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From 7c926492d38a3feef4b4b29c91b7c03eb1b8b546 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime.ripard@free-electrons.com>
Date: Mon, 14 Nov 2016 21:53:03 +0100
Subject: 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>
---
.../bindings/pinctrl/allwinner,sunxi-pinctrl.txt | 14 ++++
drivers/pinctrl/sunxi/pinctrl-sunxi.c | 84 ++++++++++++++++++++++
drivers/pinctrl/sunxi/pinctrl-sunxi.h | 7 ++
3 files changed, 105 insertions(+)
--- 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.
--- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
+++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
@@ -1122,6 +1122,88 @@ static int sunxi_pinctrl_build_state(str
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_d
pctl);
}
+ sunxi_pinctrl_setup_debounce(pctl, node);
+
dev_info(&pdev->dev, "initialized sunXi PIO driver\n");
return 0;
--- 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(
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;
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