On 日, 2016-08-21 at 21:37 +0800, Zhang Rui wrote:

On 五, 2016-08-19 at 11:59 -0700, Eric Anholt wrote:

quoted

Zhang Rui [off-list ref] writes:

quoted

On 四, 2016-08-18 at 11:39 -0700, Eric Anholt wrote:

quoted

Eric Anholt [off-list ref] writes:

quoted

kernel@martin.sperl.org writes:

quoted

From: Martin Sperl <redacted>

Add basic thermal driver for bcm2835 SOC.

This driver currently relies on the firmware setting up the
tsense HW block and does not set it up itself.

Signed-off-by: Martin Sperl <redacted>

ChangeLog:
 V1 -> V2: added specific settings depending on
compatiblity
	   added trip point based on register
	   setting up ctrl-register if HW is not enabled by
firmware
	     as per recommendation of Eric (untested)
	   check that clock frequency is in range
	     (1.9 - 5MHz - as per comment in clk-bcm2835.c)
---

diff --git a/drivers/thermal/bcm/Makefile

b/drivers/thermal/bcm/Makefile
new file mode 100644
index 0000000..13456d2

--- /dev/null
+++ b/drivers/thermal/bcm/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_BCM2835_THERMAL)		:=

bcm2835_thermal.o

diff --git a/drivers/thermal/bcm/bcm2835_thermal.c

b/drivers/thermal/bcm/bcm2835_thermal.c
new file mode 100644
index 0000000..73138cb

--- /dev/null
+++ b/drivers/thermal/bcm/bcm2835_thermal.c

+static const struct of_device_id

bcm2835_thermal_of_match_table[];
+static int bcm2835_thermal_probe(struct platform_device
*pdev)
+{

+	/* enable clock and check rate */
+	clk_prepare_enable(data->clk);
+	rate = clk_get_rate(data->clk);
+	if ((rate < 1920000) || (rate > 5000000)) {
+		dev_warn(&pdev->dev,
+			 "Clock %pCn is running at %pCr
Hz,
which is outside the recommended range of 1.9 to 5.0
MHz\n",
+			 data->clk, data->clk);
+	}
+
+	/* register it */
+	tz =
thermal_zone_device_register("bcm2835_thermal",
+					  1, 0, data,
+					  &bcm2835_thermal
_o
ps,
+					  NULL, 0, 0);

I notice that the polling_delay is set to 0, but we're not
using
interrupts to trigger the trip.  Is it valid to expose a trip
without a
polling_delay or interrupts?  Should passive_delay be set as
well?

This is up to the thermal maintainers.  As far as I'm
concerned,
it's:

Acked-by: Eric Anholt <redacted>

One it lands I'll pull the defconfig and DT bits.

Ping on this question to thermal maintainers.  I'd still love
to
see
this driver land.

hmmm, how is this driver supposed to work?
With this patch set, I think the only benefit is that we can get
the
temperature and trip point information via thermal sysfs
interface,
but
kernel thermal control is a no-op here, right?

Yeah.  It seems useful to be able to get the information.  Once we
land
this, I hope someone can add interrupt support so that there are
actual
trip points.

sounds reasonable to me.

BTW, can you add a "TODO" comment for this gap?

thanks,
rui

Another question, why you need a separate directory for a single
file, bcm2835_thermal.c?

thanks,
rui
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