Add new kscan_gpio_demux driver

+ zmk,kscan_gpio_demux is now a compatible kscan option
+ kscan_gpio_demux is based heavily off of the implementation of
kscan_gpio_matrix, modified to address cols using an n-to-1
demultiplexer chip instead of discrete IO
+ Added zmk,kscan_gpio_demux.yaml file
* modified CMakeLists to include new source files

3 files changed, 293 insertions, 0 deletions

diff --git a/app/drivers/zephyr/CMakeLists.txt b/app/drivers/zephyr/CMakeLists.txt
index fc43fb8..e3a192d 100644
--- a/app/drivers/zephyr/CMakeLists.txt
+++ b/app/drivers/zephyr/CMakeLists.txt
@@ -5,6 +5,7 @@ if(CONFIG_ZMK_KSCAN_GPIO_DRIVER)
   zephyr_library_sources(
     kscan_gpio_matrix.c
     kscan_gpio_direct.c
+    kscan_gpio_demux.c
     )
 
   zephyr_library_sources_ifdef(CONFIG_EC11 ec11.c)
diff --git a/app/drivers/zephyr/dts/bindings/zmk,kscan-gpio-demux.yaml b/app/drivers/zephyr/dts/bindings/zmk,kscan-gpio-demux.yaml
new file mode 100644
index 0000000..a2d8d24
--- /dev/null
+++ b/app/drivers/zephyr/dts/bindings/zmk,kscan-gpio-demux.yaml
@@ -0,0 +1,22 @@
+# Copyright (c) 2020, The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: GPIO keyboard demux controller
+
+compatible: "zmk,kscan-gpio-demux"
+
+include: kscan.yaml
+
+properties:
+  input-gpios:
+    type: phandle-array
+    required: true
+  output-gpios:
+    type: phandle-array
+    required: true
+  debounce-period:
+    type: int
+    default: 5
+  polling-interval-msec:
+    type: int
+    default: 25
diff --git a/app/drivers/zephyr/kscan_gpio_demux.c b/app/drivers/zephyr/kscan_gpio_demux.c
new file mode 100644
index 0000000..98c04e6
--- /dev/null
+++ b/app/drivers/zephyr/kscan_gpio_demux.c
@@ -0,0 +1,270 @@
+/*
+ * Copyright (c) 2020 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_kscan_gpio_demux
+
+#include <device.h>
+#include <drivers/kscan.h>
+#include <drivers/gpio.h>
+#include <logging/log.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#if DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)
+
+struct kscan_gpio_item_config {
+    char *label;
+    gpio_pin_t pin;
+    gpio_flags_t flags;
+};
+
+// Helper macro
+#define PWR_TWO(x) (1 << (x))
+
+// Define GPIO cfg
+#define _KSCAN_GPIO_ITEM_CFG_INIT(n, prop, idx)                                                    \
+    {                                                                                              \
+        .label = DT_INST_GPIO_LABEL_BY_IDX(n, prop, idx),                                          \
+        .pin = DT_INST_GPIO_PIN_BY_IDX(n, prop, idx),                                              \
+        .flags = DT_INST_GPIO_FLAGS_BY_IDX(n, prop, idx),                                          \
+    },
+
+// Define row and col cfg
+#define _KSCAN_GPIO_INPUT_CFG_INIT(idx, n) _KSCAN_GPIO_ITEM_CFG_INIT(n, input_gpios, idx)
+#define _KSCAN_GPIO_OUTPUT_CFG_INIT(idx, n) _KSCAN_GPIO_ITEM_CFG_INIT(n, output_gpios, idx)
+
+// Check debounce config
+#define CHECK_DEBOUNCE_CFG(n, a, b) COND_CODE_0(DT_INST_PROP(n, debounce_period), a, b)
+
+// Define the row and column lengths
+#define INST_MATRIX_INPUTS(n) DT_INST_PROP_LEN(n, input_gpios)
+#define INST_DEMUX_GPIOS(n) DT_INST_PROP_LEN(n, output_gpios)
+#define INST_MATRIX_OUTPUTS(n) PWR_TWO(INST_DEMUX_GPIOS(n))
+#define POLL_INTERVAL(n) DT_INST_PROP(n, polling_interval_msec)
+
+#define GPIO_INST_INIT(n)                                                                          \
+    struct kscan_gpio_irq_callback_##n {                                                           \
+        struct CHECK_DEBOUNCE_CFG(n, (k_work), (k_delayed_work)) * work;                           \
+        struct gpio_callback callback;                                                             \
+        struct device *dev;                                                                        \
+    };                                                                                             \
+                                                                                                   \
+    static struct kscan_gpio_irq_callback_##n irq_callbacks_##n[INST_MATRIX_INPUTS(n)];            \
+                                                                                                   \
+    struct kscan_gpio_config_##n {                                                                 \
+        struct kscan_gpio_item_config rows[INST_MATRIX_INPUTS(n)];                                 \
+        struct kscan_gpio_item_config cols[INST_DEMUX_GPIOS(n)];                                   \
+    };                                                                                             \
+                                                                                                   \
+    struct kscan_gpio_data_##n {                                                                   \
+        kscan_callback_t callback;                                                                 \
+        struct k_timer poll_timer;                                                                 \
+        struct CHECK_DEBOUNCE_CFG(n, (k_work), (k_delayed_work)) work;                             \
+        bool matrix_state[INST_MATRIX_INPUTS(n)][INST_MATRIX_OUTPUTS(n)];                          \
+        struct device *rows[INST_MATRIX_INPUTS(n)];                                                \
+        struct device *cols[INST_MATRIX_OUTPUTS(n)];                                               \
+        struct device *dev;                                                                        \
+    };                                                                                             \
+    /* IO/GPIO SETUP */                                                                            \
+    /* gpio_input_devices are PHYSICAL IO devices */                                               \
+    static struct device **kscan_gpio_input_devices_##n(struct device *dev) {                      \
+        struct kscan_gpio_data_##n *data = dev->driver_data;                                       \
+        return data->rows;                                                                         \
+    }                                                                                              \
+                                                                                                   \
+    static const struct kscan_gpio_item_config *kscan_gpio_input_configs_##n(struct device *dev) { \
