct imx_sc_sensor *sensor)
> > +{
> > +	struct thermal_zone_device *tzd;
> > +
> > +	tzd = devm_thermal_zone_of_sensor_register(&pdev->dev,
> > +						   sensor->resource_id,
> > +						   sensor,
> > +						   &imx_sc_thermal_ops);
> > +	if (IS_ERR(tzd)) {
> > +		dev_err(&pdev->dev, "failed to register sensor: %d\n",
> > +			sensor->resource_id);
> > +		return PTR_ERR(tzd);
> > +	}
> > +
> > +	sensor->tzd = tzd;
> > +
> > +	return 0;
> > +}
> > +
> > +static int imx_sc_thermal_get_sensor_id(struct device_node
> > +*sensor_np, u32 *id) {
> > +	struct of_phandle_args sensor_specs;
> > +	int ret;
> > +
> > +	ret = of_parse_phandle_with_args(sensor_np, "thermal-sensors",
> > +			"#thermal-sensor-cells",
> > +			0, &sensor_specs);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (sensor_specs.args_count >= 1) {
> > +		*id = sensor_specs.args[0];
> > +		WARN(sensor_specs.args_count > 1,
> > +				"%pOFn: too many cells in sensor specifier %d\n",
> > +				sensor_specs.np, sensor_specs.args_count);
> > +	} else {
> > +		return -EINVAL;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> 
> So, there should be no need for doing a search of sensor ids. In fact, if the
> amount of sensors or the type of sensors supported changes, i.e.
> the sensor ids are do not match, you should have a different compatible, IMO.

So do you mean I can just read the sensor id (actually it is our SoC's resource id) from the
DTB file's each child node of thermal_zones? Then I can skip the search of sensor ids, just
add a sensor id property and read it out during thermal driver probe? Yes, this looks like
easier, is my understanding correct? If yes, I can do it in next version. Thanks.

Anson

> 
> > +static int imx_sc_thermal_probe(struct platform_device *pdev) {
> > +	struct device_node *np = pdev->dev.of_node;
> > +	struct device_node *sensor_np = NULL;
> > +	struct imx_sc_thermal_data *data;
> > +	struct imx_sc_sensor *sensors;
> > +	u32 sensor_num;
> > +	int ret, i;
> > +
> > +	ret = imx_scu_get_handle(&thermal_ipc_handle);
> > +	if (ret)
> > +		return ret;
> > +
> > +	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> > +	if (!data)
> > +		return -ENOMEM;
> > +
> > +	ret = of_property_read_u32(np, "tsens-num", &sensor_num);
> > +	if (ret || !sensor_num) {
> > +		dev_err(&pdev->dev, "failed to get valid temp sensor number!\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	sensors = devm_kzalloc(&pdev->dev, sizeof(*data->sensor) * sensor_num,
> > +			       GFP_KERNEL);
> > +	if (!sensors)
> > +		return -ENOMEM;
> > +
> > +	data->sensor = sensors;
> > +
> > +	np = of_find_node_by_name(NULL, "thermal-zones");
> > +	if (!np)
> > +		return -ENODEV;
> > +
> > +	for (i = 0; i < sensor_num; i++) {
> > +		struct imx_sc_sensor *sensor = &data->sensor[i];
> > +
> > +		sensor_np = of_get_next_child(np, sensor_np);
> > +		ret = imx_sc_thermal_get_sensor_id(sensor_np,
> &sensor->resource_id);
> > +		if (ret < 0) {
> > +			dev_err(&pdev->dev,
> > +				"failed to get valid sensor resource id: %d\n",
> > +				ret);
> > +			break;
> > +		}
> > +
> > +		ret = imx_sc_thermal_register_sensor(pdev, sensor);
> > +		if (ret) {
> > +			dev_err(&pdev->dev, "failed to register thermal sensor: %d\n",
> > +				ret);
> > +			break;
> > +		}
> > +	}
> > +
> > +	of_node_put(np);
> > +	of_node_put(sensor_np);
> > +
> > +	return ret;
> > +}
> > +
> > +static const struct of_device_id imx_sc_thermal_table[] = {
> > +	{ .compatible = "fsl,imx8qxp-sc-thermal", },
> > +	{}
> > +};
> > +MODULE_DEVICE_TABLE(of, imx_sc_thermal_table);
> > +
> > +static struct platform_driver imx_sc_thermal_driver = {
> > +		.probe = imx_sc_thermal_probe,
> > +		.driver = {
> > +			.name = "imx-sc-thermal",
> > +			.of_match_table = imx_sc_thermal_table,
> > +		},
> > +};
> > +module_platform_driver(imx_sc_thermal_driver);
> > +
> > +MODULE_AUTHOR("Anson Huang <Anson.Huang@xxxxxxx>");
> > +MODULE_DESCRIPTION("Thermal driver for NXP i.MX SoCs with system
> > +controller"); MODULE_LICENSE("GPL v2");
> > --
> > 2.7.4
> >