Message-ID: <20150917130520.GD4684@lukather>
Date:	Thu, 17 Sep 2015 15:05:20 +0200
From:	Maxime Ripard <maxime.ripard@...e-electrons.com>
To:	yassinjaffer@...il.com
Cc:	linux-sunxi@...glegroups.com, dmitry.torokhov@...il.com,
	linux-input@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] input: Add new sun4i-keypad driver

Hi,

On Wed, Sep 16, 2015 at 12:05:56AM +1000, yassinjaffer@...il.com wrote:
> From: Yassin Jaffer <yassinjaffer@...il.com>
> 
> Allwinnner SUN4i Keypad controller is used to interface a SoC
> with a matrix-typekeypad device.
> The keypad controller supports multiple row and column lines.
> A key can be placed at each intersection of a unique
> row and a unique column.
> The keypad controller can sense a key-press and key-release and report the
> event using a interrupt to the cpu.
> This patch adds a driver support to this.
> The keypad controller driver does not give proper information
> if more that two keys are selected.
> 
> Signed-off-by: Yassin Jaffer <yassinjaffer@...il.com>
> ---
>  drivers/input/keyboard/Kconfig        |  11 ++
>  drivers/input/keyboard/Makefile       |   1 +
>  drivers/input/keyboard/sun4i-keypad.c | 361 ++++++++++++++++++++++++++++++++++
>  3 files changed, 373 insertions(+)
>  create mode 100644 drivers/input/keyboard/sun4i-keypad.c
> 
> diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
> index 2e80107..4f2f3f8 100644
> --- a/drivers/input/keyboard/Kconfig
> +++ b/drivers/input/keyboard/Kconfig
> @@ -590,6 +590,17 @@ config KEYBOARD_SUN4I_LRADC
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called sun4i-lradc-keys.
>  
> +config KEYBOARD_SUN4I_KEYPAD
> +	tristate "Allwinner sun4i keypad support"
> +	depends on ARCH_SUNXI

Is this IP found on all the know SoCs, or just a subset of them?

You probably want to add || COMPILE_TEST in that depends on too.

> +	select INPUT_MATRIXKMAP
> +	help
> +	  This selects support for the Allwinner keypad
> +	  on Allwinner sunxi SoCs.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called sun4i-keypad.
> +
>  config KEYBOARD_DAVINCI
>  	tristate "TI DaVinci Key Scan"
>  	depends on ARCH_DAVINCI_DM365
> diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
> index 1d416dd..d9f54b4 100644
> --- a/drivers/input/keyboard/Makefile
> +++ b/drivers/input/keyboard/Makefile
> @@ -57,6 +57,7 @@ obj-$(CONFIG_KEYBOARD_STMPE)		+= stmpe-keypad.o
>  obj-$(CONFIG_KEYBOARD_STOWAWAY)		+= stowaway.o
>  obj-$(CONFIG_KEYBOARD_ST_KEYSCAN)	+= st-keyscan.o
>  obj-$(CONFIG_KEYBOARD_SUN4I_LRADC)	+= sun4i-lradc-keys.o
> +obj-$(CONFIG_KEYBOARD_SUN4I_KEYPAD)	+= sun4i-keypad.o
>  obj-$(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/sun4i-keypad.c b/drivers/input/keyboard/sun4i-keypad.c
> new file mode 100644
> index 0000000..995f9665
> --- /dev/null
> +++ b/drivers/input/keyboard/sun4i-keypad.c
> @@ -0,0 +1,361 @@
> +/*
> + * Allwinner sun4i keypad Controller driver
> + *
> + * Copyright (C) 2015 Yassin Jaffer <yassinjaffer@...il.com>
> + *
> + * Parts of this software are based on (derived from):
> + * Copyright (C) 2013-2015 liming@...winnertech.com,
> + *			 qys<qinyongshen@...winnertech.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/interrupt.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/of_platform.h>
> +#include <linux/slab.h>
> +#include <linux/input.h>
> +#include <linux/input/matrix_keypad.h>
> +
> +/*
> + * Keypad Controller registers
> + */
> +#define KP_CTL			0x00  /* Keypad Control register */
> +#define KP_TIMING		0x04  /* Keypad Timing register */
> +#define KP_INT_CFG		0x08  /* Keypad interrupt Config register */
> +#define KP_INT_STA		0x0c  /* Keypad interrupt Status register */
> +
> +#define KP_IN_OFFSET		0x10 /* Keypad Input Data register 0 */
> +#define KP_INX_OFFSET(reg_n)	(KP_IN_OFFSET + 4 * (reg_n))
> +
> +/* KP_CTL bits */
> +#define ENABLE(x)		((x) << 0)
> +#define COLMASK(x)		((~x & 0xff) << 8)
> +#define ROWMASK(x)		((~x & 0xff) << 16)

Having the name of the register in that define would be great, to spot
more easily issues (writing a value to another register, for example).

