Re: [PATCH 1/5] drivers: input: keyboard: st-keyscan: add keyscan driver

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: 2014-03-05 06:46:12
Also in: linux-arm-kernel, linux-input, lkml

Hi Gabriel,

On Wed, Mar 05, 2014 at 04:39:28AM +0100, Gabriel FERNANDEZ wrote:

quoted hunk ↗ jump to hunk

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: Giuseppe Condorelli <redacted>
Signed-off-by: Gabriel Fernandez <redacted>
---
 .../devicetree/bindings/input/st-keypad.txt        |  50 ++++
 drivers/input/keyboard/Kconfig                     |  12 +
 drivers/input/keyboard/Makefile                    |   1 +
 drivers/input/keyboard/st-keyscan.c                | 323 +++++++++++++++++++++
 4 files changed, 386 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/st-keypad.txt
 create mode 100644 drivers/input/keyboard/st-keyscan.c

diff --git a/Documentation/devicetree/bindings/input/st-keypad.txt b/Documentation/devicetree/bindings/input/st-keypad.txt
new file mode 100644
index 0000000..63eb07a
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/st-keypad.txt

@@ -0,0 +1,50 @@
+* ST Keypad controller device tree bindings
+
+The ST keypad controller device tree binding is based on the
+matrix-keymap.
+
+Required properties:
+
+- compatible: "st,keypad"
+
+- reg: Register base address of st-keypad controler.
+
+- interrupts: Interrupt numberof st-keypad controler.
+
+- clocks: Must contain one entry, for the module clock.
+  See ../clocks/clock-bindings.txt for details.
+
+- pinctrl-0: Should specify pin control groups used for this controller.
+
+- pinctrl-names: Should contain only one value - "default".
+
+- 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.
+
+- st,debounce_us: Debouncing interval time in microseconds
+
+
+Example:
+
+keyscan: keyscan@fe4b0000 {
+	compatible = "st,keypad";
+	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 = < /* in0	in1	in2	in3 */
+		KEY_F13 KEY_F9  KEY_F5 KEY_F1		/* out0 */
+		KEY_F14 KEY_F10 KEY_F6 KEY_F2		/* out1 */
+		KEY_F15 KEY_F11 KEY_F7 KEY_F3		/* out2 */
+		KEY_F16 KEY_F12 KEY_F8 KEY_F4 >;	/* out3 */
+};

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index a673c9f..9e29125 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig

@@ -512,6 +512,18 @@ config KEYBOARD_STOWAWAY
 	  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
+	select INPUT_EVDEV
+	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 stm-keyscan.
+
 config KEYBOARD_SUNKBD
 	tristate "Sun Type 4 and Type 5 keyboard"
 	select SERIO

diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index a699b61..5fd020a 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile

@@ -50,6 +50,7 @@ obj-$(CONFIG_KEYBOARD_SH_KEYSC)		+= sh_keysc.o
 obj-$(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

diff --git a/drivers/input/keyboard/st-keyscan.c b/drivers/input/keyboard/st-keyscan.c
new file mode 100644
index 0000000..606cc19
--- /dev/null
+++ b/drivers/input/keyboard/st-keyscan.c

