[PATCH resend v2] input: Add new sun4i-lradc-keys driver

[PATCH resend v2] input: Add new sun4i-lradc-keys driver

[Hans de Goede]

Hi Dmitry,

AFAIK everyone likes the new dt interface from v2, so this one should have
been merged, but it appears to have fallen through the cracks.

Can you please queue this up for 3.19 or 3.20 ?

Note this is an unmodified resend of the v2 I send a while back, for
completeness sake here is the changelog:

Changes in v2:
-Change devicetree bindings to use a per key subnode, like gpio-keys does

Thanks & Regards,

Hans

[PATCH resend v2] input: Add new sun4i-lradc-keys driver

[Hans de Goede]

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 <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
--
Changes in v2:
-Change devicetree bindings to use a per key subnode, like gpio-keys does
---
 .../devicetree/bindings/input/sun4i-lradc-keys.txt |  62 +++++
 MAINTAINERS                                        |   7 +
 drivers/input/keyboard/Kconfig                     |  10 +
 drivers/input/keyboard/Makefile                    |   1 +
 drivers/input/keyboard/sun4i-lradc-keys.c          | 258 +++++++++++++++++++++
 5 files changed, 338 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..b9c32f6
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt
@@ -0,0 +1,62 @@
+Allwinner sun4i low res adc attached tablet keys
+------------------------------------------------
+
+Required properties:
+ - compatible: "allwinner,sun4i-a10-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-a10-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 µV at lradc input when this key is pressed.
+
+Example:
+
+#include <dt-bindings/input/input.h>
+
+	lradc: lradc@01c22800 {
+		compatible = "allwinner,sun4i-a10-lradc-keys";
+		reg = <0x01c22800 0x100>;
+		interrupts = <31>;
+		vref-supply = <&reg_vcc3v0>;
+
+		button@191 {
+			label = "Volume Up";
+			linux,code = <KEY_VOLUMEUP>;
+			channel = <0>;
+			voltage = <191274>;
+		};
+
+		button@392 {
+			label = "Volume Down";
+			linux,code = <KEY_VOLUMEDOWN>;
+			channel = <0>;
+			voltage = <392644>;
+		};
+
+		button@601 {
+			label = "Menu";
+			linux,code = <KEY_MENU>;
+			channel = <0>;
+			voltage = <601151>;
+		};
+
+		button@795 {
+			label = "Enter";
+			linux,code = <KEY_ENTER>;
+			channel = <0>;
+			voltage = <795090>;
+		};
+
+		button@987 {
+			label = "Home";
+			linux,code = <KEY_HOMEPAGE>;
+			channel = <0>;
+			voltage = <987387>;
+		};
+	};
diff --git a/MAINTAINERS b/MAINTAINERS
index fdffe96..fb3d33e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9193,6 +9193,13 @@ 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 <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
+L:	linux-input-u79uwXL29TY76Z2rM5mHXA@public.gmane.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 <kda-u1c8ncikuMvVAZt0uhVF+Ni2O/JbrIOy@public.gmane.org>
 L:	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.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..f11f002
--- /dev/null
+++ b/drivers/input/keyboard/sun4i-lradc-keys.c
@@ -0,0 +1,258 @@
+/*
+ * Allwinner sun4i low res adc attached tablet keys driver
+ *
+ * Copyright (C) 2014 Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
+ *
+ * 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-a10-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-a10-lradc-keys", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);
+
+static struct platform_driver sun4i_lradc_driver = {
+	.driver = {
+		.name	= "sun4i-a10-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 <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>");
+MODULE_LICENSE("GPL");
-- 
2.1.0

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Re: [PATCH resend v2] input: Add new sun4i-lradc-keys driver

[Dmitry Torokhov]

On Wednesday, December 17, 2014 03:43:31 PM Hans de Goede wrote:
> +       /*
> +        * 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;
> +       }

Can release and press be reported simultaneously? Should we process release 
first?

Thanks.

-- 
Dmitry

Re: [PATCH resend v2] input: Add new sun4i-lradc-keys driver

[Hans de Goede]

Hi,

On 17-12-14 18:32, Dmitry Torokhov wrote:
> On Wednesday, December 17, 2014 03:43:31 PM Hans de Goede wrote:
>> +       /*
>> +        * 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;
>> +       }
>
> Can release and press be reported simultaneously? Should we process release
> first?

Good question, I guess if we are somehow really slow with processing the interrupt
that this may happen. So I'll do a v3 swapping the 2.

Regards,

Hans