drivers/gpu/drm/nouveau/nvkm/subdev/therm/fanpwm.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/nouveau/nvkm/subdev/therm/fanpwm.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/nouveau/nvkm/subdev/therm/fanpwm.c
Extension
.c
Size
3306 bytes
Lines
111
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct nvkm_fanpwm {
	struct nvkm_fan base;
	struct dcb_gpio_func func;
};

static int
nvkm_fanpwm_get(struct nvkm_therm *therm)
{
	struct nvkm_fanpwm *fan = (void *)therm->fan;
	struct nvkm_device *device = therm->subdev.device;
	struct nvkm_gpio *gpio = device->gpio;
	int card_type = device->card_type;
	u32 divs, duty;
	int ret;

	ret = therm->func->pwm_get(therm, fan->func.line, &divs, &duty);
	if (ret == 0 && divs) {
		divs = max(divs, duty);
		if (card_type <= NV_40 || (fan->func.log[0] & 1))
			duty = divs - duty;
		return (duty * 100) / divs;
	}

	return nvkm_gpio_get(gpio, 0, fan->func.func, fan->func.line) * 100;
}

static int
nvkm_fanpwm_set(struct nvkm_therm *therm, int percent)
{
	struct nvkm_fanpwm *fan = (void *)therm->fan;
	int card_type = therm->subdev.device->card_type;
	u32 divs, duty;
	int ret;

	divs = fan->base.perf.pwm_divisor;
	if (fan->base.bios.pwm_freq) {
		divs = 1;
		if (therm->func->pwm_clock)
			divs = therm->func->pwm_clock(therm, fan->func.line);
		divs /= fan->base.bios.pwm_freq;
	}

	duty = ((divs * percent) + 99) / 100;
	if (card_type <= NV_40 || (fan->func.log[0] & 1))
		duty = divs - duty;

	ret = therm->func->pwm_set(therm, fan->func.line, divs, duty);
	if (ret == 0)
		ret = therm->func->pwm_ctrl(therm, fan->func.line, true);
	return ret;
}

int
nvkm_fanpwm_create(struct nvkm_therm *therm, struct dcb_gpio_func *func)
{
	struct nvkm_device *device = therm->subdev.device;
	struct nvkm_bios *bios = device->bios;
	struct nvkm_fanpwm *fan;
	struct nvbios_therm_fan info = {};
	u32 divs, duty;

	nvbios_fan_parse(bios, &info);

	if (!nvkm_boolopt(device->cfgopt, "NvFanPWM", func->param) ||
	    !therm->func->pwm_ctrl || info.type == NVBIOS_THERM_FAN_TOGGLE ||
	     therm->func->pwm_get(therm, func->line, &divs, &duty) == -ENODEV)
		return -ENODEV;

	fan = kzalloc_obj(*fan);
	if (!fan)
		return -ENOMEM;

	therm->fan = &fan->base;
	fan->base.type = "PWM";
	fan->base.get = nvkm_fanpwm_get;
	fan->base.set = nvkm_fanpwm_set;
	fan->func = *func;
	return 0;
}

Annotation

Implementation Notes