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spi: spi-ep93xx: convert to the queued driver infrastructure 

The SPI core provides infrastructure for standard message queueing. Use
that instead of handling it in the driver.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Mika Westerberg <mika.westerberg@iki.fi>
Signed-off-by: Mark Brown <broonie@linaro.org>
This commit is contained in:
H Hartley Sweeten 2013-07-08 09:12:37 -07:00 committed by Mark Brown
parent f7ef1da9e2
commit 84ddb3c1df
1 changed files with 19 additions and 146 deletions
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165
drivers/spi/spi-ep93xx.c
View File

@ -26,7 +26,6 @@
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>
#include <linux/sched.h>
#include <linux/scatterlist.h>
#include <linux/spi/spi.h>
@ -70,19 +69,13 @@
/**
* struct ep93xx_spi - EP93xx SPI controller structure
* @lock: spinlock that protects concurrent accesses to fields @running,
* @current_msg and @msg_queue
* @pdev: pointer to platform device
* @clk: clock for the controller
* @regs_base: pointer to ioremap()'d registers
* @sspdr_phys: physical address of the SSPDR register
* @min_rate: minimum clock rate (in Hz) supported by the controller
* @max_rate: maximum clock rate (in Hz) supported by the controller
* @running: is the queue running
* @wq: workqueue used by the driver
* @msg_work: work that is queued for the driver
* @wait: wait here until given transfer is completed
* @msg_queue: queue for the messages
* @current_msg: message that is currently processed (or %NULL if none)
* @tx: current byte in transfer to transmit
* @rx: current byte in transfer to receive
@ -96,30 +89,15 @@
* @tx_sgt: sg table for TX transfers
* @zeropage: dummy page used as RX buffer when only TX buffer is passed in by
* the client
*
* This structure holds EP93xx SPI controller specific information. When
* @running is %true, driver accepts transfer requests from protocol drivers.
* @current_msg is used to hold pointer to the message that is currently
* processed. If @current_msg is %NULL, it means that no processing is going
* on.
*
* Most of the fields are only written once and they can be accessed without
* taking the @lock. Fields that are accessed concurrently are: @current_msg,
* @running, and @msg_queue.
*/
struct ep93xx_spi {
spinlock_t lock;
const struct platform_device *pdev;
struct clk *clk;
void __iomem *regs_base;
unsigned long sspdr_phys;
unsigned long min_rate;
unsigned long max_rate;
bool running;
struct workqueue_struct *wq;
struct work_struct msg_work;
struct completion wait;
struct list_head msg_queue;
struct spi_message *current_msg;
size_t tx;
size_t rx;
@ -230,7 +208,7 @@ static int ep93xx_spi_calc_divisors(const struct ep93xx_spi *espi,
/*
* Make sure that max value is between values supported by the
* controller. Note that minimum value is already checked in
* ep93xx_spi_transfer().
* ep93xx_spi_transfer_one_message().
*/
rate = clamp(rate, espi->min_rate, espi->max_rate);
@ -305,54 +283,6 @@ static int ep93xx_spi_setup(struct spi_device *spi)
return 0;
}
/**
* ep93xx_spi_transfer() - queue message to be transferred
* @spi: target SPI device
* @msg: message to be transferred
*
* This function is called by SPI device drivers when they are going to transfer
* a new message. It simply puts the message in the queue and schedules
* workqueue to perform the actual transfer later on.
*
* Returns %0 on success and negative error in case of failure.
*/
static int ep93xx_spi_transfer(struct spi_device *spi, struct spi_message *msg)
{
struct ep93xx_spi *espi = spi_master_get_devdata(spi->master);
struct spi_transfer *t;
unsigned long flags;
if (!msg || !msg->complete)
return -EINVAL;
/* first validate each transfer */
list_for_each_entry(t, &msg->transfers, transfer_list) {
if (t->speed_hz && t->speed_hz < espi->min_rate)
return -EINVAL;
}
/*
* Now that we own the message, let's initialize it so that it is
* suitable for us. We use @msg->status to signal whether there was
* error in transfer and @msg->state is used to hold pointer to the
* current transfer (or %NULL if no active current transfer).
*/
msg->state = NULL;
msg->status = 0;
msg->actual_length = 0;
spin_lock_irqsave(&espi->lock, flags);
if (!espi->running) {
spin_unlock_irqrestore(&espi->lock, flags);
return -ESHUTDOWN;
}
list_add_tail(&msg->queue, &espi->msg_queue);
queue_work(espi->wq, &espi->msg_work);
spin_unlock_irqrestore(&espi->lock, flags);
return 0;
}
/**
* ep93xx_spi_cleanup() - cleans up master controller specific state
* @spi: SPI device to cleanup
@ -801,50 +731,29 @@ static void ep93xx_spi_process_message(struct ep93xx_spi *espi,
ep93xx_spi_disable(espi);
}
#define work_to_espi(work) (container_of((work), struct ep93xx_spi, msg_work))
/**
* ep93xx_spi_work() - EP93xx SPI workqueue worker function
* @work: work struct
*
* Workqueue worker function. This function is called when there are new
* SPI messages to be processed. Message is taken out from the queue and then
* passed to ep93xx_spi_process_message().
