input: it8xxx2_kbd: add a kso-ignore-mask property

The it8xxx2_kbd KSO pins can be used as both keyboard scan and GPIO. By
default the keyboard scanning driver controls the output level of all
the KSO signals from 0 to (col-size - 1), meaning that any line in
between used as GPIO is going to have its output value overridden.

Add a kso-ignore-mask property to the keyboard scan driver to allow
specifiying extra pins that should not be controlled by the driver.

Signed-off-by: Fabio Baltieri <[email protected]>

Author: fabiobaltieri

drivers/input/input_ite_it8xxx2_kbd.c

@@ -44,6 +44,8 @@ struct it8xxx2_kbd_config {
 	struct gpio_dt_spec kso16_gpios;
 	/* KSO17 GPIO cells */
 	struct gpio_dt_spec kso17_gpios;
+	/* Mask of signals to ignore */
+	uint32_t kso_ignore_mask;
 };
 
 struct it8xxx2_kbd_data {
@@ -59,7 +61,7 @@ static void it8xxx2_kbd_drive_column(const struct device *dev, int col)
 	const struct it8xxx2_kbd_config *const config = dev->config;
 	const struct input_kbd_matrix_common_config *common = &config->common;
 	struct kscan_it8xxx2_regs *const inst = config->base;
-	const uint32_t kso_mask = BIT_MASK(common->col_size);
+	const uint32_t kso_mask = BIT_MASK(common->col_size) & ~config->kso_ignore_mask;
 	const uint8_t ksol_mask = kso_mask & 0xff;
 	const uint8_t ksoh1_mask = (kso_mask >> 8) & 0xff;
 	uint32_t kso_val;
@@ -76,17 +78,14 @@ static void it8xxx2_kbd_drive_column(const struct device *dev, int col)
 		kso_val = kso_mask ^ BIT(col);
 	}
 
-	/* Set KSO[17:0] output data */
-	inst->KBS_KSOL = (inst->KBS_KSOL & ~ksol_mask) | (kso_val & ksol_mask);
-	/*
-	 * Disable global interrupts for critical section
-	 * The KBS_KSOH1 register contains both keyboard and GPIO output settings.
+	/* Set KSO[17:0] output data, disable global interrupts for critical section.
+	 * The KBS_KSO* registers contains both keyboard and GPIO output settings.
 	 * Not all bits are for the keyboard will be driven, so a critical section
 	 * is needed to avoid race conditions.
 	 */
 	key = irq_lock();
+	inst->KBS_KSOL = (inst->KBS_KSOL & ~ksol_mask) | (kso_val & ksol_mask);
 	inst->KBS_KSOH1 = (inst->KBS_KSOH1 & ~ksoh1_mask) | ((kso_val >> 8) & ksoh1_mask);
-	/* Restore interrupts */
 	irq_unlock(key);
 
 	if (common->col_size > 16) {
@@ -153,7 +152,7 @@ static int it8xxx2_kbd_init(const struct device *dev)
 	const struct input_kbd_matrix_common_config *common = &config->common;
 	struct it8xxx2_kbd_data *data = dev->data;
 	struct kscan_it8xxx2_regs *const inst = config->base;
-	const uint32_t kso_mask = BIT_MASK(common->col_size);
+	const uint32_t kso_mask = BIT_MASK(common->col_size) & ~config->kso_ignore_mask;
 	const uint8_t ksol_mask = kso_mask & 0xff;
 	const uint8_t ksoh1_mask = (kso_mask >> 8) & 0xff;
 	int status;
@@ -248,6 +247,7 @@ static const struct it8xxx2_kbd_config it8xxx2_kbd_cfg_0 = {
 	.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(0),
 	.kso16_gpios = GPIO_DT_SPEC_INST_GET(0, kso16_gpios),
 	.kso17_gpios = GPIO_DT_SPEC_INST_GET(0, kso17_gpios),
+	.kso_ignore_mask = DT_INST_PROP(0, kso_ignore_mask),
 };
 
 static struct it8xxx2_kbd_data it8xxx2_kbd_data_0;

dts/bindings/input/ite,it8xxx2-kbd.yaml

@@ -35,6 +35,14 @@ properties:
     description: |
       The KSO17 pin for the selected port.
 
+  kso-ignore-mask:
+    type: int
+    default: 0
+    description: |
+      Bitmask of KSO signals to ignore, this can be used to instruct the driver
+      to skip KSO signals between 0 and (col-size - 1) that are used as GPIOs.
+      Default to 0 (no signals masked).
+
   pinctrl-0:
     required: true