diff options
Diffstat (limited to 'drivers/spi/spi_stmp.c')
-rw-r--r-- | drivers/spi/spi_stmp.c | 696 |
1 files changed, 696 insertions, 0 deletions
diff --git a/drivers/spi/spi_stmp.c b/drivers/spi/spi_stmp.c new file mode 100644 index 000000000000..5862ea8269d0 --- /dev/null +++ b/drivers/spi/spi_stmp.c @@ -0,0 +1,696 @@ +/* + * Freescale STMP378X SPI master driver + * + * Author: dmitry pervushin <dimka@embeddedalley.com> + * + * Copyright 2008-2009 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/errno.h> +#include <asm/dma.h> + +#include <mach/stmp3xxx.h> +#include <mach/platform.h> +#include <mach/regs-ssp.h> +#include <mach/regs-apbh.h> +#include "spi_stmp.h" + +/* 0 means DMA modei(recommended, default), !0 - PIO mode */ +static int pio /* = 0 */; +static int debug; + +/** + * stmp_spi_init_hw + * + * Initialize the SSP port + */ +static int stmp_spi_init_hw(struct stmp_spi *ss) +{ + int err; + + err = stmp37xx_spi_pins_request((char *)dev_name(ss->master_dev), ss->id); + 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((void *)ss->regs, 0); + stmp3xxx_dma_reset_channel(ss->dma); + + return 0; + +out_free_pins: + stmp37xx_spi_pins_release((char *)dev_name(ss->master_dev), ss->id); +out: + return err; +} + +static void stmp_spi_release_hw(struct stmp_spi *ss) +{ + if (ss->clk && !IS_ERR(ss->clk)) { + clk_disable(ss->clk); + clk_put(ss->clk); + } + stmp37xx_spi_pins_release((char *)dev_name(ss->master_dev), ss->id); +} + +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; + + ss = spi_master_get_devdata(spi->master); + + 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; + + __raw_writel(BF(ss->divider, SSP_TIMING_CLOCK_DIVIDE) | + BF(rate - 1, SSP_TIMING_CLOCK_RATE), ss->regs + HW_SSP_TIMING); + + __raw_writel(BF(BV_SSP_CTRL1_SSP_MODE__SPI, SSP_CTRL1_SSP_MODE) | + BF(BV_SSP_CTRL1_WORD_LENGTH__EIGHT_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); + + __raw_writel(0x00, ss->regs + HW_SSP_CMD0_SET); + + return 0; +} + + +static void stmp_spi_cleanup(struct spi_device *spi) +{ + struct stmp37xx_spi_platform_data *pdata = spi->dev.platform_data; + + if (pdata && pdata->hw_release) + pdata->hw_release(spi); +} + +/* the spi->mode bits understood by this driver: */ +#define MODEBITS (SPI_CPOL | SPI_CPHA) +static int stmp_spi_setup(struct spi_device *spi) +{ + struct stmp37xx_spi_platform_data *pdata; + struct stmp_spi *ss; + int err = 0; + + ss = spi_master_get_devdata(spi->master); + + if (!spi->bits_per_word) + spi->bits_per_word = 8; + + if (spi->mode & ~MODEBITS) { + dev_err(&spi->dev, "%s: unsupported mode bits %x\n", + __func__, spi->mode & ~MODEBITS); + err = -EINVAL; + goto out; + } + + dev_dbg(&spi->dev, "%s, mode %d, %u bits/w\n", + __func__, spi->mode & MODEBITS, spi->bits_per_word); + + pdata = spi->dev.platform_data; + + if (pdata && pdata->hw_init) { + err = pdata->hw_init(spi); + if (err) + goto out; + } + + err = stmp_spi_setup_transfer(spi, NULL); + if (err) + goto out2; + return 0; + +out2: + if (pdata) + pdata->hw_release(spi); +out: + dev_err(&spi->dev, "Failed to setup transfer, error = %d\n", err); + return err; +} + +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, int write) +{ + u32 c0 = 0; + dma_addr_t spi_buf_dma = dma_buf; + int count, 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); + count = 10000; + while ((__raw_readl(ss->regs + HW_SSP_CTRL0) & BM_SSP_CTRL0_RUN) && count--) + continue; + if (count <= 0) { + printk(KERN_ERR"%c: timeout on line %s:%d\n", + write ? 