Some light is required to get edible mushrooms to fruit. Depending on the mushroom a week or two in a month long grow cycle. Selective use of UV lamps will add vitamin D. Read all about this in exhaustive detail in the UN Training Manual on Mushroom Cultivation and Growing Mushrooms from Penn State.
The next problem is most edible mushrooms grow on organic matter, where is this coming from? The obvious choice is "night soil", but I don't know how well edible mushrooms will grow in that. Furthermore, this is a closed loop, humans eat the mushrooms, the mushrooms eat human waste, and it will eventually run out of energy.
If you get them growing, you can't live on mushrooms alone. You'll slowly die of malnutrition. Looking at the nutrition information for oyster, Crimini, and white mushrooms you'll see great holes in their nutrient balance. Particularly the essential vitamins. This leads to blindness (A), nerve problems (E), bleeding (K), anemia (Folic Acid), and neurologic dysfunction (B12).
Such a setup may be able to use cavefish for supplementary protein and nutrition, but cave ecosystems are extraordinarily fragile and likely would not yield much. You'd be better off using some power for lights to grow supplementary vegetables high in the missing nutrients.
Finally, mushrooms are a poor source of calories. They're mostly water. Depending on the variety, 100g of raw mushrooms will get you 20 to 40 calories. Compare to 100g of black beans will get you 130 calories.