diff options
Diffstat (limited to 'drivers/spi/spi_stmp.c')
| -rw-r--r-- | drivers/spi/spi_stmp.c | 679 |
1 files changed, 679 insertions, 0 deletions
diff --git a/drivers/spi/spi_stmp.c b/drivers/spi/spi_stmp.c new file mode 100644 index 0000000..d871dc2 --- /dev/null +++ b/drivers/spi/spi_stmp.c @@ -0,0 +1,679 @@ +/* + * Freescale STMP378X SPI master driver + * + * Author: dmitry pervushin <dimka@embeddedalley.com> + * + * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved. + * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved. + */ + +/* + * The code contained herein is licensed under the GNU General Public + * License. You may obtain a copy of the GNU General Public License + * Version 2 or later at the following locations: + * + * http://www.opensource.org/licenses/gpl-license.html + * http://www.gnu.org/copyleft/gpl.html + */ +#include <linux/module.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/platform_device.h> +#include <linux/spi/spi.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/dma-mapping.h> +#include <linux/delay.h> + +#include <mach/platform.h> +#include <mach/stmp3xxx.h> +#include <mach/dma.h> +#include <mach/regs-ssp.h> +#include <mach/regs-apbh.h> + + +/* 0 means DMA mode(recommended, default), !0 - PIO mode */ +static int pio; +static int clock; + +/* default timeout for busy waits is 2 seconds */ +#define STMP_SPI_TIMEOUT (2 * HZ) + +struct stmp_spi { + int id; + + void * __iomem regs; /* vaddr of the control registers */ + + int irq, err_irq; + u32 dma; + struct stmp3xxx_dma_descriptor d; + + u32 speed_khz; + u32 saved_timings; + u32 divider; + + struct clk *clk; + struct device *master_dev; + + struct work_struct work; + struct workqueue_struct *workqueue; + + /* lock protects queue access */ + spinlock_t lock; + struct list_head queue; + + struct completion done; +}; + +#define busy_wait(cond) \ + ({ \ + unsigned long end_jiffies = jiffies + STMP_SPI_TIMEOUT; \ + bool succeeded = false; \ + do { \ + if (cond) { \ + succeeded = true; \ + break; \ + } \ + cpu_relax(); \ + } while (time_before(end_jiffies, jiffies)); \ + succeeded; \ + }) + +/** + * stmp_spi_init_hw + * Initialize the SSP port + */ +static int stmp_spi_init_hw(struct stmp_spi *ss) +{ + int err = 0; + void *pins = ss->master_dev->platform_data; + + err = stmp3xxx_request_pin_group(pins, dev_name(ss->master_dev)); + if (err) + goto out; + + ss->clk = clk_get(NULL, "ssp"); + if (IS_ERR(ss->clk)) { + err = PTR_ERR(ss->clk); + goto out_free_pins; + } + clk_enable(ss->clk); + + stmp3xxx_reset_block(ss->regs, false); + stmp3xxx_dma_reset_channel(ss->dma); + + return 0; + +out_free_pins: + stmp3xxx_release_pin_group(pins, dev_name(ss->master_dev)); +out: + return err; +} + +static void stmp_spi_release_hw(struct stmp_spi *ss) +{ + void *pins = ss->master_dev->platform_data; + + if (ss->clk && !IS_ERR(ss->clk)) { + clk_disable(ss->clk); + clk_put(ss->clk); + } + stmp3xxx_release_pin_group(pins, dev_name(ss->master_dev)); +} + +static int stmp_spi_setup_transfer(struct spi_device *spi, + struct spi_transfer *t) +{ + u8 bits_per_word; + u32 hz; + struct stmp_spi *ss = spi_master_get_devdata(spi->master); + u16 rate; + + bits_per_word = spi->bits_per_word; + if (t && t->bits_per_word) + bits_per_word = t->bits_per_word; + + /* + * Calculate speed: + * - by default, use maximum speed