*
* After message is transferred, protocol driver is notified by calling
* @msg->complete(). In case of error, @msg->status is set to negative error
* number, otherwise it contains zero (and @msg->actual_length is updated).
*/
static void ep93xx_spi_work(struct work_struct *work)
static int ep93xx_spi_transfer_one_message(struct spi_master *master,
struct spi_message *msg)
{
struct ep93xx_spi *espi = work_to_espi(work);
struct spi_message *msg;
struct ep93xx_spi *espi = spi_master_get_devdata(master);
struct spi_transfer *t;
spin_lock_irq(&espi->lock);
if (!espi->running || espi->current_msg ||
list_empty(&espi->msg_queue)) {
spin_unlock_irq(&espi->lock);
return;
/* first validate each transfer */
list_for_each_entry(t, &msg->transfers, transfer_list) {
if (t->speed_hz < espi->min_rate)
return -EINVAL;
}
msg = list_first_entry(&espi->msg_queue, struct spi_message, queue);
list_del_init(&msg->queue);
msg->state = NULL;
msg->status = 0;
msg->actual_length = 0;
espi->current_msg = msg;
spin_unlock_irq(&espi->lock);
ep93xx_spi_process_message(espi, msg);
/*
* Update the current message and re-schedule ourselves if there are
* more messages in the queue.
*/
spin_lock_irq(&espi->lock);
espi->current_msg = NULL;
if (espi->running && !list_empty(&espi->msg_queue))
queue_work(espi->wq, &espi->msg_work);
spin_unlock_irq(&espi->lock);
/* notify the protocol driver that we are done with this message */
msg->complete(msg->context);
spi_finalize_current_message(master);
return 0;
}
static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id)
@ -984,7 +893,7 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
return -ENOMEM;
master->setup = ep93xx_spi_setup;
master->transfer = ep93xx_spi_transfer;
master->transfer_one_message = ep93xx_spi_transfer_one_message;
master->cleanup = ep93xx_spi_cleanup;
master->bus_num = pdev->id;
master->num_chipselect = info->num_chipselect;
@ -1002,7 +911,6 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
goto fail_release_master;
}
spin_lock_init(&espi->lock);
init_completion(&espi->wait);
/*
@ -1031,23 +939,13 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
if (info->use_dma && ep93xx_spi_setup_dma(espi))
dev_warn(&pdev->dev, "DMA setup failed. Falling back to PIO\n");
espi->wq = create_singlethread_workqueue("ep93xx_spid");
if (!espi->wq) {
dev_err(&pdev->dev, "unable to create workqueue\n");
error = -ENOMEM;
goto fail_free_dma;
}
INIT_WORK(&espi->msg_work, ep93xx_spi_work);
INIT_LIST_HEAD(&espi->msg_queue);
espi->running = true;
/* make sure that the hardware is disabled */
ep93xx_spi_write_u8(espi, SSPCR1, 0);
error = spi_register_master(master);
if (error) {
dev_err(&pdev->dev, "failed to register SPI master\n");
goto fail_free_queue;
goto fail_free_dma;
}
dev_info(&pdev->dev, "EP93xx SPI Controller at 0x%08lx irq %d\n",
@ -1055,8 +953,6 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
return 0;
fail_free_queue:
destroy_workqueue(espi->wq);
fail_free_dma:
ep93xx_spi_release_dma(espi);
fail_release_master:
@ -1070,29 +966,6 @@ static int ep93xx_spi_remove(struct platform_device *pdev)
struct spi_master *master = platform_get_drvdata(pdev);
struct ep93xx_spi *espi = spi_master_get_devdata(master);
spin_lock_irq(&espi->lock);
espi->running = false;
spin_unlock_irq(&espi->lock);
destroy_workqueue(espi->wq);
/*
* Complete remaining messages with %-ESHUTDOWN status.
*/
spin_lock_irq(&espi->lock);
while (!list_empty(&espi->msg_queue)) {
struct spi_message *msg;
msg = list_first_entry(&espi->msg_queue,
struct spi_message, queue);
list_del_init(&msg->queue);
msg->status = -ESHUTDOWN;
spin_unlock_irq(&espi->lock);
msg->complete(msg->context);
spin_lock_irq(&espi->lock);
}
spin_unlock_irq(&espi->lock);
ep93xx_spi_release_dma(espi);
spi_unregister_master(master);