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Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 5485ef89197c..197c9e0ac2a6 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2464,6 +2464,8 @@ static int spi_get_gpio_descs(struct spi_controller *ctlr)
 	int nb, i;
 	struct gpio_desc **cs;
 	struct device *dev = &ctlr->dev;
+	unsigned long native_cs_mask = 0;
+	unsigned int num_cs_gpios = 0;
 
 	nb = gpiod_count(dev, "cs");
 	ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
@@ -2505,7 +2507,22 @@ static int spi_get_gpio_descs(struct spi_controller *ctlr)
 			if (!gpioname)
 				return -ENOMEM;
 			gpiod_set_consumer_name(cs[i], gpioname);
+			num_cs_gpios++;
+			continue;
+		}
+
+		if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
+			dev_err(dev, "Invalid native chip select %d\n", i);
+			return -EINVAL;
 		}
+		native_cs_mask |= BIT(i);
+	}
+
+	ctlr->unused_native_cs = ffz(native_cs_mask);
+	if (num_cs_gpios && ctlr->max_native_cs &&
+	    ctlr->unused_native_cs >= ctlr->max_native_cs) {
+		dev_err(dev, "No unused native chip select available\n");
+		return -EINVAL;
 	}
 
 	return 0;