[PATCH 1/3] of: Add prefix parameter to of_modalias_node().

[David Daney]

From: David Daney <david.daney at cavium.com>

When generating MODALIASes, it is convenient to add things like "spi:"
or "i2c:" to the front of the strings.  This allows the standard
modprobe to find the right driver when automatically populating bus
children from the device tree structure.

Add a prefix parameter, and adjust callers.  For
of_register_spi_devices() use the "spi:" prefix.

Signed-off-by: David Daney <david.daney at cavium.com>
Cc: Liam Girdwood <lrg at ti.com>
Cc: Timur Tabi <timur at freescale.com>
Cc: Mark Brown <broonie at opensource.wolfsonmicro.com>
Cc: Jaroslav Kysela <perex at perex.cz>
Cc: Takashi Iwai <tiwai at suse.de>
Cc: alsa-devel at alsa-project.org
Cc: linuxppc-dev at lists.ozlabs.org
---
 drivers/of/base.c            |   22 ++++++++++++++++------
 drivers/of/of_i2c.c          |    2 +-
 drivers/of/of_spi.c          |    2 +-
 include/linux/of.h           |    3 ++-
 sound/soc/fsl/mpc8610_hpcd.c |    2 +-
 sound/soc/fsl/p1022_ds.c     |    2 +-
 6 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 5806449..f05a520 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -575,26 +575,36 @@ EXPORT_SYMBOL(of_find_matching_node);
 /**
  * of_modalias_node - Lookup appropriate modalias for a device node
  * @node:	pointer to a device tree node
+ * @prefix:	prefix to be added to the compatible property, may be NULL
  * @modalias:	Pointer to buffer that modalias value will be copied into
  * @len:	Length of modalias value
  *
- * Based on the value of the compatible property, this routine will attempt
- * to choose an appropriate modalias value for a particular device tree node.
- * It does this by stripping the manufacturer prefix (as delimited by a ',')
- * from the first entry in the compatible list property.
+ * Based on the value of the compatible property, this routine will
+ * attempt to choose an appropriate modalias value for a particular
+ * device tree node.  It does this by stripping the manufacturer
+ * prefix (as delimited by a ',') from the first entry in the
+ * compatible list property, and appending it to the prefix.
  *
  * This routine returns 0 on success, <0 on failure.
  */
-int of_modalias_node(struct device_node *node, char *modalias, int len)
+int of_modalias_node(struct device_node *node, const char *prefix,
+		     char *modalias, int len)
 {
 	const char *compatible, *p;
 	int cplen;
 
+	if (len < 1)
+		return -EINVAL;
+
 	compatible = of_get_property(node, "compatible", &cplen);
 	if (!compatible || strlen(compatible) > cplen)
 		return -ENODEV;
 	p = strchr(compatible, ',');
-	strlcpy(modalias, p ? p + 1 : compatible, len);
+	if (prefix)
+		strlcpy(modalias, prefix, len);
+	else
+		modalias[0] = 0;
+	strlcat(modalias, p ? p + 1 : compatible, len);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_modalias_node);
diff --git a/drivers/of/of_i2c.c b/drivers/of/of_i2c.c
index f37fbeb..23b05ee 100644
--- a/drivers/of/of_i2c.c
+++ b/drivers/of/of_i2c.c
@@ -37,7 +37,7 @@ void of_i2c_register_devices(struct i2c_adapter *adap)
 
 		dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
 
-		if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
+		if (of_modalias_node(node, NULL, info.type, sizeof(info.type)) < 0) {
 			dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
 				node->full_name);
 			continue;
diff --git a/drivers/of/of_spi.c b/drivers/of/of_spi.c
index 6dbc074..c329c6d 100644
--- a/drivers/of/of_spi.c
+++ b/drivers/of/of_spi.c
@@ -42,7 +42,7 @@ void of_register_spi_devices(struct spi_master *master)
 		}
 
 		/* Select device driver */
-		if (of_modalias_node(nc, spi->modalias,
+		if (of_modalias_node(nc, SPI_MODULE_PREFIX, spi->modalias,
 				     sizeof(spi->modalias)) < 0) {
 			dev_err(&master->dev, "cannot find modalias for %s\n",
 				nc->full_name);
diff --git a/include/linux/of.h b/include/linux/of.h
index fa7fb1d..ee34d76 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -233,7 +233,8 @@ extern int of_n_addr_cells(struct device_node *np);
 extern int of_n_size_cells(struct device_node *np);
 extern const struct of_device_id *of_match_node(
 	const struct of_device_id *matches, const struct device_node *node);
-extern int of_modalias_node(struct device_node *node, char *modalias, int len);
+extern int of_modalias_node(struct device_node *node,
+			    const char *prefix, char *modalias, int len);
 extern struct device_node *of_parse_phandle(struct device_node *np,
 					    const char *phandle_name,
 					    int index);
diff --git a/sound/soc/fsl/mpc8610_hpcd.c b/sound/soc/fsl/mpc8610_hpcd.c
index 3fea5a1..1fa0682 100644
--- a/sound/soc/fsl/mpc8610_hpcd.c
+++ b/sound/soc/fsl/mpc8610_hpcd.c
@@ -254,7 +254,7 @@ static int codec_node_dev_name(struct device_node *np, char *buf, size_t len)
 	char temp[DAI_NAME_SIZE];
 	struct i2c_client *i2c;
 
-	of_modalias_node(np, temp, DAI_NAME_SIZE);
+	of_modalias_node(np, NULL, temp, DAI_NAME_SIZE);
 
 	iprop = of_get_property(np, "reg", NULL);
 	if (!iprop)
diff --git a/sound/soc/fsl/p1022_ds.c b/sound/soc/fsl/p1022_ds.c
index 982a1c9..3ea51ec 100644
--- a/sound/soc/fsl/p1022_ds.c
+++ b/sound/soc/fsl/p1022_ds.c
@@ -257,7 +257,7 @@ static int codec_node_dev_name(struct device_node *np, char *buf, size_t len)
 	char temp[DAI_NAME_SIZE];
 	struct i2c_client *i2c;
 
-	of_modalias_node(np, temp, DAI_NAME_SIZE);
+	of_modalias_node(np, NULL, temp, DAI_NAME_SIZE);
 
 	iprop = of_get_property(np, "reg", NULL);
 	if (!iprop)
-- 
1.7.2.3