Re: [PATCH v2 3/8] input: misc: Add driver for AXP20x Power Enable Key

[Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>]

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On Sat, Mar 15, 2014 at 04:43:40PM +0100, Carlo Caione wrote:
> This patch add support for the Power Enable Key found on MFD AXP202 and
> AXP209. Besides the basic support for the button, the driver adds two
> entries in sysfs to configure the time delay for power on/off.
> 
> Signed-off-by: Carlo Caione <carlo-KA+7E9HrN00dnm+yROfE0A@public.gmane.org>
> ---
>  drivers/input/misc/Kconfig      |  11 ++
>  drivers/input/misc/Makefile     |   1 +
>  drivers/input/misc/axp20x-pek.c | 267 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 279 insertions(+)
>  create mode 100644 drivers/input/misc/axp20x-pek.c

From what I understood of the MFD framework, you usually have a MFD
core driver that gets loaded from the DT and instantiate its various
functions through sub-devices, that are registered through
mfd_add_devices, and the drivers for these sub-devices are supported
in sub-drivers that are located in the driver/mfd, alongside the core
driver.

I believe that such a pattern allows for two interesting things:
  - You don't have to search around the whole kernel tree to find
    where a given sub-feature is supported.
  - You don't have to cripple your DT with instantiation of all the
    subcomponents, while you only really have one device.

Do you have a reason for not following this pattern?

