pinctrl: sunxi: Add support for interrupt debouncing

The pin controller found in the Allwinner SoCs has support for interrupts
debouncing.

However, this is not done per-pin, preventing us from using the generic
pinconf binding for that, but per irq bank, which, depending on the SoC,
ranges from one to five.

Introduce a device-wide property to deal with this using a microsecond
resolution. We can re-use the per-pin input-debounce property for that, so
let's do it!

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt
index 35eef433e518776f07c137ead8fa686445339a12..de1378b4efadca8bc6b39c428f486a1c77c3aad0 100644 (file)
--- a/Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt
+++ b/Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt
@@ -28,6 +28,20 @@ Required properties:
 - reg: Should contain the register physical address and length for the
   pin controller.
 
+- clocks: phandle to the clocks feeding the pin controller:
+  - "apb": the gated APB parent clock
+  - "hosc": the high frequency oscillator in the system
+  - "losc": the low frequency oscillator in the system
+
+Note: For backward compatibility reasons, the hosc and losc clocks are only
+required if you need to use the optional input-debounce property. Any new
+device tree should set them.
+
+Optional properties:
+  - input-debounce: Array of debouncing periods in microseconds. One period per
+    irq bank found in the controller. 0 if no setup required.
+
+
 Please refer to pinctrl-bindings.txt in this directory for details of the
 common pinctrl bindings used by client devices.
 

diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.c b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
index fa11a3100346a81226965fcb077368ffb2808d31..2339d4718b4dbfae9d14d36655cb716b04253a10 100644 (file)
--- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
+++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
@@ -1122,6 +1122,88 @@ static int sunxi_pinctrl_build_state(struct platform_device *pdev)
        return 0;
 }
 
+static int sunxi_pinctrl_get_debounce_div(struct clk *clk, int freq, int *diff)
+{
+       unsigned long clock = clk_get_rate(clk);
+       unsigned int best_diff = ~0, best_div;
+       int i;
+
+       for (i = 0; i < 8; i++) {
+               int cur_diff = abs(freq - (clock >> i));
+
+               if (cur_diff < best_diff) {
+                       best_diff = cur_diff;
+                       best_div = i;
+               }
+       }
+
+       *diff = best_diff;
+       return best_div;
+}
+
+static int sunxi_pinctrl_setup_debounce(struct sunxi_pinctrl *pctl,
+                                       struct device_node *node)
+{
+       unsigned int hosc_diff, losc_diff;
+       unsigned int hosc_div, losc_div;
+       struct clk *hosc, *losc;
+       u8 div, src;
+       int i, ret;
+
+       /* Deal with old DTs that didn't have the oscillators */
+       if (of_count_phandle_with_args(node, "clocks", "#clock-cells") != 3)
+               return 0;
+
+       /* If we don't have any setup, bail out */
+       if (!of_find_property(node, "input-debounce", NULL))
+               return 0;
+
+       losc = devm_clk_get(pctl->dev, "losc");
+       if (IS_ERR(losc))
+               return PTR_ERR(losc);
+
+       hosc = devm_clk_get(pctl->dev, "hosc");
+       if (IS_ERR(hosc))
+               return PTR_ERR(hosc);
+
+       for (i = 0; i < pctl->desc->irq_banks; i++) {
+               unsigned long debounce_freq;
+               u32 debounce;
+
+               ret = of_property_read_u32_index(node, "input-debounce",
+                                                i, &debounce);
+               if (ret)
+                       return ret;
+
+               if (!debounce)
+                       continue;
+
+               debounce_freq = DIV_ROUND_CLOSEST(USEC_PER_SEC, debounce);
+               losc_div = sunxi_pinctrl_get_debounce_div(losc,
+                                                         debounce_freq,
+                                                         &losc_diff);
+
+               hosc_div = sunxi_pinctrl_get_debounce_div(hosc,
+                                                         debounce_freq,
+                                                         &hosc_diff);
+
+               if (hosc_diff < losc_diff) {
+                       div = hosc_div;
+                       src = 1;
+               } else {
+                       div = losc_div;
+                       src = 0;
+               }
+
+               writel(src | div << 4,
+                      pctl->membase +
+                      sunxi_irq_debounce_reg_from_bank(i,
+                                                       pctl->desc->irq_bank_base));
+       }
+
+       return 0;
+}
+
 int sunxi_pinctrl_init(struct platform_device *pdev,
                       const struct sunxi_pinctrl_desc *desc)
 {
@@ -1284,6 +1366,8 @@ int sunxi_pinctrl_init(struct platform_device *pdev,
                                                 pctl);
        }
 
+       sunxi_pinctrl_setup_debounce(pctl, node);
+
        dev_info(&pdev->dev, "initialized sunXi PIO driver\n");
 
        return 0;

diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.h b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
index a7efb31d65234742bb0ea1ca1268844cdd50dabb..f78a44a03189fa2bf7124c1ce5f9d47c8e37278c 100644 (file)
--- a/drivers/pinctrl/sunxi/pinctrl-sunxi.h
+++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
@@ -69,6 +69,8 @@
 #define IRQ_STATUS_IRQ_BITS            1
 #define IRQ_STATUS_IRQ_MASK            ((1 << IRQ_STATUS_IRQ_BITS) - 1)
 
+#define IRQ_DEBOUNCE_REG       0x218
+
 #define IRQ_MEM_SIZE           0x20
 
 #define IRQ_EDGE_RISING                0x00
@@ -265,6 +267,11 @@ static inline u32 sunxi_irq_ctrl_offset(u16 irq)
        return irq_num * IRQ_CTRL_IRQ_BITS;
 }
 
+static inline u32 sunxi_irq_debounce_reg_from_bank(u8 bank, unsigned bank_base)
+{
+       return IRQ_DEBOUNCE_REG + (bank_base + bank) * IRQ_MEM_SIZE;
+}
+
 static inline u32 sunxi_irq_status_reg_from_bank(u8 bank, unsigned bank_base)
 {
        return IRQ_STATUS_REG + (bank_base + bank) * IRQ_MEM_SIZE;