mfd: stmfx: Reset chip on resume as supply was disabled

STMFX supply is disabled during suspend. To avoid a too early access to
the STMFX firmware on resume, reset the chip and wait for its firmware to
be loaded.

Fixes: 06252ade ("mfd: Add ST Multi-Function eXpander (STMFX) core driver")
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/stmfx.c

@@ -501,6 +501,13 @@ static int stmfx_resume(struct device *dev)
 		}
 	}
 
+	/* Reset STMFX - supply has been stopped during suspend */
+	ret = stmfx_chip_reset(stmfx);
+	if (ret) {
+		dev_err(stmfx->dev, "Failed to reset chip: %d\n", ret);
+		return ret;
+	}
+
 	ret = regmap_raw_write(stmfx->map, STMFX_REG_SYS_CTRL,
 			       &stmfx->bkp_sysctrl, sizeof(stmfx->bkp_sysctrl));
 	if (ret)