Something like KP_CTL_ENABLE(x) in this case.

> +/* KP_TIMING bits */
> +#define SCAN_CYCLE(x)		((x) << 0)
> +#define DBC_CYCLE(x)		((x) << 16)
> +
> +/* KP_INT_CFG bits */
> +#define KP_IRQ_FEDGE		BIT(0)
> +#define	KP_IRQ_REDGE		BIT(1)
> +
> +/* KP_INT_STA bits */
> +#define KP_STA_FEDGE		BIT(0)
> +#define	KP_STA_REDGE		BIT(1)
> +
> +#define KP_MAX_ROWS		8
> +#define KP_MAX_COLS		8
> +#define N_ROWS_REG		2
> +#define KP_ROW_SHIFT		3
> +#define KP_BIT_SHIFT            32
> +
> +#define MAX_MATRIX_KEY_NUM	(KP_MAX_ROWS * KP_MAX_COLS)
> +
> +#define KP_BASE_CLK		1000000
> +#define MIN_CYCLE		0x10
> +#define MIN_SCAN_CYCLE		0x100
> +#define MIN_DBC_CYCLE		0x200
> +
> +/*
> + * keypad Controller structure: stores sunxi keypad controller information
> + *
> + * @dev:		parent device
> + * @input:		pointer to input device object
> + * @apb_clk:		keypad Controller APB clock
> + * @clk:		keypad Controller mod clock
> + * @base:		keypad controller registers
> + * @irq:		interrupt
> + * @rows_en_mask:	Masks for enabled rows
> + * @cols_en_mask:	Masks for enabled cols
> + * @keymap:		matrix scan code table for keycodes
> + * @key_press_state:	cached keys press state
> + * @debounce_cycl:	keypad specific debounce cycle
> + * @scan_cycl:		keypad specific scan cycle
> + * @autorepeat:         flag for auto repetition
> + */
> +struct sun4i_keypad_data {
> +	struct device *dev;
> +	struct input_dev *input;
> +
> +	struct clk *apb_clk;
> +	struct clk *clk;
> +	void __iomem *base;
> +	int	irq;
> +
> +	unsigned short	rows_en_mask;
> +	unsigned short	cols_en_mask;
> +
> +	unsigned short	keymap[MAX_MATRIX_KEY_NUM];
> +
> +	unsigned int press_state[N_ROWS_REG];
> +
> +	unsigned int debounce_cycl;
> +	unsigned int scan_cycl;
> +	bool	autorepeat;
> +};
> +
> +static void sun4i_keypad_scan(struct sun4i_keypad_data *keypad, bool edge)
> +{
> +	struct input_dev *input_dev = keypad->input;
> +	u32 key_scan[N_ROWS_REG];
> +	unsigned long change;
> +	unsigned short code;
> +	int reg_nr, bit_nr, key_up;
> +
> +	for (reg_nr = 0; reg_nr < N_ROWS_REG; reg_nr++) {
> +		key_scan[reg_nr] = ~(readl(keypad->base +
> +					KP_INX_OFFSET(reg_nr)));
> +
> +		change = edge ? key_scan[reg_nr] :
> +			keypad->press_state[reg_nr] ^ key_scan[reg_nr];
> +
> +		key_up = edge || (change & keypad->press_state[reg_nr]);
> +
> +		for_each_set_bit(bit_nr, &change, BITS_PER_LONG) {
> +			code = keypad->keymap[KP_BIT_SHIFT * reg_nr + bit_nr];
> +			input_report_key(input_dev, code, key_up);
> +			input_sync(input_dev);

I don't think you need to do an input_sync call each time for eah
input_report_key.

> +		}
> +
> +		keypad->press_state[reg_nr] = edge ?  0 : key_scan[reg_nr];
> +	}
> +}
> +
> +static irqreturn_t sun4i_keypad_irq(int irq, void *dev_id)
> +{
> +	struct sun4i_keypad_data *keypad = dev_id;
> +	u32 intr_status;
> +
> +	intr_status  = readl(keypad->base + KP_INT_STA);
> +
> +	/* release only gives a valid information for a single key release */
> +	if (intr_status & KP_STA_REDGE)
> +		sun4i_keypad_scan(keypad, true);
> +
> +	/* press does not give valid information when
> +	 * multiple rows are selected
> +	*/

/*
 * This is the multi-line comment style
 */

> +	if (intr_status & KP_STA_FEDGE)
> +		sun4i_keypad_scan(keypad, false);
> +
> +	writel(intr_status, keypad->base + KP_INT_STA);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int sun4i_keypad_open(struct input_dev *dev)
> +{
> +	struct sun4i_keypad_data *keypad = input_get_drvdata(dev);
> +	int reg_nr;
> +
> +	if (clk_prepare_enable(keypad->apb_clk))
> +		return -EINVAL;
> +
> +	if (clk_prepare_enable(keypad->clk)) {
> +		clk_disable_unprepare(keypad->apb_clk);
> +		return -EINVAL;
> +	}
> +
> +	for (reg_nr = 0; reg_nr < N_ROWS_REG; reg_nr++)
> +		keypad->press_state[reg_nr] = ~(readl(keypad->base +
> +							KP_INX_OFFSET(reg_nr)));
> +
> +	writel(KP_IRQ_FEDGE | KP_IRQ_REDGE, keypad->base + KP_INT_CFG);
> +
> +	writel(SCAN_CYCLE(keypad->scan_cycl) |
> +		DBC_CYCLE(keypad->debounce_cycl), keypad->base + KP_TIMING);
> +
> +	writel(ENABLE(1) | ROWMASK(keypad->rows_en_mask) |
> +		COLMASK(keypad->cols_en_mask), keypad->base + KP_CTL);
> +
> +	return 0;
> +}
> +
> +static void sun4i_keypad_close(struct input_dev *dev)
> +{
> +	struct sun4i_keypad_data *keypad = input_get_drvdata(dev);
> +
> +	writel(ENABLE(0) | ROWMASK(keypad->rows_en_mask) |
> +		COLMASK(keypad->cols_en_mask), keypad->base + KP_CTL);
> +
> +	clk_disable_unprepare(keypad->clk);
> +	clk_disable_unprepare(keypad->apb_clk);
> +}
> +
> +static int sun4i_keypad_parse_dt(struct device *dev,
> +				 struct sun4i_keypad_data *keypad)
> +{
> +	struct device_node *np;
> +
> +	np = dev->of_node;
> +	if (!np)
> +		return -EINVAL;
> +
> +	of_property_read_u32(np, "debounce-cycle", &keypad->debounce_cycl);
> +	if (keypad->debounce_cycl < MIN_CYCLE)
> +		keypad->debounce_cycl = MIN_DBC_CYCLE;
> +
> +	of_property_read_u32(np, "scan-cycle", &keypad->scan_cycl);
> +	if (keypad->scan_cycl < MIN_CYCLE)
> +		keypad->scan_cycl = MIN_SCAN_CYCLE;
> +
> +	if (of_property_read_bool(np, "autorepeat"))
> +		keypad->autorepeat = true;
> +
> +	return 0;
> +}
> +
> +static int sun4i_keypad_probe(struct platform_device *pdev)
> +{
> +	struct sun4i_keypad_data *keypad;
> +	struct device *dev = &pdev->dev;
> +	int row, col, code;
> +	int ret = 0;
> +
> +	keypad = devm_kzalloc(dev, sizeof(struct sun4i_keypad_data),
> +			      GFP_KERNEL);
> +	if (!keypad)
> +		return -ENOMEM;
> +
> +	ret  = sun4i_keypad_parse_dt(dev, keypad);
> +	if (ret)
> +		return ret;
> +
> +	keypad->base = devm_ioremap_resource(dev,
> +			      platform_get_resource(pdev, IORESOURCE_MEM, 0));

Usually, it gets called on two lines to make it clearer.

