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Message-ID: <CANEJEGuOOAbgKkJu6bY7rP2s+P3M3+5cUVr6=cqGqqTn06=7Jw@mail.gmail.com>
Date: Wed, 18 May 2016 15:17:00 -0700
From: Grant Grundler <grundler@...omium.org>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: Grant Grundler <grundler@...omium.org>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
devicetree <devicetree@...r.kernel.org>,
linux-input <linux-input@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
Hung-yu Wu <hywu@...gle.com>,
Kumar Gala <galak@...eaurora.org>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Grant Likely <grant.likely@...aro.org>
Subject: Re: [PATCH 2/2 V4] Input: add Atmel Captouch Button driver
On Wed, May 18, 2016 at 2:59 PM, Dmitry Torokhov
<dmitry.torokhov@...il.com> wrote:
> On Tue, May 17, 2016 at 12:29:32PM -0700, Grant Grundler wrote:
>> From: Daniel Hung-yu Wu <hywu@...gle.com>
>>
>> Add I2C driver for Atmel Capacitive Touch Button device.
>>
>> Signed-off-by: Hung-yu Wu <hywu@...gle.com>
>> Signed-off-by: Grant Grundler <grundler@...omium.org>
>
> Applied, thank you.
Awesome! Thanks for your help Dmitry! :)
grant
>
>> ---
>> drivers/input/misc/Kconfig | 13 ++
>> drivers/input/misc/Makefile | 1 +
>> drivers/input/misc/atmel_captouch.c | 287 ++++++++++++++++++++++++++++++++++++
>> 3 files changed, 299 insertions(+)
>> create mode 100644 drivers/input/misc/atmel_captouch.c
>>
>> V4: wordsmithing comments at top of file.
>> Added missing semicolon to CONFIG_OF data struct.
>>
>> V3: use dash, not underscore in nodename. Wordsmith Kconfig help text.
>>
>> V2: split Documentation/devicetree/bindings from driver patch.
>> rename "atmel,atmegaxx_captouch" to "atmel,captouch" since it's irrelevant
>> which controller implements the register set/controller.
>>
>> V1: posted https://lkml.org/lkml/2016/5/3/613
>>
>> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
>> index 838824b..d8b6620 100644
>> --- a/drivers/input/misc/Kconfig
>> +++ b/drivers/input/misc/Kconfig
>> @@ -82,6 +82,19 @@ config INPUT_ARIZONA_HAPTICS
>> To compile this driver as a module, choose M here: the
>> module will be called arizona-haptics.
>>
>> +config INPUT_ATMEL_CAPTOUCH
>> + tristate "Atmel Capacitive Touch Button Driver"
>> + depends on OF || COMPILE_TEST
>> + help
>> + Say Y here if an Atmel Capacitive Touch Button device which
>> + implements "captouch" protocol is connected to I2C bus. Typically
>> + this device consists of Atmel Touch sensor controlled by AtMegaXX
>> + MCU running firmware based on Qtouch library.
>> + One should find "atmel,captouch" node in the board specific DTS.
>> +
>> + To compile this driver as a module, choose M here: the
>> + module will be called atmel_captouch.
>> +
>> config INPUT_BMA150
>> tristate "BMA150/SMB380 acceleration sensor support"
>> depends on I2C
>> diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
>> index f77268e..b5ec626 100644
>> --- a/drivers/input/misc/Makefile
>> +++ b/drivers/input/misc/Makefile
>> @@ -17,6 +17,7 @@ obj-$(CONFIG_INPUT_APANEL) += apanel.o
>> obj-$(CONFIG_INPUT_ARIZONA_HAPTICS) += arizona-haptics.o
>> obj-$(CONFIG_INPUT_ATI_REMOTE2) += ati_remote2.o
>> obj-$(CONFIG_INPUT_ATLAS_BTNS) += atlas_btns.o
>> +obj-$(CONFIG_INPUT_ATMEL_CAPTOUCH) += atmel_captouch.o
>> obj-$(CONFIG_INPUT_BFIN_ROTARY) += bfin_rotary.o
>> obj-$(CONFIG_INPUT_BMA150) += bma150.o
>> obj-$(CONFIG_INPUT_CM109) += cm109.o
>> diff --git a/drivers/input/misc/atmel_captouch.c b/drivers/input/misc/atmel_captouch.c
>> new file mode 100644
>> index 0000000..91bfc73
>> --- /dev/null
>> +++ b/drivers/input/misc/atmel_captouch.c
>> @@ -0,0 +1,287 @@
>> +/*
>> + * Atmel Capacitive Touch Button Driver
>> + *
>> + * Copyright (C) 2016 Google, inc.
>> + *
>> + * This software is licensed under the terms of the GNU General Public
>> + * License version 2, as published by the Free Software Foundation, and
>> + * may be copied, distributed, and modified under those terms.
>> + *
>> + * 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.
>> + */
>> +
>> +/*
>> + * It's irrelevant the HW used to develop captouch driver is based
>> + * on Atmega88PA part and uses QtouchADC parts for sensing touch.
