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Commit 497cb447 authored by Mark Brown's avatar Mark Brown
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Merge remote-tracking branch 'spi/topic/ep93xx' into spi-next

parents afa8f0cd 6a3fc31f
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Showing with 81 additions and 272 deletions
drivers/spi/spi-ep93xx.c
View file @ 497cb447
......@@ -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;
......@@ -136,50 +114,36 @@ struct ep93xx_spi {
/**
* struct ep93xx_spi_chip - SPI device hardware settings
* @spi: back pointer to the SPI device
* @rate: max rate in hz this chip supports
* @div_cpsr: cpsr (pre-scaler) divider
* @div_scr: scr divider
* @dss: bits per word (4 - 16 bits)
* @ops: private chip operations
*
* This structure is used to store hardware register specific settings for each
* SPI device. Settings are written to hardware by function
* ep93xx_spi_chip_setup().
*/
struct ep93xx_spi_chip {
const struct spi_device *spi;
unsigned long rate;
u8 div_cpsr;
u8 div_scr;
u8 dss;
struct ep93xx_spi_chip_ops *ops;
};
/* converts bits per word to CR0.DSS value */
#define bits_per_word_to_dss(bpw) ((bpw) - 1)
static inline void
ep93xx_spi_write_u8(const struct ep93xx_spi *espi, u16 reg, u8 value)
static void ep93xx_spi_write_u8(const struct ep93xx_spi *espi,
u16 reg, u8 value)
{
__raw_writeb(value, espi->regs_base + reg);
writeb(value, espi->regs_base + reg);
}
static inline u8
ep93xx_spi_read_u8(const struct ep93xx_spi *spi, u16 reg)
static u8 ep93xx_spi_read_u8(const struct ep93xx_spi *spi, u16 reg)
{
return __raw_readb(spi->regs_base + reg);
return readb(spi->regs_base + reg);
}
static inline void
ep93xx_spi_write_u16(const struct ep93xx_spi *espi, u16 reg, u16 value)
static void ep93xx_spi_write_u16(const struct ep93xx_spi *espi,
u16 reg, u16 value)
{
__raw_writew(value, espi->regs_base + reg);
writew(value, espi->regs_base + reg);
}
static inline u16
ep93xx_spi_read_u16(const struct ep93xx_spi *spi, u16 reg)
static u16 ep93xx_spi_read_u16(const struct ep93xx_spi *spi, u16 reg)
{
return __raw_readw(spi->regs_base + reg);
return readw(spi->regs_base + reg);
}
static int ep93xx_spi_enable(const struct ep93xx_spi *espi)
......@@ -230,17 +194,13 @@ static void ep93xx_spi_disable_interrupts(const struct ep93xx_spi *espi)
/**
* ep93xx_spi_calc_divisors() - calculates SPI clock divisors
* @espi: ep93xx SPI controller struct
* @chip: divisors are calculated for this chip
* @rate: desired SPI output clock rate
*
* Function calculates cpsr (clock pre-scaler) and scr divisors based on
* given @rate and places them to @chip->div_cpsr and @chip->div_scr. If,
* for some reason, divisors cannot be calculated nothing is stored and
* %-EINVAL is returned.
* @div_cpsr: pointer to return the cpsr (pre-scaler) divider
* @div_scr: pointer to return the scr divider
*/
static int ep93xx_spi_calc_divisors(const struct ep93xx_spi *espi,
struct ep93xx_spi_chip *chip,
unsigned long rate)
unsigned long rate,
u8 *div_cpsr, u8 *div_scr)
{
unsigned long spi_clk_rate = clk_get_rate(espi->clk);
int cpsr, scr;
......@@ -248,7 +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);
......@@ -263,8 +223,8 @@ static int ep93xx_spi_calc_divisors(const struct ep93xx_spi *espi,
for (cpsr = 2; cpsr <= 254; cpsr += 2) {
for (scr = 0; scr <= 255; scr++) {
if ((spi_clk_rate / (cpsr * (scr + 1))) <= rate) {
chip->div_scr = (u8)scr;
chip->div_cpsr = (u8)cpsr;
*div_scr = (u8)scr;
*div_cpsr = (u8)cpsr;
return 0;
}
}
......@@ -319,72 +279,10 @@ static int ep93xx_spi_setup(struct spi_device *spi)
spi_set_ctldata(spi, chip);
}
if (spi->max_speed_hz != chip->rate) {
int err;
err = ep93xx_spi_calc_divisors(espi, chip, spi->max_speed_hz);
if (err != 0) {
spi_set_ctldata(spi, NULL);
kfree(chip);
return err;
}
chip->rate = spi->max_speed_hz;
}
chip->dss = bits_per_word_to_dss(spi->bits_per_word);
ep93xx_spi_cs_control(spi, false);
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
......@@ -409,39 +307,40 @@ static void ep93xx_spi_cleanup(struct spi_device *spi)
* ep93xx_spi_chip_setup() - configures hardware according to given @chip
* @espi: ep93xx SPI controller struct
* @chip: chip specific settings
*
* This function sets up the actual hardware registers with settings given in
* @chip. Note that no validation is done so make sure that callers validate
* settings before calling this.
