Subject: [PATCH v2 1/4] input: Add new sun4i-lradc-keys driver

From: [email-masked] (Hans de Goede)
Date: Wed, 22 Oct 2014 12:45:22 +0200

Hi,

On 10/21/2014 07:04 PM, Maxime Ripard wrote:
> Hi Hans,
> 
> Thanks, a lot for respinning this.
> 
> On Tue, Oct 21, 2014 at 10:24:47AM +0200, Hans de Goede wrote:
>> Allwinnner sunxi SoCs have a low resolution adc (called lradc) which is
>> specifically designed to have various (tablet) keys (ie home, back, search,
>> etc). attached to it using a resistor network. This adds a driver for this.
>>
>> There are 2 channels, currently this driver only supports chan0 since there
>> are no boards known to use chan1.
>>
>> This has been tested on an olimex a10s-olinuxino-micro, a13-olinuxino, and
>> a20-olinuxino-micro.
>>
>> Signed-off-by: Hans de Goede <[email-masked]>
>> --
>> Changes in v2:
>> -Change devicetree bindings to use a per key subnode, like gpio-keys does
>> ---
>>  .../devicetree/bindings/input/sun4i-lradc-keys.txt |  57 +++++
>>  MAINTAINERS                                        |   7 +
>>  drivers/input/keyboard/Kconfig                     |  10 +
>>  drivers/input/keyboard/Makefile                    |   1 +
>>  drivers/input/keyboard/sun4i-lradc-keys.c          | 259 +++++++++++++++++++++
>>  5 files changed, 334 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt
>>  create mode 100644 drivers/input/keyboard/sun4i-lradc-keys.c
>>
>> diff --git a/Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt b/Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt
>> new file mode 100644
>> index 0000000..36a141b
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt
>> @@ -0,0 +1,57 @@
>> +Allwinner sun4i low res adc attached tablet keys
>> +------------------------------------------------
>> +
>> +Required properties:
>> + - compatible: "allwinner,sun4i-lradc-keys"
>> + - reg: mmio address range of the chip
>> + - interrupts: interrupt to which the chip is connected
>> + - vref-supply: powersupply for the lradc reference voltage
>> +
>> +Each key is represented as a sub-node of "allwinner,sun4i-lradc-keys":
>> +
>> +Required subnode-properties:
>> +	- label: Descriptive name of the key.
>> +	- linux,code: Keycode to emit.
>> +	- channel: Channel this key is attached to, mut be 0 or 1.
>> +	- voltage: Voltage in ?V at lradc input when this key is pressed.
>> +
>> +Example:
>> +
>> +#include <dt-bindings/input/input.h>
>> +
>> +	lradc: lradc at 01c22800 {
>> +		compatible = "allwinner,sun4i-lradc-keys";
> 
> You're still using the old pattern for the compatible here, it should
> be allwinner,sun4i-a10-lradc-keys.

Will fix for the next version.

> 
>> +		reg = <0x01c22800 0x100>;
>> +		interrupts = <31>;
>> +		vref-supply = <&reg_vcc3v0>;
>> +		button at 19 {
> 
> I guess the node address in centivolts aren't really that common,
> maybe in mV instead?

Ack for using mV, will fix for the next version.

> 
>> +			label = "Volume Up";
>> +			linux,code = <KEY_VOLUMEUP>;
>> +			channel = <0>;
>> +			voltage = <191274>;
>> +		};
> 
> And a newline between the nodes please.

Will fix for the next version.

