[PATCH v2 2/3] SPI: Add i.MX 23/28 SPI driver support
Alexander Aring
alex.aring at gmail.com
Tue Feb 5 07:34:56 EST 2013
Hi,
On Tue, Feb 05, 2013 at 12:46:56PM +0100, Michael Grzeschik wrote:
> Signed-off-by: Michael Grzeschik <m.grzeschik at pengutronix.de>
> ---
> changes since v1:
> - renamed patch to more clear subject
> - whitespace fixes
> - catched more error returns, as EIO
> - explicit affected archs as kconfig dependency
> - used dev_{dbg,info,err} instead of printf
> - removed unneded xzalloc failure catch
> - returning value from driver_register on spi_init
>
> arch/arm/mach-mxs/include/mach/ssp.h | 2 +
> drivers/spi/Kconfig | 5 +
> drivers/spi/Makefile | 1 +
> drivers/spi/mxs_spi.c | 306 ++++++++++++++++++++++++++++++++++
> 4 files changed, 314 insertions(+)
> create mode 100644 drivers/spi/mxs_spi.c
>
> diff --git a/arch/arm/mach-mxs/include/mach/ssp.h b/arch/arm/mach-mxs/include/mach/ssp.h
> index aa2b27a..5eee5c0 100644
> --- a/arch/arm/mach-mxs/include/mach/ssp.h
> +++ b/arch/arm/mach-mxs/include/mach/ssp.h
> @@ -64,6 +64,7 @@
> #define SSP_CTRL0_BUS_WIDTH(x) (((x) & 0x3) << 22)
> #define SSP_CTRL0_WAIT_FOR_IRQ (1 << 21)
> #define SSP_CTRL0_WAIT_FOR_CMD (1 << 20)
> +#define SSP_CTRL0_SSP_ASSERT_OUT(x) (((x) & 0x3) << 20)
> #define SSP_CTRL0_LONG_RESP (1 << 19)
> #define SSP_CTRL0_GET_RESP (1 << 17)
> #define SSP_CTRL0_ENABLE (1 << 16)
> @@ -92,6 +93,7 @@
> /* bit definition for register HW_SSP_CTRL1 */
> #define SSP_CTRL1_POLARITY (1 << 9)
> #define SSP_CTRL1_PHASE (1 << 10)
> +#define SSP_CTRL1_DMA_ENABLE (1 << 13)
> #define SSP_CTRL1_WORD_LENGTH(x) (((x) & 0xf) << 4)
> #define SSP_CTRL1_SSP_MODE(x) ((x) & 0xf)
>
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index 10b8fea..f14e28f 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -33,6 +33,11 @@ config DRIVER_SPI_IMX_2_3
> depends on ARCH_IMX51 || ARCH_IMX53 || ARCH_IMX6
> default y
>
> +config DRIVER_SPI_MXS
> + bool "i.MX (23,28) SPI Master driver"
> + depends on ARCH_IMX23 || ARCH_IMX28
> + depends on SPI
> +
> config DRIVER_SPI_OMAP3
> bool "OMAP3 McSPI Master driver"
> depends on ARCH_OMAP3
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index b53061e..642b7ec 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -1,5 +1,6 @@
> obj-$(CONFIG_SPI) += spi.o
> obj-$(CONFIG_DRIVER_SPI_IMX) += imx_spi.o
> +obj-$(CONFIG_DRIVER_SPI_MXS) += mxs_spi.o
> obj-$(CONFIG_DRIVER_SPI_ALTERA) += altera_spi.o
> obj-$(CONFIG_DRIVER_SPI_ATMEL) += atmel_spi.o
> obj-$(CONFIG_DRIVER_SPI_OMAP3) += omap3_spi.o
> diff --git a/drivers/spi/mxs_spi.c b/drivers/spi/mxs_spi.c
> new file mode 100644
> index 0000000..3c6c11b
> --- /dev/null
> +++ b/drivers/spi/mxs_spi.c
> @@ -0,0 +1,306 @@
> +/*
> + * Freescale i.MX28 SPI driver
> + *
> + * Copyright (C) 2013 Michael Grzeschik <mgr at pengutronix.de>
> + *
> + * Copyright (C) 2011 Marek Vasut <marek.vasut at gmail.com>
> + * on behalf of DENX Software Engineering GmbH
> + *
> + * 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.
> + *
> + */
> +
> +#include <common.h>
> +#include <init.h>
> +#include <malloc.h>
> +#include <spi/spi.h>
> +#include <clock.h>
> +#include <errno.h>
> +#include <io.h>
> +#include <linux/clk.h>
> +#include <asm/mmu.h>
> +#include <mach/generic.h>
> +#include <mach/imx-regs.h>
> +#include <mach/mxs.h>
> +#include <mach/clock.h>
> +#include <mach/ssp.h>
> +
> +#define MXS_SPI_MAX_TIMEOUT (10 * MSECOND)
> +
> +#define SPI_XFER_BEGIN 0x01 /* Assert CS before transfer */
> +#define SPI_XFER_END 0x02 /* Deassert CS after transfer */
> +
> +struct mxs_spi {
> + struct spi_master master;
> + uint32_t max_khz;
> + uint32_t mode;
> + struct clk *clk;
> + void __iomem *regs;
> +};
> +
> +static inline struct mxs_spi *to_mxs(struct spi_master *master)
> +{
> + return container_of(master, struct mxs_spi, master);
> +}
> +
> +/*
> + * Set SSP/MMC bus frequency, in kHz
> + */
> +static void imx_set_ssp_busclock(struct spi_master *master, uint32_t freq)
> +{
> + struct mxs_spi *mxs = to_mxs(master);
> + const uint32_t sspclk = imx_get_sspclk(master->bus_num);
> + uint32_t val;
> + uint32_t divide, rate, tgtclk;
> +
> + /*
> + * SSP bit rate = SSPCLK / (CLOCK_DIVIDE * (1 + CLOCK_RATE)),
> + * CLOCK_DIVIDE has to be an even value from 2 to 254, and
> + * CLOCK_RATE could be any integer from 0 to 255.