* @speed_hz: transfer speed
* @bits_per_word: transfer bits_per_word
*/
static void ep93xx_spi_chip_setup(const struct ep93xx_spi *espi,
const struct ep93xx_spi_chip *chip)
static int ep93xx_spi_chip_setup(const struct ep93xx_spi *espi,
const struct ep93xx_spi_chip *chip,
u32 speed_hz, u8 bits_per_word)
{
u8 dss = bits_per_word_to_dss(bits_per_word);
u8 div_cpsr = 0;
u8 div_scr = 0;
u16 cr0;
int err;
cr0 = chip->div_scr << SSPCR0_SCR_SHIFT;
err = ep93xx_spi_calc_divisors(espi, speed_hz, &div_cpsr, &div_scr);
if (err)
return err;
cr0 = div_scr << SSPCR0_SCR_SHIFT;
cr0 |= (chip->spi->mode & (SPI_CPHA|SPI_CPOL)) << SSPCR0_MODE_SHIFT;
cr0 |= chip->dss;
cr0 |= dss;
dev_dbg(&espi->pdev->dev, "setup: mode %d, cpsr %d, scr %d, dss %d\n",
chip->spi->mode, chip->div_cpsr, chip->div_scr, chip->dss);
chip->spi->mode, div_cpsr, div_scr, dss);
dev_dbg(&espi->pdev->dev, "setup: cr0 %#x", cr0);
ep93xx_spi_write_u8(espi, SSPCPSR, chip->div_cpsr);
ep93xx_spi_write_u8(espi, SSPCPSR, div_cpsr);
ep93xx_spi_write_u16(espi, SSPCR0, cr0);
}
static inline int bits_per_word(const struct ep93xx_spi *espi)
{
struct spi_message *msg = espi->current_msg;
struct spi_transfer *t = msg->state;
return t->bits_per_word;
return 0;
}
static void ep93xx_do_write(struct ep93xx_spi *espi, struct spi_transfer *t)
{
if (bits_per_word(espi) > 8) {
if (t->bits_per_word > 8) {
u16 tx_val = 0;
if (t->tx_buf)
......@@ -460,7 +359,7 @@ static void ep93xx_do_write(struct ep93xx_spi *espi, struct spi_transfer *t)
static void ep93xx_do_read(struct ep93xx_spi *espi, struct spi_transfer *t)
{
if (bits_per_word(espi) > 8) {
if (t->bits_per_word > 8) {
u16 rx_val;
rx_val = ep93xx_spi_read_u16(espi, SSPDR);
......@@ -546,7 +445,7 @@ ep93xx_spi_dma_prepare(struct ep93xx_spi *espi, enum dma_transfer_direction dir)
size_t len = t->len;
int i, ret, nents;
if (bits_per_word(espi) > 8)
if (t->bits_per_word > 8)
buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
else
buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
......@@ -610,7 +509,7 @@ ep93xx_spi_dma_prepare(struct ep93xx_spi *espi, enum dma_transfer_direction dir)
}
if (WARN_ON(len)) {
dev_warn(&espi->pdev->dev, "len = %d expected 0!", len);
dev_warn(&espi->pdev->dev, "len = %zu expected 0!", len);
return ERR_PTR(-EINVAL);
}
......@@ -708,38 +607,17 @@ static void ep93xx_spi_process_transfer(struct ep93xx_spi *espi,
struct spi_transfer *t)
{
struct ep93xx_spi_chip *chip = spi_get_ctldata(msg->spi);
int err;
msg->state = t;
/*
* Handle any transfer specific settings if needed. We use
* temporary chip settings here and restore original later when
* the transfer is finished.
