From bdf034d98676d143cb88f7b999a71fff5775fcd4 Mon Sep 17 00:00:00 2001 From: Julian Andres Klode Date: Tue, 27 Sep 2011 19:00:56 +0200 Subject: [PATCH] staging: nvec: Document public and private API Add kernel-doc comments describing the functions and structs we currently have. Signed-off-by: Julian Andres Klode Acked-by: Marc Dietrich Signed-off-by: Greg Kroah-Hartman --- drivers/staging/nvec/nvec.c | 109 +++++++++++++++++++++++++++++++++++- drivers/staging/nvec/nvec.h | 86 +++++++++++++++++++++++++++- 2 files changed, 191 insertions(+), 4 deletions(-) diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c index dc3c0c64ed86..057c8889ff03 100644 --- a/drivers/staging/nvec/nvec.c +++ b/drivers/staging/nvec/nvec.c @@ -71,6 +71,15 @@ static struct mfd_cell nvec_devices[] = { }, }; +/** + * nvec_register_notifier - Register a notifier with nvec + * @nvec: A &struct nvec_chip + * @nb: The notifier block to register + * + * Registers a notifier with @nvec. The notifier will be added to an atomic + * notifier chain that is called for all received messages except those that + * correspond to a request initiated by nvec_write_sync(). + */ int nvec_register_notifier(struct nvec_chip *nvec, struct notifier_block *nb, unsigned int events) { @@ -78,6 +87,12 @@ int nvec_register_notifier(struct nvec_chip *nvec, struct notifier_block *nb, } EXPORT_SYMBOL_GPL(nvec_register_notifier); +/** + * nvec_status_notifier - The final notifier + * + * Prints a message about control events not handled in the notifier + * chain. + */ static int nvec_status_notifier(struct notifier_block *nb, unsigned long event_type, void *data) { @@ -93,6 +108,14 @@ static int nvec_status_notifier(struct notifier_block *nb, return NOTIFY_OK; } +/** + * nvec_msg_alloc: + * @nvec: A &struct nvec_chip + * + * Allocate a single &struct nvec_msg object from the message pool of + * @nvec. The result shall be passed to nvec_msg_free() if no longer + * used. + */ static struct nvec_msg *nvec_msg_alloc(struct nvec_chip *nvec) { int i; @@ -109,6 +132,13 @@ static struct nvec_msg *nvec_msg_alloc(struct nvec_chip *nvec) return NULL; } +/** + * nvec_msg_free: + * @nvec: A &struct nvec_chip + * @msg: A message (must be allocated by nvec_msg_alloc() and belong to @nvec) + * + * Free the given message + */ static void nvec_msg_free(struct nvec_chip *nvec, struct nvec_msg *msg) { if (msg != &nvec->tx_scratch) @@ -147,6 +177,13 @@ static size_t nvec_msg_size(struct nvec_msg *msg) return 0; } +/** + * nvec_gpio_set_value - Set the GPIO value + * @nvec: A &struct nvec_chip + * @value: The value to write (0 or 1) + * + * Like gpio_set_value(), but generating debugging information + */ static void nvec_gpio_set_value(struct nvec_chip *nvec, int value) { dev_dbg(nvec->dev, "GPIO changed from %u to %u\n", @@ -154,6 +191,18 @@ static void nvec_gpio_set_value(struct nvec_chip *nvec, int value) gpio_set_value(nvec->gpio, value); } +/** + * nvec_write_async - Asynchronously write a message to NVEC + * @nvec: An nvec_chip instance + * @data: The message data, starting with the request type + * @size: The size of @data + * + * Queue a single message to be transferred to the embedded controller + * and return immediately. + * + * Returns: 0 on success, a negative error code on failure. If a failure + * occured, the nvec driver may print an error. + */ int nvec_write_async(struct nvec_chip *nvec, const unsigned char *data, short size) { @@ -178,6 +227,20 @@ int nvec_write_async(struct nvec_chip *nvec, const unsigned char *data, } EXPORT_SYMBOL(nvec_write_async); +/** + * nvec_write_sync - Write a message to nvec and read the response + * @nvec: An &struct nvec_chip + * @data: The data to write + * @size: The size of @data + * + * This is similar to nvec_write_async(), but waits for the + * request to be answered before returning. This function + * uses a mutex and can thus not be called from e.g. + * interrupt handlers. + * + * Returns: A pointer to the response message on