Hi Marek,
2017-08-17 20:56 GMT+09:00 Marek Vasut marek.vasut@gmail.com:
On 08/17/2017 09:01 AM, Masahiro Yamada wrote:
2017-08-17 15:39 GMT+09:00 Jaehoon Chung jh80.chung@samsung.com:
On 08/13/2017 01:55 AM, Marek Vasut wrote:
On 08/10/2017 09:49 AM, Masahiro Yamada wrote:
Hi.
2017-08-07 17:30 GMT+09:00 Marek Vasut marek.vasut@gmail.com:
On 08/07/2017 04:30 AM, Masahiro Yamada wrote: > Hi Marek,
Hi Masahiro,
This is gonna be a great discussion, let's wrestle about consts and ints :-)
> 2017-08-06 4:23 GMT+09:00 Marek Vasut marek.vasut@gmail.com: >> On 08/03/2017 02:36 PM, Masahiro Yamada wrote: >>> Hi Marek, >> >> Hi, >> >> [...] >> >>>> +static u32 uniphier_sd_readl(struct uniphier_sd_priv *priv, const u32 reg) >>> >>> "const" is unneeded here. >> >> Why? The function should not modify reg , so it is const. > > > Because "const" is useless here. > > The "reg" is not a pointer, so it is obvious > that there is no impact to the callers. > > > > Moreover, whether "reg" is constant or not > depends on how you implement the function. > > > If you force "const" to the argument, the only choice for the implementation > will be as follows: > > > > static u32 uniphier_sd_readl(struct uniphier_sd_priv *priv, const u32 reg) > { > if (priv->caps & UNIPHIER_SD_CAP_64BIT) > return readl(priv->regbase + (reg << 1)); > else > return readl(priv->regbase + reg); > } > > > > If you want to implement the function as follows, you need to drop "const". > > static u32 uniphier_sd_readl(struct uniphier_sd_priv *priv, u32 reg) > { > if (priv->caps & UNIPHIER_SD_CAP_64BIT) > reg <<= 1; > > return readl(priv->regbase + reg); > }
My argument would be that the const prevents you from accidentally modifying the $reg inside the function.
Is there any case about modifying the regs value in this function? Well..I think that it makes sense about both. (Masahiro and Marek opinion)
But There is nothing wrong to prevent from accidentally.
In my opinion, const is useful for pointer dereference, but unneeded in this case.
I believe it is the taste from what I saw from Linux code. So, I follow it.
I don't care either way, I was just wrestling Masahiro for the sake of it (you know the thing about wrestling engineers). There's a V2, so feel free to collect that if Masahiro can give me an AB/RB.
I still see const in 1/5 and 3/5.
Please remove them if my AB/RB is needed.