linux-kernel - Re: [PATCH 1/2] thermal: tsens: Add support for SDM845 platform

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Date:   Tue, 12 Jun 2018 13:39:49 +0300
From:   Amit Kucheria <amit.kucheria@...aro.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     linux-arm-msm@...r.kernel.org,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Eduardo Valentin <edubezval@...il.com>,
        Zhang Rui <rui.zhang@...el.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        "open list:THERMAL" <linux-pm@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] thermal: tsens: Add support for SDM845 platform

On Mon, Jun 4, 2018 at 6:03 PM, Bjorn Andersson
<bjorn.andersson@...aro.org> wrote:
> On Sat 02 Jun 04:11 PDT 2018, Amit Kucheria wrote:
>> diff --git a/drivers/thermal/qcom/tsens-sdm845.c b/drivers/thermal/qcom/tsens-sdm845.c
> [..]
>> +#define TRDY_OFFSET     0xe4
>> +#define TRDY_READY_BIT  BIT(1)
>
> This is bit 0.

Oops, fixed.

>> +
>> +#define STATUS_OFFSET        0xa0
>> +#define LAST_TEMP_MASK       0xfff
>> +#define STATUS_VALID_BIT     BIT(21)
>> +#define CODE_SIGN_BIT                BIT(11)
>> +
>> +static int get_temp_sdm845(struct tsens_device *tmdev, int id, int *temp)
>> +{
>> +     struct tsens_sensor *s = &tmdev->sensor[id];
>> +     u32 code;
>> +     unsigned int sensor_addr;
>> +     int last_temp = 0, last_temp2 = 0, last_temp3 = 0, ret;
>> +
>> +     ret = regmap_read(tmdev->map, TRDY_OFFSET, &code);
>> +     if (ret)
>> +             return ret;
>> +     if (code & TRDY_READY_BIT)
>> +             return -ENODATA;
>
> This section is the only difference from 8996, but this register is
> identical to 8996 and 8998. So I think you should add this to
> tsens-8996.c and we can use that for 8996, 8998 and sdm845.
>
> Perhaps we should name it tsens-v2, as that seems to be the common
> denominator for these, according to the documentation.

Thanks for confirming that the block is identical^Wsimilar across
8996, 8998, sdm845 (and possible others). I suspected as much but
didn't check in a lot of detail.

I expected the 845 to gain more features over time, hence the reason
for a separate file and a custom get_temp(). Now, I'll fold all of
them into a common tsens-v2 function.

We'll also need to change how we regmap the 8998 and sdm845 tsens
registers because the offsets are not the same and hence not handled
corrently by tsens-common.c/init_common().