diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/spi/Makefile | 1 | ||||
| -rw-r--r-- | drivers/spi/spi-mxs.c | 674 |
3 files changed, 682 insertions, 0 deletions
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index 5f84b5563c2d..6992b30b4e42 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -364,6 +364,13 @@ config SPI_STMP3XXX help SPI driver for Freescale STMP37xx/378x SoC SSP interface +config SPI_MXS + tristate "Freescale MXS SPI controller" + depends on ARCH_MXS + select STMP_DEVICE + help + SPI driver for Freescale MXS devices. + config SPI_TEGRA tristate "Nvidia Tegra SPI controller" depends on ARCH_TEGRA && (TEGRA_SYSTEM_DMA || TEGRA20_APB_DMA) diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index 3920dcf4c740..3b72d87b3309 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -36,6 +36,7 @@ obj-$(CONFIG_SPI_LM70_LLP) += spi-lm70llp.o obj-$(CONFIG_SPI_MPC512x_PSC) += spi-mpc512x-psc.o obj-$(CONFIG_SPI_MPC52xx_PSC) += spi-mpc52xx-psc.o obj-$(CONFIG_SPI_MPC52xx) += spi-mpc52xx.o +obj-$(CONFIG_SPI_MXS) += spi-mxs.o obj-$(CONFIG_SPI_NUC900) += spi-nuc900.o obj-$(CONFIG_SPI_OC_TINY) += spi-oc-tiny.o obj-$(CONFIG_SPI_OMAP_UWIRE) += spi-omap-uwire.o diff --git a/drivers/spi/spi-mxs.c b/drivers/spi/spi-mxs.c new file mode 100644 index 000000000000..edf1360ab09e --- /dev/null +++ b/drivers/spi/spi-mxs.c @@ -0,0 +1,674 @@ +/* + * Freescale MXS SPI master driver + * + * Copyright 2012 DENX Software Engineering, GmbH. + * Copyright 2012 Freescale Semiconductor, Inc. + * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved. + * + * Rework and transition to new API by: + * Marek Vasut <marex@denx.de> + * + * Based on previous attempt by: + * Fabio Estevam <fabio.estevam@freescale.com> + * + * Based on code from U-Boot bootloader by: + * Marek Vasut <marex@denx.de> + * + * Based on spi-stmp.c, which is: + * Author: Dmitry Pervushin <dimka@embeddedalley.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/ioport.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/of_gpio.h> +#include <linux/platform_device.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/dma-mapping.h> +#include <linux/dmaengine.h> +#include <linux/highmem.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/completion.h> +#include <linux/gpio.h> +#include <linux/regulator/consumer.h> +#include <linux/module.h> +#include <linux/pinctrl/consumer.h> +#include <linux/stmp_device.h> +#include <linux/spi/spi.h> +#include <linux/spi/mxs-spi.h> + +#define DRIVER_NAME "mxs-spi" + +/* Use 10S timeout for very long transfers, it should suffice. */ +#define SSP_TIMEOUT 10000 + +#define SG_MAXLEN 0xff00 + +struct mxs_spi { + struct mxs_ssp ssp; + struct completion c; +}; + +static int mxs_spi_setup_transfer(struct spi_device *dev, + struct spi_transfer *t) +{ + struct mxs_spi *spi = spi_master_get_devdata(dev->master); + struct mxs_ssp *ssp = &spi->ssp; + uint8_t bits_per_word; + uint32_t hz = 0; + + bits_per_word = dev->bits_per_word; + if (t && t->bits_per_word) + bits_per_word = t->bits_per_word; + + if (bits_per_word != 8) { + dev_err(&dev->dev, "%s, unsupported bits_per_word=%d\n", + __func__, bits_per_word); + return -EINVAL; + } + + hz = dev->max_speed_hz; + if (t && t->speed_hz) + hz = min(hz, t->speed_hz); + if (hz == 0) { + dev_err(&dev->dev, "Cannot continue with zero clock\n"); + return -EINVAL; + } + + mxs_ssp_set_clk_rate(ssp, hz); + + writel(BF_SSP_CTRL1_SSP_MODE(BV_SSP_CTRL1_SSP_MODE__SPI) | + BF_SSP_CTRL1_WORD_LENGTH + (BV_SSP_CTRL1_WORD_LENGTH__EIGHT_BITS) | + ((dev->mode & SPI_CPOL) ? BM_SSP_CTRL1_POLARITY : 0) | + ((dev->mode & SPI_CPHA) ? BM_SSP_CTRL1_PHASE : 0), + ssp->base + HW_SSP_CTRL1(ssp)); + + writel(0x0, ssp->base + HW_SSP_CMD0); + writel(0x0, ssp->base + HW_SSP_CMD1); + + return 0; +} + +static int mxs_spi_setup(struct spi_device *dev) +{ + int err = 0; + + if (!dev->bits_per_word) + dev->bits_per_word = 8; + + if (dev->mode & ~(SPI_CPOL | SPI_CPHA)) + return -EINVAL; + + err = mxs_spi_setup_transfer(dev, NULL); + if (err) { + dev_err(&dev->dev, + "Failed to setup transfer, error = %d\n", err); + } + + return err; +} + +static uint32_t mxs_spi_cs_to_reg(unsigned cs) +{ + uint32_t select = 0; + + /* + * i.MX28 Datasheet: 17.10.1: HW_SSP_CTRL0 + * + * The bits BM_SSP_CTRL0_WAIT_FOR_CMD and BM_SSP_CTRL0_WAIT_FOR_IRQ + * in HW_SSP_CTRL0 register do have multiple usage, please refer to + * the datasheet for further details. In SPI mode, they are used to + * toggle the chip-select lines (nCS pins). + */ + if (cs & 1) + select |= BM_SSP_CTRL0_WAIT_FOR_CMD; + if (cs & 2) + select |= BM_SSP_CTRL0_WAIT_FOR_IRQ; + + return select; +} + +static void mxs_spi_set_cs(struct mxs_spi *spi, unsigned cs) +{ + const uint32_t mask = + BM_SSP_CTRL0_WAIT_FOR_CMD | BM_SSP_CTRL0_WAIT_FOR_IRQ; + uint32_t select; + struct mxs_ssp *ssp = &spi->ssp; + + writel(mask, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR); + select = mxs_spi_cs_to_reg(cs); + writel(select, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); +} + +static inline void mxs_spi_enable(struct mxs_spi *spi) +{ + struct mxs_ssp *ssp = &spi->ssp; + + writel(BM_SSP_CTRL0_LOCK_CS, + ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); + writel(BM_SSP_CTRL0_IGNORE_CRC, + ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR); +} + +static inline void mxs_spi_disable(struct mxs_spi *spi) +{ + struct mxs_ssp *ssp = &spi->ssp; + + writel(BM_SSP_CTRL0_LOCK_CS, + ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR); + writel(BM_SSP_CTRL0_IGNORE_CRC, + ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); +} + +static int mxs_ssp_wait(struct mxs_spi *spi, int offset, int mask, bool set) +{ + const unsigned long timeout = jiffies + msecs_to_jiffies(SSP_TIMEOUT); + struct mxs_ssp *ssp = &spi->ssp; + uint32_t reg; + + do { + reg = readl_relaxed(ssp->base + offset); + + if (!set) + reg = ~reg; + + reg &= mask; + + if (reg == mask) + return 0; + } while (time_before(jiffies, timeout)); + + return -ETIMEDOUT; +} + +static void mxs_ssp_dma_irq_callback(void *param) +{ + struct mxs_spi *spi = param; + complete(&spi->c); +} + +static irqreturn_t mxs_ssp_irq_handler(int irq, void *dev_id) +{ + struct mxs_ssp *ssp = dev_id; + dev_err(ssp->dev, "%s[%i] CTRL1=%08x STATUS=%08x\n", + __func__, __LINE__, + readl(ssp->base + HW_SSP_CTRL1(ssp)), + readl(ssp->base + HW_SSP_STATUS(ssp))); + return IRQ_HANDLED; +} + +static int mxs_spi_txrx_dma(struct mxs_spi *spi, int cs, + unsigned char *buf, int len, + int *first, int *last, int write) +{ + struct mxs_ssp *ssp = &spi->ssp; + struct dma_async_tx_descriptor *desc = NULL; + const bool vmalloced_buf = is_vmalloc_addr(buf); + const int desc_len = vmalloced_buf ? PAGE_SIZE : SG_MAXLEN; + const int sgs = DIV_ROUND_UP(len, desc_len); + int sg_count; + int min, ret; + uint32_t ctrl0; + struct