> 
> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
> index 7904ab0..87244fb 100644
> --- a/drivers/input/misc/Kconfig
> +++ b/drivers/input/misc/Kconfig
> @@ -393,6 +393,17 @@ config INPUT_RETU_PWRBUTTON
>  	  To compile this driver as a module, choose M here. The module will
>  	  be called retu-pwrbutton.
>  
> +config INPUT_AXP20X_PEK
> +	tristate "X-Powers AXP20X power button driver"
> +	depends on MFD_AXP20X
> +	help
> +	  Say Y here if you want to enable power key reporting via the
> +	  AXP20X PMIC.
> +
> +	  To compile this driver as a module, choose M here. The module will
> +	  be called axp20x-pek.
> +
> +
>  config INPUT_TWL4030_PWRBUTTON
>  	tristate "TWL4030 Power button Driver"
>  	depends on TWL4030_CORE
> diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
> index cda71fc..624abf5 100644
> --- a/drivers/input/misc/Makefile
> +++ b/drivers/input/misc/Makefile
> @@ -50,6 +50,7 @@ obj-$(CONFIG_INPUT_POWERMATE)		+= powermate.o
>  obj-$(CONFIG_INPUT_PWM_BEEPER)		+= pwm-beeper.o
>  obj-$(CONFIG_INPUT_RB532_BUTTON)	+= rb532_button.o
>  obj-$(CONFIG_INPUT_RETU_PWRBUTTON)	+= retu-pwrbutton.o
> +obj-$(CONFIG_INPUT_AXP20X_PEK)		+= axp20x-pek.o
>  obj-$(CONFIG_INPUT_GPIO_ROTARY_ENCODER)	+= rotary_encoder.o
>  obj-$(CONFIG_INPUT_SGI_BTNS)		+= sgi_btns.o
>  obj-$(CONFIG_INPUT_SIRFSOC_ONKEY)	+= sirfsoc-onkey.o
> diff --git a/drivers/input/misc/axp20x-pek.c b/drivers/input/misc/axp20x-pek.c
> new file mode 100644
> index 0000000..060212f
> --- /dev/null
> +++ b/drivers/input/misc/axp20x-pek.c
> @@ -0,0 +1,267 @@
> +/*
> + * axp20x power button driver.
> + *
> + * Copyright (C) 2013 Carlo Caione <carlo-KA+7E9HrN00dnm+yROfE0A@public.gmane.org>
> + *
> + * This file is subject to the terms and conditions of the GNU General
> + * Public License. See the file "COPYING" in the main directory of this
> + * archive for more details.
> + *
> + * 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/errno.h>
> +#include <linux/irq.h>
> +#include <linux/init.h>
> +#include <linux/input.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/axp20x.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +#define AXP20X_PEK_STARTUP_MASK		(0xc0)
> +#define AXP20X_PEK_SHUTDOWN_MASK	(0x03)
> +
> +static const char const *startup_time[] = { "128ms", "3s" , "1s", "2s" };
> +static const char const *shutdown_time[] = { "4s", "6s" , "8s", "10s" };
> +
> +struct axp20x_pek {
> +	struct axp20x_dev *axp20x;
> +	struct input_dev *input;
> +	int irq_dbr;
> +	int irq_dbf;
> +};
> +
> +struct axp20x_pek_ext_attr {
> +	const char const **str;
> +	unsigned int mask;
> +};
> +
> +static struct axp20x_pek_ext_attr axp20x_pek_startup_ext_attr = {
> +	.str	= startup_time,
> +	.mask	= AXP20X_PEK_STARTUP_MASK,
> +};
> +
> +static struct axp20x_pek_ext_attr axp20x_pek_shutdown_ext_attr = {
> +	.str	= shutdown_time,
> +	.mask	= AXP20X_PEK_SHUTDOWN_MASK,
> +};
> +
> +static struct axp20x_pek_ext_attr *get_axp_ext_attr(struct device_attribute *attr)
> +{
> +	return container_of(attr, struct dev_ext_attribute, attr)->var;
> +}
> +
> +static ssize_t axp20x_show_ext_attr(struct device *dev, struct device_attribute *attr,
> +			     char *buf)
> +{
> +	struct axp20x_pek *axp20x_pek = dev_get_drvdata(dev);
> +	struct axp20x_pek_ext_attr *axp20x_ea = get_axp_ext_attr(attr);
> +	unsigned int val;
> +	int ret, i;
> +	int cnt = 0;
> +
> +	ret = regmap_read(axp20x_pek->axp20x->regmap, AXP20X_PEK_KEY, &val);
> +	if (ret != 0)
> +		return ret;
> +
> +	val &= axp20x_ea->mask;
> +	val >>= ffs(axp20x_ea->mask) - 1;
> +
> +	for (i = 0; i < 4; i++) {
> +		if (val == i)
> +			cnt += sprintf(buf + cnt, "[%s] ", axp20x_ea->str[i]);
> +		else
> +			cnt += sprintf(buf + cnt, "%s ", axp20x_ea->str[i]);
> +	}
> +
> +	cnt += sprintf(buf + cnt, "\n");
> +
> +	return cnt;
> +}
> +
> +static ssize_t axp20x_store_ext_attr(struct device *dev, struct device_attribute *attr,
> +			      const char *buf, size_t count)
> +{
> +	struct axp20x_pek *axp20x_pek = dev_get_drvdata(dev);
> +	struct axp20x_pek_ext_attr *axp20x_ea = get_axp_ext_attr(attr);
> +	char val_str[20];
> +	int ret, i;
> +	size_t len;
> +
> +	val_str[sizeof(val_str) - 1] = '\0';
> +	strncpy(val_str, buf, sizeof(val_str) - 1);
> +	len = strlen(val_str);
> +
> +	if (len && val_str[len - 1] == '\n')
