diff options
Diffstat (limited to 'drivers/spi/spi.c')
| -rw-r--r-- | drivers/spi/spi.c | 59 |
1 files changed, 37 insertions, 22 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 4831edbae2d5..e84d21597943 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -23,6 +23,7 @@ #include <linux/device.h> #include <linux/init.h> #include <linux/cache.h> +#include <linux/mutex.h> #include <linux/spi/spi.h> @@ -185,7 +186,7 @@ struct boardinfo { }; static LIST_HEAD(board_list); -static DECLARE_MUTEX(board_lock); +static DEFINE_MUTEX(board_lock); /** @@ -199,6 +200,8 @@ static DECLARE_MUTEX(board_lock); * platforms may not be able to use spi_register_board_info though, and * this is exported so that for example a USB or parport based adapter * driver could add devices (which it would learn about out-of-band). + * + * Returns the new device, or NULL. */ struct spi_device *spi_new_device(struct spi_master *master, struct spi_board_info *chip) @@ -207,7 +210,20 @@ struct spi_device *spi_new_device(struct spi_master *master, struct device *dev = master->cdev.dev; int status; - /* NOTE: caller did any chip->bus_num checks necessary */ + /* NOTE: caller did any chip->bus_num checks necessary. + * + * Also, unless we change the return value convention to use + * error-or-pointer (not NULL-or-pointer), troubleshootability + * suggests syslogged diagnostics are best here (ugh). + */ + + /* Chipselects are numbered 0..max; validate. */ + if (chip->chip_select >= master->num_chipselect) { + dev_err(dev, "cs%d > max %d\n", + chip->chip_select, + master->num_chipselect); + return NULL; + } if (!spi_master_get(master)) return NULL; @@ -235,10 +251,10 @@ struct spi_device *spi_new_device(struct spi_master *master, proxy->controller_state = NULL; proxy->dev.release = spidev_release; - /* drivers may modify this default i/o setup */ + /* drivers may modify this initial i/o setup */ status = master->setup(proxy); if (status < 0) { - dev_dbg(dev, "can't %s %s, status %d\n", + dev_err(dev, "can't %s %s, status %d\n", "setup", proxy->dev.bus_id, status); goto fail; } @@ -248,7 +264,7 @@ struct spi_device *spi_new_device(struct spi_master *master, */ status = device_register(&proxy->dev); if (status < 0) { - dev_dbg(dev, "can't %s %s, status %d\n", + dev_err(dev, "can't %s %s, status %d\n", "add", proxy->dev.bus_id, status); goto fail; } @@ -292,9 +308,9 @@ spi_register_board_info(struct spi_board_info const *info, unsigned n) bi->n_board_info = n; memcpy(bi->board_info, info, n * sizeof *info); - down(&board_lock); + mutex_lock(&board_lock); list_add_tail(&bi->list, &board_list); - up(&board_lock); + mutex_unlock(&board_lock); return 0; } @@ -302,13 +318,11 @@ spi_register_board_info(struct spi_board_info const *info, unsigned n) * creates board info from kernel command lines */ -static void __init_or_module -scan_boardinfo(struct spi_master *master) +static void scan_boardinfo(struct spi_master *master) { struct boardinfo *bi; - struct device *dev = master->cdev.dev; - down(&board_lock); + mutex_lock(&board_lock); list_for_each_entry(bi, &board_list, list) { struct spi_board_info *chip = bi->board_info; unsigned n; @@ -316,21 +330,13 @@ scan_boardinfo(struct spi_master *master) for (n = bi->n_board_info; n > 0; n--, chip++) { if (chip->bus_num != master->bus_num) continue; - /* some controllers only have one chip, so they - * might not use chipselects. otherwise, the - * chipselects are numbered 0..max. + /* NOTE: this relies on spi_new_device to + * issue diagnostics when given bogus inputs */ - if (chip->chip_select >= master->num_chipselect - && master->num_chipselect) { - dev_dbg(dev, "cs%d > max %d\n", - chip->chip_select, - master->num_chipselect); - continue; - } (void) spi_new_device(master, chip); } } - up(&board_lock); + mutex_unlock(&board_lock); } /*-------------------------------------------------------------------------*/ @@ -419,8 +425,17 @@ int spi_register_master(struct spi_master *master) if (!dev) return -ENODEV; + /* even if it's just one always-selected device, there must + * be at least one chipselect + */ + if (master->num_chipselect == 0) + return -EINVAL; + /* convention: dynamically assigned bus IDs count down from the max */ if (master->bus_num < 0) { + /* FIXME switch to an IDR based scheme, something like + * I2C now uses, so we can't run out of "dynamic" IDs + */ master->bus_num = atomic_dec_return(&dyn_bus_id); dynamic = 1; } |