Input: add st-keyscan driver

This patch adds ST Keyscan driver to use the keypad hw a subset of ST
boards provide. Specific board setup will be put in the given dt.

Signed-off-by: Gabriel Fernandez <[e-mail]>
Signed-off-by: Giuseppe Condorelli <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

Documentation/devicetree/bindings/input/st-keyscan.txt

···
+* ST Keyscan controller Device Tree bindings
+
+The ST keyscan controller Device Tree binding is based on the
+matrix-keymap.
+
+Required properties:
+- compatible: "st,sti-keyscan"
+
+- reg: Register base address and size of st-keyscan controller.
+
+- interrupts: Interrupt number for the st-keyscan controller.
+
+- clocks: Must contain one entry, for the module clock.
+  See ../clocks/clock-bindings.txt for details.
+
+- pinctrl: Should specify pin control groups used for this controller.
+  See ../pinctrl/pinctrl-bindings.txt for details.
+
+- linux,keymap: The keymap for keys as described in the binding document
+  devicetree/bindings/input/matrix-keymap.txt.
+
+- keypad,num-rows: Number of row lines connected to the keypad controller.
+
+- keypad,num-columns: Number of column lines connected to the keypad
+  controller.
+
+Optional property:
+- st,debounce_us: Debouncing interval time in microseconds
+
+Example:
+
+keyscan: keyscan@fe4b0000 {
+	compatible = "st,sti-keyscan";
+	reg = <0xfe4b0000 0x2000>;
+	interrupts = <GIC_SPI 212 IRQ_TYPE_NONE>;
+	clocks	= <&CLK_SYSIN>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_keyscan>;
+
+	keypad,num-rows = <4>;
+	keypad,num-columns = <4>;
+	st,debounce_us = <5000>;
+
+	linux,keymap = < MATRIX_KEY(0x00, 0x00, KEY_F13)
+			 MATRIX_KEY(0x00, 0x01, KEY_F9)
+			 MATRIX_KEY(0x00, 0x02, KEY_F5)
+			 MATRIX_KEY(0x00, 0x03, KEY_F1)
+			 MATRIX_KEY(0x01, 0x00, KEY_F14)
+			 MATRIX_KEY(0x01, 0x01, KEY_F10)
+			 MATRIX_KEY(0x01, 0x02, KEY_F6)
+			 MATRIX_KEY(0x01, 0x03, KEY_F2)
+			 MATRIX_KEY(0x02, 0x00, KEY_F15)
+			 MATRIX_KEY(0x02, 0x01, KEY_F11)
+			 MATRIX_KEY(0x02, 0x02, KEY_F7)
+			 MATRIX_KEY(0x02, 0x03, KEY_F3)
+			 MATRIX_KEY(0x03, 0x00, KEY_F16)
+			 MATRIX_KEY(0x03, 0x01, KEY_F12)
+			 MATRIX_KEY(0x03, 0x02, KEY_F8)
+			 MATRIX_KEY(0x03, 0x03, KEY_F4) >;
+	};

drivers/input/keyboard/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called stowaway.
 
+config KEYBOARD_ST_KEYSCAN
+	tristate "STMicroelectronics keyscan support"
+	depends on ARCH_STI || COMPILE_TEST
+	select INPUT_MATRIXKMAP
+	help
+	  Say Y here if you want to use a keypad attached to the keyscan block
+	  on some STMicroelectronics SoC devices.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called st-keyscan.
+
 config KEYBOARD_SUNKBD
 	tristate "Sun Type 4 and Type 5 keyboard"
 	select SERIO

drivers/input/keyboard/Makefile

···
 obj-$(CONFIG_KEYBOARD_SPEAR)		+= spear-keyboard.o
 obj-$(CONFIG_KEYBOARD_STMPE)		+= stmpe-keypad.o
 obj-$(CONFIG_KEYBOARD_STOWAWAY)		+= stowaway.o
+obj-$(CONFIG_KEYBOARD_ST_KEYSCAN)	+= st-keyscan.o
 obj-$(CONFIG_KEYBOARD_SUNKBD)		+= sunkbd.o
 obj-$(CONFIG_KEYBOARD_TC3589X)		+= tc3589x-keypad.o
 obj-$(CONFIG_KEYBOARD_TEGRA)		+= tegra-kbc.o