page *vm_page; + void *sg_buf; + struct { + uint32_t pio[4]; + struct scatterlist sg; + } *dma_xfer; + + if (!len) + return -EINVAL; + + dma_xfer = kzalloc(sizeof(*dma_xfer) * sgs, GFP_KERNEL); + if (!dma_xfer) + return -ENOMEM; + + INIT_COMPLETION(spi->c); + + ctrl0 = readl(ssp->base + HW_SSP_CTRL0); + ctrl0 |= BM_SSP_CTRL0_DATA_XFER | mxs_spi_cs_to_reg(cs); + + if (*first) + ctrl0 |= BM_SSP_CTRL0_LOCK_CS; + if (!write) + ctrl0 |= BM_SSP_CTRL0_READ; + + /* Queue the DMA data transfer. */ + for (sg_count = 0; sg_count < sgs; sg_count++) { + min = min(len, desc_len); + + /* Prepare the transfer descriptor. */ + if ((sg_count + 1 == sgs) && *last) + ctrl0 |= BM_SSP_CTRL0_IGNORE_CRC; + + if (ssp->devid == IMX23_SSP) + ctrl0 |= min; + + dma_xfer[sg_count].pio[0] = ctrl0; + dma_xfer[sg_count].pio[3] = min; + + if (vmalloced_buf) { + vm_page = vmalloc_to_page(buf); + if (!vm_page) { + ret = -ENOMEM; + goto err_vmalloc; + } + sg_buf = page_address(vm_page) + + ((size_t)buf & ~PAGE_MASK); + } else { + sg_buf = buf; + } + + sg_init_one(&dma_xfer[sg_count].sg, sg_buf, min); + ret = dma_map_sg(ssp->dev, &dma_xfer[sg_count].sg, 1, + write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); + + len -= min; + buf += min; + + /* Queue the PIO register write transfer. */ + desc = dmaengine_prep_slave_sg(ssp->dmach, + (struct scatterlist *)dma_xfer[sg_count].pio, + (ssp->devid == IMX23_SSP) ? 1 : 4, + DMA_TRANS_NONE, + sg_count ? DMA_PREP_INTERRUPT : 0); + if (!desc) { + dev_err(ssp->dev, + "Failed to get PIO reg. write descriptor.\n"); + ret = -EINVAL; + goto err_mapped; + } + + desc = dmaengine_prep_slave_sg(ssp->dmach, + &dma_xfer[sg_count].sg, 1, + write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + + if (!desc) { + dev_err(ssp->dev, + "Failed to get DMA data write descriptor.\n"); + ret = -EINVAL; + goto err_mapped; + } + } + + /* + * The last descriptor must have this callback, + * to finish the DMA transaction. + */ + desc->callback = mxs_ssp_dma_irq_callback; + desc->callback_param = spi; + + /* Start the transfer. */ + dmaengine_submit(desc); + dma_async_issue_pending(ssp->dmach); + + ret = wait_for_completion_timeout(&spi->c, + msecs_to_jiffies(SSP_TIMEOUT)); + if (!ret) { + dev_err(ssp->dev, "DMA transfer timeout\n"); + ret = -ETIMEDOUT; + goto err_vmalloc; + } + + ret = 0; + +err_vmalloc: + while (--sg_count >= 0) { +err_mapped: + dma_unmap_sg(ssp->dev, &dma_xfer[sg_count].sg, 1, + write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); + } + + kfree(dma_xfer); + + return ret; +} + +static int mxs_spi_txrx_pio(struct mxs_spi *spi, int cs, + unsigned char *buf, int len, + int *first, int *last, int write) +{ + struct mxs_ssp *ssp = &spi->ssp; + + if (*first) + mxs_spi_enable(spi); + + mxs_spi_set_cs(spi, cs); + + while (len--) { + if (*last && len == 0) + mxs_spi_disable(spi); + + if (ssp->devid == IMX23_SSP) { + writel(BM_SSP_CTRL0_XFER_COUNT, + ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR); + writel(1, + ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); + } else { + writel(1, ssp->base + HW_SSP_XFER_SIZE); + } + + if (write) + writel(BM_SSP_CTRL0_READ, + ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR); + else + writel(BM_SSP_CTRL0_READ, + ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); + + writel(BM_SSP_CTRL0_RUN, + ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); + + if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 