[PATCH v2 1/2] add driver for cypress cy8cmbr3102

[Patrick Vogelaar <Patrick.Vogelaar@gigatronik.com>]

Version 2:
* removed .owner
* based on branch next

Signed-off-by: Patrick Vogelaar <Patrick.Vogelaar@gigatronik.com>
---
 drivers/input/misc/Kconfig       |  12 +++
 drivers/input/misc/Makefile      |   1 +
 drivers/input/misc/cy8cmbr3102.c | 221 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 234 insertions(+)
 create mode 100644 drivers/input/misc/cy8cmbr3102.c

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 5b6c522..be3071e 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -822,4 +822,16 @@ config INPUT_HISI_POWERKEY
 	  To compile this driver as a module, choose M here: the
 	  module will be called hisi_powerkey.
 
+config INPUT_CY8CMBR3102
+	tristate "Cypress CY8CMBR3102 CapSense Express controller"
+	depends on I2C
+	select INPUT_POLLDEV
+	default n
+	help
+	  Say yes here to enable support for the Cypress CY8CMBR3102
+	  CapSense Express controller.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called cy8cmbr3102.
+
 endif
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index b10523f..f9959ed 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -77,3 +77,4 @@ obj-$(CONFIG_INPUT_WM831X_ON)		+= wm831x-on.o
 obj-$(CONFIG_INPUT_XEN_KBDDEV_FRONTEND)	+= xen-kbdfront.o
 obj-$(CONFIG_INPUT_YEALINK)		+= yealink.o
 obj-$(CONFIG_INPUT_IDEAPAD_SLIDEBAR)	+= ideapad_slidebar.o
+obj-$(CONFIG_INPUT_CY8CMBR3102)		+= cy8cmbr3102.o
diff --git a/drivers/input/misc/cy8cmbr3102.c b/drivers/input/misc/cy8cmbr3102.c
new file mode 100644
index 0000000..ed67a63
--- /dev/null
+++ b/drivers/input/misc/cy8cmbr3102.c
@@ -0,0 +1,221 @@
+/* Driver for Cypress CY8CMBR3102 CapSense Express Controller
+ *
+ * (C) 2017 by Gigatronik Technologies GmbH
+ * Author: Patrick Vogelaar <patrick.vogelaar@gigatronik.com>
+ * All rights reserved.
+ *
+ * This code is based on mma8450.c and atmel_captouch.c.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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.
+ *
+ * NOTE: This implementation does not implement the full range of functions the
+ * Cypress CY8CMBR3102 CapSense Express controller provides. It only implements
+ * its use for connected touch buttons (yet).
+ */
+
+#define DRV_VERSION "0.1"
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input-polldev.h>
+#include <linux/of.h>
+
+/* I2C Registers */
+#define CY8CMBR3102_DEVICE_ID_REG		0x90
+#define CY8CMBR3102_BUTTON_STAT			0xAA
+
+
+#define CY8CMBR3102_MAX_NUM_OF_BUTTONS		0x02
+#define CY8CMBR3102_DRV_NAME			"cy8cmbr3102"
+#define CY8CMBR3102_POLL_INTERVAL		200
+#define CY8CMBR3102_POLL_INTERVAL_MAX		300
+#define CY8CMBR3102_DEVICE_ID			2561
+#define CY8CMBR3102_MAX_RETRY			5
+
+/*
+ * @i2c_client: I2C slave device client pointer
+ * @idev: Input (polled) device pointer
+ * @num_btn: Number of buttons
+ * @keycodes: map of button# to KeyCode
+ * @cy8cmbr3102_lock: mutex lock
+ */
+struct cy8cmbr3102_device {
+	struct i2c_client *client;
+	struct input_polled_dev *idev;
+	u32 num_btn;
+	u32 keycodes[CY8CMBR3102_MAX_NUM_OF_BUTTONS];
+	struct mutex cy8cmbr3102_lock;
+};
+
+static const struct i2c_device_id cy8cmbr3102_idtable[] = {
+		{"cy8cmbr3102", 0},
+		{}
+};
+MODULE_DEVICE_TABLE(i2c, cy8cmbr3102_idtable);
+
+static void cy8cmbr3102_poll(struct input_polled_dev *idev)
+{
+	struct cy8cmbr3102_device *dev = idev->private;
+	int i, ret, btn_state;
+
+	mutex_lock(&dev->cy8cmbr3102_lock);
+
+	ret = i2c_smbus_read_word_data(dev->client, CY8CMBR3102_BUTTON_STAT);
+	if (ret < 0) {
+		dev_err(&dev->client->dev, "i2c io error: %d\n", ret);
+		mutex_unlock(&dev->cy8cmbr3102_lock);
+		return;
+	}
+
+	for (i = 0; i < dev->num_btn; i++) {
+		btn_state = ret & (0x1 << i);