>> +		button at 39 {
>> +			label = "Volume Down";
>> +			linux,code = <KEY_VOLUMEDOWN>;
>> +			channel = <0>;
>> +			voltage = <392644>;
>> +		};
>> +		button at 60 {
>> +			label = "Menu";
>> +			linux,code = <KEY_MENU>;
>> +			channel = <0>;
>> +			voltage = <601151>;
>> +		};
>> +		button at 80 {
>> +			label = "Enter";
>> +			linux,code = <KEY_ENTER>;
>> +			channel = <0>;
>> +			voltage = <795090>;
>> +		};
>> +		button at 98 {
>> +			label = "Home";
>> +			linux,code = <KEY_HOME>;
>> +			channel = <0>;
>> +			voltage = <987387>;
>> +		};
>> +	};
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index a20df9b..73d1aef 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -8932,6 +8932,13 @@ F:	arch/m68k/sun3*/
>>  F:	arch/m68k/include/asm/sun3*
>>  F:	drivers/net/ethernet/i825xx/sun3*
>>  
>> +SUN4I LOW RES ADC ATTACHED TABLET KEYS DRIVER
>> +M:	Hans de Goede <[email-masked]>
>> +L:	linux-input at vger.kernel.org
>> +S:	Maintained
>> +F:	Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt
>> +F:	drivers/input/keyboard/sun4i-lradc-keys.c
>> +
>>  SUNDANCE NETWORK DRIVER
>>  M:	Denis Kirjanov <[email-masked]>
>>  L:	netdev at vger.kernel.org
>> diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
>> index a3958c6..2d11b44 100644
>> --- a/drivers/input/keyboard/Kconfig
>> +++ b/drivers/input/keyboard/Kconfig
>> @@ -567,6 +567,16 @@ config KEYBOARD_STMPE
>>  	  To compile this driver as a module, choose M here: the module will be
>>  	  called stmpe-keypad.
>>  
>> +config KEYBOARD_SUN4I_LRADC
>> +	tristate "Allwinner sun4i low res adc attached tablet keys support"
>> +	depends on ARCH_SUNXI
>> +	help
>> +	  This selects support for the Allwinner low res adc attached tablet
>> +	  keys found on Allwinner sunxi SoCs.
>> +
>> +	  To compile this driver as a module, choose M here: the
>> +	  module will be called sun4i-lradc-keys.
>> +
>>  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 0a33456..a35269a 100644
>> --- a/drivers/input/keyboard/Makefile
>> +++ b/drivers/input/keyboard/Makefile
>> @@ -53,6 +53,7 @@ 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-$(CONFIG_KEYBOARD_SUN4I_LRADC)	+= sun4i-lradc-keys.o
>>  obj-$(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-lradc-keys.c b/drivers/input/keyboard/sun4i-lradc-keys.c
>> new file mode 100644
>> index 0000000..63a1aff
>> --- /dev/null
>> +++ b/drivers/input/keyboard/sun4i-lradc-keys.c
>> @@ -0,0 +1,259 @@
>> +/*
>> + * Allwinner sun4i low res adc attached tablet keys driver
>> + *
>> + * Copyright (C) 2014 Hans de Goede <[email-masked]>
>> + *
>> + * 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.
>> + */
>> +
>> +/*
>> + * Allwinnner sunxi SoCs have a lradc which is specifically designed to have
>> + * various (tablet) keys (ie home, back, search, etc). attached to it using
>> + * a resistor network. This driver is for the keys on such boards.
>> + *
>> + * There are 2 channels, currently this driver only supports channel 0 since
>> + * there are no boards known to use channel 1.
>> + */
>> +
>> +#include <linux/err.h>
>> +#include <linux/init.h>
>> +#include <linux/input.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/io.h>
>> +#include <linux/module.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regulator/consumer.h>
>> +#include <linux/slab.h>
>> +
>> +#define LRADC_CTRL		0x00
>> +#define LRADC_INTC		0x04
>> +#define LRADC_INTS		0x08
>> +#define LRADC_DATA0		0x0c
>> +#define LRADC_DATA1		0x10
>> +
>> +/* LRADC_CTRL bits */
