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SubjectRe: [PATCH 08/13] thermal/drivers/hisi: Fix configuration register setting
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On 04/09/2017 02:58, Leo Yan wrote:
> On Sat, Sep 02, 2017 at 10:34:34AM +0200, Daniel Lezcano wrote:
>> On 02/09/2017 04:54, Leo Yan wrote:
>>> On Wed, Aug 30, 2017 at 10:47:32AM +0200, Daniel Lezcano wrote:
>>>> The TEMP0_CFG configuration register contains different field to set up the
>>>> temperature controller. However in the code, nothing prevents a setup to
>>>> overwrite the previous one: eg. writing the hdak value overwrites the sensor
>>>> selection, the sensor selection overwrites the hdak value.
>>>>
>>>> In order to prevent such thing, use a regmap-like mechanism by reading the
>>>> value before, set the corresponding bits and write the result.
>>>>
>>>> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
>>>> ---
>>>> drivers/thermal/hisi_thermal.c | 30 +++++++++++++++++++++++++-----
>>>> 1 file changed, 25 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c
>>>> index d77a938..3e03908 100644
>>>> --- a/drivers/thermal/hisi_thermal.c
>>>> +++ b/drivers/thermal/hisi_thermal.c
>>>> @@ -132,19 +132,39 @@ static inline void hisi_thermal_enable(void __iomem *addr, int value)
>>>> writel(value, addr + TEMP0_EN);
>>>> }
>>>>
>>>> -static inline void hisi_thermal_sensor_select(void __iomem *addr, int sensor)
>>>> +static inline int hisi_thermal_get_temperature(void __iomem *addr)
>>>> {
>>>> - writel((sensor << 12), addr + TEMP0_CFG);
>>>> + return hisi_thermal_step_to_temp(readl(addr + TEMP0_VALUE));
>>>> }
>>>>
>>>> -static inline int hisi_thermal_get_temperature(void __iomem *addr)
>>>> +/*
>>>> + * Temperature configuration register - Sensor selection
>>>> + *
>>>> + * Bits [19:12]
>>>> + *
>>>> + * 0x0: local sensor (default)
>>>> + * 0x1: remote sensor 1 (ACPU cluster 1)
>>>> + * 0x2: remote sensor 2 (ACPU cluster 0)
>>>> + * 0x3: remote sensor 3 (G3D)
>>>> + */
>>>> +static inline void hisi_thermal_sensor_select(void __iomem *addr, int sensor)
>>>> {
>>>> - return hisi_thermal_step_to_temp(readl(addr + TEMP0_VALUE));
>>>> + writel(readl(addr + TEMP0_CFG) | (sensor << 12), addr + TEMP0_CFG);
>>>
>>> nitpick: maybe it's better to firstly clear related bits and then set
>>> value?
>>
>> Sorry, I don't get the comment. Can you elaborate ?
>
> Sure, here I am bit concern there the mixing old bits value and new
> setting bits. My suggested code likes below:
>
> u32 val;
>
> val = readl(addr + TEMP0_CFG);
> val &= ~0xF000;
> val |= (sensor << 12);
> writel(val, addr + TEMP0_CFG);

Oh, yes. Good catch.


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