From a020ed7521a9737bcf3e34eb880867c60c3c68d0 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Mon, 3 Apr 2006 15:49:04 -0700 Subject: [PATCH] SPI: busnum == 0 needs to work We need to be able to have a "SPI bus 0" matching chip numbering; but that number was wrongly used to flag dynamic allocation of a bus number. This patch resolves that issue; now negative numbers trigger dynamic alloc. It also updates the how-to-write-a-controller-driver overview to mention this stuff. Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/spi') diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 1168ef01588..7a3f733051e 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -395,7 +395,7 @@ EXPORT_SYMBOL_GPL(spi_alloc_master); int __init_or_module spi_register_master(struct spi_master *master) { - static atomic_t dyn_bus_id = ATOMIC_INIT(0); + static atomic_t dyn_bus_id = ATOMIC_INIT((1<<16) - 1); struct device *dev = master->cdev.dev; int status = -ENODEV; int dynamic = 0; @@ -404,7 +404,7 @@ spi_register_master(struct spi_master *master) return -ENODEV; /* convention: dynamically assigned bus IDs count down from the max */ - if (master->bus_num == 0) { + if (master->bus_num < 0) { master->bus_num = atomic_dec_return(&dyn_bus_id); dynamic = 1; } -- cgit v1.2.3-70-g09d2