>> + * Calling this driver "captouch" is an arbitrary way to distinguish
>> + * the protocol this driver supports from other atmel/qtouch drivers.
>> + *
>> + * captouch driver supports a newer/different version of the I2C
>> + * registers/commands than the qt1070.c driver.
>> + * Don't let the similarity of the general driver structure fool you. :)
>> + *
>> + * For raw i2c access from userspace, use i2cset/i2cget
>> + * to poke at /dev/i2c-N devices.
>> + */
>> +
>> +#include <linux/device.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/init.h>
>> +#include <linux/i2c.h>
>> +#include <linux/input.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/slab.h>
>> +
>> +/* Maximum number of buttons supported */
>> +#define MAX_NUM_OF_BUTTONS 8
>> +
>> +/* Registers */
>> +#define REG_KEY1_THRESHOLD 0x02
>> +#define REG_KEY2_THRESHOLD 0x03
>> +#define REG_KEY3_THRESHOLD 0x04
>> +#define REG_KEY4_THRESHOLD 0x05
>> +
>> +#define REG_KEY1_REF_H 0x20
>> +#define REG_KEY1_REF_L 0x21
>> +#define REG_KEY2_REF_H 0x22
>> +#define REG_KEY2_REF_L 0x23
>> +#define REG_KEY3_REF_H 0x24
>> +#define REG_KEY3_REF_L 0x25
>> +#define REG_KEY4_REF_H 0x26
>> +#define REG_KEY4_REF_L 0x27
>> +
>> +#define REG_KEY1_DLT_H 0x30
>> +#define REG_KEY1_DLT_L 0x31
>> +#define REG_KEY2_DLT_H 0x32
>> +#define REG_KEY2_DLT_L 0x33
>> +#define REG_KEY3_DLT_H 0x34
>> +#define REG_KEY3_DLT_L 0x35
>> +#define REG_KEY4_DLT_H 0x36
>> +#define REG_KEY4_DLT_L 0x37
>> +
>> +#define REG_KEY_STATE 0x3C
>> +
>> +/*
>> + * @i2c_client: I2C slave device client pointer
>> + * @input: Input device pointer
>> + * @num_btn: Number of buttons
>> + * @keycodes: map of button# to KeyCode
>> + * @prev_btn: Previous key state to detect button "press" or "release"
>> + * @xfer_buf: I2C transfer buffer
>> + */
>> +struct atmel_captouch_device {
>> + struct i2c_client *client;
>> + struct input_dev *input;
>> + u32 num_btn;
>> + u32 keycodes[MAX_NUM_OF_BUTTONS];
>> + u8 prev_btn;
>> + u8 xfer_buf[8] ____cacheline_aligned;
>> +};
>> +
>> +/*
>> + * Read from I2C slave device
>> + * The protocol is that the client has to provide both the register address
>> + * and the length, and while reading back the device would prepend the data
>> + * with address and length for verification.
>> + */
>> +static int atmel_read(struct atmel_captouch_device *capdev,
>> + u8 reg, u8 *data, size_t len)
>> +{
>> + struct i2c_client *client = capdev->client;
>> + struct device *dev = &client->dev;
>> + struct i2c_msg msg[2];
>> + int err;
>> +
>> + if (len > sizeof(capdev->xfer_buf) - 2)
>> + return -EINVAL;
>> +
>> + capdev->xfer_buf[0] = reg;
>> + capdev->xfer_buf[1] = len;
>> +
>> + msg[0].addr = client->addr;
>> + msg[0].flags = 0;
>> + msg[0].buf = capdev->xfer_buf;
>> + msg[0].len = 2;
>> +
>> + msg[1].addr = client->addr;
>> + msg[1].flags = I2C_M_RD;
>> + msg[1].buf = capdev->xfer_buf;
>> + msg[1].len = len + 2;
>> +
>> + err = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
>> + if (err != ARRAY_SIZE(msg))
>> + return err < 0 ? err : -EIO;
>> +
>> + if (capdev->xfer_buf[0] != reg) {
>> + dev_err(dev, "I2C read error: register address does not match\n");
>> + return -ECOMM;
>> + }
>> +
>> + memcpy(data, &capdev->xfer_buf[2], len);
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * Handle interrupt and report the key changes to the input system.
>> + * Multi-touch can be supported; however, it really depends on whether
>> + * the device can multi-touch.
