Thread (9 messages) 9 messages, 4 authors, 2018-02-07

[PATCH] pinctrl: msm: allow the gpio base to be configurable

From: Bjorn Andersson <hidden>
Date: 2018-01-29 00:51:33
Also in: linux-arm-msm, linux-gpio

On Sun 28 Jan 15:29 PST 2018, Timur Tabi wrote:
On 1/28/18 5:23 PM, Bjorn Andersson wrote:
quoted
What platform has multiple TLMMs?

[..]
An upcoming one.
Cool :)
quoted
quoted
diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index b7b6849625ec..4dc76e15bd14 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -901,7 +901,7 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
  		return -EINVAL;
  	chip = &pctrl->chip;
-	chip->base = 0;
quoted
My bad, this should have been -1.
Perhaps, but it's been 0 for a very long time, so I don't want to break any
existing platforms by suddenly relocating all GPIOs across all Qualcomm
platforms.
Yeah, I see that I got this wrong when I wrote the driver 4 years ago...

There should be no in-kernel users depending on these numbers being hard
coded, so anyone depending on these numbers starting at 0 would be user
space - doing so incorrectly.
What do you think about my other idea?
With static numbering of gpios you end up having cross-instance and
cross-driver tweaks to make things fit the number space. In particular
when you combine different gpio chips in different ways for different
devices this becomes a mess.

That's why the idea of static gpio numbering was abandoned a long long
time ago. So while it does solve an immediate problem for you it is
proven not to be the right solution in the long run...

Regards,
Bjorn
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