drivers/input/keyboard/st-keyscan.c

···
+/*
+ * STMicroelectronics Key Scanning driver
+ *
+ * Copyright (c) 2014 STMicroelectonics Ltd.
+ * Author: Stuart Menefy <[e-mail]>
+ *
+ * Based on sh_keysc.c, copyright 2008 Magnus Damm
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/input/matrix_keypad.h>
+
+#define ST_KEYSCAN_MAXKEYS 16
+
+#define KEYSCAN_CONFIG_OFF		0x0
+#define KEYSCAN_CONFIG_ENABLE		0x1
+#define KEYSCAN_DEBOUNCE_TIME_OFF	0x4
+#define KEYSCAN_MATRIX_STATE_OFF	0x8
+#define KEYSCAN_MATRIX_DIM_OFF		0xc
+#define KEYSCAN_MATRIX_DIM_X_SHIFT	0x0
+#define KEYSCAN_MATRIX_DIM_Y_SHIFT	0x2
+
+struct st_keyscan {
+	void __iomem *base;
+	int irq;
+	struct clk *clk;
+	struct input_dev *input_dev;
+	unsigned long last_state;
+	unsigned int n_rows;
+	unsigned int n_cols;
+	unsigned int debounce_us;
+};
+
+static irqreturn_t keyscan_isr(int irq, void *dev_id)
+{
+	struct st_keyscan *keypad = dev_id;
+	unsigned short *keycode = keypad->input_dev->keycode;
+	unsigned long state, change;
+	int bit_nr;
+
+	state = readl(keypad->base + KEYSCAN_MATRIX_STATE_OFF) & 0xffff;
+	change = keypad->last_state ^ state;
+	keypad->last_state = state;
+
+	for_each_set_bit(bit_nr, &change, BITS_PER_LONG)
+		input_report_key(keypad->input_dev,
+				 keycode[bit_nr], state & BIT(bit_nr));
+
+	input_sync(keypad->input_dev);
+
+	return IRQ_HANDLED;
+}
+
+static int keyscan_start(struct st_keyscan *keypad)
+{
+	int error;
+
+	error = clk_enable(keypad->clk);
+	if (error)
+		return error;
+
+	writel(keypad->debounce_us * (clk_get_rate(keypad->clk) / 1000000),
+	       keypad->base + KEYSCAN_DEBOUNCE_TIME_OFF);
+
+	writel(((keypad->n_cols - 1) << KEYSCAN_MATRIX_DIM_X_SHIFT) |
+	       ((keypad->n_rows - 1) << KEYSCAN_MATRIX_DIM_Y_SHIFT),
+	       keypad->base + KEYSCAN_MATRIX_DIM_OFF);
+
+	writel(KEYSCAN_CONFIG_ENABLE, keypad->base + KEYSCAN_CONFIG_OFF);
+
+	return 0;
+}
+
+static void keyscan_stop(struct st_keyscan *keypad)
+{
+	writel(0, keypad->base + KEYSCAN_CONFIG_OFF);
+
+	clk_disable(keypad->clk);
+}
+
+static int keyscan_open(struct input_dev *dev)
+{
+	struct st_keyscan *keypad = input_get_drvdata(dev);
+
+	return keyscan_start(keypad);
+}
+
+static void keyscan_close(struct input_dev *dev)
+{
+	struct st_keyscan *keypad = input_get_drvdata(dev);
+
+	keyscan_stop(keypad);
+}
+
+static int keypad_matrix_key_parse_dt(struct st_keyscan *keypad_data)
+{
+	struct device *dev = keypad_data->input_dev->dev.parent;
+	struct device_node *np = dev->of_node;
+	int error;
+
+	error = matrix_keypad_parse_of_params(dev, &keypad_data->n_rows,
+					      &keypad_data->n_cols);
+	if (error) {
+		dev_err(dev, "failed to parse keypad params\n");
+		return error;
+	}
+
+	of_property_read_u32(np, "st,debounce-us", &keypad_data->debounce_us);
+
+	dev_dbg(dev, "n_rows=%d n_col=%d debounce=%d\n",
+		keypad_data->n_rows, keypad_data->n_cols,
+		keypad_data->debounce_us);
+
+	return 0;
+}
+
+static int keyscan_probe(struct platform_device *pdev)
+{
+	struct st_keyscan *keypad_data;
+	struct input_dev *input_dev;
+	struct resource *res;
+	int error;
+
+	if (!pdev->dev.of_node) {
+		dev_err(&pdev->dev, "no DT data present\n");
+		return -EINVAL;
+	}
+
+	keypad_data = devm_kzalloc(&pdev->dev, sizeof(*keypad_data),
+				   GFP_KERNEL);
+	if (!keypad_data)
+		return -ENOMEM;
+