>> + */
>> +static irqreturn_t atmel_captouch_isr(int irq, void *data)
>> +{
>> + struct atmel_captouch_device *capdev = data;
>> + struct device *dev = &capdev->client->dev;
>> + int error;
>> + int i;
>> + u8 new_btn;
>> + u8 changed_btn;
>> +
>> + error = atmel_read(capdev, REG_KEY_STATE, &new_btn, 1);
>> + if (error) {
>> + dev_err(dev, "failed to read button state: %d\n", error);
>> + goto out;
>> + }
>> +
>> + dev_dbg(dev, "%s: button state %#02x\n", __func__, new_btn);
>> +
>> + changed_btn = new_btn ^ capdev->prev_btn;
>> + capdev->prev_btn = new_btn;
>> +
>> + for (i = 0; i < capdev->num_btn; i++) {
>> + if (changed_btn & BIT(i))
>> + input_report_key(capdev->input,
>> + capdev->keycodes[i],
>> + new_btn & BIT(i));
>> + }
>> +
>> + input_sync(capdev->input);
>> +
>> +out:
>> + return IRQ_HANDLED;
>> +}
>> +
>> +/*
>> + * Probe function to setup the device, input system and interrupt
>> + */
>> +static int atmel_captouch_probe(struct i2c_client *client,
>> + const struct i2c_device_id *id)
>> +{
>> + struct atmel_captouch_device *capdev;
>> + struct device *dev = &client->dev;
>> + struct device_node *node;
>> + int i;
>> + int err;
>> +
>> + if (!i2c_check_functionality(client->adapter,
>> + I2C_FUNC_SMBUS_BYTE_DATA |
>> + I2C_FUNC_SMBUS_WORD_DATA |
>> + I2C_FUNC_SMBUS_I2C_BLOCK)) {
>> + dev_err(dev, "needed i2c functionality is not supported\n");
>> + return -EINVAL;
>> + }
>> +
>> + capdev = devm_kzalloc(dev, sizeof(*capdev), GFP_KERNEL);
>> + if (!capdev)
>> + return -ENOMEM;
>> +
>> + capdev->client = client;
>> + i2c_set_clientdata(client, capdev);
>> +
>> + err = atmel_read(capdev, REG_KEY_STATE,
>> + &capdev->prev_btn, sizeof(capdev->prev_btn));
>> + if (err) {
>> + dev_err(dev, "failed to read initial button state: %d\n", err);
>> + return err;
>> + }
>> +
>> + capdev->input = devm_input_allocate_device(dev);
>> + if (!capdev->input) {
>> + dev_err(dev, "failed to allocate input device\n");
>> + return -ENOMEM;
>> + }
>> +
>> + capdev->input->id.bustype = BUS_I2C;
>> + capdev->input->id.product = 0x880A;
>> + capdev->input->id.version = 0;
>> + capdev->input->name = "ATMegaXX Capacitive Button Controller";
>> + __set_bit(EV_KEY, capdev->input->evbit);
>> +
>> + node = dev->of_node;
>> + if (!node) {
>> + dev_err(dev, "failed to find matching node in device tree\n");
>> + return -EINVAL;
>> + }
>> +
>> + if (of_property_read_bool(node, "autorepeat"))
>> + __set_bit(EV_REP, capdev->input->evbit);
>> +
>> + capdev->num_btn = of_property_count_u32_elems(node, "linux,keymap");
>> + if (capdev->num_btn > MAX_NUM_OF_BUTTONS)
>> + capdev->num_btn = MAX_NUM_OF_BUTTONS;
>> +
>> + err = of_property_read_u32_array(node, "linux,keycodes",
>> + capdev->keycodes,
>> + capdev->num_btn);
>> + if (err) {
>> + dev_err(dev,
>> + "failed to read linux,keycode property: %d\n", err);
>> + return err;
>> + }
>> +
>> + for (i = 0; i < capdev->num_btn; i++)
>> + __set_bit(capdev->keycodes[i], capdev->input->keybit);
>> +
>> + capdev->input->keycode = capdev->keycodes;
>> + capdev->input->keycodesize = sizeof(capdev->keycodes[0]);
>> + capdev->input->keycodemax = capdev->num_btn;
>> +
>> + err = input_register_device(capdev->input);
>> + if (err)
>> + return err;
>> +
>> + err = devm_request_threaded_irq(dev, client->irq, NULL,
>> + atmel_captouch_isr, IRQF_ONESHOT,
>> + "atmel_captouch", capdev);
>> + if (err) {
>> + dev_err(dev, "failed to request irq %d: %d\n",
>> + client->irq, err);
>> + return err;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +#ifdef CONFIG_OF
>> +static const struct of_device_id atmel_captouch_of_id[] = {
>> + {
>> + .compatible = "atmel,captouch",
>> + },
>> + { /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, atmel_captouch_of_id);
>> +#endif
>> +
>> +static const struct i2c_device_id atmel_captouch_id[] = {
>> + { "atmel_captouch", 0 },
>> + { }
>> +};
>> +MODULE_DEVICE_TABLE(i2c, atmel_captouch_id);
>> +
>> +static struct i2c_driver atmel_captouch_driver = {
>> + .probe = atmel_captouch_probe,
>> + .id_table = atmel_captouch_id,
>> + .driver = {
>> + .name = "atmel_captouch",
>> + .of_match_table = of_match_ptr(atmel_captouch_of_id),
>> + },
>> +};
>> +module_i2c_driver(atmel_captouch_driver);
>> +
>> +/* Module information */
>> +MODULE_AUTHOR("Hung-yu Wu <hywu@...gle.com>");
>> +MODULE_DESCRIPTION("Atmel ATmegaXX Capacitance Touch Sensor I2C Driver");
>> +MODULE_LICENSE("GPL v2");
>> --
>> 2.1.2
>>
>
> --
> Dmitry
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