+        const struct kscan_gpio_config_##n *cfg = dev->config_info;                                \
+        return cfg->rows;                                                                          \
+    }                                                                                              \
+                                                                                                   \
+    /* gpio_output_devices are PHYSICAL IO devices */                                              \
+    static struct device **kscan_gpio_output_devices_##n(struct device *dev) {                     \
+        struct kscan_gpio_data_##n *data = dev->driver_data;                                       \
+        return data->cols;                                                                         \
+    }                                                                                              \
+                                                                                                   \
+    static const struct kscan_gpio_item_config *kscan_gpio_output_configs_##n(                     \
+        struct device *dev) {                                                                      \
+        const struct kscan_gpio_config_##n *cfg = dev->config_info;                                \
+        /* If row2col, rows = outputs & cols = inputs */                                           \
+        return cfg->cols;                                                                          \
+    }                                                                                              \
+    /* POLLING SETUP */                                                                            \
+    static void kscan_gpio_timer_handler(struct k_timer *timer) {                                  \
+        struct kscan_gpio_data_##n *data =                                                         \
+            CONTAINER_OF(timer, struct kscan_gpio_data_##n, poll_timer);                           \
+        k_work_submit(&data->work.work);                                                           \
+    }                                                                                              \
+                                                                                                   \
+    /* Read the state of the input GPIOs */                                                        \
+    /* This is the core matrix_scan func */                                                        \
+    static int kscan_gpio_read_##n(struct device *dev) {                                           \
+        bool submit_follow_up_read = false;                                                        \
+        struct kscan_gpio_data_##n *data = dev->driver_data;                                       \
+        static bool read_state[INST_MATRIX_INPUTS(n)][INST_MATRIX_OUTPUTS(n)];                     \
+        for (int o = 0; o < INST_MATRIX_OUTPUTS(n); o++) {                                         \
+            /* Iterate over bits and set GPIOs accordingly */                                      \
+            for (u8_t bit = 0; bit < INST_DEMUX_GPIOS(n); bit++) {                                 \
+                u8_t state = (o & (0b1 << bit)) >> bit;                                            \
+                struct device *out_dev = kscan_gpio_output_devices_##n(dev)[bit];                  \
+                const struct kscan_gpio_item_config *out_cfg =                                     \
+                    &kscan_gpio_output_configs_##n(dev)[bit];                                      \
+                gpio_pin_set(out_dev, out_cfg->pin, state);                                        \
+            }                                                                                      \
+                                                                                                   \
+            for (int i = 0; i < INST_MATRIX_INPUTS(n); i++) {                                      \
+                /* Get the input device (port) */                                                  \
+                struct device *in_dev = kscan_gpio_input_devices_##n(dev)[i];                      \
+                /* Get the input device config (pin) */                                            \
+                const struct kscan_gpio_item_config *in_cfg =                                      \
+                    &kscan_gpio_input_configs_##n(dev)[i];                                         \
+                read_state[i][o] = gpio_pin_get(in_dev, in_cfg->pin) > 0;                          \
+            }                                                                                      \
+        }                                                                                          \
+        for (int r = 0; r < INST_MATRIX_INPUTS(n); r++) {                                          \
+            for (int c = 0; c < INST_MATRIX_OUTPUTS(n); c++) {                                     \
+                bool pressed = read_state[r][c];                                                   \
+                submit_follow_up_read = (submit_follow_up_read || pressed);                        \
+                if (pressed != data->matrix_state[r][c]) {                                         \
+                    LOG_DBG("Sending event at %d,%d state %s", r, c, (pressed ? "on" : "off"));    \
+                    data->matrix_state[r][c] = pressed;                                            \
+                    data->callback(dev, r, c, pressed);                                            \
+                }                                                                                  \
+            }                                                                                      \
+        }                                                                                          \
+        if (submit_follow_up_read) {                                                               \
+            CHECK_DEBOUNCE_CFG(n, ({ k_work_submit(&data->work); }), ({                            \
+                                   k_delayed_work_cancel(&data->work);                             \
+                                   k_delayed_work_submit(&data->work, K_MSEC(5));                  \
