On Mon, 2021-09-06 at 16:20 +0800, Chen-Yu Tsai wrote:

On Sat, Sep 4, 2021 at 4:40 PM zhiyong.tao [off-list ref]
wrote:

quoted

On Thu, 2021-09-02 at 11:35 +0800, Chen-Yu Tsai wrote:

quoted

On Thu, Sep 2, 2021 at 10:54 AM zhiyong.tao <
zhiyong.tao@mediatek.com

quoted

wrote:

On Wed, 2021-09-01 at 12:35 +0800, Chen-Yu Tsai wrote:

quoted

On Mon, Aug 30, 2021 at 8:36 AM Zhiyong Tao <
zhiyong.tao@mediatek.com> wrote:

quoted

This patch adds rsel define for mt8195.

Signed-off-by: Zhiyong Tao <redacted>
---
 include/dt-bindings/pinctrl/mt65xx.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/dt-bindings/pinctrl/mt65xx.h

b/include/dt-
bindings/pinctrl/mt65xx.h
index 7e16e58fe1f7..f5934abcd1bd 100644

--- a/include/dt-bindings/pinctrl/mt65xx.h
+++ b/include/dt-bindings/pinctrl/mt65xx.h

@@ -16,6 +16,15 @@
 #define MTK_PUPD_SET_R1R0_10 102
 #define MTK_PUPD_SET_R1R0_11 103

+#define MTK_PULL_SET_RSEL_000  200
+#define MTK_PULL_SET_RSEL_001  201
+#define MTK_PULL_SET_RSEL_010  202
+#define MTK_PULL_SET_RSEL_011  203
+#define MTK_PULL_SET_RSEL_100  204
+#define MTK_PULL_SET_RSEL_101  205
+#define MTK_PULL_SET_RSEL_110  206
+#define MTK_PULL_SET_RSEL_111  207

Could you keep the spacing between constants tighter, or have
no
spacing
at all? Like having MTK_PULL_SET_RSEL_000 defined as 104 and
so
on. This
would reduce the chance of new macro values colliding with
actual
resistor
values set in the datasheets, plus a contiguous space would
be
easy to
rule as macros.

ChenYu

Hi chenyu,
By the current solution, it won't be mixed used by
MTK_PULL_SET_RSEL_XXX
and real  resistor value.
If user use MTK_PULL_SET_RSEL_XXX, They don't care the define
which
means how much resistor value.

What I meant was that by keeping the value space tight, we avoid
the
situation where in some new chip, one of the RSEL resistors
happens
to
be 200 or 300 ohms. 100 is already taken, so there's nothing we
can
do if new designs actually do have 100 ohm settings.

quoted

We think that we don't contiguous macro space for different
register.
It may increase code complexity to make having
MTK_PULL_SET_RSEL_000
defined as 104.

Can you elaborate? It is a simple range check and offset
handling.
Are
you concerned that a new design would have R2R1R0 and you would
like
the macros to be contiguous?

BTW I don't quite get why decimal base values (100, 200, etc.)
were
chosen. One would think that binary bases are easier to handle in
code.


ChenYu

Yes,we concerned that a new design would have R2R1R0 and we would
like
the macros to be contiguous in the feature. we reserve it.

I see. That makes sense. Do you expect to see R3 or even R4 in the
future?
Or put another way, do you expect to see resistor values of 150 or
200
supported?

Maybe we could reserve 200 and start from 201 for the RSEL macros?

Some planning needs to be done here to avoid value clashes.

quoted

We think that decimal and binary base values are the same for the
feature.

With decimal numbers you end up wasting a bit more space, since the
hardware is always using binary values. I just found it odd, that's
all.

ChenYu

quoted

quoted

quoted

Thanks.

Hi ChenYu,

In the next version, we provide a solution which we discussed internal
to avoid value clashes.
 
The solution:
1. We will keep the define "MTK_PULL_SET_RSEL_000 200". It won't
change.

2. We will add a property in pio dtsi node, for example,
the property name is "rsel_resistance_in_si_unit".
We will add a flag "rsel_si_unit" in pinctrl device.
in probe function, we will identify the property name
"rsel_resistance_in_si_unit" to set the flag "rsel_si_unit" value.
So it can void value clashes.

3.We will provide the define "MTK_PULL_SET_RSEL_000 200" and si unit
two solution. users can support which solution by add property
"rsel_resistance_in_si_unit" in dts node or not.

Thanks.

quoted

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 #define MTK_DRIVE_2mA  2
 #define MTK_DRIVE_4mA  4
 #define MTK_DRIVE_6mA  6
--
2.18.0
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