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

Maxime Ripard
2014-10-21T17:04:11Z

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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 <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 | 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 µV at lradc input when this key is pressed.
> +
> +Example:
> +
> +#include <dt-bindings/input/input.h>
> +
> + lradc: lradc@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.

> + reg = <0x01c22800 0x100>;
> + interrupts = <31>;
> + vref-supply = <&reg_vcc3v0>;
> + button@19 {

I guess the node address in centivolts aren't really that common,
maybe in mV instead?

> + label = "Volume Up";
> + linux,code = <KEY_VOLUMEUP>;
> + channel = <0>;
> + voltage = <191274>;
> + };

And a newline between the nodes please.

> + button@39 {
> + label = "Volume Down";
> + linux,code = <KEY_VOLUMEDOWN>;
> + channel = <0>;
> + voltage = <392644>;
> + };
> + button@60 {
> + label = "Menu";
> + linux,code = <KEY_MENU>;
> + channel = <0>;
> + voltage = <601151>;
> + };
> + button@80 {
> + label = "Enter";
> + linux,code = <KEY_ENTER>;
> + channel = <0>;
> + voltage = <795090>;
> + };
> + button@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 <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..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 <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-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.

> + .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 <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>");
> +MODULE_LICENSE("GPL");
> --
> 2.1.0
>

Looking good otherwise, thanks!

Maxime

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

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