1 files changed, 51 insertions, 9 deletions

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index d4e7a09598fa..7f1260c78270 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -1,14 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * OF helpers for the GPIO API
  *
  * Copyright (c) 2007-2008  MontaVista Software, Inc.
  *
  * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
  */
 
 #include <linux/device.h>
@@ -58,7 +54,8 @@ static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip,
 }
 
 static void of_gpio_flags_quirks(struct device_node *np,
-				 enum of_gpio_flags *flags)
+				 enum of_gpio_flags *flags,
+				 int index)
 {
 	/*
 	 * Some GPIO fixed regulator quirks.
@@ -92,6 +89,51 @@ static void of_gpio_flags_quirks(struct device_node *np,
 		pr_info("%s uses legacy open drain flag - update the DTS if you can\n",
 			of_node_full_name(np));
 	}
+
+	/*
+	 * Legacy handling of SPI active high chip select. If we have a
+	 * property named "cs-gpios" we need to inspect the child node
+	 * to determine if the flags should have inverted semantics.
+	 */
+	if (IS_ENABLED(CONFIG_SPI_MASTER) &&
+	    of_property_read_bool(np, "cs-gpios")) {
+		struct device_node *child;
+		u32 cs;
+		int ret;
+
+		for_each_child_of_node(np, child) {
+			ret = of_property_read_u32(child, "reg", &cs);
+			if (!ret)
+				continue;
+			if (cs == index) {
+				/*
+				 * SPI children have active low chip selects
+				 * by default. This can be specified negatively
+				 * by just omitting "spi-cs-high" in the
+				 * device node, or actively by tagging on
+				 * GPIO_ACTIVE_LOW as flag in the device
+				 * tree. If the line is simultaneously
+				 * tagged as active low in the device tree
+				 * and has the "spi-cs-high" set, we get a
+				 * conflict and the "spi-cs-high" flag will
+				 * take precedence.
+				 */
+				if (of_property_read_bool(np, "spi-cs-high")) {
+					if (*flags & OF_GPIO_ACTIVE_LOW) {
+						pr_warn("%s GPIO handle specifies active low - ignored\n",
+							of_node_full_name(np));
+						*flags &= ~OF_GPIO_ACTIVE_LOW;
+					}
+				} else {
+					if (!(*flags & OF_GPIO_ACTIVE_LOW))
+						pr_info("%s enforce active low on chipselect handle\n",
+							of_node_full_name(np));
+					*flags |= OF_GPIO_ACTIVE_LOW;
+				}
+				break;
+			}
+		}
+	}
 }
 
 /**
@@ -132,7 +174,7 @@ struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
 		goto out;
 
 	if (flags)
-		of_gpio_flags_quirks(np, flags);
+		of_gpio_flags_quirks(np, flags, index);
 
 	pr_debug("%s: parsed '%s' property of node '%pOF[%d]' - status (%d)\n",
 		 __func__, propname, np, index,
@@ -349,8 +391,8 @@ static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
 	else if (of_property_read_bool(np, "output-high"))
 		*dflags |= GPIOD_OUT_HIGH;
 	else {
-		pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
-			desc_to_gpio(desc), np->name);
+		pr_warn("GPIO line %d (%pOFn): no hogging state specified, bailing out\n",
+			desc_to_gpio(desc), np);
 		return ERR_PTR(-EINVAL);
 	}