Re: [PATCH v2 2/2] gpio: Add Cadence GPIO driver
From: Bartosz Golaszewski <hidden>
Date: 2018-12-18 12:51:02
Also in:
linux-gpio, lkml
pon., 17 gru 2018 o 23:22 Linus Walleij [off-list ref] napisał(a):
On Mon, Dec 17, 2018 at 4:51 PM Bartosz Golaszewski [off-list ref] wrote:quoted
The driver looks good but is there any particular reason not to use regmap for register IO?I thought we only use regmap for MMIO when the register range is shared (as in a system controller) so that some registers are for this, some register or even bits in a register for some other driver, so they need the spinlock in the regmap to protect the register range.
This is what syscon is for. Regmap simply abstracts any register IO. For instance: there's no locking in this driver. Are we sure it's not needed? Regmap provides internal locking for you in the form of a mutex or spinlock. Also: it looks like the interrupts here are quite simple with a single bit per interrupt in the status register and the same layout in the mask register - it could probably profit from using the regmap_irq_chip and not bother with reimplementing irq_chip callbacks.
It is also nice for shadowing/caching of register contents I guess, wat does this driver get from regmap MMIO?
Code shrinkage IMO. Note that I'm not blocking this from being merged - I just think that using modern frameworks is always a good idea. Best regards, Bartosz Golaszewski
Yours, Linus Walleij