>> +#define FIRST_CONVERT_DLY(x)	((x) << 24) /* 8 bits */
>> +#define CHAN_SELECT(x)		((x) << 22) /* 2 bits */
>> +#define CONTINUE_TIME_SEL(x)	((x) << 16) /* 4 bits */
>> +#define KEY_MODE_SEL(x)		((x) << 12) /* 2 bits */
>> +#define LEVELA_B_CNT(x)		((x) << 8)  /* 4 bits */
>> +#define HOLD_EN(x)		((x) << 6)
>> +#define LEVELB_VOL(x)		((x) << 4)  /* 2 bits */
>> +#define SAMPLE_RATE(x)		((x) << 2)  /* 2 bits */
>> +#define ENABLE(x)		((x) << 0)
>> +
>> +/* LRADC_INTC and LRADC_INTS bits */
>> +#define CHAN1_KEYUP_IRQ		BIT(12)
>> +#define CHAN1_ALRDY_HOLD_IRQ	BIT(11)
>> +#define CHAN1_HOLD_IRQ		BIT(10)
>> +#define	CHAN1_KEYDOWN_IRQ	BIT(9)
>> +#define CHAN1_DATA_IRQ		BIT(8)
>> +#define CHAN0_KEYUP_IRQ		BIT(4)
>> +#define CHAN0_ALRDY_HOLD_IRQ	BIT(3)
>> +#define CHAN0_HOLD_IRQ		BIT(2)
>> +#define	CHAN0_KEYDOWN_IRQ	BIT(1)
>> +#define CHAN0_DATA_IRQ		BIT(0)
>> +
>> +struct sun4i_lradc_keymap {
>> +	u32 voltage;
>> +	u32 keycode;
>> +};
>> +
>> +struct sun4i_lradc_data {
>> +	struct device *dev;
>> +	struct input_dev *input;
>> +	void __iomem *base;
>> +	struct regulator *vref_supply;
>> +	struct sun4i_lradc_keymap *chan0_map;
>> +	u32 chan0_map_count;
>> +	u32 chan0_keycode;
>> +	u32 vref;
>> +};
>> +
>> +static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
>> +{
>> +	struct sun4i_lradc_data *lradc = dev_id;
>> +	u32 i, ints, val, voltage, diff, keycode = 0, closest = 0xffffffff;
>> +
>> +	ints  = readl(lradc->base + LRADC_INTS);
>> +
>> +	/*
>> +	 * lradc supports only one keypress at a time, release does not give
>> +	 * any info as to which key was released, so we cache the keycode.
>> +	 */
>> +	if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) {
>> +		val = readl(lradc->base + LRADC_DATA0) & 0x3f;
>> +		voltage = val * lradc->vref / 63;
>> +
>> +		for (i = 0; i < lradc->chan0_map_count; i++) {
>> +			diff = abs(lradc->chan0_map[i].voltage - voltage);
>> +			if (diff < closest) {
>> +				closest = diff;
>> +				keycode = lradc->chan0_map[i].keycode;
>> +			}
>> +		}
>> +
>> +		lradc->chan0_keycode = keycode;
>> +		input_report_key(lradc->input, lradc->chan0_keycode, 1);
>> +	}
>> +
>> +	if (ints & CHAN0_KEYUP_IRQ) {
>> +		input_report_key(lradc->input, lradc->chan0_keycode, 0);
>> +		lradc->chan0_keycode = 0;
>> +	}
>> +
>> +	input_sync(lradc->input);
>> +
>> +	writel(ints, lradc->base + LRADC_INTS);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static int sun4i_lradc_open(struct input_dev *dev)
>> +{
>> +	struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
>> +	int ret;
>> +
>> +	ret = regulator_enable(lradc->vref_supply);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/* lradc Vref internally is divided by 2/3 */
>> +	lradc->vref = regulator_get_voltage(lradc->vref_supply) * 2 / 3;
>> +
>> +	/*
>> +	 * Set sample time to 4 ms / 250 Hz. Wait 2 * 4 ms for key to
>> +	 * stabilize on press, wait (1 + 1) * 4 ms for key release
>> +	 */
>> +	writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
>> +		SAMPLE_RATE(0) | ENABLE(1), lradc->base + LRADC_CTRL);
>> +
>> +	writel(CHAN0_KEYUP_IRQ | CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC);
>> +
>> +	return 0;
>> +}
>> +
>> +static void sun4i_lradc_close(struct input_dev *dev)
>> +{
>> +	struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
>> +
>> +	/* Disable lradc, leave other settings unchanged */
>> +	writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
>> +		SAMPLE_RATE(2), lradc->base + LRADC_CTRL);
>> +	writel(0, lradc->base + LRADC_INTC);
