diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 3b9010a67397..5bf680fcb170 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -311,10 +311,10 @@ static void spi_statistics_add_transfer_stats(struct spi_statistics *stats, spin_unlock_irqrestore(&stats->lock, flags); } -/* modalias support makes "modprobe $MODALIAS" new-style hotplug work, +/* + * modalias support makes "modprobe $MODALIAS" new-style hotplug work, * and the sysfs version makes coldplug work too. */ - static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, const char *name) { while (id->name[0]) { @@ -492,7 +492,8 @@ EXPORT_SYMBOL_GPL(__spi_register_driver); /*-------------------------------------------------------------------------*/ -/* SPI devices should normally not be created by SPI device drivers; that +/* + * SPI devices should normally not be created by SPI device drivers; that * would make them board-specific. Similarly with SPI controller drivers. * Device registration normally goes into like arch/.../mach.../board-YYY.c * with other readonly (flashable) information about mainboard devices. @@ -508,8 +509,8 @@ static LIST_HEAD(spi_controller_list); /* * Used to protect add/del operation for board_info list and - * spi_controller list, and their matching process - * also used to protect object of type struct idr + * spi_controller list, and their matching process also used + * to protect object of type struct idr. */ static DEFINE_MUTEX(board_lock); @@ -616,7 +617,8 @@ static int __spi_add_device(struct spi_device *spi) else if (ctlr->cs_gpios) spi->cs_gpio = ctlr->cs_gpios[spi->chip_select]; - /* Drivers may modify this initial i/o setup, but will + /* + * Drivers may modify this initial i/o setup, but will * normally rely on the device being setup. Devices * using SPI_CS_HIGH can't coexist well otherwise... */ @@ -710,7 +712,8 @@ struct spi_device *spi_new_device(struct spi_controller *ctlr, struct spi_device *proxy; 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 @@ -878,7 +881,6 @@ static void *spi_res_alloc(struct spi_device *spi, spi_res_release_t release, /** * spi_res_free - free an spi resource * @res: pointer to the custom data of a resource - * */ static void spi_res_free(void *res) { @@ -973,7 +975,7 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force) gpiod_set_value_cansleep(spi->cs_gpiod, activate); } else { /* - * invert the enable line, as active low is + * Invert the enable line, as active low is * default for SPI. */ gpio_set_value_cansleep(spi->cs_gpio, !enable); @@ -1711,16 +1713,7 @@ static void spi_pump_messages(struct kthread_work *work) } /** - * spi_take_timestamp_pre - helper for drivers to collect the beginning of the - * TX timestamp for the requested byte from the SPI - * transfer. The frequency with which this function - * must be called (once per word, once for the whole - * transfer, once per batch of words etc) is arbitrary - * as long as the @tx buffer offset is greater than or - * equal to the requested byte at the time of the - * call. The timestamp is only taken once, at the - * first such call. It is assumed that the driver - * advances its @tx buffer pointer monotonically. + * spi_take_timestamp_pre - helper to collect the beginning of the TX timestamp * @ctlr: Pointer to the spi_controller structure of the driver * @xfer: Pointer to the transfer being timestamped * @progress: How many words (not bytes) have been transferred so far @@ -1730,6 +1723,14 @@ static void spi_pump_messages(struct kthread_work *work) * spi_take_timestamp_post or otherwise system will crash. * WARNING: for fully predictable results, the CPU frequency must * also be under control (governor). + * + * This is a helper for drivers to collect the beginning of the TX timestamp + * for the requested byte from the SPI transfer. The frequency with which this + * function must be called (once per word, once for the whole transfer, once + * per batch of words etc) is arbitrary as long as the @tx buffer offset is + * greater than or equal to the requested byte at the time of the call. The + * timestamp is only taken once, at the first such call. It is assumed that + * the driver advances its @tx buffer pointer monotonically. */ void spi_take_timestamp_pre(struct spi_controller *ctlr, struct spi_transfer *xfer, @@ -1757,16 +1758,16 @@ void spi_take_timestamp_pre(struct spi_controller *ctlr, EXPORT_SYMBOL_GPL(spi_take_timestamp_pre); /** - * spi_take_timestamp_post - helper for drivers to collect the end of the - * TX timestamp for the requested byte from the SPI - * transfer. Can be called with an arbitrary - * frequency: only the first call where @tx exceeds - * or is equal to the requested word will be - * timestamped. + * spi_take_timestamp_post - helper to collect the end of the TX timestamp * @ctlr: Pointer to the spi_controller structure of the driver * @xfer: Pointer to the transfer being timestamped * @progress: How many words (not bytes) have been transferred so far * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU. + * + * This is a helper for drivers to collect the end of the TX timestamp