+                               }))                                                                 \
+        }                                                                                          \
+        return 0;                                                                                  \
+    }                                                                                              \
+                                                                                                   \
+    static void kscan_gpio_work_handler_##n(struct k_work *work) {                                 \
+        struct kscan_gpio_data_##n *data = CONTAINER_OF(work, struct kscan_gpio_data_##n, work);   \
+        kscan_gpio_read_##n(data->dev);                                                            \
+    }                                                                                              \
+                                                                                                   \
+    static void kscan_gpio_irq_callback_handler_##n(struct device *dev, struct gpio_callback *cb,  \
+                                                    gpio_port_pins_t pin) {                        \
+        struct kscan_gpio_irq_callback_##n *data =                                                 \
+            CONTAINER_OF(cb, struct kscan_gpio_irq_callback_##n, callback);                        \
+        CHECK_DEBOUNCE_CFG(n, ({ k_work_submit(data->work); }), ({                                 \
+                               k_delayed_work_cancel(data->work);                                  \
+                               k_delayed_work_submit(data->work,                                   \
+                                                     K_MSEC(DT_INST_PROP(n, debounce_period)));    \
+                           }))                                                                     \
+    }                                                                                              \
+                                                                                                   \
+    static struct kscan_gpio_data_##n kscan_gpio_data_##n = {                                      \
+        .rows = {[INST_MATRIX_INPUTS(n) - 1] = NULL}, .cols = {[INST_DEMUX_GPIOS(n) - 1] = NULL}}; \
+                                                                                                   \
+    /* KSCAN API configure function */                                                             \
+    static int kscan_gpio_configure_##n(struct device *dev, kscan_callback_t callback) {           \
+        LOG_DBG("KSCAN API configure");                                                            \
+        struct kscan_gpio_data_##n *data = dev->driver_data;                                       \
+        if (!callback) {                                                                           \
+            return -EINVAL;                                                                        \
+        }                                                                                          \
+        data->callback = callback;                                                                 \
+        LOG_DBG("Configured GPIO %d", n);                                                          \
+        return 0;                                                                                  \
+    };                                                                                             \
+                                                                                                   \
+    /* KSCAN API enable function */                                                                \
+    static int kscan_gpio_enable_##n(struct device *dev) {                                         \
+        LOG_DBG("KSCAN API enable");                                                               \
+        struct kscan_gpio_data_##n *data = dev->driver_data;                                       \
+        k_timer_start(&data->poll_timer, K_MSEC(POLL_INTERVAL(n)), K_MSEC(POLL_INTERVAL(n)));      \
+        return 0;                                                                                  \
+    };                                                                                             \
+                                                                                                   \
+    /* KSCAN API disable function */                                                               \
+    static int kscan_gpio_disable_##n(struct device *dev) {                                        \
+        LOG_DBG("KSCAN API disable");                                                              \
+        struct kscan_gpio_data_##n *data = dev->driver_data;                                       \
+        k_timer_stop(&data->poll_timer);                                                           \
+        return 0;                                                                                  \
+    };                                                                                             \
+                                                                                                   \
+    /* GPIO init function*/                                                                        \
+    static int kscan_gpio_init_##n(struct device *dev) {                                           \
+        LOG_DBG("KSCAN GPIO init");                                                                \
+        struct kscan_gpio_data_##n *data = dev->driver_data;                                       \
+        int err;                                                                                   \
+        /* configure input devices*/                                                               \
+        struct device **input_devices = kscan_gpio_input_devices_##n(dev);                         \
+        for (int i = 0; i < INST_MATRIX_INPUTS(n); i++) {                                          \
+            const struct kscan_gpio_item_config *in_cfg = &kscan_gpio_input_configs_##n(dev)[i];   \
+            input_devices[i] = device_get_binding(in_cfg->label);                                  \
+            if (!input_devices[i]) {                                                               \