> +		val_str[len - 1] = '\0';
> +
> +	for (i = 0; i < 4; i++) {
> +		if (!strcmp(val_str, axp20x_ea->str[i])) {
> +
> +			i <<= ffs(axp20x_ea->mask) - 1;
> +			ret = regmap_update_bits(axp20x_pek->axp20x->regmap,
> +						 AXP20X_PEK_KEY,
> +						 axp20x_ea->mask, i);
> +			if (ret != 0)
> +				return -EINVAL;
> +			return count;
> +		}
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static struct dev_ext_attribute axp20x_dev_attr_startup = {
> +	.attr	= __ATTR(startup, 0644, axp20x_show_ext_attr, axp20x_store_ext_attr),
> +	.var	= &axp20x_pek_startup_ext_attr
> +};
> +
> +static struct dev_ext_attribute axp20x_dev_attr_shutdown = {
> +	__ATTR(shutdown, 0644, axp20x_show_ext_attr, axp20x_store_ext_attr),
> +	&axp20x_pek_shutdown_ext_attr
> +};
> +
> +static struct attribute *dev_attrs[] = {
> +	&axp20x_dev_attr_startup.attr.attr,
> +	&axp20x_dev_attr_shutdown.attr.attr,
> +	NULL,
> +};
> +
> +static struct attribute_group dev_attr_group = {
> +	.attrs	= dev_attrs,
> +};
> +
> +static const struct attribute_group *dev_attr_groups[] = {
> +	&dev_attr_group,
> +	NULL,
> +};
> +
> +static irqreturn_t axp20x_pek_irq(int irq, void *pwr)
> +{
> +	struct input_dev *idev = pwr;
> +	struct axp20x_pek *axp20x_pek = input_get_drvdata(idev);
> +
> +	if (irq == axp20x_pek->irq_dbr)
> +		input_report_key(idev, KEY_POWER, true);
> +	else if (irq == axp20x_pek->irq_dbf)
> +		input_report_key(idev, KEY_POWER, false);
> +
> +	input_sync(idev);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int axp20x_pek_probe(struct platform_device *pdev)
> +{
> +	struct axp20x_pek *axp20x_pek;
> +	struct axp20x_dev *axp20x;
> +	struct input_dev *idev;
> +	int error;
> +
> +	axp20x_pek = devm_kzalloc(&pdev->dev, sizeof(struct axp20x_pek),
> +				  GFP_KERNEL);
> +	if (!axp20x_pek)
> +		return -ENOMEM;
> +
> +	axp20x_pek->axp20x = dev_get_drvdata(pdev->dev.parent);
> +	axp20x = axp20x_pek->axp20x;
> +
> +	axp20x_pek->irq_dbr = platform_get_irq_byname(pdev, "PEK_DBR");
> +	if (axp20x_pek->irq_dbr < 0) {
> +		dev_err(&pdev->dev, "No IRQ for PEK_DBR, error=%d\n",
> +				axp20x_pek->irq_dbr);
> +		return axp20x_pek->irq_dbr;
> +	}
> +	axp20x_pek->irq_dbr = regmap_irq_get_virq(axp20x->regmap_irqc,
> +						  axp20x_pek->irq_dbr);
> +
> +	axp20x_pek->irq_dbf = platform_get_irq_byname(pdev, "PEK_DBF");
> +	if (axp20x_pek->irq_dbf < 0) {
> +		dev_err(&pdev->dev, "No IRQ for PEK_DBF, error=%d\n",
> +				axp20x_pek->irq_dbf);
> +		return axp20x_pek->irq_dbf;
> +	}
> +	axp20x_pek->irq_dbf = regmap_irq_get_virq(axp20x->regmap_irqc,
> +						  axp20x_pek->irq_dbf);
> +
> +	axp20x_pek->input = devm_input_allocate_device(&pdev->dev);
> +	if (!axp20x_pek->input)
> +		return -ENOMEM;
> +
> +	idev = axp20x_pek->input;
> +
> +	idev->name = "axp20x-pek";
> +	idev->phys = "m1kbd/input2";
> +	idev->dev.parent = &pdev->dev;
> +
> +	input_set_capability(idev, EV_KEY, KEY_POWER);
> +
> +	input_set_drvdata(idev, axp20x_pek);
> +
> +	error = devm_request_threaded_irq(&pdev->dev, axp20x_pek->irq_dbr,
> +					  NULL, axp20x_pek_irq, 0,
> +					  "axp20x-pek-dbr", idev);
> +	if (error) {
> +		dev_err(axp20x->dev, "Failed to request dbr IRQ#%d: %d\n",
> +			axp20x_pek->irq_dbr, error);
> +
> +		return error;
> +	}
> +
> +	error = devm_request_threaded_irq(&pdev->dev, axp20x_pek->irq_dbf,
> +					  NULL, axp20x_pek_irq, 0,
> +					  "axp20x-pek-dbf", idev);
> +	if (error) {
> +		dev_err(axp20x->dev, "Failed to request dbf IRQ#%d: %d\n",
> +			axp20x_pek->irq_dbf, error);
> +		return error;
> +	}
> +
> +	idev->dev.groups = dev_attr_groups;
> +	error = input_register_device(idev);
> +	if (error) {
> +		dev_err(axp20x->dev, "Can't register input device: %d\n", error);
> +		return error;
> +	}
> +
> +	platform_set_drvdata(pdev, axp20x_pek);
> +
> +	return 0;
> +}
> +
> +static int axp20x_pek_remove(struct platform_device *pdev)
> +{
> +	struct axp20x_pek *axp20x_pek = platform_get_drvdata(pdev);
> +
> +	input_unregister_device(axp20x_pek->input);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id axp20x_pek_match[] = {
> +	{ .compatible = "x-powers,axp20x-pek", },

No pattern-matching compatible strings please.

Thanks!
Maxime

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

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