Re: [PATCH V3 2/4] soc/tegra: pmc: Correct type of variable for tegra_pmc_readl()

Laxman Dewangan
2016-05-05T12:47:26Z

On Thursday 05 May 2016 06:13 PM, Jon Hunter wrote:
> On 05/05/16 10:52, Laxman Dewangan wrote:
>> On Thursday 05 May 2016 03:19 PM, Jon Hunter wrote:
>>> On 04/05/16 12:39, Laxman Dewangan wrote:
>>>> The function tegra_pmc_readl() returns the u32 type data and hence
>>>> change the data type of variable where this data is stored to u32
>>>> type.
>>>>
>>>> Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
>>>>
>>>> ---
>>>> Changes from V1:
>>>> -This is new in series as per discussion on V1 series to use u32 for
>>>> tegra_pmc_readl.
>>>>
>>>> Changes from V2:
>>>> - Make unsigned long to u32 for some missed variable from V1.
>>>> ---
>>>> drivers/soc/tegra/pmc.c | 24 ++++++++++++++----------
>>>> 1 file changed, 14 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
>>>> index 2c3f1f9..eff9425 100644
>>>> --- a/drivers/soc/tegra/pmc.c
>>>> +++ b/drivers/soc/tegra/pmc.c
>>>> @@ -844,7 +844,8 @@ static void tegra_powergate_init(struct tegra_pmc
>>>> *pmc)
>>>> static int tegra_io_rail_prepare(unsigned int id, unsigned long
>>>> *request,
>>>> unsigned long *status, unsigned int *bit)
>>>> {
>>>> - unsigned long rate, value;
>>>> + unsigned long rate;
>>>> + u32 value;
>>>> *bit = id % 32;
>>>> @@ -868,17 +869,18 @@ static int tegra_io_rail_prepare(unsigned int
>>>> id, unsigned long *request,
>>>> tegra_pmc_writel(DPD_SAMPLE_ENABLE, DPD_SAMPLE);
>>>> /* must be at least 200 ns, in APB (PCLK) clock cycles */
>>>> - value = DIV_ROUND_UP(1000000000, rate);
>>>> - value = DIV_ROUND_UP(200, value);
>>>> + rate = DIV_ROUND_UP(1000000000, rate);
>>>> + rate = DIV_ROUND_UP(200, rate);
>>>> + value = (u32)rate;
>>> Although it is unlikely, I think that we should check it is less
>>> than U32_MAX, return an error if it is not.
>> rate = DIV_ROUNC_UP(200, rate) means
>>
>> rate = (200 + rate -1)/rate
>>
>> and can not be more than 200 in any case (if rate =1).
>> So no need of the error check.
> OK, yes you are right. In that case there is no need to cast and so I
> would leave this code as-is and not change the type.
>

You mean keep value as unsigned long for value?

I think we can still say value as u32 and simply write
value = rate

Just remove the casting.