This patch adds touch key support for six-channel members of the
Azoteq ProxFusion family of sensor devices.

Signed-off-by: Jeff LaBundy <j...@labundy.com>
---
 drivers/input/keyboard/Kconfig       |  10 ++
 drivers/input/keyboard/Makefile      |   1 +
 drivers/input/keyboard/iqs62x-keys.c | 340 +++++++++++++++++++++++++++++++++++
 3 files changed, 351 insertions(+)
 create mode 100644 drivers/input/keyboard/iqs62x-keys.c

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 8911bc2..ab10aff 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -657,6 +657,16 @@ config KEYBOARD_IPAQ_MICRO
          To compile this driver as a module, choose M here: the
          module will be called ipaq-micro-keys.
 
+config KEYBOARD_IQS62X
+       tristate "Azoteq IQS620A/621/622/624/625 touch keys"
+       depends on MFD_IQS62X
+       help
+         Say Y here to enable touch-key support for six-channel members of
+         the Azoteq ProxFusion family of sensor devices.
+
+         To compile this driver as a module, choose M here: the module will
+         be called iqs62x-keys.
+
 config KEYBOARD_OMAP
        tristate "TI OMAP keypad support"
        depends on ARCH_OMAP1
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 9510325..ee85b7f 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_KEYBOARD_TCA8418)                += 
tca8418_keypad.o
 obj-$(CONFIG_KEYBOARD_HIL)             += hil_kbd.o
 obj-$(CONFIG_KEYBOARD_HIL_OLD)         += hilkbd.o
 obj-$(CONFIG_KEYBOARD_IPAQ_MICRO)      += ipaq-micro-keys.o
+obj-$(CONFIG_KEYBOARD_IQS62X)          += iqs62x-keys.o
 obj-$(CONFIG_KEYBOARD_IMX)             += imx_keypad.o
 obj-$(CONFIG_KEYBOARD_HP6XX)           += jornada680_kbd.o
 obj-$(CONFIG_KEYBOARD_HP7XX)           += jornada720_kbd.o
diff --git a/drivers/input/keyboard/iqs62x-keys.c 
b/drivers/input/keyboard/iqs62x-keys.c
new file mode 100644
index 0000000..9d929f1
--- /dev/null
+++ b/drivers/input/keyboard/iqs62x-keys.c
@@ -0,0 +1,340 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Azoteq IQS620A/621/622/624/625 Touch Keys
+ *
+ * Copyright (C) 2019
+ * Author: Jeff LaBundy <j...@labundy.com>
+ */
+
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/kernel.h>
+#include <linux/mfd/iqs62x.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+enum {
+       IQS62X_SW_HALL_N,
+       IQS62X_SW_HALL_S,
+};
+
+static const char * const iqs62x_switch_names[] = {
+       [IQS62X_SW_HALL_N] = "hall_switch_north",
+       [IQS62X_SW_HALL_S] = "hall_switch_south",
+};
+
+struct iqs62x_switch_desc {
+       enum iqs62x_event_flag flag;
+       unsigned int code;
+       bool enabled;
+};
+
+struct iqs62x_keys_private {
+       struct iqs62x_core *iqs62x;
+       struct input_dev *input;
+       struct notifier_block notifier;
+       struct iqs62x_switch_desc switches[ARRAY_SIZE(iqs62x_switch_names)];
+       unsigned int keycode[IQS62X_NUM_KEYS];
+       unsigned int keycodemax;
+       u8 interval;
+};
+
+static int iqs62x_keys_parse_prop(struct platform_device *pdev,
+                                 struct iqs62x_keys_private *iqs62x_keys)
+{
+       struct device_node *keys_node = pdev->dev.of_node;
+       struct device_node *hall_node;
+       unsigned int val;
+       int ret, i;
+
+       if (!keys_node)
+               return 0;
+
+       ret = of_property_read_variable_u32_array(keys_node, "linux,keycodes",
+                                                 iqs62x_keys->keycode, 0,
+                                                 IQS62X_NUM_KEYS);
+       if (ret < 0) {
+               dev_err(&pdev->dev, "Failed to read keycodes: %d\n", ret);
+               return ret;
+       }
+       iqs62x_keys->keycodemax = ret;
+
+       for (i = 0; i < ARRAY_SIZE(iqs62x_keys->switches); i++) {
+               hall_node = of_get_child_by_name(keys_node,
+                                                iqs62x_switch_names[i]);
+               if (!hall_node)
+                       continue;
+
+               ret = of_property_read_u32(hall_node, "linux,code", &val);
+               if (ret < 0) {
+                       dev_err(&pdev->dev, "Failed to read switch code: %d\n",
+                               ret);
+                       of_node_put(hall_node);
+                       return ret;
+               }
+
+               if (of_property_read_bool(hall_node, "azoteq,use-prox"))
+                       iqs62x_keys->switches[i].flag = (i == IQS62X_SW_HALL_N ?
