diff options
Diffstat (limited to 'drivers/spi/spi.c')
| -rw-r--r-- | drivers/spi/spi.c | 71 |
1 files changed, 56 insertions, 15 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index aed78093b130..b851888a0a0b 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -40,9 +40,13 @@ #include <linux/ioport.h> #include <linux/acpi.h> #include <linux/highmem.h> +#include <linux/idr.h> #define CREATE_TRACE_POINTS #include <trace/events/spi.h> +#define SPI_DYN_FIRST_BUS_NUM 0 + +static DEFINE_IDR(spi_master_idr); static void spidev_release(struct device *dev) { @@ -420,6 +424,7 @@ static LIST_HEAD(spi_controller_list); /* * Used to protect add/del opertion for board_info list and * spi_controller list, and their matching process + * also used to protect object of type struct idr */ static DEFINE_MUTEX(board_lock); @@ -2051,11 +2056,10 @@ static int of_spi_register_master(struct spi_controller *ctlr) */ int spi_register_controller(struct spi_controller *ctlr) { - static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); struct device *dev = ctlr->dev.parent; struct boardinfo *bi; int status = -ENODEV; - int dynamic = 0; + int id; if (!dev) return -ENODEV; @@ -2071,17 +2075,29 @@ int spi_register_controller(struct spi_controller *ctlr) */ if (ctlr->num_chipselect == 0) return -EINVAL; - - if ((ctlr->bus_num < 0) && ctlr->dev.of_node) - ctlr->bus_num = of_alias_get_id(ctlr->dev.of_node, "spi"); - - /* convention: dynamically assigned bus IDs count down from the max */ + + /* allocate dynamic bus number using Linux idr */ + if ((ctlr->bus_num < 0) && ctlr->dev.of_node) { + id = of_alias_get_id(ctlr->dev.of_node, "spi"); + if (id >= 0) { + ctlr->bus_num = id; + 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; + } + } if (ctlr->bus_num < 0) { - /* FIXME switch to an IDR based scheme, something like - * I2C now uses, so we can't run out of "dynamic" IDs - */ - ctlr->bus_num = atomic_dec_return(&dyn_bus_id); - dynamic = 1; + mutex_lock(&board_lock); + id = idr_alloc(&spi_master_idr, ctlr, + SPI_DYN_FIRST_BUS_NUM, 0, GFP_KERNEL); + mutex_unlock(&board_lock); + if (WARN(id < 0, "couldn't get idr")) + return id; + + ctlr->bus_num = id; } INIT_LIST_HEAD(&ctlr->queue); @@ -2099,11 +2115,16 @@ int spi_register_controller(struct spi_controller *ctlr) */ dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num); status = device_add(&ctlr->dev); - if (status < 0) + if (status < 0) { + /* free bus id */ + mutex_lock(&board_lock); + idr_remove(&spi_master_idr, ctlr->bus_num); + mutex_unlock(&board_lock); goto done; - dev_dbg(dev, "registered %s %s%s\n", + } + dev_dbg(dev, "registered %s %s\n", spi_controller_is_slave(ctlr) ? "slave" : "master", - dev_name(&ctlr->dev), dynamic ? " (dynamic)" : ""); + dev_name(&ctlr->dev)); /* If we're using a queued driver, start the queue */ if (ctlr->transfer) @@ -2112,6 +2133,10 @@ int spi_register_controller(struct spi_controller *ctlr) status = spi_controller_initialize_queue(ctlr); if (status) { device_del(&ctlr->dev); + /* free bus id */ + mutex_lock(&board_lock); + idr_remove(&spi_master_idr, ctlr->bus_num); + mutex_unlock(&board_lock); goto done; } } @@ -2190,8 +2215,20 @@ static int __unregister(struct device *dev, void *null) */ void spi_unregister_controller(struct spi_controller *ctlr) { + struct spi_controller *found; int dummy; + /* First make sure that this controller was ever added */ + mutex_lock(&board_lock); + found = idr_find(&spi_master_idr, ctlr->bus_num); + mutex_unlock(&board_lock); + if (found != ctlr) { + dev_dbg(&ctlr->dev, + "attempting to delete unregistered controller [%s]\n", + dev_name(&ctlr->dev)); + return; + } + if (ctlr->queued) { if (spi_destroy_queue(ctlr)) dev_err(&ctlr->dev, "queue remove failed\n"); @@ -2203,6 +2240,10 @@ void spi_unregister_controller(struct spi_controller *ctlr) dummy = device_for_each_child(&ctlr->dev, NULL, __unregister); device_unregister(&ctlr->dev); + /* free bus id */ + mutex_lock(&board_lock); + idr_remove(&spi_master_idr, ctlr->bus_num); + mutex_unlock(&board_lock); } EXPORT_SYMBOL_GPL(spi_unregister_controller); |