drivers: auxdisplay: hd44780: get rid of excessive delays

Express delay values in nanoseconds. Set the default delay time values
as specified in the HD44780 reference manual.

Signed-off-by: Jan Kuliga <[email protected]>

Author: kuliga

drivers/auxdisplay/auxdisplay_hd44780.c

@@ -82,9 +82,9 @@ static void hd44780_pulse_enable_line(const struct device *dev)
 	const struct auxdisplay_hd44780_config *const config = dev->config;
 
 	gpio_pin_set_dt(&config->e_gpio, 1);
-	k_sleep(K_USEC(config->enable_line_rise_delay));
+	k_sleep(K_NSEC(config->enable_line_rise_delay));
 	gpio_pin_set_dt(&config->e_gpio, 0);
-	k_sleep(K_USEC(config->enable_line_fall_delay));
+	k_sleep(K_NSEC(config->enable_line_fall_delay));
 }
 
 static void auxdisplay_hd44780_command(const struct device *dev, bool rs, uint8_t cmd,
@@ -567,8 +567,8 @@ static const struct auxdisplay_driver_api auxdisplay_hd44780_auxdisplay_api = {
 		.line_addresses[2] = DT_INST_PROP_BY_IDX(inst, line_addresses, 2),		\
 		.line_addresses[3] = DT_INST_PROP_BY_IDX(inst, line_addresses, 3),		\
 		.backlight_gpio = GPIO_DT_SPEC_INST_GET_OR(inst, backlight_gpios, {0}),		\
-		.enable_line_rise_delay = DT_INST_PROP(inst, enable_line_rise_delay_us),	\
-		.enable_line_fall_delay = DT_INST_PROP(inst, enable_line_fall_delay_us),	\
+		.enable_line_rise_delay = DT_INST_PROP(inst, enable_line_rise_delay_ns),	\
+		.enable_line_fall_delay = DT_INST_PROP(inst, enable_line_fall_delay_ns),	\
 		.clear_delay = DT_INST_PROP(inst, clear_command_delay_us),			\
 		.boot_delay = DT_INST_PROP(inst, boot_delay_ms),				\
 	};											\

dts/bindings/auxdisplay/hit,hd44780.yaml

@@ -56,18 +56,18 @@ properties:
       Array of addresses for each row, will use defaults if not provided.
       Default is as per Hitachi HD44780 specification.
 
-  enable-line-rise-delay-us:
+  enable-line-rise-delay-ns:
     type: int
-    default: 800
+    default: 450
     description: |
-      Delay time (in us) to wait after enable line rises before setting low.
+      Delay time (in ns) to wait after enable line rises before setting low.
       Default is as per Hitachi HD44780 specification.
 
-  enable-line-fall-delay-us:
+  enable-line-fall-delay-ns:
     type: int
-    default: 100
+    default: 550
     description: |
-      Delay time (in us) to wait after enable line falls before sending
+      Delay time (in ns) to wait after enable line falls before sending
       another command. Default is as per Hitachi HD44780 specification.
 
   clear-command-delay-us: