diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index 722b5eb1f709..ddfdb903047a 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -834,6 +834,20 @@ static void dw_spi_hw_init(struct device *dev, struct dw_spi *dws)
 			DW_SPI_GET_BYTE(dws->ver, 1));
 	}
 
+	/*
+	 * Try to detect the number of native chip-selects if the platform
+	 * driver didn't set it up. There can be up to 16 lines configured.
+	 */
+	if (!dws->num_cs) {
+		u32 ser;
+
+		dw_writel(dws, DW_SPI_SER, 0xffff);
+		ser = dw_readl(dws, DW_SPI_SER);
+		dw_writel(dws, DW_SPI_SER, 0);
+
+		dws->num_cs = hweight16(ser);
+	}
+
 	/*
 	 * Try to detect the FIFO depth if not set by interface driver,
 	 * the depth could be from 2 to 256 from HW spec