+                LOG_ERR("Unable to find input GPIO device");                                       \
+                return -EINVAL;                                                                    \
+            }                                                                                      \
+            err = gpio_pin_configure(input_devices[i], in_cfg->pin, GPIO_INPUT | in_cfg->flags);   \
+            if (err) {                                                                             \
+                LOG_ERR("Unable to configure pin %d on %s for input", in_cfg->pin, in_cfg->label); \
+                return err;                                                                        \
+            } else {                                                                               \
+                LOG_DBG("Configured pin %d on %s for input", in_cfg->pin, in_cfg->label);          \
+            }                                                                                      \
+            irq_callbacks_##n[i].work = &data->work;                                               \
+            irq_callbacks_##n[i].dev = dev;                                                        \
+            gpio_init_callback(&irq_callbacks_##n[i].callback,                                     \
+                               kscan_gpio_irq_callback_handler_##n, BIT(in_cfg->pin));             \
+            err = gpio_add_callback(input_devices[i], &irq_callbacks_##n[i].callback);             \
+            if (err) {                                                                             \
+                LOG_ERR("Error adding the callback to the column device");                         \
+                return err;                                                                        \
+            }                                                                                      \
+        }                                                                                          \
+        /* configure output devices*/                                                              \
+        struct device **output_devices = kscan_gpio_output_devices_##n(dev);                       \
+        for (int o = 0; o < INST_DEMUX_GPIOS(n); o++) {                                            \
+            const struct kscan_gpio_item_config *out_cfg = &kscan_gpio_output_configs_##n(dev)[o]; \
+            output_devices[o] = device_get_binding(out_cfg->label);                                \
+            if (!output_devices[o]) {                                                              \
+                LOG_ERR("Unable to find output GPIO device");                                      \
+                return -EINVAL;                                                                    \
+            }                                                                                      \
+            err = gpio_pin_configure(output_devices[o], out_cfg->pin,                              \
+                                     GPIO_OUTPUT_ACTIVE | out_cfg->flags);                         \
+            if (err) {                                                                             \
+                LOG_ERR("Unable to configure pin %d on %s for output", out_cfg->pin,               \
+                        out_cfg->label);                                                           \
+                return err;                                                                        \
+            } else {                                                                               \
+                LOG_DBG("Configured pin %d on %s for output", out_cfg->pin, out_cfg->label);       \
+            }                                                                                      \
+        }                                                                                          \
+        data->dev = dev;                                                                           \
+                                                                                                   \
+        k_timer_init(&data->poll_timer, kscan_gpio_timer_handler, NULL);                           \
+                                                                                                   \
+        (CHECK_DEBOUNCE_CFG(n, (k_work_init), (k_delayed_work_init)))(                             \
+            &data->work, kscan_gpio_work_handler_##n);                                             \
+        return 0;                                                                                  \
+    }                                                                                              \
+                                                                                                   \
+    static const struct kscan_driver_api gpio_driver_api_##n = {                                   \
+        .config = kscan_gpio_configure_##n,                                                        \
+        .enable_callback = kscan_gpio_enable_##n,                                                  \
+        .disable_callback = kscan_gpio_disable_##n,                                                \
+    };                                                                                             \
+                                                                                                   \
+    static const struct kscan_gpio_config_##n kscan_gpio_config_##n = {                            \
+        .rows = {UTIL_LISTIFY(INST_MATRIX_INPUTS(n), _KSCAN_GPIO_INPUT_CFG_INIT, n)},              \
+        .cols = {UTIL_LISTIFY(INST_DEMUX_GPIOS(n), _KSCAN_GPIO_OUTPUT_CFG_INIT, n)},               \
+    };                                                                                             \
+                                                                                                   \
+    DEVICE_AND_API_INIT(kscan_gpio_##n, DT_INST_LABEL(n), kscan_gpio_init_##n,                     \
+                        &kscan_gpio_data_##n, &kscan_gpio_config_##n, APPLICATION,                 \
+                        CONFIG_APPLICATION_INIT_PRIORITY, &gpio_driver_api_##n);
+
+DT_INST_FOREACH_STATUS_OKAY(GPIO_INST_INIT)
+
+#endif /* DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT) */