for + * the requested byte from the SPI transfer. Can be called with an arbitrary + * frequency: only the first call where @tx exceeds or is equal to the + * requested word will be timestamped. */ void spi_take_timestamp_post(struct spi_controller *ctlr, struct spi_transfer *xfer, @@ -1899,10 +1900,12 @@ void spi_finalize_current_message(struct spi_controller *ctlr) spi_unmap_msg(ctlr, mesg); - /* In the prepare_messages callback the spi bus has the opportunity to - * split a transfer to smaller chunks. - * Release splited transfers here since spi_map_msg is done on the - * splited transfers. + /* + * In the prepare_messages callback the SPI bus has the opportunity + * to split a transfer to smaller chunks. + * + * Release the split transfers here since spi_map_msg() is done on + * the split transfers. */ spi_res_release(ctlr, mesg); @@ -2944,8 +2947,9 @@ int spi_register_controller(struct spi_controller *ctlr) if (!ctlr->max_dma_len) ctlr->max_dma_len = INT_MAX; - /* register the device, then userspace will see it. - * registration fails if the bus ID is in use. + /* + * Register the device, then userspace will see it. + * Registration fails if the bus ID is in use. */ dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num); @@ -3211,16 +3215,18 @@ static struct spi_replaced_transfers *spi_replace_transfers( /* init the replaced_transfers list */ INIT_LIST_HEAD(&rxfer->replaced_transfers); - /* assign the list_entry after which we should reinsert + /* + * Assign the list_entry after which we should reinsert * the @replaced_transfers - it may be spi_message.messages! */ rxfer->replaced_after = xfer_first->transfer_list.prev; /* remove the requested number of transfers */ for (i = 0; i < remove; i++) { - /* if the entry after replaced_after it is msg->transfers + /* + * If the entry after replaced_after it is msg->transfers * then we have been requested to remove more transfers - * than are in the list + * than are in the list. */ if (rxfer->replaced_after->next == &msg->transfers) { dev_err(&msg->spi->dev, @@ -3236,15 +3242,17 @@ static struct spi_replaced_transfers *spi_replace_transfers( return ERR_PTR(-EINVAL); } - /* remove the entry after replaced_after from list of - * transfers and add it to list of replaced_transfers + /* + * Remove the entry after replaced_after from list of + * transfers and add it to list of replaced_transfers. */ list_move_tail(rxfer->replaced_after->next, &rxfer->replaced_transfers); } - /* create copy of the given xfer with identical settings - * based on the first transfer to get removed + /* + * Create copy of the given xfer with identical settings + * based on the first transfer to get removed. */ for (i = 0; i < insert; i++) { /* we need to run in reverse order */ @@ -3292,18 +3300,20 @@ static int __spi_split_transfer_maxsize(struct spi_controller *ctlr, return PTR_ERR(srt); xfers = srt->inserted_transfers; - /* now handle each of those newly inserted spi_transfers - * note that the replacements spi_transfers all are preset + /* + * Now handle each of those newly inserted spi_transfers. + * Note that the replacements spi_transfers all are preset * to the same values as *xferp, so tx_buf, rx_buf and len * are all identical (as well as most others) * so we just have to fix up len and the pointers. * - * this also includes support for the depreciated - * spi_message.is_dma_mapped interface + * This also includes support for the depreciated + * spi_message.is_dma_mapped interface. */ - /* the first transfer just needs the length modified, so we - * run it outside the loop + /* + * The first transfer just needs the length modified, so we + * run it outside the loop. */ xfers[0].len = min_t(size_t, maxsize, xfer[0].len); @@ -3323,8 +3333,9 @@ static int __spi_split_transfer_maxsize(struct spi_controller *ctlr, xfers[i].len = min(maxsize, xfers[i].len - offset); } - /* we set up xferp to the last entry we have inserted, - * so that we skip those already split transfers + /* + * We set up xferp to the last entry we have inserted, + * so that we skip those already split transfers. */ *xferp = &xfers[count - 1]; @@ -3356,11 +3367,12 @@ int spi_split_transfers_maxsize(struct spi_controller *ctlr, struct spi_transfer *xfer; int ret; - /* iterate over the transfer_list, + /* + * Iterate over the transfer_list, * but note that xfer is advanced to the last transfer inserted * to avoid checking sizes again unnecessarily (also xfer does - * potentiall belong to a different list by the time the - * replacement has happened + * potentially belong to a different list by the time the + * replacement has happened). */ list_for_each_entry(xfer, &msg->transfers, transfer_list) { if (xfer->len > maxsize) { @@ -3421,8 +3433,8 @@ int spi_setup(struct spi_device *spi) int status; /* - * check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO - * are set at the same time + * Check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO + * are set at the same time. */ if ((hweight_long(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) || @@ -3432,20 +3444,21 @@ int spi_setup(struct