'W':'C', __func__, __LINE__); + 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) +{ + __raw_writel(BM_SSP_CTRL0_LOCK_CS, ss->regs + HW_SSP_CTRL0_SET); + __raw_writel(BM_SSP_CTRL0_IGNORE_CRC, ss->regs + HW_SSP_CTRL0_CLR); +} + +static inline void stmp_spi_disable(struct stmp_spi *ss) +{ + __raw_writel(BM_SSP_CTRL0_LOCK_CS, ss->regs + HW_SSP_CTRL0_CLR); + __raw_writel(BM_SSP_CTRL0_IGNORE_CRC, ss->regs + HW_SSP_CTRL0_SET); +} + +static int stmp_spi_txrx_pio(struct stmp_spi *ss, int cs, + unsigned char *buf, int len, + int *first, int *last, int write) +{ + int count; + + if (*first) { + stmp_spi_enable(ss); + *first = 0; + } + + __raw_writel(stmp_spi_cs(cs), ss->regs + HW_SSP_CTRL0_SET); + + while (len--) { + if (*last && len == 0) { + stmp_spi_disable(ss); + *last = 0; + } + __raw_writel(BM_SSP_CTRL0_XFER_COUNT, + ss->regs + HW_SSP_CTRL0_CLR); + __raw_writel(1, ss->regs + HW_SSP_CTRL0_SET); /* byte-by-byte */ + + if (write) + __raw_writel(BM_SSP_CTRL0_READ, + ss->regs + HW_SSP_CTRL0_CLR); + else + __raw_writel(BM_SSP_CTRL0_READ, + ss->regs + HW_SSP_CTRL0_SET); + + /* Run! */ + __raw_writel(BM_SSP_CTRL0_RUN, ss->regs + HW_SSP_CTRL0_SET); + count = 10000; + while (((__raw_readl(ss->regs + HW_SSP_CTRL0) & BM_SSP_CTRL0_RUN) == 0) && count--) + continue; + if (count <= 0) { + printk(KERN_ERR"%c: timeout on line %s:%d\n", + write ? 'W':'C', __func__, __LINE__); + break; + } + + if (write) + __raw_writel(*buf, ss->regs + HW_SSP_DATA); + + /* Set TRANSFER */ + __raw_writel(BM_SSP_CTRL0_DATA_XFER, + ss->regs + HW_SSP_CTRL0_SET); + + if (!write) { + count = 10000; + while (count-- && + (__raw_readl(ss->regs + HW_SSP_STATUS) & + BM_SSP_STATUS_FIFO_EMPTY)) + continue; + if (count <= 0) { + printk(KERN_ERR"%c: timeout on line %s:%d\n", + write ? 'W':'C', __func__, __LINE__); + break; + } + *buf = (__raw_readl(ss->regs + HW_SSP_DATA) & 0xFF); + } + + count = 10000; + while ((__raw_readl(ss->regs + HW_SSP_CTRL0) & BM_SSP_CTRL0_RUN) && count--) + continue; + if (count <= 0) { + printk(KERN_ERR"%c: timeout on line %s:%d\n", + write ? 'W':'C', __func__, __LINE__); + 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) +{ + int first, last; + struct spi_transfer *t, *tmp_t; + int status = 0; + int cs; + + first = last = 0; + + cs = m->spi->chip_select; + + list_for_each_entry_safe(t, tmp_t, &m->transfers, transfer_list) { + + stmp_spi_setup_transfer(m->spi, t); + + if (&t->transfer_list == m->transfers.next) + first = !0; + if (&t->transfer_list == m->transfers.prev) + last = !0; + if (t->rx_buf && t->tx_buf) { + pr_debug("%s: cannot send and receive simultaneously\n", + __func__); + return -EINVAL; + } + + /* + REVISIT: + here driver completely ignores setting of t->cs_change + */ + if (t->tx_buf) { + status = pio ? + stmp_spi_txrx_pio(ss, cs, (void *)t->tx_buf, + t->len, &first, &last, 1) : + stmp_spi_txrx_dma(ss, cs, (void *)t->tx_buf, + t->tx_dma, t->len, &first, &last, 1); + if (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); + } + } + if (t->rx_buf) { + status = pio ? + stmp_spi_txrx_pio(ss, cs, t->rx_buf, + t->len, &first, &last, 