Signed-off-by: Patrick Vogelaar <patrick.vogel...@gigatronik.com>
---
 drivers/input/misc/Kconfig       |  12 +++
 drivers/input/misc/Makefile      |   1 +
 drivers/input/misc/cy8cmbr3102.c | 222 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 235 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..e2f5167
--- /dev/null
+++ b/drivers/input/misc/cy8cmbr3102.c
@@ -0,0 +1,222 @@
+/* Driver for Cypress CY8CMBR3102 CapSense Express Controller
+ *
+ * (C) 2017 by Gigatronik Technologies GmbH
+ * Author: Patrick Vogelaar <patrick.vogel...@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",
+                       .owner          = THIS_MODULE,
+                       .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.vogel...@gigatronik.com>");
+MODULE_DESCRIPTION("Cypress CY8CMBR3102 CapSense Express controller");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
-- 
2.7.4

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