1)) + return -ETIMEDOUT; + + if (write) + writel(*buf, ssp->base + HW_SSP_DATA(ssp)); + + writel(BM_SSP_CTRL0_DATA_XFER, + ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); + + if (!write) { + if (mxs_ssp_wait(spi, HW_SSP_STATUS(ssp), + BM_SSP_STATUS_FIFO_EMPTY, 0)) + return -ETIMEDOUT; + + *buf = (readl(ssp->base + HW_SSP_DATA(ssp)) & 0xff); + } + + if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 0)) + return -ETIMEDOUT; + + buf++; + } + + if (len <= 0) + return 0; + + return -ETIMEDOUT; +} + +static int mxs_spi_transfer_one(struct spi_master *master, + struct spi_message *m) +{ + struct mxs_spi *spi = spi_master_get_devdata(master); + struct mxs_ssp *ssp = &spi->ssp; + 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) { + + status = mxs_spi_setup_transfer(m->spi, t); + if (status) + break; + + if (&t->transfer_list == m->transfers.next) + first = 1; + if (&t->transfer_list == m->transfers.prev) + last = 1; + if ((t->rx_buf && t->tx_buf) || (t->rx_dma && t->tx_dma)) { + dev_err(ssp->dev, + "Cannot send and receive simultaneously\n"); + status = -EINVAL; + break; + } + + /* + * Small blocks can be transfered via PIO. + * Measured by empiric means: + * + * dd if=/dev/mtdblock0 of=/dev/null bs=1024k count=1 + * + * DMA only: 2.164808 seconds, 473.0KB/s + * Combined: 1.676276 seconds, 610.9KB/s + */ + if (t->len < 32) { + writel(BM_SSP_CTRL1_DMA_ENABLE, + ssp->base + HW_SSP_CTRL1(ssp) + + STMP_OFFSET_REG_CLR); + + if (t->tx_buf) + status = mxs_spi_txrx_pio(spi, cs, + (void *)t->tx_buf, + t->len, &first, &last, 1); + if (t->rx_buf) + status = mxs_spi_txrx_pio(spi, cs, + t->rx_buf, t->len, + &first, &last, 0); + } else { + writel(BM_SSP_CTRL1_DMA_ENABLE, + ssp->base + HW_SSP_CTRL1(ssp) + + STMP_OFFSET_REG_SET); + + if (t->tx_buf) + status = mxs_spi_txrx_dma(spi, cs, + (void *)t->tx_buf, t->len, + &first, &last, 1); + if (t->rx_buf) + status = mxs_spi_txrx_dma(spi, cs, + t->rx_buf, t->len, + &first, &last, 0); + } + + if (status) { + stmp_reset_block(ssp->base); + break; + } + + m->actual_length += t->len; + first = last = 0; + } + + m->status = 0; + spi_finalize_current_message(master); + + return status; +} + +static bool mxs_ssp_dma_filter(struct dma_chan *chan, void *param) +{ + struct mxs_ssp *ssp = param; + + if (!mxs_dma_is_apbh(chan)) + return false; + + if (chan->chan_id != ssp->dma_channel) + return false; + + chan->private = &ssp->dma_data; + + return true; +} + +static const struct of_device_id mxs_spi_dt_ids[] = { + { .compatible = "fsl,imx23-spi", .data = (void *) IMX23_SSP, }, + { .compatible = "fsl,imx28-spi", .data = (void *) IMX28_SSP, }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, mxs_spi_dt_ids); + +static int __devinit mxs_spi_probe(struct platform_device *pdev) +{ + const struct of_device_id *of_id = + of_match_device(mxs_spi_dt_ids, &pdev->dev); + struct device_node *np = pdev->dev.of_node; + struct spi_master *master; + struct mxs_spi *spi; + struct mxs_ssp *ssp; + struct resource *iores, *dmares; + struct pinctrl *pinctrl; + struct clk *clk; + void __iomem *base; + int devid, dma_channel, clk_freq; + int ret = 0, irq_err, irq_dma; + dma_cap_mask_t mask; + + /* + * Default clock speed for the SPI core. 160MHz seems to + * work reasonably well with most SPI flashes, so use this + * as a default. Override with "clock-frequency" DT prop. + */ + const int