>> +
>> +	regulator_disable(lradc->vref_supply);
>> +}
>> +
>> +static int sun4i_lradc_probe(struct platform_device *pdev)
>> +{
>> +	struct sun4i_lradc_data *lradc;
>> +	struct device *dev = &pdev->dev;
>> +	struct device_node *pp, *np = dev->of_node;
>> +	u32 channel;
>> +	int i, ret;
>> +
>> +	lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL);
>> +	if (!lradc)
>> +		return -ENOMEM;
>> +
>> +	lradc->chan0_map_count = of_get_child_count(np);
>> +	lradc->chan0_map = devm_kmalloc(dev, lradc->chan0_map_count *
>> +				sizeof(struct sun4i_lradc_keymap), GFP_KERNEL);
>> +	if (!lradc->chan0_map)
>> +		return -ENOMEM;
>> +
>> +	i = 0;
>> +	for_each_child_of_node(np, pp) {
>> +		struct sun4i_lradc_keymap *map = &lradc->chan0_map[i];
>> +
>> +		ret = of_property_read_u32(pp, "channel", &channel);
>> +		if (ret || channel != 0) {
>> +			dev_err(dev, "%s: Inval channel prop\n", pp->name);
>> +			return -EINVAL;
>> +		}
>> +
>> +		ret = of_property_read_u32(pp, "voltage", &map->voltage);
>> +		if (ret) {
>> +			dev_err(dev, "%s: Inval voltage prop\n", pp->name);
>> +			return -EINVAL;
>> +		}
>> +
>> +		ret = of_property_read_u32(pp, "linux,code", &map->keycode);
>> +		if (ret) {
>> +			dev_err(dev, "%s: Inval linux,code prop\n", pp->name);
>> +			return -EINVAL;
>> +		}
>> +
>> +		i++;
>> +	}
>> +
>> +	lradc->vref_supply = devm_regulator_get(dev, "vref");
>> +	if (IS_ERR(lradc->vref_supply))
>> +		return PTR_ERR(lradc->vref_supply);
>> +
>> +	lradc->dev = dev;
>> +	lradc->input = devm_input_allocate_device(dev);
>> +	if (!lradc->input)
>> +		return -ENOMEM;
>> +
>> +	lradc->input->name = pdev->name;
>> +	lradc->input->phys = "sun4i_lradc/input0";
>> +	lradc->input->open = sun4i_lradc_open;
>> +	lradc->input->close = sun4i_lradc_close;
>> +	lradc->input->id.bustype = BUS_HOST;
>> +	lradc->input->id.vendor = 0x0001;
>> +	lradc->input->id.product = 0x0001;
>> +	lradc->input->id.version = 0x0100;
>> +	lradc->input->evbit[0] =  BIT(EV_SYN) | BIT(EV_KEY);
>> +	for (i = 0; i < lradc->chan0_map_count; i++)
>> +		set_bit(lradc->chan0_map[i].keycode, lradc->input->keybit);
>> +	input_set_drvdata(lradc->input, lradc);
>> +
>> +	lradc->base = devm_ioremap_resource(dev,
>> +			      platform_get_resource(pdev, IORESOURCE_MEM, 0));
>> +	if (IS_ERR(lradc->base))
>> +		return PTR_ERR(lradc->base);
>> +
>> +	ret = devm_request_irq(dev, platform_get_irq(pdev, 0), sun4i_lradc_irq,
>> +			       0, "sun4i-lradc-keys", lradc);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = input_register_device(lradc->input);
>> +	if (ret)
>> +		return ret;
>> +
>> +	platform_set_drvdata(pdev, lradc);
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id sun4i_lradc_of_match[] = {
>> +	{ .compatible = "allwinner,sun4i-lradc-keys", },
>> +	{ /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);
>> +
>> +static struct platform_driver sun4i_lradc_driver = {
>> +	.driver = {
>> +		.owner	= THIS_MODULE,
> 
> You can drop the owner field, it's already filled by
> module_platform_driver.

Will fix for the next version.

> 
>> +		.name	= "sun4i-lradc-keys",
>> +		.of_match_table = of_match_ptr(sun4i_lradc_of_match),
>> +	},
>> +	.probe	= sun4i_lradc_probe,
>> +};
>> +
>> +module_platform_driver(sun4i_lradc_driver);
>> +
>> +MODULE_DESCRIPTION("Allwinner sun4i low res adc attached tablet keys driver");
>> +MODULE_AUTHOR("Hans de Goede <[email-masked]>");
>> +MODULE_LICENSE("GPL");
>> -- 
>> 2.1.0
>>
> 
> Looking good otherwise, thanks!

Thanks for the review.

Regards,

Hans