from ssp clk + * - if device overrides it, use it + * - if transfer specifies other speed, use transfer's one + */ + hz = 1000 * ss->speed_khz / ss->divider; + if (spi->max_speed_hz) + hz = min(hz, spi->max_speed_hz); + if (t && t->speed_hz) + hz = min(hz, t->speed_hz); + + if (hz == 0) { + dev_err(&spi->dev, "Cannot continue with zero clock\n"); + return -EINVAL; + } + + if (bits_per_word != 8) { + dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n", + __func__, bits_per_word); + return -EINVAL; + } + + dev_dbg(&spi->dev, "Requested clk rate = %uHz, max = %uHz/%d = %uHz\n", + hz, ss->speed_khz, ss->divider, + ss->speed_khz * 1000 / ss->divider); + + if (ss->speed_khz * 1000 / ss->divider < hz) { + dev_err(&spi->dev, "%s, unsupported clock rate %uHz\n", + __func__, hz); + return -EINVAL; + } + + rate = 1000 * ss->speed_khz/ss->divider/hz; + + writel(BF(ss->divider, SSP_TIMING_CLOCK_DIVIDE) | + BF(rate - 1, SSP_TIMING_CLOCK_RATE), + HW_SSP_TIMING + ss->regs); + + writel(BF(1 /* mode SPI */, SSP_CTRL1_SSP_MODE) | + BF(4 /* 8 bits */, SSP_CTRL1_WORD_LENGTH) | + ((spi->mode & SPI_CPOL) ? BM_SSP_CTRL1_POLARITY : 0) | + ((spi->mode & SPI_CPHA) ? BM_SSP_CTRL1_PHASE : 0) | + (pio ? 0 : BM_SSP_CTRL1_DMA_ENABLE), + ss->regs + HW_SSP_CTRL1); + + return 0; +} + +static int stmp_spi_setup(struct spi_device *spi) +{ + /* spi_setup() does basic checks, + * stmp_spi_setup_transfer() does more later + */ + if (spi->bits_per_word != 8) { + dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n", + __func__, spi->bits_per_word); + return -EINVAL; + } + return 0; +} + +static inline u32 stmp_spi_cs(unsigned cs) +{ + return ((cs & 1) ? BM_SSP_CTRL0_WAIT_FOR_CMD : 0) | + ((cs & 2) ? BM_SSP_CTRL0_WAIT_FOR_IRQ : 0); +} + +static int stmp_spi_txrx_dma(struct stmp_spi *ss, int cs, + unsigned char *buf, dma_addr_t dma_buf, int len, + int first, int last, bool write) +{ + u32 c0 = 0; + dma_addr_t spi_buf_dma = dma_buf; + int status = 0; + enum dma_data_direction dir = write ? DMA_TO_DEVICE : DMA_FROM_DEVICE; + + c0 |= (first ? BM_SSP_CTRL0_LOCK_CS : 0); + c0 |= (last ? BM_SSP_CTRL0_IGNORE_CRC : 0); + c0 |= (write ? 0 : BM_SSP_CTRL0_READ); + c0 |= BM_SSP_CTRL0_DATA_XFER; + + c0 |= stmp_spi_cs(cs); + + c0 |= BF(len, SSP_CTRL0_XFER_COUNT); + + if (!dma_buf) + spi_buf_dma = dma_map_single(ss->master_dev, buf, len, dir); + + ss->d.command->cmd = + BF(len, APBH_CHn_CMD_XFER_COUNT) | + BF(1, APBH_CHn_CMD_CMDWORDS) | + BM_APBH_CHn_CMD_WAIT4ENDCMD | + BM_APBH_CHn_CMD_IRQONCMPLT | + BF(write ? BV_APBH_CHn_CMD_COMMAND__DMA_READ : + BV_APBH_CHn_CMD_COMMAND__DMA_WRITE, + APBH_CHn_CMD_COMMAND); + ss->d.command->pio_words[0] = c0; + ss->d.command->buf_ptr = spi_buf_dma; + + stmp3xxx_dma_reset_channel(ss->dma); + stmp3xxx_dma_clear_interrupt(ss->dma); + stmp3xxx_dma_enable_interrupt(ss->dma); + init_completion(&ss->done); + stmp3xxx_dma_go(ss->dma, &ss->d, 1); + wait_for_completion(&ss->done); + + if (!busy_wait(readl(ss->regs + HW_SSP_CTRL0) & BM_SSP_CTRL0_RUN)) + status = ETIMEDOUT; + + if (!dma_buf) + dma_unmap_single(ss->master_dev, spi_buf_dma, len, dir); + + return status; +} + +static inline void stmp_spi_enable(struct stmp_spi *ss) +{ + stmp3xxx_setl(BM_SSP_CTRL0_LOCK_CS, ss->regs + HW_SSP_CTRL0); + stmp3xxx_clearl(BM_SSP_CTRL0_IGNORE_CRC, ss->regs + HW_SSP_CTRL0); +} + +static inline void stmp_spi_disable(struct