[PATCH v3 3/6] spi: expand device name to include all CS lines for multi-CS devices

The device name for SPI devices was formatted as <controller>.<cs0>,
always using only the first chip-select index, ignoring the remaining CS
lines.

Change the naming format to <controller>.<cs0>+<cs1>+... so that all
active chip-selects are reflected in the device name. Single-CS devices
are not affected since the loop only appends extra indices when
num_chipselect is greater than one.

Signed-off-by: Jonathan Santos <[email protected]>
---
Changes in v3:
* replaced `int idx = 1` by `unsigned int idx = 1` in the for loop.

Changes in v2:
* New patch.
---
 drivers/spi/spi.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 55fb96fea243..9ccfa5be557b 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -594,6 +594,8 @@ static void spi_dev_set_name(struct spi_device *spi)
 {
 	struct device *dev = &spi->dev;
 	struct fwnode_handle *fwnode = dev_fwnode(dev);
+	char cs_str[32];
+	int cs_len;
 
 	if (is_acpi_device_node(fwnode)) {
 		dev_set_name(dev, "spi-%s", acpi_dev_name(to_acpi_device_node(fwnode)));
@@ -605,8 +607,12 @@ static void spi_dev_set_name(struct spi_device *spi)
 		return;
 	}
 
-	dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
-		     spi_get_chipselect(spi, 0));
+	cs_len = scnprintf(cs_str, sizeof(cs_str), "%u", spi_get_chipselect(spi, 0));
+	for (unsigned int idx = 1; idx < spi->num_chipselect; idx++)
+		cs_len += scnprintf(cs_str + cs_len, sizeof(cs_str) - cs_len,
+				    "+%u", spi_get_chipselect(spi, idx));
+
+	dev_set_name(&spi->dev, "%s.%s", dev_name(&spi->controller->dev), cs_str);
 }
 
 /*
-- 
2.34.1