From: jon.mason@broadcom.com (Jon Mason)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V2 2/2] thermal: broadcom: add Northstar thermal driver
Date: Fri, 31 Mar 2017 13:29:50 -0400 [thread overview]
Message-ID: <CAC3K-4p5r=a+zM25xApf4Sxr2mGnaY8z0ugKdzw=WqCxrY8MEA@mail.gmail.com> (raw)
In-Reply-To: <cfbb429d-5dd9-88b4-eeae-a288def7b56f@milecki.pl>
On Fri, Mar 31, 2017 at 10:49 AM, Rafa? Mi?ecki <rafal@milecki.pl> wrote:
> On 03/31/2017 04:23 PM, Jon Mason wrote:
>>
>> On Fri, Mar 31, 2017 at 3:03 AM, Rafa? Mi?ecki <zajec5@gmail.com> wrote:
>>>
>>> On 03/24/2017 03:35 PM, Jon Mason wrote:
>>>>
>>>>
>>>> On Thu, Mar 23, 2017 at 11:30:45PM +0100, Rafa? Mi?ecki wrote:
>>>>>
>>>>>
>>>>> diff --git a/drivers/thermal/broadcom/ns-thermal.c
>>>>> b/drivers/thermal/broadcom/ns-thermal.c
>>>>> new file mode 100644
>>>>> index 000000000000..acf3a4de62a4
>>>>> --- /dev/null
>>>>> +++ b/drivers/thermal/broadcom/ns-thermal.c
>>>>> @@ -0,0 +1,98 @@
>>>>> +/*
>>>>> + * Copyright (C) 2017 Rafa? Mi?ecki <rafal@milecki.pl>
>>>>> + *
>>>>> + * This program is free software; you can redistribute it and/or
>>>>> modify
>>>>> + * it under the terms of the GNU General Public License version 2 as
>>>>> + * published by the Free Software Foundation.
>>>>> + */
>>>>> +
>>>>> +#include <linux/module.h>
>>>>> +#include <linux/of_address.h>
>>>>> +#include <linux/platform_device.h>
>>>>> +#include <linux/thermal.h>
>>>>> +
>>>>> +#define PVTMON_CONTROL0 0x00
>>>>> +#define PVTMON_CONTROL0_SEL_MASK 0x0000000e
>>>>> +#define PVTMON_CONTROL0_SEL_TEMP_MONITOR 0x00000000
>>>>> +#define PVTMON_CONTROL0_SEL_TEST_MODE 0x0000000e
>>>>> +#define PVTMON_STATUS 0x08
>>>>> +
>>>>> +struct ns_thermal {
>>>>> + void __iomem *pvtmon;
>>>>> +};
>>>>> +
>>>>> +static int ns_thermal_get_temp(void *data, int *temp)
>>>>> +{
>>>>> + struct ns_thermal *ns_thermal = data;
>>>>> + u32 val;
>>>>> +
>>>>> + val = readl(ns_thermal->pvtmon + PVTMON_CONTROL0);
>>>>> + if ((val & PVTMON_CONTROL0_SEL_MASK) !=
>>>>> PVTMON_CONTROL0_SEL_TEMP_MONITOR) {
>>>>> + val &= ~PVTMON_CONTROL0_SEL_MASK;
>>>>> + val |= PVTMON_CONTROL0_SEL_TEMP_MONITOR;
>>>>
>>>>
>>>>
>>>> I think this is slightly confusing here. If this was off, ORing in 0
>>>> will not enable it. I think we need to flip the #define to make it
>>>> PVTMON_CONTROL0_SEL_TEMP_MONITOR_DISABLE (or a less crappy name).
>>>> then use this line here to toggle it. Something like
>>>>
>>>> val &= ~PVTMON_CONTROL0_SEL_TEMP_MONITOR_DISABLE;
>>>
>>>
>>>
>>> I don't understand this, can you help me further?
>>>
>>> OR-ing with 0 is only a cosmetic thing obviously - just to make it clear
>>> which
>>> value we expect to be set in bits 1:3. The important part is:
>>> val &= ~PVTMON_CONTROL0_SEL_MASK;
>>
>>
>> You are using a side effect of the masking to clear/enable the block.
>> I'm simply saying that we should be explicit about enabling it. My
>> concern is that using the side effect hides what is being done and
>> could result in a bug somewhere down the line. I think this is
>> improbable based on the code, but wanted to err on the side of
>> caution.
>
>
> Well, I'm clearing current mode selection and "selecting" the mode I want.
> By
> OR-ing PVTMON_CONTROL0_SEL_TEMP_MONITOR I'm clearly indicating I want temp
> monitor more.
>
> How else I could make it more obvious? Should I add some comment maybe?
I think it would be acceptable to remove the ORing of the 0, and
simply put a comment there that the masking of it is clearing the 0th
bit, thus enabling the IP block.
next prev parent reply other threads:[~2017-03-31 17:29 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170318155632.18099-1-zajec5@gmail.com>
2017-03-23 22:30 ` [PATCH V2 1/2] dt-bindings: thermal: add support for Broadcom's Northstar thermal Rafał Miłecki
2017-03-23 22:30 ` [PATCH V2 2/2] thermal: broadcom: add Northstar thermal driver Rafał Miłecki
2017-03-24 14:35 ` Jon Mason
2017-03-31 7:03 ` Rafał Miłecki
2017-03-31 14:23 ` Jon Mason
2017-03-31 14:49 ` Rafał Miłecki
2017-03-31 17:29 ` Jon Mason [this message]
2017-03-31 3:15 ` Eduardo Valentin
2017-03-31 7:08 ` Rafał Miłecki
2017-03-31 3:17 ` [PATCH V2 1/2] dt-bindings: thermal: add support for Broadcom's Northstar thermal Eduardo Valentin
2017-03-31 7:31 ` [PATCH V3 " Rafał Miłecki
2017-03-31 7:31 ` [PATCH V3 2/2] thermal: broadcom: add Northstar thermal driver Rafał Miłecki
2017-03-31 20:11 ` [PATCH V4 1/2] dt-bindings: thermal: add support for Broadcom's Northstar thermal Rafał Miłecki
2017-03-31 20:11 ` [PATCH V4 2/2] thermal: broadcom: add Northstar thermal driver Rafał Miłecki
2017-04-01 19:54 ` Eduardo Valentin
2017-04-01 20:20 ` Florian Fainelli
2017-04-01 21:41 ` Rafał Miłecki
2017-04-01 19:51 ` [PATCH V4 1/2] dt-bindings: thermal: add support for Broadcom's Northstar thermal Eduardo Valentin
2017-04-01 21:50 ` Rafał Miłecki
2017-04-02 4:13 ` Eduardo Valentin
2017-04-03 3:07 ` Jon Mason
2017-04-03 14:54 ` Jon Mason
2017-04-03 14:57 ` Rafał Miłecki
2017-04-03 15:48 ` [PATCH V5 " Rafał Miłecki
2017-04-03 15:48 ` [PATCH V5 2/2] thermal: broadcom: add Northstar thermal driver Rafał Miłecki
2017-04-07 4:42 ` Eduardo Valentin
2017-04-14 12:16 ` Rafał Miłecki
2017-04-14 15:16 ` Eduardo Valentin
2017-04-14 15:19 ` Rafał Miłecki
2017-04-17 20:09 ` Stefan Wahren
2017-04-10 15:00 ` [PATCH V5 1/2] dt-bindings: thermal: add support for Broadcom's Northstar thermal Rob Herring
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