success, + * %NULL on failure. + */ struct nvec_msg *nvec_write_sync(struct nvec_chip *nvec, const unsigned char *data, short size) { @@ -209,7 +272,14 @@ struct nvec_msg *nvec_write_sync(struct nvec_chip *nvec, } EXPORT_SYMBOL(nvec_write_sync); -/* TX worker */ +/** + * nvec_request_master - Process outgoing messages + * @work: A &struct work_struct (the tx_worker member of &struct nvec_chip) + * + * Processes all outgoing requests by sending the request and awaiting the + * response, then continuing with the next request. Once a request has a + * matching response, it will be freed and removed from the list. + */ static void nvec_request_master(struct work_struct *work) { struct nvec_chip *nvec = container_of(work, struct nvec_chip, tx_work); @@ -241,6 +311,14 @@ static void nvec_request_master(struct work_struct *work) spin_unlock_irqrestore(&nvec->tx_lock, flags); } +/** + * parse_msg - Print some information and call the notifiers on an RX message + * @nvec: A &struct nvec_chip + * @msg: A message received by @nvec + * + * Paarse some pieces of the message and then call the chain of notifiers + * registered via nvec_register_notifier. + */ static int parse_msg(struct nvec_chip *nvec, struct nvec_msg *msg) { if ((msg->data[0] & 1 << 7) == 0 && msg->data[3]) { @@ -260,7 +338,13 @@ static int parse_msg(struct nvec_chip *nvec, struct nvec_msg *msg) return 0; } -/* RX worker */ +/** + * nvec_dispatch - Process messages received from the EC + * @work: A &struct work_struct (the tx_worker member of &struct nvec_chip) + * + * Process messages previously received from the EC and put into the RX + * queue of the &struct nvec_chip instance associated with @work. + */ static void nvec_dispatch(struct work_struct *work) { struct nvec_chip *nvec = container_of(work, struct nvec_chip, rx_work); @@ -288,6 +372,12 @@ static void nvec_dispatch(struct work_struct *work) spin_unlock_irqrestore(&nvec->rx_lock, flags); } +/** + * nvec_tx_completed - Complete the current transfer + * @nvec: A &struct nvec_chip + * + * This is called when we have received an END_TRANS on a TX transfer. + */ static void nvec_tx_completed(struct nvec_chip *nvec) { /* We got an END_TRANS, let's skip this, maybe there's an event */ @@ -300,6 +390,12 @@ static void nvec_tx_completed(struct nvec_chip *nvec) } } +/** + * nvec_rx_completed - Complete the current transfer + * @nvec: A &struct nvec_chip + * + * This is called when we have received an END_TRANS on a RX transfer. + */ static void nvec_rx_completed(struct nvec_chip *nvec) { if (nvec->rx->pos != nvec_msg_size(nvec->rx)) @@ -340,6 +436,11 @@ static void nvec_invalid_flags(struct nvec_chip *nvec, unsigned int status, /** * nvec_tx_set - Set the message to transfer (nvec->tx) + * @nvec: A &struct nvec_chip + * + * Gets the first entry from the tx_data list of @nvec and sets the + * tx member to it. If the tx_data list is empty, this uses the + * tx_scratch message to send a no operation message. */ static void nvec_tx_set(struct nvec_chip *nvec) { @@ -366,6 +467,10 @@ static void nvec_tx_set(struct nvec_chip *nvec) * nvec_interrupt - Interrupt handler * @irq: The IRQ * @dev: The nvec device + * + * Interrupt handler that fills our RX buffers and empties our TX + * buffers. This uses a finite state machine with ridiculous amounts + * of error checking, in order to be fairly reliable. */ static irqreturn_t nvec_interrupt(int irq, void *dev) { diff --git a/drivers/staging/nvec/nvec.h b/drivers/staging/nvec/nvec.h index a39cfc15b4cb..d1e4f57f8513 100644 --- a/drivers/staging/nvec/nvec.h +++ b/drivers/staging/nvec/nvec.h @@ -6,6 +6,7 @@ * Authors: Pierre-Hugues Husson * Ilya Petrov * Marc Dietrich + * Julian Andres Klode * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive @@ -32,13 +33,37 @@ */ #define NVEC_MSG_SIZE 34 -enum { +/** + * enum nvec_event_size - The size of an event message + * @NVEC_2BYTES: The message has one command byte and one data byte + * @NVEC_3BYTES: The message has one command byte