Input: add new sun4i-lradc-keys driver
authorHans de Goede <hdegoede@redhat.com>
Thu, 18 Dec 2014 17:24:50 +0000 (09:24 -0800)
committerDmitry Torokhov <dmitry.torokhov@gmail.com>
Mon, 22 Dec 2014 02:59:21 +0000 (18:59 -0800)
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@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt [new file with mode: 0644]
MAINTAINERS
drivers/input/keyboard/Kconfig
drivers/input/keyboard/Makefile
drivers/input/keyboard/sun4i-lradc-keys.c [new file with mode: 0644]

diff --git a/Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt b/Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt
new file mode 100644 (file)
index 0000000..b9c32f6
--- /dev/null
@@ -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>;
+               };
+       };
index f73bb41798322b3e42cd780ba43c71f454ca218a..21b834b191d02a017130ec50d298bdfbf310af7e 100644 (file)
@@ -8806,6 +8806,13 @@ 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@redhat.com>
+L:     linux-input@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 <kda@linux-powerpc.org>
 L:     netdev@vger.kernel.org
index a5d9b3f3c8714ee5a307e166afa4bf90e23864bf..a89ba7cb96f1ec21780916a23d44966743e5ad4c 100644 (file)
@@ -568,6 +568,16 @@ 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
index febafa527eb65d9c08350307df6d9178a0239b9c..470767884bd8c33ec51b7c3a5e5aa63a8e7eb59f 100644 (file)
@@ -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 (file)
index 0000000..cc8f7dd
--- /dev/null
@@ -0,0 +1,286 @@
+/*
+ * Allwinner sun4i low res adc attached tablet keys driver
+ *
+ * Copyright (C) 2014 Hans de Goede <hdegoede@redhat.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.
+ */
+
+/*
+ * 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_KEYUP_IRQ) {
+               input_report_key(lradc->input, lradc->chan0_keycode, 0);
+               lradc->chan0_keycode = 0;
+       }
+
+       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);
+       }
+
+       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 error;
+
+       error = regulator_enable(lradc->vref_supply);
+       if (error)
+               return error;
+
+       /* 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_load_dt_keymap(struct device *dev,
+                                     struct sun4i_lradc_data *lradc)
+{
+       struct device_node *np, *pp;
+       int i;
+       int error;
+
+       np = dev->of_node;
+       if (!np)
+               return -EINVAL;
+
+       lradc->chan0_map_count = of_get_child_count(np);
+       if (lradc->chan0_map_count == 0) {
+               dev_err(dev, "keymap is missing in device tree\n");
+               return -EINVAL;
+       }
+
+       lradc->chan0_map = devm_kmalloc_array(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];
+               u32 channel;
+
+               error = of_property_read_u32(pp, "channel", &channel);
+               if (error || channel != 0) {
+                       dev_err(dev, "%s: Inval channel prop\n", pp->name);
+                       return -EINVAL;
+               }
+
+               error = of_property_read_u32(pp, "voltage", &map->voltage);
+               if (error) {
+                       dev_err(dev, "%s: Inval voltage prop\n", pp->name);
+                       return -EINVAL;
+               }
+
+               error = of_property_read_u32(pp, "linux,code", &map->keycode);
+               if (error) {
+                       dev_err(dev, "%s: Inval linux,code prop\n", pp->name);
+                       return -EINVAL;
+               }
+
+               i++;
+       }
+
+       return 0;
+}
+
+static int sun4i_lradc_probe(struct platform_device *pdev)
+{
+       struct sun4i_lradc_data *lradc;
+       struct device *dev = &pdev->dev;
+       int i;
+       int error;
+
+       lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL);
+       if (!lradc)
+               return -ENOMEM;
+
+       error = sun4i_lradc_load_dt_keymap(dev, lradc);
+       if (error)
+               return error;
+
+       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;
+
+       __set_bit(EV_KEY, lradc->input->evbit);
+       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);
+
+       error = devm_request_irq(dev, platform_get_irq(pdev, 0),
+                                sun4i_lradc_irq, 0,
+                                "sun4i-a10-lradc-keys", lradc);
+       if (error)
+               return error;
+
+       error = input_register_device(lradc->input);
+       if (error)
+               return error;
+
+       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@redhat.com>");
+MODULE_LICENSE("GPL");