linux-kernel - [PATCH] pinctrl/sunxi: adding input-debounce-ns property

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Message-ID: <c3bc06e3-4193-dc0b-b2b3-d54636481e28@trexom.it>
Date:   Wed, 10 Feb 2021 17:22:37 +0100
From:   Marjan Pascolo <marjan.pascolo@...xom.it>
To:     Maxime Ripard <maxime@...no.tech>, wens@...e.org,
        Jernej Skrabec <jernej.skrabec@...l.net>
Cc:     dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] pinctrl/sunxi: adding input-debounce-ns property

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@...no.tech>
Signed-off-by: Marjan Pascolo <marjan.pascolo@...xom.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