[PATCH 06/10 V3] spi: Add SPI driver for mx233/mx28
Marek Vasut
marex at denx.de
Fri Aug 3 11:26:11 EDT 2012
This is slightly reworked version of the SPI driver.
Support for DT has been added and it's been converted
to queued API.
Based on previous attempt by:
Fabio Estevam <fabio.estevam at freescale.com>
Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Attila Kinali <attila at kinali.ch>
Cc: Chris Ball <cjb at laptop.org>
CC: Dong Aisheng <b29396 at freescale.com>
Cc: Grant Likely <grant.likely at secretlab.ca>
Cc: Linux ARM kernel <linux-arm-kernel at lists.infradead.org>
Cc: Mark Brown <broonie at opensource.wolfsonmicro.com>
CC: Shawn Guo <shawn.guo at linaro.org>
---
drivers/spi/Kconfig | 7 +
drivers/spi/Makefile | 1 +
drivers/spi/spi-mxs.c | 431 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 439 insertions(+)
create mode 100644 drivers/spi/spi-mxs.c
V3: Drop mxs_spi_cleanup()
Set "hz" unconditionally to dev->max_speed_hz and then trim it down.
Add comment about how Freescale is recycling random bits in CTRL0 register.
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 5f84b55..6992b30 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 3920dcf..3b72d87 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 0000000..7bf826f
--- /dev/null
+++ b/drivers/spi/spi-mxs.c
@@ -0,0 +1,431 @@
+/*
+ * 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 at denx.de>
+ *
+ * Based on previous attempt by:
+ * Fabio Estevam <fabio.estevam at freescale.com>
+ *
+ * Based on code from U-Boot bootloader by:
+ * Marek Vasut <marex at denx.de>
+ *
+ * Based on spi-stmp.c, which is:
+ * Author: Dmitry Pervushin <dimka at 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/fsl/mxs-dma.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"
+
+#define SSP_TIMEOUT 1000 /* 1000 ms */
+
+struct mxs_spi {
+ struct mxs_ssp ssp;
+};
+
+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)
+{
+ unsigned long timeout = jiffies + msecs_to_jiffies(SSP_TIMEOUT);
+ struct mxs_ssp *ssp = &spi->ssp;
+ uint32_t reg;
+
+ while (1) {
+ reg = readl_relaxed(ssp->base + offset);
+
+ if (set && ((reg & mask) == mask))
+ break;
+
+ if (!set && ((~reg & mask) == mask))
+ break;
+
+ udelay(1);
+
+ if (time_after(jiffies, timeout))
+ return -ETIMEDOUT;
+ }
+ return 0;
+}
+
+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) {
+ dev_err(ssp->dev,
+ "Cannot send and receive simultaneously\n");
+ status = -EINVAL;
+ break;
+ }
+
+ 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);
+
+ m->actual_length += t->len;
+ if (status)
+ break;
+
+ first = last = 0;
+ }
+
+ m->status = 0;
+ spi_finalize_current_message(master);
+
+ return status;
+}
+
+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;
+ struct pinctrl *pinctrl;
+ struct clk *clk;
+ void __iomem *base;
+ int devid;
+ int ret = 0;
+
+ iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!iores)
+ 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;
+ else
+ devid = pdev->id_entry->driver_data;
+
+ 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;
+
+ clk_prepare_enable(ssp->clk);
+ 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_master_free;
+ }
+
+ return 0;
+
+out_master_free:
+ platform_set_drvdata(pdev, NULL);
+ clk_disable_unprepare(ssp->clk);
+ 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 = platform_get_drvdata(pdev);
+ spi = spi_master_get_devdata(master);
+ ssp = &spi->ssp;
+
+ spi_unregister_master(master);
+
+ platform_set_drvdata(pdev, NULL);
+
+ 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 at denx.de>");
+MODULE_DESCRIPTION("MXS SPI master driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:mxs-spi");
--
1.7.10.4
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