*/
if (t->speed_hz || t->bits_per_word) {
struct ep93xx_spi_chip tmp_chip = *chip;
if (t->speed_hz) {
int err;
err = ep93xx_spi_calc_divisors(espi, &tmp_chip,
t->speed_hz);
err = ep93xx_spi_chip_setup(espi, chip, t->speed_hz, t->bits_per_word);
if (err) {
dev_err(&espi->pdev->dev,
"failed to adjust speed\n");
"failed to setup chip for transfer\n");
msg->status = err;
return;
}
}
if (t->bits_per_word)
tmp_chip.dss = bits_per_word_to_dss(t->bits_per_word);
/*
* Set up temporary new hw settings for this transfer.
*/
ep93xx_spi_chip_setup(espi, &tmp_chip);
}
espi->rx = 0;
espi->tx = 0;
......@@ -783,9 +661,6 @@ static void ep93xx_spi_process_transfer(struct ep93xx_spi *espi,
ep93xx_spi_cs_control(msg->spi, true);
}
}
if (t->speed_hz || t->bits_per_word)
ep93xx_spi_chip_setup(espi, chip);
}
/*
......@@ -838,10 +713,8 @@ static void ep93xx_spi_process_message(struct ep93xx_spi *espi,
espi->fifo_level = 0;
/*
* Update SPI controller registers according to spi device and assert
* the chipselect.
* Assert the chipselect.
*/
ep93xx_spi_chip_setup(espi, spi_get_ctldata(msg->spi));
ep93xx_spi_cs_control(msg->spi, true);
list_for_each_entry(t, &msg->transfers, transfer_list) {
......@@ -858,50 +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);
espi->current_msg = msg;
spin_unlock_irq(&espi->lock);
ep93xx_spi_process_message(espi, msg);
msg->state = NULL;
msg->status = 0;
msg->actual_length = 0;
/*
* Update the current message and re-schedule ourselves if there are
* more messages in the queue.
*/
spin_lock_irq(&espi->lock);
espi->current_msg = msg;
ep93xx_spi_process_message(espi, msg);
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)
......@@ -1024,14 +876,24 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
info = pdev->dev.platform_data;
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "failed to get irq resources\n");
return -EBUSY;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "unable to get iomem resource\n");
return -ENODEV;
}
master = spi_alloc_master(&pdev->dev, sizeof(*espi));
if (!master) {
dev_err(&pdev->dev, "failed to allocate spi master\n");
if (!master)
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;
......@@ -1042,14 +904,13 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
espi = spi_master_get_devdata(master);
espi->clk = clk_get(&pdev->dev, NULL);
espi->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(espi->clk)) {
dev_err(&pdev->dev, "unable to get spi clock\n");
error = PTR_ERR(espi->clk);
goto fail_release_master;
}
spin_lock_init(&espi->lock);
init_completion(&espi->wait);
/*
......@@ -1060,55 +921,31 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
espi->min_rate = clk_get_rate(espi->clk) / (254 * 256);
espi->pdev = pdev;
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
error = -EBUSY;
dev_err(&pdev->dev, "failed to get irq resources\n");
goto fail_put_clock;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "unable to get iomem resource\n");
error = -ENODEV;
goto fail_put_clock;
}
espi->sspdr_phys = res->start + SSPDR;
espi->regs_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(espi->regs_base)) {
error = PTR_ERR(espi->regs_base);
goto fail_put_clock;
goto fail_release_master;
}
error = devm_request_irq(&pdev->dev, irq, ep93xx_spi_interrupt,
0, "ep93xx-spi", espi);
if (error) {
dev_err(&pdev->dev, "failed to request irq\n");
goto fail_put_clock;
goto fail_release_master;
}
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",
......@@ -1116,12 +953,8 @@ 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_put_clock:
clk_put(espi->clk);
fail_release_master:
spi_master_put(master);
......@@ -1133,31 +966,7 @@ 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);
clk_put(espi->clk);
spi_unregister_master(master);
return 0;
......
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