+		input_report_key(idev->input, dev->keycodes[i], btn_state);
+		input_sync(idev->input);
+	}
+
+	mutex_unlock(&dev->cy8cmbr3102_lock);
+}
+
+static int cy8cmbr3102_remove(struct i2c_client *client)
+{
+	struct cy8cmbr3102_device *dev = i2c_get_clientdata(client);
+	struct input_polled_dev *idev = dev->idev;
+
+	dev_dbg(&client->dev, "%s\n", __func__);
+
+	mutex_destroy(&dev->cy8cmbr3102_lock);
+	input_unregister_polled_device(idev);
+
+	return 0;
+}
+
+static int cy8cmbr3102_probe(struct i2c_client *client,
+				const struct i2c_device_id *id)
+{
+	struct cy8cmbr3102_device *drvdata;
+	struct device *dev = &client->dev;
+	struct device_node *node;
+	int i, err, ret;
+
+	dev_dbg(&client->dev, "%s\n", __func__);
+
+	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;
+	}
+
+	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
+	if (!drvdata)
+		return -ENOMEM;
+
+	drvdata->client = client;
+	i2c_set_clientdata(client, drvdata);
+
+	/* device is in low-power mode and needs to be waken up */
+	for (i = 0; (i < CY8CMBR3102_MAX_RETRY) &&
+					(ret != CY8CMBR3102_DEVICE_ID); i++) {
+		ret = i2c_smbus_read_word_data(drvdata->client,
+		CY8CMBR3102_DEVICE_ID_REG);
+		dev_dbg(dev, "DEVICE_ID (%i): %i\n", i, ret);
+	}
+
+	if (ret < 0) {
+		dev_err(&client->dev, "i2c io error: %d\n", ret);
+		return -EIO;
+	} else if (ret != CY8CMBR3102_DEVICE_ID) {
+		dev_err(&client->dev, "read device ID %i is not equal to %i!\n",
+				ret, CY8CMBR3102_DEVICE_ID);
+		return -ENXIO;
+	}
+	dev_dbg(dev, "device identified by device ID\n");
+
+	drvdata->idev = devm_input_allocate_polled_device(dev);
+	if (!drvdata->idev) {
+		dev_err(dev, "failed to allocate input device\n");
+		return -ENOMEM;
+	}
+
+	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, drvdata->idev->input->evbit);
+
+	drvdata->num_btn = of_property_count_u32_elems(node, "linux,keycodes");
+	if (drvdata->num_btn > CY8CMBR3102_MAX_NUM_OF_BUTTONS)
+		drvdata->num_btn = CY8CMBR3102_MAX_NUM_OF_BUTTONS;
+
+	err = of_property_read_u32_array(node, "linux,keycodes",
+			drvdata->keycodes, drvdata->num_btn);
+
+	if (err) {
+		dev_err(dev, "failed to read linux,keycodes property: %d\n",
+				err);
+		return err;
+	}
+
+	for (i = 0; i < drvdata->num_btn; i++)
+		__set_bit(drvdata->keycodes[i], drvdata->idev->input->keybit);
+
+	drvdata->idev->input->id.bustype = BUS_I2C;
+	drvdata->idev->input->id.product = 0x3102;
+	drvdata->idev->input->id.version = 0;
+	drvdata->idev->input->name = CY8CMBR3102_DRV_NAME;
+	drvdata->idev->poll = cy8cmbr3102_poll;
+	drvdata->idev->poll_interval = CY8CMBR3102_POLL_INTERVAL;
+	drvdata->idev->poll_interval_max = CY8CMBR3102_POLL_INTERVAL_MAX;
+	drvdata->idev->private = drvdata;
+	drvdata->idev->input->keycode = drvdata->keycodes;
+	drvdata->idev->input->keycodemax = drvdata->num_btn;
+	drvdata->idev->input->keycodesize = sizeof(drvdata->keycodes[0]);
+	__set_bit(EV_KEY, drvdata->idev->input->evbit);
+
+	mutex_init(&drvdata->cy8cmbr3102_lock);
+
+	err = input_register_polled_device(drvdata->idev);
+	if (err)
+		return err;
+
+	dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_cy8cmbr3102_match[] = {
+		{.compatible = "cypress,cy8cmbr3102", },
+		{}
+};
+MODULE_DEVICE_TABLE(of, of_cy8cmbr3102_match);
+#endif
+
+static struct i2c_driver cy8cmbr3102_driver = {
+		.driver			= {
+			.name		= "cy8cmbr3102",
+			.of_match_table	= of_match_ptr(of_cy8cmbr3102_match),
+		},
+		.probe = cy8cmbr3102_probe,
+		.remove = cy8cmbr3102_remove,
+		.id_table = cy8cmbr3102_idtable,
+};
+module_i2c_driver(cy8cmbr3102_driver);
+
+MODULE_AUTHOR("Patrick Vogelaar <patrick.vogelaar@gigatronik.com>");
+MODULE_DESCRIPTION("Cypress CY8CMBR3102 CapSense Express controller");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
-- 
2.7.4