[Nouveau] [PATCH 2/4] gpio: checking if gpu power cable is connected

[Mark Menzynski]

Tested on TU104, GP106 and GF100

Signed-off-by: Mark Menzynski <mmenzyns at redhat.com>
---
 drm/nouveau/include/nvkm/subdev/bios/gpio.h |  1 +
 drm/nouveau/nvkm/subdev/gpio/base.c         | 23 +++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/drm/nouveau/include/nvkm/subdev/bios/gpio.h b/drm/nouveau/include/nvkm/subdev/bios/gpio.h
index 2f40935f..a70ec9e8 100644
--- a/drm/nouveau/include/nvkm/subdev/bios/gpio.h
+++ b/drm/nouveau/include/nvkm/subdev/bios/gpio.h
@@ -7,6 +7,7 @@ enum dcb_gpio_func_name {
 	DCB_GPIO_TVDAC0 = 0x0c,
 	DCB_GPIO_TVDAC1 = 0x2d,
 	DCB_GPIO_FAN_SENSE = 0x3d,
+	DCB_GPIO_EXT_POWER_LOW = 0x79,
 	DCB_GPIO_LOGO_LED_PWM = 0x84,
 	DCB_GPIO_UNUSED = 0xff,
 	DCB_GPIO_VID0 = 0x04,
diff --git a/drm/nouveau/nvkm/subdev/gpio/base.c b/drm/nouveau/nvkm/subdev/gpio/base.c
index 1399d923..c4685807 100644
--- a/drm/nouveau/nvkm/subdev/gpio/base.c
+++ b/drm/nouveau/nvkm/subdev/gpio/base.c
@@ -182,12 +182,35 @@ static const struct dmi_system_id gpio_reset_ids[] = {
 	{ }
 };
 
+static enum dcb_gpio_func_name power_checks[] = {
+	DCB_GPIO_EXT_POWER_LOW,
+};
+
 static int
 nvkm_gpio_init(struct nvkm_subdev *subdev)
 {
 	struct nvkm_gpio *gpio = nvkm_gpio(subdev);
+	struct dcb_gpio_func func;
+	int ret;
+	int i;
+
 	if (dmi_check_system(gpio_reset_ids))
 		nvkm_gpio_reset(gpio, DCB_GPIO_UNUSED);
+
+	for (i = 0; i < ARRAY_SIZE(power_checks); ++i) {
+		ret = nvkm_gpio_find(gpio, 0, power_checks[i], DCB_GPIO_UNUSED,
+				     &func);
+		if (ret)
+			continue;
+
+		ret = nvkm_gpio_get(gpio, 0, func.func, func.line);
+		if (ret) {
+			nvkm_error(&gpio->subdev,
+				   "not enough power, check GPU power cable\n");
+			return -EINVAL;
+		}
+	}
+
 	return 0;
 }
 
-- 
2.21.0