stmp_spi *ss) +{ + stmp3xxx_clearl(BM_SSP_CTRL0_LOCK_CS, ss->regs + HW_SSP_CTRL0); + stmp3xxx_setl(BM_SSP_CTRL0_IGNORE_CRC, ss->regs + HW_SSP_CTRL0); +} + +static int stmp_spi_txrx_pio(struct stmp_spi *ss, int cs, + unsigned char *buf, int len, + bool first, bool last, bool write) +{ + if (first) + stmp_spi_enable(ss); + + stmp3xxx_setl(stmp_spi_cs(cs), ss->regs + HW_SSP_CTRL0); + + while (len--) { + if (last && len <= 0) + stmp_spi_disable(ss); + + stmp3xxx_clearl(BM_SSP_CTRL0_XFER_COUNT, + ss->regs + HW_SSP_CTRL0); + stmp3xxx_setl(1, ss->regs + HW_SSP_CTRL0); + + if (write) + stmp3xxx_clearl(BM_SSP_CTRL0_READ, + ss->regs + HW_SSP_CTRL0); + else + stmp3xxx_setl(BM_SSP_CTRL0_READ, + ss->regs + HW_SSP_CTRL0); + + /* Run! */ + stmp3xxx_setl(BM_SSP_CTRL0_RUN, ss->regs + HW_SSP_CTRL0); + + if (!busy_wait(readl(ss->regs + HW_SSP_CTRL0) & + BM_SSP_CTRL0_RUN)) + break; + + if (write) + writel(*buf, ss->regs + HW_SSP_DATA); + + /* Set TRANSFER */ + stmp3xxx_setl(BM_SSP_CTRL0_DATA_XFER, ss->regs + HW_SSP_CTRL0); + + if (!write) { + if (busy_wait((readl(ss->regs + HW_SSP_STATUS) & + BM_SSP_STATUS_FIFO_EMPTY))) + break; + *buf = readl(ss->regs + HW_SSP_DATA) & 0xFF; + } + + if (!busy_wait(readl(ss->regs + HW_SSP_CTRL0) & + BM_SSP_CTRL0_RUN)) + break; + + /* advance to the next byte */ + buf++; + } + + return len < 0 ? 0 : -ETIMEDOUT; +} + +static int stmp_spi_handle_message(struct stmp_spi *ss, struct spi_message *m) +{ + bool first, last; + struct spi_transfer *t, *tmp_t; + int status = 0; + int cs; + + cs = m->spi->chip_select; + + list_for_each_entry_safe(t, tmp_t, &m->transfers, transfer_list) { + + first = (&t->transfer_list == m->transfers.next); + last = (&t->transfer_list == m->transfers.prev); + + if (first || t->speed_hz || t->bits_per_word) + stmp_spi_setup_transfer(m->spi, t); + + /* reject "not last" transfers which request to change cs */ + if (t->cs_change && !last) { + dev_err(&m->spi->dev, + "Message with t->cs_change has been skipped\n"); + continue; + } + + if (t->tx_buf) { + status = pio ? + stmp_spi_txrx_pio(ss, cs, (void *)t->tx_buf, + t->len, first, last, true) : + stmp_spi_txrx_dma(ss, cs, (void *)t->tx_buf, + t->tx_dma, t->len, first, last, true); +#ifdef DEBUG + if (t->len < 0x10) + print_hex_dump_bytes("Tx ", + DUMP_PREFIX_OFFSET, + t->tx_buf, t->len); + else + pr_debug("Tx: %d bytes\n", t->len); +#endif + } + if (t->rx_buf) { + status = pio ? + stmp_spi_txrx_pio(ss, cs, t->rx_buf, + t->len, first, last, false) : + stmp_spi_txrx_dma(ss, cs, t->rx_buf, + t->rx_dma, t->len, first, last, false); +#ifdef DEBUG + if (t->len < 0x10) + print_hex_dump_bytes("Rx ", + DUMP_PREFIX_OFFSET, + t->rx_buf, t->len); + else + pr_debug("Rx: %d bytes\n", t->len); +#endif + } + + if (t->delay_usecs) + udelay(t->delay_usecs); + + if (status) + break; + + } + return status; +} + +/** + * stmp_spi_handle - handle messages from the queue + */ +static void stmp_spi_handle(struct work_struct *w) +{ + struct stmp_spi *ss = container_of(w, struct stmp_spi, work); + unsigned long flags; + struct spi_message *m; + + spin_lock_irqsave(&ss->lock, flags); + while (!list_empty(&ss->queue)) { + m = list_entry(ss->queue.next, struct spi_message, queue); + list_del_init(&m->queue); + spin_unlock_irqrestore(&ss->lock, flags); + + m->status = stmp_spi_handle_message(ss, m); + m->complete(m->context); + + spin_lock_irqsave(&ss->lock, flags); + } + spin_unlock_irqrestore(&ss->lock, flags); + + return; +} + +/** + * stmp_spi_transfer - perform message transfer. + * Called indirectly from spi_async, queues all the messages to + * spi_handle_message. + * @spi: spi device + * @m: message to be queued + */ +static int stmp_spi_transfer(struct spi_device *spi, struct spi_message *m) +{ + struct stmp_spi *ss = spi_master_get_devdata(spi->master); + unsigned long flags; + + m->status = -EINPROGRESS; + spin_lock_irqsave(&ss->lock, flags); + list_add_tail(&m->queue, &ss->queue); + queue_work(ss->workqueue, &ss->work); + spin_unlock_irqrestore(&ss->lock, flags); + return 0; +} + +static irqreturn_t stmp_spi_irq(int irq, void *dev_id) +{ + struct stmp_spi *ss = dev_id; + + stmp3xxx_dma_clear_interrupt(ss->dma); + complete(&ss->done); + return IRQ_HANDLED; +} + +static irqreturn_t stmp_spi_irq_err(int irq, void *dev_id) +{ + struct stmp_spi *ss = dev_id; + u32 c1, st; + + c1 = readl(ss->regs + HW_SSP_CTRL1); + st = readl(ss->regs + HW_SSP_STATUS); + dev_err(ss->master_dev, "%s: status = 0x%08X, c1 = 0x%08X\n", + __func__, st, c1); + stmp3xxx_clearl(c1 & 0xCCCC0000, ss->regs + HW_SSP_CTRL1); + + return IRQ_HANDLED; +} + +static int __devinit stmp_spi_probe(struct platform_device *dev) +{ + int err = 0; + struct spi_master *master; + struct stmp_spi *ss; + struct resource *r; + + master = spi_alloc_master(&dev->dev, sizeof(struct stmp_spi)); + if (master == NULL) { + err = -ENOMEM; + goto out0; + } + master->flags = SPI_MASTER_HALF_DUPLEX; + + ss = spi_master_get_devdata(master); + platform_set_drvdata(dev, master); + + /* Get resources(memory, IRQ) associated with the device */ + r = platform_get_resource(dev, IORESOURCE_MEM, 0); + if (r == NULL) { + err = -ENODEV; + goto out_put_master; + } + ss->regs = ioremap(r->start, resource_size(r)); + if (!ss->regs) { + err = -EINVAL; + goto out_put_master; + } + + ss->master_dev = &dev->dev; + ss->id = dev->id; + + INIT_WORK(&ss->work, stmp_spi_handle); + INIT_LIST_HEAD(&ss->queue); + spin_lock_init(&ss->lock); + + ss->workqueue = create_singlethread_workqueue(dev_name(&dev->dev)); + if (!ss->workqueue) { + err = -ENXIO; + goto out_put_master; + } + master->transfer = stmp_spi_transfer; + master->setup = stmp_spi_setup; + + /* the spi->mode bits understood by this driver: */ + master->mode_bits = SPI_CPOL | SPI_CPHA; + + ss->irq = platform_get_irq(dev, 0); + if (ss->irq < 0) { + err = ss->irq; + goto out_put_master; + } + ss->err_irq = platform_get_irq(dev, 1); + if (ss->err_irq < 0) { + err = ss->err_irq; + goto out_put_master; + } + + r = platform_get_resource(dev, IORESOURCE_DMA, 0); + if (r == NULL) { + err = -ENODEV; + goto out_put_master; + } + + ss->dma = r->start; + err = stmp3xxx_dma_request(ss->dma, &dev->dev, dev_name(&dev->dev)); + if (err) + goto out_put_master; + + err = stmp3xxx_dma_allocate_command(ss->dma, &ss->d); + if (err) + goto out_free_dma; + + master->bus_num = dev->id; + master->num_chipselect = 1; + + /* SPI controller initializations */ + err = stmp_spi_init_hw(ss); + if (err) { + dev_dbg(&dev->dev, "cannot initialize hardware\n"); + goto out_free_dma_desc; + } + + if (clock) { + dev_info(&dev->dev, "clock rate forced to %d\n", clock); + clk_set_rate(ss->clk, clock); + } + ss->speed_khz = clk_get_rate(ss->clk); + ss->divider = 