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Subject: [PATCH] pinctrl/sunxi: adding input-debounce-ns property
To:     Maxime Ripard <maxime@cerno.tech>, wens@csie.org,
        Jernej Skrabec <jernej.skrabec@siol.net>
Cc:     dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <d244aa6b-00b7-d768-83cb-e5a228b7ee08@trexom.it>
 <20210114081732.9386-1-giulio.benetti@benettiengineering.com>
 <20210114114219.faulkwww3dhdqwmc@gilmour>
From:   Marjan Pascolo <marjan.pascolo@trexom.it>
Message-ID: <c3bc06e3-4193-dc0b-b2b3-d54636481e28@trexom.it>
Date:   Wed, 10 Feb 2021 17:22:37 +0100
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On Allwinner SoC interrupt debounce can be controlled by two oscillator
(32KHz and 24MHz) and a prescale divider.
Oscillator and prescale divider are set through
device tree property "input-debounce" which have 1uS accuracy.
For acheive nS precision a new device tree poperty is made
named "input-debounce-ns".
"input-debounce-ns" is checked only if "input-debounce"
property is not defined.


Suggested-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Marjan Pascolo <marjan.pascolo@trexom.it>
---
---
 ?.../pinctrl/allwinner,sun4i-a10-pinctrl.yaml? |? 9 +++++++
 ?drivers/pinctrl/sunxi/pinctrl-sunxi.c???????? | 25 ++++++++++++++++---
 ?2 files changed, 30 insertions(+), 4 deletions(-)

diff --git 
a/Documentation/devicetree/bindings/pinctrl/allwinner,sun4i-a10-pinctrl.yaml 
b/Documentation/devicetree/bindings/pinctrl/allwinner,sun4i-a10-pinctrl.yaml
index 5240487dfe50..346776de3a44 100644
--- 
a/Documentation/devicetree/bindings/pinctrl/allwinner,sun4i-a10-pinctrl.yaml
+++ 
b/Documentation/devicetree/bindings/pinctrl/allwinner,sun4i-a10-pinctrl.yaml
@@ -93,6 +93,15 @@ properties:
 ???? minItems: 1
 ???? maxItems: 5

+? input-debounce-ns:
+??? description:
+????? Debouncing periods in nanoseconds, one period per interrupt
+????? bank found in the controller.
+????? Only checked if input-debounce is not present
+??? $ref: /schemas/types.yaml#/definitions/uint32-array
+??? minItems: 1
+??? maxItems: 5
+
 ?patternProperties:
 ?? # It's pretty scary, but the basic idea is that:
 ?? #?? - One node name can start with either s- or r- for PRCM nodes,
diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.c 
b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
index dc8d39ae045b..869b6d5743ba 100644
--- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
+++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
@@ -1335,14 +1335,31 @@ static int sunxi_pinctrl_setup_debounce(struct 
sunxi_pinctrl *pctl,
 ???? struct clk *hosc, *losc;
 ???? u8 div, src;
 ???? int i, ret;
+??? /* Keeping for loop below clean */
+??? const char* debounce_prop_name;
+??? unsigned long debounce_dividend;

 ???? /* Deal with old DTs that didn't have the oscillators */
 ???? if (of_clk_get_parent_count(node) != 3)
 ???? ??? return 0;

+??? /*
+??? ?* Distinguish between simple input-debounce
+??? ?* and new input-debounce-ns
+??? ?*/
+
 ???? /* If we don't have any setup, bail out */
-??? if (!of_find_property(node, "input-debounce", NULL))
-??? ??? return 0;
+??? if (!of_find_property(node, "input-debounce", NULL)) {
+??? ??? if(!of_find_property(node, "input-debounce-ns", NULL)) {
+??? ??? ??? return 0;
+??? ??? } else {
+??? ??? ??? debounce_prop_name="input-debounce-ns";
+??? ??? ??? debounce_dividend=NSEC_PER_SEC;
+??? ??? }
+??? } else {
+??? ??? debounce_prop_name="input-debounce";
+??? ??? debounce_dividend=USEC_PER_SEC;
+??? }

 ???? losc = devm_clk_get(pctl->dev, "losc");
 ???? if (IS_ERR(losc))
@@ -1356,7 +1373,7 @@ static int sunxi_pinctrl_setup_debounce(struct 
sunxi_pinctrl *pctl,
 ???? ??? unsigned long debounce_freq;
 ???? ??? u32 debounce;

-??? ??? ret = of_property_read_u32_index(node, "input-debounce",
+??? ??? ret = of_property_read_u32_index(node, debounce_prop_name,
 ???? ??? ??? ??? ??? ??? ?i, &debounce);
 ???? ??? if (ret)
 ???? ??? ??? return ret;
@@ -1364,7 +1381,7 @@ static int sunxi_pinctrl_setup_debounce(struct 
sunxi_pinctrl *pctl,
 ???? ??? if (!debounce)
 ???? ??? ??? continue;

-??? ??? debounce_freq = DIV_ROUND_CLOSEST(USEC_PER_SEC, debounce);
+??? ??? debounce_freq = DIV_ROUND_CLOSEST(debounce_dividend, debounce);
 ???? ??? losc_div = sunxi_pinctrl_get_debounce_div(losc,
 ???? ??? ??? ??? ??? ??? ??? ? debounce_freq,
 ???? ??? ??? ??? ??? ??? ??? ? &losc_diff);
-- 
2.22.0.windows.1