Add I2C driver for AtmegaXX capacitive touch device. Signed-off-by: Hung-yu Wu <hywu@xxxxxxxxxx> Signed-off-by: Grant Grundler <grundler@xxxxxxxxxxxx> --- .../bindings/input/atmel,atmegaxx_captouch.txt | 34 +++ drivers/input/misc/Kconfig | 11 + drivers/input/misc/Makefile | 1 + drivers/input/misc/atmegaxx_captouch.c | 278 +++++++++++++++++++++ 4 files changed, 324 insertions(+) create mode 100644 Documentation/devicetree/bindings/input/atmel,atmegaxx_captouch.txt create mode 100644 drivers/input/misc/atmegaxx_captouch.c For those that like to know how sausage is made, ChromeOS code review history here: https://chromium-review.googlesource.com/339950 Driver was tested with prototype HW and it reliably reports events correctly. Manual testing was just using "evtest /dev/input/event0" and watch for events. diff --git a/Documentation/devicetree/bindings/input/atmel,atmegaxx_captouch.txt b/Documentation/devicetree/bindings/input/atmel,atmegaxx_captouch.txt new file mode 100644 index 0000000..07a4b0b --- /dev/null +++ b/Documentation/devicetree/bindings/input/atmel,atmegaxx_captouch.txt @@ -0,0 +1,34 @@ +Device tree bindings for Atmel AtmegaXX capacitive touch sensor + +The node for this device must be a child of a I2C controller node, as the +device communicates via I2C. + +Required properties: + + compatible: Must be "atmel,atmegaxx_captouch". + reg: The I2C slave address of the device. + interrupts: Property describing the interrupt line the device + is connected to. The device only has one interrupt + source. + linux,keycodes: Specifies an array of numeric keycode values to + be used for reporting button presses. The array can + contain up to 8 entries. + +Optional properties: + + autorepeat: Enables the Linux input system's autorepeat + feature on the input device. + +Example: + + atmegaxx_captouch@51 { + compatible = "atmel,atmegaxx_captouch"; + reg = <0x51>; + interrupt-parent = <&tlmm>; + interrupts = <67 IRQ_TYPE_EDGE_FALLING>; + linux,keycodes = <BTN_0>, <BTN_1>, + <BTN_2>, <BTN_3>, + <BTN_4>, <BTN_5>, + <BTN_6>, <BTN_7>; + autorepeat; + }; diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig index 838824b..4cee1ac 100644 --- a/drivers/input/misc/Kconfig +++ b/drivers/input/misc/Kconfig @@ -82,6 +82,17 @@ config INPUT_ARIZONA_HAPTICS To compile this driver as a module, choose M here: the module will be called arizona-haptics. +config INPUT_ATMEGAXX_CAPTOUCH + tristate "Atmel AtmegaXX Capacitive Touch" + depends on OF || COMPILE_TEST + help + Say Y here if an Atmel Capacitive Touch device is connected to + an I2C bus. One should find "atmel,atmegaxx_captouch" node in + the board specific DTS. + + To compile this driver as a module, choose M here: the + module will be called atmegaxx_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..7254bd6c 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-$(CONFIG_INPUT_ATMEGAXX_CAPTOUCH) += atmegaxx_captouch.o obj-$(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/atmegaxx_captouch.c b/drivers/input/misc/atmegaxx_captouch.c new file mode 100644 index 0000000..bd886c1 --- /dev/null +++ b/drivers/input/misc/atmegaxx_captouch.c @@ -0,0 +1,278 @@ +/* + * Atmel Atmegaxx Capacitive Touch 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. + */ + +/* + * 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 atmegaxx_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 atmegaxx_read(struct atmegaxx_captouch_device *atmegaxx, + u8 reg, u8 *data, size_t len) +{ + struct i2c_client *client = atmegaxx->client; + struct device *dev = &client->dev; + struct i2c_msg msg[2]; + int err; + + if (len > sizeof(atmegaxx->xfer_buf) - 2) + return -EINVAL; + + atmegaxx->xfer_buf[0] = reg; + atmegaxx->xfer_buf[1] = len; + + msg[0].addr = client->addr; + msg[0].flags = 0; + msg[0].buf = atmegaxx->xfer_buf; + msg[0].len = 2; + + msg[1].addr = client->addr; + msg[1].flags = I2C_M_RD; + msg[1].buf = atmegaxx->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 (atmegaxx->xfer_buf[0] != reg) { + dev_err(dev, "I2C read error: register address does not match\n"); + return -ECOMM; + } + + memcpy(data, &atmegaxx->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 atmegaxx_captouch_isr(int irq, void *data) +{ + struct atmegaxx_captouch_device *atmegaxx = data; + struct device *dev = &atmegaxx->client->dev; + int error; + int i; + u8 new_btn; + u8 changed_btn; + + error = atmegaxx_read(atmegaxx, 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 ^ atmegaxx->prev_btn; + atmegaxx->prev_btn = new_btn; + + for (i = 0; i < atmegaxx->num_btn; i++) { + if (changed_btn & BIT(i)) + input_report_key(atmegaxx->input, + atmegaxx->keycodes[i], + new_btn & BIT(i)); + } + + input_sync(atmegaxx->input); + +out: + return IRQ_HANDLED; +} + +/* + * Probe function to setup the device, input system and interrupt + */ +static int atmegaxx_captouch_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct atmegaxx_captouch_device *atmegaxx; + 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; + } + + atmegaxx = devm_kzalloc(dev, sizeof(*atmegaxx), GFP_KERNEL); + if (!atmegaxx) + return -ENOMEM; + + atmegaxx->client = client; + i2c_set_clientdata(client, atmegaxx); + + err = atmegaxx_read(atmegaxx, REG_KEY_STATE, + &atmegaxx->prev_btn, sizeof(atmegaxx->prev_btn)); + if (err) { + dev_err(dev, "failed to read initial button state: %d\n", err); + return err; + } + + atmegaxx->input = devm_input_allocate_device(dev); + if (!atmegaxx->input) { + dev_err(dev, "failed to allocate input device\n"); + return -ENOMEM; + } + + atmegaxx->input->id.bustype = BUS_I2C; + atmegaxx->input->id.product = 0x880A; + atmegaxx->input->id.version = 0; + atmegaxx->input->name = "ATMegaXX Capacitive Button Controller"; + __set_bit(EV_KEY, atmegaxx->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, atmegaxx->input->evbit); + + atmegaxx->num_btn = of_property_count_u32_elems(node, "linux,keymap"); + if (atmegaxx->num_btn > MAX_NUM_OF_BUTTONS) + atmegaxx->num_btn = MAX_NUM_OF_BUTTONS; + + err = of_property_read_u32_array(node, "linux,keycodes", + atmegaxx->keycodes, + atmegaxx->num_btn); + if (err) { + dev_err(dev, + "failed to read linux,keycode property: %d\n", err); + return err; + } + + for (i = 0; i < atmegaxx->num_btn; i++) + __set_bit(atmegaxx->keycodes[i], atmegaxx->input->keybit); + + atmegaxx->input->keycode = atmegaxx->keycodes; + atmegaxx->input->keycodesize = sizeof(atmegaxx->keycodes[0]); + atmegaxx->input->keycodemax = atmegaxx->num_btn; + + err = input_register_device(atmegaxx->input); + if (err) + return err; + + err = devm_request_threaded_irq(dev, client->irq, NULL, + atmegaxx_captouch_isr, IRQF_ONESHOT, + "atmegaxx_captouch", atmegaxx); + 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 atmegaxx_captouch_of_id[] = { + { + .compatible = "atmel,atmegaxx_captouch", + }, + { /* sentinel */ } +} +MODULE_DEVICE_TABLE(of, atmegaxx_captouch_of_id); +#endif + +static const struct i2c_device_id atmegaxx_captouch_id[] = { + { "atmegaxx_captouch", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, atmegaxx_captouch_id); + +static struct i2c_driver atmegaxx_captouch_driver = { + .probe = atmegaxx_captouch_probe, + .id_table = atmegaxx_captouch_id, + .driver = { + .name = "atmegaxx_captouch", + .of_match_table = of_match_ptr(atmegaxx_captouch_of_id), + }, +}; +module_i2c_driver(atmegaxx_captouch_driver); + +/* Module information */ +MODULE_AUTHOR("Hung-yu Wu <hywu@xxxxxxxxxx>"); +MODULE_DESCRIPTION("Atmel ATmegaXX Capacitance Touch Sensor I2C Driver"); +MODULE_LICENSE("GPL v2"); -- 2.1.2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
