Re: [PATCHv9 02/20] thermal: introduce device tree parser
From: Wei Ni <hidden>
Date: 2014-01-07 02:44:37
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On 01/06/2014 10:54 PM, Eduardo Valentin wrote:
* PGP Signed by an unknown key On 06-01-2014 09:51, Mark Rutland wrote:quoted
On Thu, Jan 02, 2014 at 05:50:06PM +0000, Matthew Longnecker wrote:quoted
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I think the platform driver may set governor for the thermal zone, so how about to add a property named as "governor", and parse it to tzp->governor_name, something like: ret = of_property_read_string(child, "governor", &str); if (ret == 0) if (strlen(str) < THERMAL_NAME_LENGTH) strcpy(tzp->governor_name, str); Thanks. Wei.DT is supposed to describe the hardware, right? The governor isn't hardware -- it's a software control policy. On the other hand, that control policy must be tuned according to the behaviors of the platform hardware otherwise the system will be unstable. Is it appropriate to be naming the governor in DT? If so, is it equally appropriate to describe any governor-specific parameters in DT (even though they are pure software constructs)?The dt should be relatively static -- if the hardware doesn't change the dt shouldn't have to. The governers are not static. We can introduce new ones and throw away old ones at any time. Tuning parameters can also change at any time. I'd prefer to not have governer details described in the dt, and the choice of governer and configuration of its tuning parameters should be made at runtime somehow.Agreed.
Yes, I think so, but the of-thermal driver handle the thermal_zone_device_register, and pass the "tzp" without governor_name, so the created thermal_zone's governor will be NULL, then it can't run into the governor->throttle() if needed. And currently there have no interface to support updating governor and configuration at runtime. I think it's better to initialize the governor_name when register the thermal zone device in the of-thermal driver. Thanks.
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Thanks, Mark.