samples: drivers: pwm: Add a sample to test pwm capture

Add a sample to test pwm capture function.

Signed-off-by: Saravanan Sekar <[email protected]>

Author: ssekar15

samples/drivers/pwm/capture/CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(pwm_capture)
+
+target_sources(app PRIVATE src/main.c)

samples/drivers/pwm/capture/README.rst

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+.. zephyr:code-sample:: capture
+   :name: PWM Capture
+   :relevant-api: pwm_interface
+
+   Capture a PWM signal.
+
+Overview
+********
+This sample provides an example application using the :ref:`PWM API <pwm_api>` capture
+API to measure the period and pulse width of an external PWM signal.
+
+Requirements
+************
+
+This sample requires the support of a timer IP compatible with pwm capture block.
+
+Building and Running
+********************
+
+ .. zephyr-app-commands::
+    :zephyr-app: samples/drivers/pwm/capture
+    :host-os: unix
+    :board: lp_mspm0g3507
+    :goals: run
+    :compact:
+
+Sample Output
+=============
+
+ .. code-block:: console
+
+    PWM capture lp_mspm0g3507/mspm0g350
+
+    timclk 80000000 Hz
+    {period:1000  pulse width: 499} in TIMCLK cycle
+    {period: 80000.000000 Hz duty: 49.900002}
+
+    <repeats endlessly>

samples/drivers/pwm/capture/boards/lp_mspm0g3507.overlay

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+/*
+ * Copyright (c) 2025 Linumiz GmbH
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	aliases {
+		capture = &pwma1;
+	};
+};
+
+&pinctrl {
+	tima1_ccp0_pb4 {
+		input-enable;
+		bias-pull-down;
+	};
+};
+
+&tima1 {
+	status = "okay";
+
+	pwma1: pwma1 {
+		pinctrl-0 = <&tima1_ccp0_pb4>;
+		pinctrl-names = "default";
+		ti,cc-index = <0>;
+		ti,cc-mode = "PULSE_WIDTH";
+		ti,period = <0xFFFF>;
+		status = "okay";
+	};
+};

samples/drivers/pwm/capture/prj.conf

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+CONFIG_PWM=y
+CONFIG_PWM_CAPTURE=y
+CONFIG_REQUIRES_FLOAT_PRINTF=y

samples/drivers/pwm/capture/sample.yaml

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+sample:
+  name: PWM capture
+  description: input capture for PWM signal, time and duration application
+common:
+  tags:
+    - drivers
+    - pwm
+  harness: console
+  harness_config:
+    type: multi_line
+    ordered: true
+    regex:
+      - "timclk ([0-9]*) Hz"
+      - "{period: ([0-9]*)  pulse width: ([0-9]*)} in TIMCLK cycle"
+      - "{period: ([0-9]*) Hz duty: ([0-9]*)}"
+  depends_on: pwm
+tests:
+  sample.drivers.pwm.capture:
+    platform_allow:
+      - lp_mspm0g3507

samples/drivers/pwm/capture/src/main.c

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+/*
+ * Copyright (c) 2025 Linumiz
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <zephyr/kernel.h>
+#include "zephyr/drivers/pwm.h"
+
+int main(void)
+{
+	int ret;
+	uint64_t tim_clk_cycles;
+	const struct device *const dev = DEVICE_DT_GET(DT_ALIAS(capture));
+
+	printk("PWM capture %s\n", CONFIG_BOARD_TARGET);
+	if (!device_is_ready(dev)) {
+		printk("device is not ready\n");
+		return 0;
+	}
+
+	pwm_get_cycles_per_sec(dev, 0, &tim_clk_cycles);
+	printk("timclk %llu Hz\n", tim_clk_cycles);
+
+	while (1) {
+		uint32_t period = 0;
+		uint32_t width = 0;
+
+		k_msleep(250);
+		ret = pwm_capture_cycles(dev, 0,
+					 (PWM_CAPTURE_TYPE_BOTH | PWM_CAPTURE_MODE_SINGLE),
+					 &period, &width, Z_TIMEOUT_MS(500));
+
+		if (ret == -EBUSY) {
+			pwm_disable_capture(dev, 0);
+			continue;
+		}
+
+		if (ret) {
+			printk("capture cycle err %d\n", ret);
+			continue;
+		}
+
+		printk("{period:%u  pulse width: %u} in TIMCLK cycle\n",
+			period,
+			width);
+
+		printk("{period: %f Hz duty: %f}\n",
+			(float)tim_clk_cycles / (float)period,
+			(float)(width * 100) / (float)period);
+	}
+
+	return 0;
+}

samples/drivers/pwm/index.rst

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+.. zephyr:code-sample-category:: pwm
+   :name: PWM
+   :show-listing:
+
+   These samples demonstrate how to use the :ref:`pwm <pwm_api>` driver API.