+                                                        IQS62X_EVENT_HALL_N_P :
+                                                        IQS62X_EVENT_HALL_S_P);
+               else
+                       iqs62x_keys->switches[i].flag = (i == IQS62X_SW_HALL_N ?
+                                                        IQS62X_EVENT_HALL_N_T :
+                                                        IQS62X_EVENT_HALL_S_T);
+
+               iqs62x_keys->switches[i].code = val;
+               iqs62x_keys->switches[i].enabled = true;
+
+               of_node_put(hall_node);
+       }
+
+       return 0;
+}
+
+static int iqs62x_keys_init(struct iqs62x_keys_private *iqs62x_keys)
+{
+       struct iqs62x_core *iqs62x = iqs62x_keys->iqs62x;
+       enum iqs62x_event_flag flag;
+       unsigned int event_mask_reg;
+       unsigned int event_mask = 0;
+       unsigned int val;
+       int error, i;
+
+       switch (iqs62x->dev_desc->prod_num) {
+       case IQS620_PROD_NUM:
+       case IQS621_PROD_NUM:
+       case IQS622_PROD_NUM:
+               event_mask_reg = IQS620_GLBL_EVENT_MASK;
+
+               /*
+                * Discreet button, hysteresis and SAR UI flags represent keys
+                * and are unmasked if mapped to a valid keycode.
+                */
+               for (i = 0; i < iqs62x_keys->keycodemax; i++) {
+                       if (iqs62x_keys->keycode[i] == KEY_RESERVED)
+                               continue;
+
+                       if (iqs62x_events[i].reg == IQS62X_EVENT_PROX)
+                               event_mask |= iqs62x->dev_desc->prox_mask;
+                       else if (iqs62x_events[i].reg == IQS62X_EVENT_HYST)
+                               event_mask |= (iqs62x->dev_desc->hyst_mask |
+                                              iqs62x->dev_desc->sar_mask);
+               }
+
+               error = regmap_read(iqs62x->map, iqs62x->dev_desc->hall_flags,
+                                   &val);
+               if (error)
+                       return error;
+
+               /*
+                * Hall UI flags represent switches and are unmasked if their
+                * corresponding child nodes are present.
+                */
+               for (i = 0; i < ARRAY_SIZE(iqs62x_keys->switches); i++) {
+                       if (!(iqs62x_keys->switches[i].enabled))
+                               continue;
+
+                       flag = iqs62x_keys->switches[i].flag;
+
+                       if (iqs62x_events[flag].reg != IQS62X_EVENT_HALL)
+                               continue;
+
+                       event_mask |= iqs62x->dev_desc->hall_mask;
+
+                       input_report_switch(iqs62x_keys->input,
+                                           iqs62x_keys->switches[i].code,
+                                           (val & iqs62x_events[flag].mask) ==
+                                           iqs62x_events[flag].val);
+               }
+
+               input_sync(iqs62x_keys->input);
+               break;
+
+       case IQS624_PROD_NUM:
+               event_mask_reg = IQS624_HALL_UI;
+
+               /*
+                * Interval change events represent keys and are unmasked if
+                * either wheel movement flag is mapped to a valid keycode.
+                */
+               if (iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_UP] != KEY_RESERVED)
+                       event_mask |= IQS624_HALL_UI_INT_EVENT;
+
+               if (iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_DN] != KEY_RESERVED)
+                       event_mask |= IQS624_HALL_UI_INT_EVENT;
+
+               error = regmap_read(iqs62x->map, iqs62x->dev_desc->interval,
+                                   &val);
+               if (error)
+                       return error;
+
+               iqs62x_keys->interval = val;
+               break;
+
+       default:
+               return 0;
+       }
+
+       return regmap_update_bits(iqs62x->map, event_mask_reg, event_mask, 0);
+}
+
+static int iqs62x_keys_notifier(struct notifier_block *notifier,
+                               unsigned long event_flags, void *context)
+{
+       struct iqs62x_event_data *event_data = context;
+       struct iqs62x_keys_private *iqs62x_keys;
+       int error, i;
+
+       iqs62x_keys = container_of(notifier, struct iqs62x_keys_private,
+                                  notifier);
+
+       if (event_flags & BIT(IQS62X_EVENT_SYS_RESET)) {
+               error = iqs62x_keys_init(iqs62x_keys);
+               if (error) {
+                       dev_err(iqs62x_keys->input->dev.parent,
+                               "Failed to re-initialize device: %d\n", error);
+                       return NOTIFY_BAD;
+               }
+
+               return NOTIFY_OK;
+       }
+
+       for (i = 0; i < iqs62x_keys->keycodemax; i++) {
+               if (iqs62x_events[i].reg == IQS62X_EVENT_WHEEL &&
+                   event_data->interval == iqs62x_keys->interval)
+                       continue;
+
+               input_report_key(iqs62x_keys->input, iqs62x_keys->keycode[i],
+                                event_flags & BIT(i));
+       }
+
+       for (i = 0; i < ARRAY_SIZE(iqs62x_keys->switches); i++)
+               if (iqs62x_keys->switches[i].enabled)
+                       input_report_switch(iqs62x_keys->input,
+                                           iqs62x_keys->switches[i].code,
+                                           event_flags &
+                                           BIT(iqs62x_keys->switches[i].flag));
+
+       input_sync(iqs62x_keys->input);
+
+       if (event_data->interval == iqs62x_keys->interval)
+               return NOTIFY_OK;
+
+       /*
+        * Each frame contains at most one wheel event (up or down), in which
+        * case a full keystroke is emulated.
+        */
+       if (event_flags & BIT(IQS62X_EVENT_WHEEL_UP)) {
+               input_report_key(iqs62x_keys->input,
+                                iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_UP],
+                                0);
+               input_sync(iqs62x_keys->input);
+       } else if (event_flags & BIT(IQS62X_EVENT_WHEEL_DN)) {
+               input_report_key(iqs62x_keys->input,
+                                iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_DN],
+                                0);
+               input_sync(iqs62x_keys->input);
+       }
+
+       iqs62x_keys->interval = event_data->interval;
+
+       return NOTIFY_OK;
+}
+
+static int iqs62x_keys_probe(struct platform_device *pdev)
+{
+       struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);
+       struct iqs62x_keys_private *iqs62x_keys;
+       struct input_dev *input;
+       int error, i;
+
+       iqs62x_keys = devm_kzalloc(&pdev->dev, sizeof(*iqs62x_keys),
+                                  GFP_KERNEL);
+       if (!iqs62x_keys)
+               return -ENOMEM;
+
+       platform_set_drvdata(pdev, iqs62x_keys);
+
+       error = iqs62x_keys_parse_prop(pdev, iqs62x_keys);
+       if (error)
+               return error;
+
+       input = devm_input_allocate_device(&pdev->dev);
+       if (!input)
+               return -ENOMEM;
+
+       input->keycodemax = iqs62x_keys->keycodemax;
+       input->keycode = iqs62x_keys->keycode;
+       input->keycodesize = sizeof(*iqs62x_keys->keycode);
+
+       input->name = iqs62x->dev_desc->dev_name;
+       input->id.bustype = BUS_I2C;
+
+       __set_bit(EV_KEY, input->evbit);
+
+       for (i = 0; i < iqs62x_keys->keycodemax; i++)
+               __set_bit(iqs62x_keys->keycode[i], input->keybit);
+
+       __clear_bit(KEY_RESERVED, input->keybit);
+
+       for (i = 0; i < ARRAY_SIZE(iqs62x_keys->switches); i++)
+               if (iqs62x_keys->switches[i].enabled) {
+                       __set_bit(EV_SW, input->evbit);
+                       __set_bit(iqs62x_keys->switches[i].code, input->swbit);
+               }
+
+       iqs62x_keys->iqs62x = iqs62x;
+       iqs62x_keys->input = input;
+
+       error = iqs62x_keys_init(iqs62x_keys);
+       if (error) {
+               dev_err(&pdev->dev, "Failed to initialize device: %d\n", error);
+               return error;
+       }
+
+       error = input_register_device(iqs62x_keys->input);
+       if (error) {
+               dev_err(&pdev->dev, "Failed to register device: %d\n", error);
+               return error;
+       }
+
+       iqs62x_keys->notifier.notifier_call = iqs62x_keys_notifier;
+       error = blocking_notifier_chain_register(&iqs62x_keys->iqs62x->nh,
+                                                &iqs62x_keys->notifier);
+       if (error)
+               dev_err(&pdev->dev, "Failed to register notifier: %d\n", error);
+
+       return error;
+}
+
+static int iqs62x_keys_remove(struct platform_device *pdev)
+{
+       struct iqs62x_keys_private *iqs62x_keys = platform_get_drvdata(pdev);
+       int error;
+
+       error = blocking_notifier_chain_unregister(&iqs62x_keys->iqs62x->nh,
+                                                  &iqs62x_keys->notifier);
+       if (error)
+               dev_err(&pdev->dev,
+                       "Failed to unregister notifier: %d\n", error);
+
+       return error;
+}
+
+static struct platform_driver iqs62x_keys_platform_driver = {
+       .driver = {
+               .name   = IQS62X_DRV_NAME_KEYS,
+       },
+       .probe          = iqs62x_keys_probe,
+       .remove         = iqs62x_keys_remove,
+};
+module_platform_driver(iqs62x_keys_platform_driver);
+
+MODULE_AUTHOR("Jeff LaBundy <j...@labundy.com>");
+MODULE_DESCRIPTION("Azoteq IQS620A/621/622/624/625 Touch Keys");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" IQS62X_DRV_NAME_KEYS);
-- 
2.7.4

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