2; + dev_info(&dev->dev, "max possible speed %d = %ld/%d kHz\n", + ss->speed_khz, clk_get_rate(ss->clk), ss->divider); + + /* Register for SPI interrupt */ + err = request_irq(ss->irq, stmp_spi_irq, 0, + dev_name(&dev->dev), ss); + if (err) { + dev_dbg(&dev->dev, "request_irq failed, %d\n", err); + goto out_release_hw; + } + + /* ..and shared interrupt for all SSP controllers */ + err = request_irq(ss->err_irq, stmp_spi_irq_err, IRQF_SHARED, + dev_name(&dev->dev), ss); + if (err) { + dev_dbg(&dev->dev, "request_irq(error) failed, %d\n", err); + goto out_free_irq; + } + + err = spi_register_master(master); + if (err) { + dev_dbg(&dev->dev, "cannot register spi master, %d\n", err); + goto out_free_irq_2; + } + dev_info(&dev->dev, "at (mapped) 0x%08X, irq=%d, bus %d, %s mode\n", + (u32)ss->regs, ss->irq, master->bus_num, + pio ? "PIO" : "DMA"); + return 0; + +out_free_irq_2: + free_irq(ss->err_irq, ss); +out_free_irq: + free_irq(ss->irq, ss); +out_free_dma_desc: + stmp3xxx_dma_free_command(ss->dma, &ss->d); +out_free_dma: + stmp3xxx_dma_release(ss->dma); +out_release_hw: + stmp_spi_release_hw(ss); +out_put_master: + if (ss->workqueue) + destroy_workqueue(ss->workqueue); + if (ss->regs) + iounmap(ss->regs); + platform_set_drvdata(dev, NULL); + spi_master_put(master); +out0: + return err; +} + +static int __devexit stmp_spi_remove(struct platform_device *dev) +{ + struct stmp_spi *ss; + struct spi_master *master; + + master = platform_get_drvdata(dev); + if (master == NULL) + goto out0; + ss = spi_master_get_devdata(master); + + spi_unregister_master(master); + + free_irq(ss->err_irq, ss); + free_irq(ss->irq, ss); + stmp3xxx_dma_free_command(ss->dma, &ss->d); + stmp3xxx_dma_release(ss->dma); + stmp_spi_release_hw(ss); + destroy_workqueue(ss->workqueue); + iounmap(ss->regs); + spi_master_put(master); + platform_set_drvdata(dev, NULL); +out0: + return 0; +} + +#ifdef CONFIG_PM +static int stmp_spi_suspend(struct platform_device *pdev, pm_message_t pmsg) +{ + struct stmp_spi *ss; + struct spi_master *master; + + master = platform_get_drvdata(pdev); + ss = spi_master_get_devdata(master); + + ss->saved_timings = readl(HW_SSP_TIMING + ss->regs); + clk_disable(ss->clk); + + return 0; +} + +static int stmp_spi_resume(struct platform_device *pdev) +{ + struct stmp_spi *ss; + struct spi_master *master; + + master = platform_get_drvdata(pdev); + ss = spi_master_get_devdata(master); + + clk_enable(ss->clk); + stmp3xxx_reset_block(ss->regs, false); + writel(ss->saved_timings, ss->regs + HW_SSP_TIMING); + + return 0; +} + +#else +#define stmp_spi_suspend NULL +#define stmp_spi_resume NULL +#endif + +static struct platform_driver stmp_spi_driver = { + .probe = stmp_spi_probe, + .remove = __devexit_p(stmp_spi_remove), + .driver = { + .name = "stmp3xxx_ssp", + .owner = THIS_MODULE, + }, + .suspend = stmp_spi_suspend, + .resume = stmp_spi_resume, +}; + +static int __init stmp_spi_init(void) +{ + return platform_driver_register(&stmp_spi_driver); +} + +static void __exit stmp_spi_exit(void) +{ + platform_driver_unregister(&stmp_spi_driver); +} + +module_init(stmp_spi_init); +module_exit(stmp_spi_exit); +module_param(pio, int, S_IRUGO); +module_param(clock, int, S_IRUGO); +MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com>"); +MODULE_DESCRIPTION("STMP3xxx SPI/SSP driver"); +MODULE_LICENSE("GPL"); |