0): + stmp_spi_txrx_dma(ss, cs, t->rx_buf, + t->rx_dma, t->len, &first, &last, 0); + if (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); + } + } + + if (status) + break; + + first = last = 0; + + } + return status; +} + +/** + * stmp_spi_handle + * + * The workhorse of the driver - it handles messages from the list + * + **/ +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; + + BUG_ON(w == NULL); + + 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); + if (m->complete) + m->complete(m->context); + + spin_lock_irqsave(&ss->lock, flags); + } + spin_unlock_irqrestore(&ss->lock, flags); + + return; +} + +/** + * stmp_spi_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 = __raw_readl(ss->regs + HW_SSP_CTRL1); + st = __raw_readl(ss->regs + HW_SSP_STATUS); + printk(KERN_ERR"IRQ - ERROR!, status = 0x%08X, c1 = 0x%08X\n", st, c1); + __raw_writel(c1 & 0xCCCC0000, ss->regs + HW_SSP_CTRL1_CLR); + + return IRQ_HANDLED; +} + +static int __init stmp_spi_probe(struct platform_device *dev) +{ + int err = 0; + struct spi_master *master; + struct stmp_spi *ss; + struct resource *r; + u32 mem; + + /* Get resources(memory, IRQ) associated with the device */ + master = spi_alloc_master(&dev->dev, sizeof(struct stmp_spi)); + + if (master == NULL) { + err = -ENOMEM; + goto out0; + } + + platform_set_drvdata(dev, master); + + r = platform_get_resource(dev, IORESOURCE_MEM, 0); + if (r == NULL) { + err = -ENODEV; + goto out_put_master; + } + + ss = spi_master_get_devdata(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)); + master->transfer = stmp_spi_transfer; + master->setup = stmp_spi_setup; + master->cleanup = stmp_spi_cleanup; + + if (!request_mem_region(r->start, + r->end - r->start + 1, dev_name(&dev->dev))) { + err = -ENXIO; + goto out_put_master; + } + mem = r->start; + + ss->regs = r->start - STMP3XXX_REGS_PHBASE + STMP3XXX_REGS_BASE; + + ss->irq = platform_get_irq(dev, 0); + if (ss->irq < 0) { + err = -ENXIO; + 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, (char *)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; + } + + clk_set_rate(ss->clk, 120000); + 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; + } + err = request_irq(IRQ_SSP_ERROR, 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 0x%08X mapped to 0x%08X, irq=%d, bus %d, %s\n", + mem, (u32)ss->regs, ss->irq, + master->bus_num, pio ? "PIO" : "DMA"); + return 0; + +out_free_irq_2: + free_irq(IRQ_SSP_ERROR, 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: + 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); + if (ss == NULL) + goto out1; + free_irq(ss->irq, ss); + if (ss->workqueue) + destroy_workqueue(ss->workqueue); + stmp3xxx_dma_free_command(ss->dma, &ss->d); + stmp3xxx_dma_release(ss->dma); + stmp_spi_release_hw(ss); + platform_set_drvdata(dev, 0); +out1: + spi_master_put(master); +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 = __raw_readl(ss->regs + HW_SSP_TIMING); + 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); + __raw_writel(BM_SSP_CTRL0_SFTRST | BM_SSP_CTRL0_CLKGATE, + ss->regs + HW_SSP_CTRL0_CLR); + __raw_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(debug, int, S_IRUGO); +MODULE_AUTHOR("dmitry pervushin <dimka@embeddedalley.com>"); +MODULE_DESCRIPTION("STMP37xx SPI/SSP"); +MODULE_LICENSE("GPL"); |