and two data bytes + * @NVEC_VAR_SIZE: The message has one command byte, one count byte, and as + * up to as many bytes as the number in the count byte. The + * maximum is 32 + * + * Events can be fixed or variable sized. This is useless on other message + * types, which are always variable sized. + */ +enum nvec_event_size { NVEC_2BYTES, NVEC_3BYTES, NVEC_VAR_SIZE, }; -enum { +/** + * enum nvec_msg_type - The type of a message + * @NVEC_SYS: A system request/response + * @NVEC_BAT: A battery request/response + * @NVEC_KBD: A keyboard request/response + * @NVEC_PS2: A mouse request/response + * @NVEC_CNTL: A EC control request/response + * @NVEC_KB_EVT: An event from the keyboard + * @NVEC_PS2_EVT: An event from the mouse + * + * Events can be fixed or variable sized. This is useless on other message + * types, which are always variable sized. + */ +enum nvec_msg_type { NVEC_SYS = 1, NVEC_BAT, NVEC_KBD = 5, @@ -48,6 +73,19 @@ enum { NVEC_PS2_EVT, }; +/** + * struct nvec_msg - A buffer for a single message + * @node: Messages are part of various lists in a &struct nvec_chip + * @data: The data of the message + * @size: For TX messages, the number of bytes used in @data + * @pos: For RX messages, the current position to write to. For TX messages, + * the position to read from. + * @used: Used for the message pool to mark a message as free/allocated. + * + * This structure is used to hold outgoing and incoming messages. Outgoing + * messages have a different format than incoming messages, and that is not + * documented yet. + */ struct nvec_msg { struct list_head node; unsigned char data[NVEC_MSG_SIZE]; @@ -56,17 +94,61 @@ struct nvec_msg { atomic_t used; }; +/** + * struct nvec_subdev - A subdevice of nvec, such as nvec_kbd + * @name: The name of the sub device + * @platform_data: Platform data + * @id: Identifier of the sub device + */ struct nvec_subdev { const char *name; void *platform_data; int id; }; +/** + * struct nvec_platform_data - platform data for a tegra slave controller + * @i2c_addr: number of i2c slave adapter the ec is connected to + * @gpio: gpio number for the ec request line + * + * Platform data, to be used in board definitions. For an example, take a + * look at the paz00 board in arch/arm/mach-tegra/board-paz00.c + */ struct nvec_platform_data { int i2c_addr; int gpio; }; +/** + * struct nvec_chip - A single connection to an NVIDIA Embedded controller + * @dev: The device + * @gpio: The same as for &struct nvec_platform_data + * @irq: The IRQ of the I2C device + * @i2c_addr: The address of the I2C slave + * @base: The base of the memory mapped region of the I2C device + * @clk: The clock of the I2C device + * @notifier_list: Notifiers to be called on received messages, see + * nvec_register_notifier() + * @rx_data: Received messages that have to be processed + * @tx_data: Messages waiting to be sent to the controller + * @nvec_status_notifier: Internal notifier (see nvec_status_notifier()) + * @rx_work: A work structure for the RX worker nvec_dispatch() + * @tx_work: A work structure for the TX worker nvec_request_master() + * @wq: The work queue in which @rx_work and @tx_work are executed + * @rx: The message currently being retrieved or %NULL + * @msg_pool: A pool of messages for allocation + * @tx: The message currently being transferred + * @tx_scratch: Used for building pseudo messages + * @ec_transfer: A completion that will be completed once a message has been + * received (see nvec_rx_completed()) + * @tx_lock: Spinlock for modifications on @tx_data + * @rx_lock: Spinlock for modifications on @rx_data + * @sync_write_mutex: A mutex for nvec_write_sync() + * @sync_write: A completion to signal that a synchronous message is complete + * @sync_write_pending: The first two bytes of the request (type and subtype) + * @last_sync_msg: The last synchronous message. + * @state: State of our finite state machine used in nvec_interrupt() + */ struct nvec_chip { struct device *dev; int gpio;