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path: root/drivers/gpio/gpiolib-of.c
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Diffstat (limited to 'drivers/gpio/gpiolib-of.c')
-rw-r--r--drivers/gpio/gpiolib-of.c60
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);
}