target/linux/sunxi/patches-4.9/0040-pinctrl-sunxi-Add-support-for-interrupt-debouncing.patch

   1 From 7c926492d38a3feef4b4b29c91b7c03eb1b8b546 Mon Sep 17 00:00:00 2001
   2 From: Maxime Ripard <maxime.ripard@free-electrons.com>
   3 Date: Mon, 14 Nov 2016 21:53:03 +0100
   4 Subject: pinctrl: sunxi: Add support for interrupt debouncing
   5
   6 The pin controller found in the Allwinner SoCs has support for interrupts
   7 debouncing.
   8
   9 However, this is not done per-pin, preventing us from using the generic
  10 pinconf binding for that, but per irq bank, which, depending on the SoC,
  11 ranges from one to five.
  12
  13 Introduce a device-wide property to deal with this using a microsecond
  14 resolution. We can re-use the per-pin input-debounce property for that, so
  15 let's do it!
  16
  17 Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
  18 Acked-by: Rob Herring <robh@kernel.org>
  19 Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
  20 ---
  21  .../bindings/pinctrl/allwinner,sunxi-pinctrl.txt   | 14 ++++
  22  drivers/pinctrl/sunxi/pinctrl-sunxi.c              | 84 ++++++++++++++++++++++
  23  drivers/pinctrl/sunxi/pinctrl-sunxi.h              |  7 ++
  24  3 files changed, 105 insertions(+)
  25
  26 --- a/Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt
  27 +++ b/Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt
  28 @@ -28,6 +28,20 @@ Required properties:
  29  - reg: Should contain the register physical address and length for the
  30    pin controller.
  31
  32 +- clocks: phandle to the clocks feeding the pin controller:
  33 +  - "apb": the gated APB parent clock
  34 +  - "hosc": the high frequency oscillator in the system
  35 +  - "losc": the low frequency oscillator in the system
  36 +
  37 +Note: For backward compatibility reasons, the hosc and losc clocks are only
  38 +required if you need to use the optional input-debounce property. Any new
  39 +device tree should set them.
  40 +
  41 +Optional properties:
  42 +  - input-debounce: Array of debouncing periods in microseconds. One period per
  43 +    irq bank found in the controller. 0 if no setup required.
  44 +
  45 +
  46  Please refer to pinctrl-bindings.txt in this directory for details of the
  47  common pinctrl bindings used by client devices.
  48
  49 --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
  50 +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
  51 @@ -1122,6 +1122,88 @@ static int sunxi_pinctrl_build_state(str
  52         return 0;
  53  }
  54
  55 +static int sunxi_pinctrl_get_debounce_div(struct clk *clk, int freq, int *diff)
  56 +{
  57 +       unsigned long clock = clk_get_rate(clk);
  58 +       unsigned int best_diff = ~0, best_div;
  59 +       int i;
  60 +
  61 +       for (i = 0; i < 8; i++) {
  62 +               int cur_diff = abs(freq - (clock >> i));
  63 +
  64 +               if (cur_diff < best_diff) {
  65 +                       best_diff = cur_diff;
  66 +                       best_div = i;
  67 +               }
  68 +       }
  69 +
  70 +       *diff = best_diff;
  71 +       return best_div;
  72 +}
  73 +
  74 +static int sunxi_pinctrl_setup_debounce(struct sunxi_pinctrl *pctl,
  75 +                                       struct device_node *node)
  76 +{
  77 +       unsigned int hosc_diff, losc_diff;
  78 +       unsigned int hosc_div, losc_div;
  79 +       struct clk *hosc, *losc;
  80 +       u8 div, src;
  81 +       int i, ret;
  82 +
  83 +       /* Deal with old DTs that didn't have the oscillators */
  84 +       if (of_count_phandle_with_args(node, "clocks", "#clock-cells") != 3)
  85 +               return 0;
  86 +
  87 +       /* If we don't have any setup, bail out */
  88 +       if (!of_find_property(node, "input-debounce", NULL))
  89 +               return 0;
  90 +
  91 +       losc = devm_clk_get(pctl->dev, "losc");
  92 +       if (IS_ERR(losc))
  93 +               return PTR_ERR(losc);
  94 +
  95 +       hosc = devm_clk_get(pctl->dev, "hosc");
  96 +       if (IS_ERR(hosc))
  97 +               return PTR_ERR(hosc);
  98 +
  99 +       for (i = 0; i < pctl->desc->irq_banks; i++) {
 100 +               unsigned long debounce_freq;
 101 +               u32 debounce;
 102 +
 103 +               ret = of_property_read_u32_index(node, "input-debounce",
 104 +                                                i, &debounce);
 105 +               if (ret)
 106 +                       return ret;
 107 +
 108 +               if (!debounce)
 109 +                       continue;
 110 +
 111 +               debounce_freq = DIV_ROUND_CLOSEST(USEC_PER_SEC, debounce);
 112 +               losc_div = sunxi_pinctrl_get_debounce_div(losc,
 113 +                                                         debounce_freq,
 114 +                                                         &losc_diff);
 115 +
 116 +               hosc_div = sunxi_pinctrl_get_debounce_div(hosc,
 117 +                                                         debounce_freq,
 118 +                                                         &hosc_diff);
 119 +
 120 +               if (hosc_diff < losc_diff) {
 121 +                       div = hosc_div;
 122 +                       src = 1;
 123 +               } else {
 124 +                       div = losc_div;
 125 +                       src = 0;
 126 +               }
 127 +
 128 +               writel(src | div << 4,
 129 +                      pctl->membase +
 130 +                      sunxi_irq_debounce_reg_from_bank(i,
 131 +                                                       pctl->desc->irq_bank_base));
 132 +       }
 133 +
 134 +       return 0;
 135 +}
 136 +
 137  int sunxi_pinctrl_init(struct platform_device *pdev,
 138                        const struct sunxi_pinctrl_desc *desc)
 139  {
 140 @@ -1284,6 +1366,8 @@ int sunxi_pinctrl_init(struct platform_d
 141                                                  pctl);
 142         }
 143
 144 +       sunxi_pinctrl_setup_debounce(pctl, node);
 145 +
 146         dev_info(&pdev->dev, "initialized sunXi PIO driver\n");
 147
 148         return 0;
 149 --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.h
 150 +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
 151 @@ -69,6 +69,8 @@
 152  #define IRQ_STATUS_IRQ_BITS            1
 153  #define IRQ_STATUS_IRQ_MASK            ((1 << IRQ_STATUS_IRQ_BITS) - 1)
 154
 155 +#define IRQ_DEBOUNCE_REG       0x218
 156 +
 157  #define IRQ_MEM_SIZE           0x20
 158
 159  #define IRQ_EDGE_RISING                0x00
 160 @@ -265,6 +267,11 @@ static inline u32 sunxi_irq_ctrl_offset(
 161         return irq_num * IRQ_CTRL_IRQ_BITS;
 162  }
 163
 164 +static inline u32 sunxi_irq_debounce_reg_from_bank(u8 bank, unsigned bank_base)
 165 +{
 166 +       return IRQ_DEBOUNCE_REG + (bank_base + bank) * IRQ_MEM_SIZE;
 167 +}
 168 +
 169  static inline u32 sunxi_irq_status_reg_from_bank(u8 bank, unsigned bank_base)
 170  {
 171         return IRQ_STATUS_REG + (bank_base + bank) * IRQ_MEM_SIZE;