[PATCH V3 2/5] thermal: bcm2835: add thermal driver for bcm2835 soc

[Eric Anholt]

kernel at martin.sperl.org writes:

> From: Martin Sperl <kernel at martin.sperl.org>
>
> 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 <kernel at martin.sperl.org>
>
> 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_ops,
> +					  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 <eric at anholt.net>

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