+	input_dev = devm_input_allocate_device(&pdev->dev);
+	if (!input_dev) {
+		dev_err(&pdev->dev, "failed to allocate the input device\n");
+		return -ENOMEM;
+	}
+
+	input_dev->name = pdev->name;
+	input_dev->phys = "keyscan-keys/input0";
+	input_dev->dev.parent = &pdev->dev;
+	input_dev->open = keyscan_open;
+	input_dev->close = keyscan_close;
+
+	input_dev->id.bustype = BUS_HOST;
+
+	error = keypad_matrix_key_parse_dt(keypad_data);
+	if (error)
+		return error;
+
+	error = matrix_keypad_build_keymap(NULL, NULL,
+					   keypad_data->n_rows,
+					   keypad_data->n_cols,
+					   NULL, input_dev);
+	if (error) {
+		dev_err(&pdev->dev, "failed to build keymap\n");
+		return error;
+	}
+
+	input_set_drvdata(input_dev, keypad_data);
+
+	keypad_data->input_dev = input_dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	keypad_data->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(keypad_data->base))
+		return PTR_ERR(keypad_data->base);
+
+	keypad_data->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(keypad_data->clk)) {
+		dev_err(&pdev->dev, "cannot get clock\n");
+		return PTR_ERR(keypad_data->clk);
+	}
+
+	error = clk_enable(keypad_data->clk);
+	if (error) {
+		dev_err(&pdev->dev, "failed to enable clock\n");
+		return error;
+	}
+
+	keyscan_stop(keypad_data);
+
+	keypad_data->irq = platform_get_irq(pdev, 0);
+	if (keypad_data->irq < 0) {
+		dev_err(&pdev->dev, "no IRQ specified\n");
+		return -EINVAL;
+	}
+
+	error = devm_request_irq(&pdev->dev, keypad_data->irq, keyscan_isr, 0,
+				 pdev->name, keypad_data);
+	if (error) {
+		dev_err(&pdev->dev, "failed to request IRQ\n");
+		return error;
+	}
+
+	error = input_register_device(input_dev);
+	if (error) {
+		dev_err(&pdev->dev, "failed to register input device\n");
+		return error;
+	}
+
+	platform_set_drvdata(pdev, keypad_data);
+
+	device_set_wakeup_capable(&pdev->dev, 1);
+
+	return 0;
+}
+
+static int keyscan_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct st_keyscan *keypad = platform_get_drvdata(pdev);
+	struct input_dev *input = keypad->input_dev;
+
+	mutex_lock(&input->mutex);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(keypad->irq);
+	else if (input->users)
+		keyscan_stop(keypad);
+
+	mutex_unlock(&input->mutex);
+	return 0;
+}
+
+static int keyscan_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct st_keyscan *keypad = platform_get_drvdata(pdev);
+	struct input_dev *input = keypad->input_dev;
+	int retval = 0;
+
+	mutex_lock(&input->mutex);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(keypad->irq);
+	else if (input->users)
+		retval = keyscan_start(keypad);
+
+	mutex_unlock(&input->mutex);
+	return retval;
+}
+
+static SIMPLE_DEV_PM_OPS(keyscan_dev_pm_ops, keyscan_suspend, keyscan_resume);
+
+static const struct of_device_id keyscan_of_match[] = {
+	{ .compatible = "st,sti-keyscan" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, keyscan_of_match);
+
+static struct platform_driver keyscan_device_driver = {
+	.probe		= keyscan_probe,
+	.driver		= {
+		.name	= "st-keyscan",
+		.pm	= &keyscan_dev_pm_ops,
+		.of_match_table = of_match_ptr(keyscan_of_match),
+	}
+};
+
+module_platform_driver(keyscan_device_driver);
+
+MODULE_AUTHOR("Stuart Menefy <[e-mail]>");
+MODULE_DESCRIPTION("STMicroelectronics keyscan device driver");
+MODULE_LICENSE("GPL");