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Date:   Sat, 23 Feb 2019 13:38:59 -0800
From:   Eduardo Valentin <edubezval@gmail.com>
To:     Anson Huang <anson.huang@nxp.com>
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Subject: Re: [PATCH V8 2/4] thermal: imx_sc: add i.MX system controller
 thermal support
Message-ID: <20190223213858.GB1472@localhost.localdomain>
References: <1550730831-14995-1-git-send-email-Anson.Huang@nxp.com>
 <1550730831-14995-2-git-send-email-Anson.Huang@nxp.com>
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Hey Anson,

On Thu, Feb 21, 2019 at 06:38:39AM +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@nxp.com>
> ---
> Changes since V7:
> 	- remove unused structure imx_sc_thermal_data to simply the driver;
> 	- move the "imx,sensor-resource-id" property from thermal zone node to scu tsens node, and
> 	  get this property using phandle;
> 	- remove unused sensor number got from dts, now it is not needed.
> ---
>  drivers/thermal/Kconfig          |  11 +++
>  drivers/thermal/Makefile         |   1 +
>  drivers/thermal/imx_sc_thermal.c | 144 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 156 insertions(+)
>  create mode 100644 drivers/thermal/imx_sc_thermal.c
> 
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 58bb7d7..fec0ef5 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -223,6 +223,17 @@ 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 486d682..4062627 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -40,6 +40,7 @@ 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..145e73b
> --- /dev/null
> +++ b/drivers/thermal/imx_sc_thermal.c
> @@ -0,0 +1,144 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2018-2019 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 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_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np, *sensor_np;
> +	int ret, i = 0;
> +
> +	ret = imx_scu_get_handle(&thermal_ipc_handle);
> +	if (ret)
> +		return ret;
> +
> +	np = of_find_node_by_name(NULL, "thermal-zones");
> +	if (!np)
> +		return -ENODEV;

I am still failing to understand why you need to do the search above
and ..

> +
> +	for_each_available_child_of_node(np, sensor_np) {
> +		struct of_phandle_args tsens_args;
> +		struct imx_sc_sensor *sensor =
> +			devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL);
> +		if (!sensor)
> +			return -ENOMEM;
> +
> +		ret = of_parse_phandle_with_args(sensor_np, "thermal-sensors",
> +				"#thermal-sensor-cells", i, &tsens_args);

the above shouldnt be needed too.

> +		if (ret < 0)
> +			return ret;
> +
> +		ret = of_property_read_u32_index(tsens_args.np,
> +			"imx,sensor-resource-id", i, &sensor->resource_id);

If you put "imx,sensor-resource-id" inside tsens node, like described in
your patch 01, you should be able to get  np from pdev->dev.of_node,
right?

Then you should be able to just read the "imx,sensor-resource-id"
directly from pdev->dev.of_node, no?

> +		if (ret) {
> +			dev_err(&pdev->dev,
> +				"failed to get valid sensor resource id: %d\n",
> +				ret);
> +			break;
> +		}
> +
> +		sensor->tzd = devm_thermal_zone_of_sensor_register(&pdev->dev,
> +								   i++,
> +								   sensor,
> +								   &imx_sc_thermal_ops);
> +		if (IS_ERR(sensor->tzd)) {
> +			dev_err(&pdev->dev, "failed to register thermal zone\n");
> +			ret = PTR_ERR(sensor->tzd);
> +			break;
> +		}
> +	}
> +
> +	of_node_put(np);
> +	of_node_put(sensor_np);
> +
> +	return ret;
> +}
> +
> +static const struct of_device_id imx_sc_thermal_table[] = {
> +	{ .compatible = "fsl,imx-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@nxp.com>");
> +MODULE_DESCRIPTION("Thermal driver for NXP i.MX SoCs with system controller");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.7.4
>