Re: [PATCH V5 2/4] thermal: imx_sc: add i.MX system controller thermal support | linux-arm-kernel

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On Tue, Jan 22, 2019 at 06:54:30AM +0000, Anson Huang wrote:
Hi, Eduardo

Best Regards!
Anson Huang

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

Hi, Eduardo

Best Regards!
Anson Huang

-----Original Message-----
From: Anson Huang
Sent: 2018年12月26日 11:36
To: 'Eduardo Valentin' <edubezval@gmail.com>
Cc: robh+dt@kernel.org; mark.rutland@arm.com;
catalin.marinas@arm.com;
will.deacon@arm.com; rui.zhang@intel.com; daniel.lezcano@linaro.org;
Aisheng Dong [off-list ref]; s.hauer@pengutronix.de;
shawnguo@kernel.org; Andy Gross [off-list ref];
arnd@arndb.de;
horms+renesas@verge.net.au; heiko@sntech.de;
horms+bjorn.andersson@linaro.org;
enric.balletbo@collabora.com; amit.kucheria@linaro.org;
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Subject: RE: [PATCH V5 2/4] thermal: imx_sc: add i.MX system
controller thermal support

Hi, Eduardo

Best Regards!
Anson Huang

-----Original Message-----
From: Eduardo Valentin [mailto:edubezval@gmail.com]
Sent: 2018年12月26日 6:44
To: Anson Huang <redacted>
Cc: robh+dt@kernel.org; mark.rutland@arm.com;
catalin.marinas@arm.com;
will.deacon@arm.com; rui.zhang@intel.com; daniel.lezcano@linaro.org;
Aisheng Dong [off-list ref]; s.hauer@pengutronix.de;
shawnguo@kernel.org; Andy Gross [off-list ref];
arnd@arndb.de;
horms+renesas@verge.net.au; heiko@sntech.de;
horms+bjorn.andersson@linaro.org;
enric.balletbo@collabora.com; amit.kucheria@linaro.org;
ezequiel@collabora.com; olof@lixom.net; devicetree@vger.kernel.org;
linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
linux-pm@vger.kernel.org; dl-linux-imx [off-list ref]
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 <redacted>
---
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
Can you be more detail about the search of sensor ids? For this SoC, there will
be more
sensors(thermal-zone) added later, like DDR controller thermal sensor and
pmic sensor etc., they will use same compatible, and in the
imx_sc_thermal_get_sensor_id(), it just read out the sensor id from the dtb's
each thermal zone's " thermal-sensors " property, I did NOT see any search
here, thanks!

Anson.
I can remove the imx_sc_thermal_get_sensor_id() in the patch, and add below property in dts, then
just read out the resource id using of_property_read_u32(), then we can save the sensor id search function
in the driver, but need to add a property in dts, is this what you mean?

.probe:
-               ret = imx_sc_thermal_get_sensor_id(sensor_np, &sensor->resource_id);
-               if (ret < 0) {
+               if (of_property_read_u32(sensor_np, "sensor-resource-id",
+                       &sensor->resource_id)) {

dts:
454         thermal_zones: thermal-zones {
455                 cpu-thermal0 {
456                         polling-delay-passive = <250>;
457                         polling-delay = <2000>;
458 +                         sensor-resource-id = <355>;
Yeah, I believe this would be best description for your case. In your
current patch you are abusing a bit of the thermal descriptor. That
sensor cell is to actually help identify the sensor within the device
tree description...

459                         thermal-sensors = <&tsens 355>;
when you add 355 that would mean this is sensor 355 of all sensors
handled by your tsens. I would actually even assume that there are at
least 355 sensors in that tsens.

I mean, there is nothing really wrong with that syntactically, but it is
a slightly different usage of that #thermal-sensors-cell.

If you I got your patch right, you need a resource-id to be sent in a
command. For that I would recommend adding a specific property, with the
prefix imx, in it. Something like imx,sensor-resource-id, or something
fits better for you.

Anson.
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