[PATCH 0/2] spi: Fix multi probing with overlays

[PATCH 0/2] spi: Fix multi probing with overlays

[Geert Uytterhoeven]

	Hi Mark, Pantelis,

This patch series fixes the issue where an SPI slave device is
registered twice when loading a DT overlay that enables or adds an SPI
master with a populated SPI bus:

    spi_sh_msiof e6e10000.spi: chipselect 0 already in use
    spi_master spi2: spi_device register error /spi@e6e10000/spidev@0
    of_spi_notify: failed to create for '/spi@e6e10000/spidev@0'

The approach followed is similar to what's currently done on i2c, as
suggested by Mark.

Thanks!

Geert Uytterhoeven (2):
  spi: Uninline spi_unregister_device()
  spi: Mark instantiated device nodes with OF_POPULATE

 drivers/spi/spi.c       | 29 +++++++++++++++++++++++++++++
 include/linux/spi/spi.h |  7 +------
 2 files changed, 30 insertions(+), 6 deletions(-)

-- 
1.9.1

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds
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[PATCH 1/2] spi: Uninline spi_unregister_device()

[Geert Uytterhoeven]

Uninline spi_unregister_device() in preparation of adding more code to
it. Add kerneldoc documentation while we're at it.

Signed-off-by: Geert Uytterhoeven <geert+renesas-gXvu3+zWzMSzQB+pC5nmwQ@public.gmane.org>
---
 drivers/spi/spi.c       | 14 ++++++++++++++
 include/linux/spi/spi.h |  7 +------
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index cebb08e4f6077e5b..afaa9427a383506a 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -605,6 +605,20 @@ struct spi_device *spi_new_device(struct spi_master *master,
 }
 EXPORT_SYMBOL_GPL(spi_new_device);
 
+/**
+ * spi_unregister_device - unregister a single SPI device
+ * @spi: spi_device to unregister
+ *
+ * Start making the passed SPI device vanish. Normally this would be handled
+ * by spi_unregister_master().
+ */
+void spi_unregister_device(struct spi_device *spi)
+{
+	if (spi)
+		device_unregister(&spi->dev);
+}
+EXPORT_SYMBOL_GPL(spi_unregister_device);
+
 static void spi_match_master_to_boardinfo(struct spi_master *master,
 				struct spi_board_info *bi)
 {
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index cce80e6dc7d11596..075bede6652104fa 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -1115,12 +1115,7 @@ spi_add_device(struct spi_device *spi);
 extern struct spi_device *
 spi_new_device(struct spi_master *, struct spi_board_info *);
 
-static inline void
-spi_unregister_device(struct spi_device *spi)
-{
-	if (spi)
-		device_unregister(&spi->dev);
-}
+extern void spi_unregister_device(struct spi_device *spi);
 
 extern const struct spi_device_id *
 spi_get_device_id(const struct spi_device *sdev);
-- 
1.9.1

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[PATCH 2/2] spi: Mark instantiated device nodes with OF_POPULATE

[Geert Uytterhoeven]

Mark (and unmark) device nodes with the POPULATE flag as appropriate.
This is required to avoid multi probing when enabling and populating SPI
buses in DT overlays.

Based on commit 4f001fd30145a6a8 ("i2c: Mark instantiated device nodes
with OF_POPULATE").

Suggested-by: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas-gXvu3+zWzMSzQB+pC5nmwQ@public.gmane.org>
---
 drivers/spi/spi.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index afaa9427a383506a..31449c554ea9585e 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -614,8 +614,12 @@ EXPORT_SYMBOL_GPL(spi_new_device);
  */
 void spi_unregister_device(struct spi_device *spi)
 {
-	if (spi)
-		device_unregister(&spi->dev);
+	if (!spi)
+		return;
+
+	if (spi->dev.of_node)
+		of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
+	device_unregister(&spi->dev);
 }
 EXPORT_SYMBOL_GPL(spi_unregister_device);
 
@@ -1562,6 +1566,8 @@ static void of_register_spi_devices(struct spi_master *master)
 		return;
 
 	for_each_available_child_of_node(master->dev.of_node, nc) {
+		if (of_node_test_and_set_flag(nc, OF_POPULATED))
+			continue;
 		spi = of_register_spi_device(master, nc);
 		if (IS_ERR(spi))
 			dev_warn(&master->dev, "Failed to create SPI device for %s\n",
@@ -2660,6 +2666,11 @@ static int of_spi_notify(struct notifier_block *nb, unsigned long action,
 		if (master == NULL)
 			return NOTIFY_OK;	/* not for us */
 
+		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
+			put_device(&master->dev);
+			return NOTIFY_OK;
+		}
+
 		spi = of_register_spi_device(master, rd->dn);
 		put_device(&master->dev);
 
@@ -2671,6 +2682,10 @@ static int of_spi_notify(struct notifier_block *nb, unsigned long action,
 		break;
 
 	case OF_RECONFIG_CHANGE_REMOVE:
+		/* already depopulated? */
+		if (!of_node_check_flag(rd->dn, OF_POPULATED))
+			return NOTIFY_OK;
+
 		/* find our device by node */
 		spi = of_find_spi_device_by_node(rd->dn);
 		if (spi == NULL)
-- 
1.9.1

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