drivers: pwm: Add support for pch intel blink driver

This patch adds support for PWM blink which is found in intel's
PCH hardwares.

Signed-off-by: Anisetti Avinash Krishna <anisetti.avinash.krishna@intel.com>

drivers/pwm/CMakeLists.txt

@@ -32,6 +32,7 @@ zephyr_library_sources_ifdef(CONFIG_PWM_PCA9685 	pwm_pca9685.c)
 zephyr_library_sources_ifdef(CONFIG_PWM_TEST		pwm_test.c)
 zephyr_library_sources_ifdef(CONFIG_PWM_RPI_PICO	pwm_rpi_pico.c)
 zephyr_library_sources_ifdef(CONFIG_PWM_BBLED_XEC	pwm_mchp_xec_bbled.c)
+zephyr_library_sources_ifdef(CONFIG_PWM_INTEL_BLINKY	pwm_intel_blinky.c)
 
 zephyr_library_sources_ifdef(CONFIG_USERSPACE   pwm_handlers.c)
 zephyr_library_sources_ifdef(CONFIG_PWM_CAPTURE pwm_capture.c)

drivers/pwm/Kconfig

@@ -85,4 +85,6 @@ source "drivers/pwm/Kconfig.test"
 
 source "drivers/pwm/Kconfig.rpi_pico"
 
+source "drivers/pwm/Kconfig.intel_blinky"
+
 endif # PWM

drivers/pwm/Kconfig.intel_blinky

@@ -0,0 +1,11 @@
+# Intel Blinky PWM configuration options
+
+# Copyright (c) 2023 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+config PWM_INTEL_BLINKY
+	bool "Blinky PWM driver"
+	default y
+	depends on DT_HAS_INTEL_BLINKY_PWM_ENABLED
+	help
+	  Enable the INTEL PCH PWM driver found on Intel SoCs

drivers/pwm/pwm_intel_blinky.c

@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2023 Intel Corporation.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT intel_blinky_pwm
+
+#include <errno.h>
+#include <soc.h>
+#include <zephyr/device.h>
+#include <zephyr/kernel.h>
+#include <zephyr/init.h>
+#include <zephyr/sys/util.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/drivers/pwm.h>
+
+#define PWM_ENABLE              0x80000000
+#define PWM_SWUP                0x40000000
+#define PWM_FREQ_INT_SHIFT      8
+#define PWM_BASE_UNIT_FRACTION	14
+#define PWM_FREQ_MAX            0x100
+#define PWM_DUTY_MAX            0x100
+
+struct bk_intel_config {
+	DEVICE_MMIO_NAMED_ROM(reg_base);
+	uint32_t reg_offset;
+	uint32_t clock_freq;
+	uint32_t max_pins;
+};
+
+struct bk_intel_runtime {
+	DEVICE_MMIO_NAMED_RAM(reg_base);
+};
+
+static int bk_intel_set_cycles(const struct device *dev, uint32_t pin,
+			       uint32_t period_cycles, uint32_t pulse_cycles,
+			       pwm_flags_t flags)
+{
+	struct bk_intel_runtime *rt = dev->data;
+	const struct bk_intel_config *cfg = dev->config;
+	uint32_t ret = 0;
+	uint32_t val = 0;
+	uint32_t duty;
+	float period;
+	float out_freq;
+	uint32_t base_unit;
+
+	if (pin >= cfg->max_pins) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	out_freq = cfg->clock_freq / (float) period_cycles;
+	period = (out_freq * PWM_FREQ_MAX) / cfg->clock_freq;
+	base_unit = (uint32_t) (period * (1 << PWM_BASE_UNIT_FRACTION));
+	duty = (pulse_cycles * PWM_DUTY_MAX) / period_cycles;
+
+	if (duty) {
+		val = PWM_DUTY_MAX - duty;
+		val |= (base_unit << PWM_FREQ_INT_SHIFT);
+	} else {
+		val = PWM_DUTY_MAX - 1;
+	}
+
+	val |= PWM_ENABLE | PWM_SWUP;
+
+	if (period >= PWM_FREQ_MAX) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	if (duty > PWM_DUTY_MAX) {
+		ret = -EINVAL;
+		goto err;
+	}
+
+	sys_write32(val, rt->reg_base + cfg->reg_offset);
+err:
+	return ret;
+}
+
+static int bk_intel_get_cycles_per_sec(const struct device *dev, uint32_t pin,
+				       uint64_t *cycles)
+{
+	const struct bk_intel_config *cfg = dev->config;
+
+	if (pin >= cfg->max_pins) {
+		return -EINVAL;
+	}
+
+	*cycles = cfg->clock_freq;
+
+	return 0;
+}
+
+static const struct pwm_driver_api api_funcs = {
+	.set_cycles = bk_intel_set_cycles,
+	.get_cycles_per_sec = bk_intel_get_cycles_per_sec,
+};
+
+static int bk_intel_init(const struct device *dev)
+{
+	struct bk_intel_runtime *runtime = dev->data;
+	const struct bk_intel_config *config = dev->config;
+
+	device_map(&runtime->reg_base,
+		   config->reg_base.phys_addr & ~0xFFU,
+		   config->reg_base.size,
+		   K_MEM_CACHE_NONE);
+
+	return 0;
+}
+
+#define BK_INTEL_DEV_CFG(n)						       \
+	static const struct bk_intel_config bk_cfg_##n = {		       \
+		DEVICE_MMIO_NAMED_ROM_INIT(reg_base, DT_DRV_INST(n)),	       \
+		.reg_offset = DT_INST_PROP(n, reg_offset),		       \
+		.max_pins = DT_INST_PROP(n, max_pins),			       \
+		.clock_freq = DT_INST_PROP(n, clock_frequency),		       \
+	};								       \
+									       \
+	static struct bk_intel_runtime bk_rt_##n;			       \
+	DEVICE_DT_INST_DEFINE(n, &bk_intel_init, NULL,			       \
+			      &bk_rt_##n, &bk_cfg_##n,			       \
+			      POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE, \
+			      &api_funcs);				       \
+
+DT_INST_FOREACH_STATUS_OKAY(BK_INTEL_DEV_CFG)

dts/bindings/pwm/intel,blinky-pwm.yaml

@@ -0,0 +1,35 @@
+# Copyright (c) 2023 Intel Corporation
+#
+# SPDX-License-Identifier: Apache-2.0
+
+description: Intel blinky PWM
+
+compatible: "intel,blinky-pwm"
+
+include: [pwm-controller.yaml, base.yaml]
+
+properties:
+  reg:
+    required: true
+
+  reg-offset:
+    type: int
+    required: true
+    description: PWM control register offset from base
+
+  clock-frequency:
+    type: int
+    required: true
+    description: PWM Peripheral Clock frequency in Hz
+
+  max-pins:
+    type: int
+    required: true
+    description: Maximum number of pins supported by platform
+
+  "#pwm-cells":
+    const: 2
+
+pwm-cells:
+  - channel
+  - period