clk_freq_default = 160000000; + + iores = platform_get_resource(pdev, IORESOURCE_MEM, 0); + irq_err = platform_get_irq(pdev, 0); + irq_dma = platform_get_irq(pdev, 1); + if (!iores || irq_err < 0 || irq_dma < 0) + return -EINVAL; + + base = devm_request_and_ioremap(&pdev->dev, iores); + if (!base) + return -EADDRNOTAVAIL; + + pinctrl = devm_pinctrl_get_select_default(&pdev->dev); + if (IS_ERR(pinctrl)) + return PTR_ERR(pinctrl); + + clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + if (np) { + devid = (enum mxs_ssp_id) of_id->data; + /* + * TODO: This is a temporary solution and should be changed + * to use generic DMA binding later when the helpers get in. + */ + ret = of_property_read_u32(np, "fsl,ssp-dma-channel", + &dma_channel); + if (ret) { + dev_err(&pdev->dev, + "Failed to get DMA channel\n"); + return -EINVAL; + } + + ret = of_property_read_u32(np, "clock-frequency", + &clk_freq); + if (ret) + clk_freq = clk_freq_default; + } else { + dmares = platform_get_resource(pdev, IORESOURCE_DMA, 0); + if (!dmares) + return -EINVAL; + devid = pdev->id_entry->driver_data; + dma_channel = dmares->start; + clk_freq = clk_freq_default; + } + + master = spi_alloc_master(&pdev->dev, sizeof(*spi)); + if (!master) + return -ENOMEM; + + master->transfer_one_message = mxs_spi_transfer_one; + master->setup = mxs_spi_setup; + master->mode_bits = SPI_CPOL | SPI_CPHA; + master->num_chipselect = 3; + master->dev.of_node = np; + master->flags = SPI_MASTER_HALF_DUPLEX; + + spi = spi_master_get_devdata(master); + ssp = &spi->ssp; + ssp->dev = &pdev->dev; + ssp->clk = clk; + ssp->base = base; + ssp->devid = devid; + ssp->dma_channel = dma_channel; + + init_completion(&spi->c); + + ret = devm_request_irq(&pdev->dev, irq_err, mxs_ssp_irq_handler, 0, + DRIVER_NAME, ssp); + if (ret) + goto out_master_free; + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + ssp->dma_data.chan_irq = irq_dma; + ssp->dmach = dma_request_channel(mask, mxs_ssp_dma_filter, ssp); + if (!ssp->dmach) { + dev_err(ssp->dev, "Failed to request DMA\n"); + goto out_master_free; + } + + clk_prepare_enable(ssp->clk); + clk_set_rate(ssp->clk, clk_freq); + ssp->clk_rate = clk_get_rate(ssp->clk) / 1000; + + stmp_reset_block(ssp->base); + + platform_set_drvdata(pdev, master); + + ret = spi_register_master(master); + if (ret) { + dev_err(&pdev->dev, "Cannot register SPI master, %d\n", ret); + goto out_free_dma; + } + + return 0; + +out_free_dma: + dma_release_channel(ssp->dmach); + clk_disable_unprepare(ssp->clk); +out_master_free: + spi_master_put(master); + return ret; +} + +static int __devexit mxs_spi_remove(struct platform_device *pdev) +{ + struct spi_master *master; + struct mxs_spi *spi; + struct mxs_ssp *ssp; + + master = spi_master_get(platform_get_drvdata(pdev)); + spi = spi_master_get_devdata(master); + ssp = &spi->ssp; + + spi_unregister_master(master); + + dma_release_channel(ssp->dmach); + + clk_disable_unprepare(ssp->clk); + + spi_master_put(master); + + return 0; +} + +static struct platform_driver mxs_spi_driver = { + .probe = mxs_spi_probe, + .remove = __devexit_p(mxs_spi_remove), + .driver = { + .name = DRIVER_NAME, + .owner = THIS_MODULE, + .of_match_table = mxs_spi_dt_ids, + }, +}; + +module_platform_driver(mxs_spi_driver); + +MODULE_AUTHOR("Marek Vasut <marex@denx.de>"); +MODULE_DESCRIPTION("MXS SPI master driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:mxs-spi"); |