> +	if (IS_ERR(keypad->base))
> +		return PTR_ERR(keypad->base);
> +
> +	keypad->dev = dev;
> +	keypad->input = devm_input_allocate_device(dev);
> +	if (!keypad->input)
> +		return -ENOMEM;
> +
> +	keypad->input->name = pdev->name;
> +	keypad->input->phys = "sun4i_keypad/input0";
> +
> +	keypad->input->id.bustype = BUS_HOST;
> +	keypad->input->id.vendor  = 0x0001;
> +	keypad->input->id.product = 0x0001;
> +	keypad->input->id.version = 0x0100;
> +
> +	keypad->input->open = sun4i_keypad_open;
> +	keypad->input->close = sun4i_keypad_close;
> +
> +	/* matrix keypad keymap as:
> +	 * row << 24 | column << 16 | key-code
> +	 */
> +	ret = matrix_keypad_build_keymap(NULL, NULL,
> +					 KP_MAX_ROWS,
> +					 KP_MAX_COLS,
> +					 keypad->keymap,
> +					 keypad->input);
> +	if (ret) {
> +		dev_err(dev, "failed to build keymap\n");
> +		return ret;
> +	}
> +
> +	/* Search for enabled rows and cols */
> +	for (row = 0; row < KP_MAX_ROWS; row++) {
> +		for (col = 0; col < KP_MAX_COLS; col++) {
> +			code = MATRIX_SCAN_CODE(row, col, KP_ROW_SHIFT);
> +			if (keypad->keymap[code] != KEY_RESERVED) {
> +				keypad->rows_en_mask |= 1 << row;
> +				keypad->cols_en_mask |= 1 << col;
> +			}
> +		}
> +	}
> +
> +	if (keypad->autorepeat)
> +		__set_bit(EV_REP, keypad->input->evbit);
> +
> +	input_set_capability(keypad->input, EV_MSC, MSC_SCAN);
> +	input_set_drvdata(keypad->input, keypad);
> +
> +	keypad->irq = platform_get_irq(pdev, 0);
> +	if (keypad->irq < 0) {
> +		dev_err(dev, "failed to get keypad IRQ\n");
> +		return -ENXIO;
> +	}
> +
> +	ret = devm_request_irq(dev, keypad->irq,
> +			       sun4i_keypad_irq, 0,
> +			       "sun4i-a10-keypad", keypad);
> +	if (ret) {
> +		dev_err(dev, "failed to request IRQ\n");
> +		return ret;
> +	}
> +
> +	keypad->apb_clk = devm_clk_get(dev, "apb");
> +	if (IS_ERR(keypad->apb_clk)) {
> +		dev_err(dev, "failed to get a apb clock.\n");
> +		return PTR_ERR(keypad->apb_clk);
> +	}
> +
> +	keypad->clk = devm_clk_get(dev, "keypad");
> +	if (IS_ERR(keypad->clk)) {
> +		dev_err(dev, "failed to get a keypad clock.\n");
> +		return PTR_ERR(keypad->clk);
> +	}
> +
> +	ret = clk_set_rate(keypad->clk, KP_BASE_CLK);
> +	if (ret) {
> +		dev_err(dev, "set keypad base clock failed!\n");
> +		return ret;
> +	}

Do you need that rate to be enforced, or is it some leftover from the
allwinner BSP?

> +	ret = input_register_device(keypad->input);
> +	if (ret)
> +		return ret;
> +
> +	platform_set_drvdata(pdev, keypad);
> +
> +	return 0;
> +}
> +
> +static int sun4i_keypad_remove(struct platform_device *pdev)
> +{
> +	struct sun4i_keypad_data *keypad = platform_get_drvdata(pdev);
> +
> +	free_irq(keypad->irq, keypad);
> +	input_unregister_device(keypad->input);
> +	kfree(keypad);

The point of using devm_ functions is precisely to remove the removal
code from both the probe error path (and you did so there), and from
the remove.

> +
> +	return 0;
> +}
> +
> +static const struct of_device_id sun4i_keypad_of_match[] = {
> +	{ .compatible = "allwinner,sun4i-a10-keypad", },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, sun4i_keypad_of_match);
> +
> +static struct platform_driver sun4i_keypad_driver = {
> +	.driver = {
> +		.name	= "sun4i-a10-keypad",
> +		.of_match_table = of_match_ptr(sun4i_keypad_of_match),
> +	},
> +	.probe	= sun4i_keypad_probe,
> +	.remove = sun4i_keypad_remove,
> +};
> +
> +module_platform_driver(sun4i_keypad_driver);
> +
> +MODULE_DESCRIPTION("Allwinner sun4i keypad controller driver");
> +MODULE_AUTHOR("Yassin Jaffer <yassinjaffer@...il.com>");
> +MODULE_LICENSE("GPL");
> +

It looks good otherwise, thanks!

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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