@@ -0,0 +1,323 @@
+/*
+ * STMicroelectronics Key Scanning driver
+ *
+ * Copyright (c) 2014 STMicroelectonics Ltd.
+ * Author: Stuart Menefy <stuart.menefy@st.com>
+ *
+ * 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		0x000
+#define KEYSCAN_CONFIG_ENABLE		1
+#define KEYSCAN_DEBOUNCE_TIME_OFF	0x004
+#define KEYSCAN_MATRIX_STATE_OFF	0x008
+#define KEYSCAN_MATRIX_DIM_OFF		0x00c
+#define KEYSCAN_MATRIX_DIM_X_SHIFT	0
+#define KEYSCAN_MATRIX_DIM_Y_SHIFT	2
+
+struct keypad_platform_data {
+	const struct matrix_keymap_data *keymap_data;
+	unsigned int num_out_pads;
+	unsigned int num_in_pads;
+	unsigned int debounce_us;
+};
+
+struct keyscan_priv {
+	void __iomem *base;
+	int irq;
+	struct clk *clk;
+	struct input_dev *input_dev;
+	struct keypad_platform_data *config;
+	unsigned int last_state;
+	u32 keycodes[ST_KEYSCAN_MAXKEYS];
+};
+
+static irqreturn_t keyscan_isr(int irq, void *dev_id)
+{
+	struct platform_device *pdev = dev_id;
+	struct keyscan_priv *priv = platform_get_drvdata(pdev);
+	int state;
+	int change;
+
+	state = readl(priv->base + KEYSCAN_MATRIX_STATE_OFF) & 0xffff;
+	change = priv->last_state ^ state;
+
+	while (change) {
+		int scancode = __ffs(change);
+		int down = state & (1 << scancode);
+
+		input_report_key(priv->input_dev, priv->keycodes[scancode],
+				 down);
+		change ^= 1 << scancode;
+	};
+
+	input_sync(priv->input_dev);
+
+	priv->last_state = state;
+
+	return IRQ_HANDLED;
+}
+
+static void keyscan_start(struct keyscan_priv *priv)
+{
+	clk_enable(priv->clk);
+
+	writel(priv->config->debounce_us * (clk_get_rate(priv->clk) / 1000000),
+	       priv->base + KEYSCAN_DEBOUNCE_TIME_OFF);
+
+	writel(((priv->config->num_in_pads - 1) << KEYSCAN_MATRIX_DIM_X_SHIFT) |
+	       ((priv->config->num_out_pads - 1) << KEYSCAN_MATRIX_DIM_Y_SHIFT),
+	       priv->base + KEYSCAN_MATRIX_DIM_OFF);
+
+	writel(KEYSCAN_CONFIG_ENABLE, priv->base + KEYSCAN_CONFIG_OFF);
+}
+
+static void keyscan_stop(struct keyscan_priv *priv)
+{
+	writel(0, priv->base + KEYSCAN_CONFIG_OFF);
+
+	clk_disable(priv->clk);
+}
+
+static int keypad_matrix_key_parse_dt(struct keyscan_priv *st_kp)
+{
+	struct device *dev = st_kp->input_dev->dev.parent;
+	struct device_node *np = dev->of_node;
+	struct keypad_platform_data *pdata;
+	int error;
+
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata) {
+		dev_err(dev, "failed to allocate driver pdata\n");
+		return -ENOMEM;
+	}
+
+	error = matrix_keypad_parse_of_params(dev, &pdata->num_out_pads,
+			&pdata->num_in_pads);
+	if (error) {
+		dev_err(dev, "failed to parse keypad params\n");
+		return error;
+	}
+
+	of_property_read_u32(np, "st,debounce_us", &pdata->debounce_us);
+
+	st_kp->config = pdata;
+
+	dev_info(dev, "rows=%d col=%d debounce=%d\n",
+			pdata->num_out_pads,
+			pdata->num_in_pads,
+			pdata->debounce_us);
+
+	error = of_property_read_u32_array(np, "linux,keymap",
+					st_kp->keycodes, ST_KEYSCAN_MAXKEYS);
+	if (error) {
+		dev_err(dev, "failed to parse keymap\n");
+		return error;
+	}

Please use standard format for matrix keymap so that you can use
matrix_keypad_build_keymap().

+
+	return 0;
+}
+
+static int __init keyscan_probe(struct platform_device *pdev)
+{
+	struct keypad_platform_data *pdata =
+		dev_get_platdata(&pdev->dev);

const struct ...

+	struct keyscan_priv *st_kp;
+	struct input_dev *input_dev;
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	int len;
+	int error;
+	int i;
+
+	if (!pdata && !pdev->dev.of_node) {
+		dev_err(&pdev->dev, "no keymap defined\n");
+		return -EINVAL;
+	}
+
+	st_kp = devm_kzalloc(dev, sizeof(*st_kp), GFP_KERNEL);
+	if (!st_kp) {
+		dev_err(dev, "failed to allocate driver data\n");
+		return -ENOMEM;
+	}
+	st_kp->config = pdata;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "no I/O memory specified\n");
+		return -ENXIO;
+	}
+
+	len = resource_size(res);
+	if (!devm_request_mem_region(dev, res->start, len, pdev->name)) {
+		dev_err(dev, "failed to reserve I/O memory\n");
+		return -EBUSY;
+	}
+
+	st_kp->base = devm_ioremap_nocache(dev, res->start, len);
+	if (st_kp->base == NULL) {
+		dev_err(dev, "failed to remap I/O memory\n");
+		return -ENXIO;
+	}
+
+	st_kp->irq = platform_get_irq(pdev, 0);
+	if (st_kp->irq < 0) {
+		dev_err(dev, "no IRQ specified\n");
+		return -ENXIO;
+	}
+
+	error = devm_request_irq(dev, st_kp->irq, keyscan_isr, 0,
+				 pdev->name, pdev);
+	if (error) {
+		dev_err(dev, "failed to request IRQ\n");
+		return error;
+	}
+
+	input_dev = devm_input_allocate_device(&pdev->dev);
+	if (!input_dev) {
+		dev_err(&pdev->dev, "failed to allocate the input device\n");
+		return -ENOMEM;
+	}
+
+	st_kp->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(st_kp->clk)) {
+		dev_err(dev, "cannot get clock");
+		return PTR_ERR(st_kp->clk);
+	}
+
+	input_dev = input_allocate_device();
+	if (!input_dev) {
+		dev_err(dev, "failed to allocate input device\n");
+		return -ENOMEM;
+	}

You already allocated it once a few lines above.