spi_device *spi) "setup: can not select any two of dual, quad and no-rx/tx at the same time\n"); return -EINVAL; } - /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden - */ + /* If it is SPI_3WIRE mode, DUAL and QUAD should be forbidden */ if ((spi->mode & SPI_3WIRE) && (spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL | SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL))) return -EINVAL; - /* help drivers fail *cleanly* when they need options - * that aren't supported with their current controller + /* + * Help drivers fail *cleanly* when they need options + * that aren't supported with their current controller. * SPI_CS_WORD has a fallback software implementation, * so it is ignored here. */ bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD | SPI_NO_TX | SPI_NO_RX); - /* nothing prevents from working with active-high CS in case if it + /* + * Nothing prevents from working with active-high CS in case if it * is driven by GPIO. */ if (gpio_is_valid(spi->cs_gpio)) @@ -3567,7 +3580,8 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) if (list_empty(&message->transfers)) return -EINVAL; - /* If an SPI controller does not support toggling the CS line on each + /* + * If an SPI controller does not support toggling the CS line on each * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO * for the CS line, we can emulate the CS-per-word hardware function by * splitting transfers into one-word transfers and ensuring that @@ -3597,7 +3611,8 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) } } - /* Half-duplex links include original MicroWire, and ones with + /* + * Half-duplex links include original MicroWire, and ones with * only one data pin like SPI_3WIRE (switches direction) or where * either MOSI or MISO is missing. They can also be caused by * software limitations. @@ -3616,7 +3631,7 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) } } - /** + /* * Set transfer bits_per_word and max speed as spi device default if * it is not set for this transfer. * Set transfer tx_nbits and rx_nbits as single transfer default @@ -3642,7 +3657,7 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) /* * SPI transfer length should be multiple of SPI word size - * where SPI word size should be power-of-two multiple + * where SPI word size should be power-of-two multiple. */ if (xfer->bits_per_word <= 8) w_size = 1; @@ -3663,7 +3678,8 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) xfer->tx_nbits = SPI_NBITS_SINGLE; if (xfer->rx_buf && !xfer->rx_nbits) xfer->rx_nbits = SPI_NBITS_SINGLE; - /* check transfer tx/rx_nbits: + /* + * Check transfer tx/rx_nbits: * 1. check the value matches one of single, dual and quad * 2. check tx/rx_nbits match the mode in spi_device */ @@ -3842,7 +3858,8 @@ static int spi_async_locked(struct spi_device *spi, struct spi_message *message) /*-------------------------------------------------------------------------*/ -/* Utility methods for SPI protocol drivers, layered on +/* + * Utility methods for SPI protocol drivers, layered on * top of the core. Some other utility methods are defined as * inline functions. */ @@ -3870,7 +3887,8 @@ static int __spi_sync(struct spi_device *spi, struct spi_message *message) SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync); SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync); - /* If we're not using the legacy transfer method then we will + /* + * If we're not using the legacy transfer method then we will * try to transfer in the calling context so special case. * This code would be less tricky if we could remove the * support for driver implemented message queues. @@ -3888,9 +3906,7 @@ static int __spi_sync(struct spi_device *spi, struct spi_message *message) } if (status == 0) { - /* Push out the messages in the calling context if we - * can. - */ + /* Push out the messages in the calling context if we can */ if (ctlr->transfer == spi_queued_transfer) { SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync_immediate); @@ -4051,7 +4067,8 @@ int spi_write_then_read(struct spi_device *spi, struct spi_transfer x[2]; u8 *local_buf; - /* Use preallocated DMA-safe buffer if we can. We can't avoid + /* + * Use preallocated DMA-safe buffer if we can. We can't avoid * copying here, (as a pure convenience thing), but we can * keep heap costs out of the hot path unless someone else is * using the pre-allocated buffer or the transfer is too large. @@ -4287,11 +4304,12 @@ err0: return status; } -/* board_info is normally registered in arch_initcall(), - * but even essential drivers wait till later +/* + * A board_info is normally registered in arch_initcall(), + * but even essential drivers wait till later. * - * REVISIT only boardinfo really needs static linking. the rest (device and - * driver registration) _could_ be dynamically linked (modular) ... costs + * REVISIT only boardinfo really needs static linking. The rest (device and + * driver registration) _could_ be dynamically linked (modular) ... Costs * include needing to have boardinfo data structures be much more public. */ postcore_initcall(spi_init);