+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* SPI init/core code
*
* Copyright (C) 2005 David Brownell
* Copyright (C) 2008 Secret Lab Technologies Ltd.
- *
- * 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.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
*/
#include <linux/kernel.h>
spi->controller->cleanup(spi);
spi_controller_put(spi->controller);
+ kfree(spi->driver_override);
kfree(spi);
}
}
static DEVICE_ATTR_RO(modalias);
+static ssize_t driver_override_store(struct device *dev,
+ struct device_attribute *a,
+ const char *buf, size_t count)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ const char *end = memchr(buf, '\n', count);
+ const size_t len = end ? end - buf : count;
+ const char *driver_override, *old;
+
+ /* We need to keep extra room for a newline when displaying value */
+ if (len >= (PAGE_SIZE - 1))
+ return -EINVAL;
+
+ driver_override = kstrndup(buf, len, GFP_KERNEL);
+ if (!driver_override)
+ return -ENOMEM;
+
+ device_lock(dev);
+ old = spi->driver_override;
+ if (len) {
+ spi->driver_override = driver_override;
+ } else {
+ /* Emptry string, disable driver override */
+ spi->driver_override = NULL;
+ kfree(driver_override);
+ }
+ device_unlock(dev);
+ kfree(old);
+
+ return count;
+}
+
+static ssize_t driver_override_show(struct device *dev,
+ struct device_attribute *a, char *buf)
+{
+ const struct spi_device *spi = to_spi_device(dev);
+ ssize_t len;
+
+ device_lock(dev);
+ len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
+ device_unlock(dev);
+ return len;
+}
+static DEVICE_ATTR_RW(driver_override);
+
#define SPI_STATISTICS_ATTRS(field, file) \
static ssize_t spi_controller_##field##_show(struct device *dev, \
struct device_attribute *attr, \
static struct attribute *spi_dev_attrs[] = {
&dev_attr_modalias.attr,
+ &dev_attr_driver_override.attr,
NULL,
};
const struct spi_device *spi = to_spi_device(dev);
const struct spi_driver *sdrv = to_spi_driver(drv);
+ /* Check override first, and if set, only use the named driver */
+ if (spi->driver_override)
+ return strcmp(spi->driver_override, drv->name) == 0;
+
/* Attempt an OF style match */
if (of_driver_match_device(dev, drv))
return 1;
enable = !enable;
if (gpio_is_valid(spi->cs_gpio)) {
- gpio_set_value(spi->cs_gpio, !enable);
+ /* Honour the SPI_NO_CS flag */
+ if (!(spi->mode & SPI_NO_CS))
+ gpio_set_value(spi->cs_gpio, !enable);
/* Some SPI masters need both GPIO CS & slave_select */
if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
spi->controller->set_cs)
*/
if (ctlr->num_chipselect == 0)
return -EINVAL;
- /* allocate dynamic bus number using Linux idr */
- if ((ctlr->bus_num < 0) && ctlr->dev.of_node) {
+ if (ctlr->bus_num >= 0) {
+ /* devices with a fixed bus num must check-in with the num */
+ mutex_lock(&board_lock);
+ id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
+ ctlr->bus_num + 1, GFP_KERNEL);
+ mutex_unlock(&board_lock);
+ if (WARN(id < 0, "couldn't get idr"))
+ return id == -ENOSPC ? -EBUSY : id;
+ ctlr->bus_num = id;
+ } else if (ctlr->dev.of_node) {
+ /* allocate dynamic bus number using Linux idr */
id = of_alias_get_id(ctlr->dev.of_node, "spi");
if (id >= 0) {
ctlr->bus_num = id;
return -EINVAL;
/* If an SPI controller does not support toggling the CS line on each
- * transfer (indicated by the SPI_CS_WORD flag), we can emulate it by
+ * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
+ * for the CS line, we can emulate the CS-per-word hardware function by
* splitting transfers into one-word transfers and ensuring that
* cs_change is set for each transfer.
*/
- if ((spi->mode & SPI_CS_WORD) && !(ctlr->mode_bits & SPI_CS_WORD)) {
+ if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
+ gpio_is_valid(spi->cs_gpio))) {
size_t maxsize;
int ret;
/*-------------------------------------------------------------------------*/
-#if IS_ENABLED(CONFIG_OF_DYNAMIC)
+#if IS_ENABLED(CONFIG_OF)
static int __spi_of_device_match(struct device *dev, void *data)
{
return dev->of_node == data;
}
/* must call put_device() when done with returned spi_device device */
-static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
+struct spi_device *of_find_spi_device_by_node(struct device_node *node)
{
struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
__spi_of_device_match);
return dev ? to_spi_device(dev) : NULL;
}
+EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
+#endif /* IS_ENABLED(CONFIG_OF) */
+#if IS_ENABLED(CONFIG_OF_DYNAMIC)
static int __spi_of_controller_match(struct device *dev, const void *data)
{
return dev->of_node == data;
projects / linux-2.6-block.git / blobdiff