+	st_kp->input_dev = input_dev;
+
+	input_dev->name = pdev->name;
+	input_dev->phys = "keyscan-keys/input0";
+	input_dev->dev.parent = dev;
+
+	input_dev->id.bustype = BUS_HOST;
+	input_dev->id.vendor = 0x0001;
+	input_dev->id.product = 0x0001;
+	input_dev->id.version = 0x0100;
+
+	if (!pdata) {
+		error = keypad_matrix_key_parse_dt(st_kp);
+		if (error)
+			return error;
+		pdata = st_kp->config;
+	}
+
+	input_dev->keycode = st_kp->keycodes;
+	input_dev->keycodesize = sizeof(st_kp->keycodes[0]);
+	input_dev->keycodemax = ARRAY_SIZE(st_kp->keycodes);
+
+	for (i = 0; i < ST_KEYSCAN_MAXKEYS; i++)
+		input_set_capability(input_dev, EV_KEY, st_kp->keycodes[i]);
+	__clear_bit(KEY_RESERVED, input_dev->keybit);
+
+	error = input_register_device(input_dev);
+	if (error) {
+		dev_err(dev, "failed to register input device\n");
+		input_free_device(input_dev);
+		platform_set_drvdata(pdev, NULL);
+		return error;
+	}
+
+	platform_set_drvdata(pdev, st_kp);
+
+	keyscan_start(st_kp);
+
+	device_set_wakeup_capable(&pdev->dev, 1);
+
+	return 0;
+}
+
+static int __exit keyscan_remove(struct platform_device *pdev)

Why is this marked as __exit? I can unbind device from driver without
unloading module (via sysfs).

+{
+	struct keyscan_priv *priv = platform_get_drvdata(pdev);
+
+	keyscan_stop(priv);

Call to keyscan_stop() shoudl go into keyscan_close() implementation.

+
+	input_unregister_device(priv->input_dev);

Not needed since you are trying to use devres-managed input device.

+	platform_set_drvdata(pdev, NULL);

Not needed. In fact, if you move keyscan_stop() into keyscan_close() you
should be able to get rid of keyscan_remove().

+
+	return 0;
+}
+
+static int keyscan_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct keyscan_priv *priv = platform_get_drvdata(pdev);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(priv->irq);
+	else
+		keyscan_stop(priv);
+
+	return 0;
+}
+
+static int keyscan_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct keyscan_priv *priv = platform_get_drvdata(pdev);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(priv->irq);
+	else
+		keyscan_start(priv);
+
+	return 0;
+}

Guard suspend/resume with CONFIG_PM_SLEEP?

+
+static const struct dev_pm_ops keyscan_dev_pm_ops = {
+	.suspend = keyscan_suspend,
+	.resume = keyscan_resume,
+};

Make it SIMPLE_DEV_PM_OPS().

+
+static const struct of_device_id keyscan_of_match[] = {
+	{ .compatible = "st,keypad" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, keyscan_of_match);
+
+__refdata struct platform_driver keyscan_device_driver = {

What is this refdata business?

+	.probe		= keyscan_probe,
+	.remove		= __exit_p(keyscan_remove),
+	.driver		= {
+		.name	= "st-keyscan",
+		.pm	= &keyscan_dev_pm_ops,
+		.of_match_table = of_match_ptr(keyscan_of_match),
+	}
+};
+
+static int __init keyscan_init(void)
+{
+	return platform_driver_register(&keyscan_device_driver);
+}
+
+static void __exit keyscan_exit(void)
+{
+	platform_driver_unregister(&keyscan_device_driver);
+}
+
+module_init(keyscan_init);
+module_exit(keyscan_exit);

I think we have module_platform_drriver() for this.

+
+MODULE_AUTHOR("Stuart Menefy [off-list ref]");
+MODULE_DESCRIPTION("STMicroelectronics keyscan device driver");
+MODULE_LICENSE("GPL");
-- 
1.9.0

Thanks.

-- 
Dmitry

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