> + */
> + for (divide = 2; divide < 254; divide += 2) {
> + rate = sspclk / freq / divide;
> + if (rate <= 256)
> + break;
> + }
> +
> + tgtclk = sspclk / divide / rate;
> + while (tgtclk > freq) {
> + rate++;
> + tgtclk = sspclk / divide / rate;
> + }
> + if (rate > 256)
> + rate = 256;
> +
> + /* Always set timeout the maximum */
> + val = SSP_TIMING_TIMEOUT_MASK |
> + SSP_TIMING_CLOCK_DIVIDE(divide) |
> + SSP_TIMING_CLOCK_RATE(rate - 1);
> + writel(val, mxs->regs + HW_SSP_TIMING);
> +
> + dev_dbg(master->dev, "SPI%d: Set freq rate to %d KHz (requested %d KHz)\n",
> + master->bus_num, tgtclk, freq);
> +}
> +
> +static int mxs_spi_setup(struct spi_device *spi)
> +{
> + struct spi_master *master = spi->master;
> + struct mxs_spi *mxs = to_mxs(master);
> + uint32_t val = 0;
> +
> + /* MXS SPI: 4 ports and 3 chip selects maximum */
> + if (master->bus_num > 3 || spi->chip_select > 2) {
> + dev_err(master->dev, "mxs_spi: invalid bus %d / chip select %d\n",
> + master->bus_num, spi->chip_select);
> + return -EINVAL;
> + }
> +
> + mxs_reset_block(mxs->regs + HW_SSP_CTRL0, 0);
> +
> + val |= SSP_CTRL0_SSP_ASSERT_OUT(spi->chip_select);
> + val |= SSP_CTRL0_BUS_WIDTH(0);
> + writel(val, mxs->regs + HW_SSP_CTRL0 + BIT_SET);
> +
> + val = SSP_CTRL1_SSP_MODE(0) | SSP_CTRL1_WORD_LENGTH(7);
> + val |= (mxs->mode & SPI_CPOL) ? SSP_CTRL1_POLARITY : 0;
> + val |= (mxs->mode & SPI_CPHA) ? SSP_CTRL1_PHASE : 0;
> + writel(val, mxs->regs + HW_SSP_CTRL1);
> +
> + writel(0x0, mxs->regs + HW_SSP_CMD0);
> + writel(0x0, mxs->regs + HW_SSP_CMD1);
> +
> + imx_set_ssp_busclock(master, spi->max_speed_hz);
> +
> + return 0;
> +}
> +
> +static void mxs_spi_start_xfer(struct mxs_spi *mxs)
> +{
> + writel(SSP_CTRL0_LOCK_CS, mxs->regs + HW_SSP_CTRL0 + BIT_SET);
> + writel(SSP_CTRL0_IGNORE_CRC, mxs->regs + HW_SSP_CTRL0 + BIT_CLR);
> +}
> +
> +static void mxs_spi_end_xfer(struct mxs_spi *mxs)
> +{
> + writel(SSP_CTRL0_LOCK_CS, mxs->regs + HW_SSP_CTRL0 + BIT_CLR);
> + writel(SSP_CTRL0_IGNORE_CRC, mxs->regs + HW_SSP_CTRL0 + BIT_SET);
> +}
> +
> +static uint32_t mxs_spi_cs_to_reg(unsigned cs)
> +{
> + uint32_t select = 0;
> +
> + if (cs & 1)
> + select |= SSP_CTRL0_WAIT_FOR_CMD;
> + if (cs & 2)
> + select |= SSP_CTRL0_WAIT_FOR_IRQ;
> +
> + return select;
> +}
> +
> +static void mxs_spi_set_cs(struct spi_device *spi)
> +{
> + const uint32_t mask = SSP_CTRL0_WAIT_FOR_CMD | SSP_CTRL0_WAIT_FOR_IRQ;
> + uint32_t select;
> + struct mxs_spi *mxs = to_mxs(spi->master);
> +
> + writel(mask, mxs->regs + HW_SSP_CTRL0 + BIT_CLR);
> + select = mxs_spi_cs_to_reg(spi->chip_select);
> + writel(select, mxs->regs + HW_SSP_CTRL0 + BIT_SET);
> +}
> +
> +static int mxs_spi_xfer_pio(struct spi_device *spi,
> + char *data, int length, int write, unsigned long flags)
> +{
> + struct mxs_spi *mxs = to_mxs(spi->master);
> + struct spi_master *master = spi->master;
> +
> + if (flags & SPI_XFER_BEGIN)
> + mxs_spi_start_xfer(mxs);
> +
> + mxs_spi_set_cs(spi);
> +
> + while (length--) {
> + if ((flags & SPI_XFER_END) && !length)
> + mxs_spi_end_xfer(mxs);
> +
> + /* We transfer 1 byte */
> + writel(1, mxs->regs + HW_SSP_XFER_COUNT);
> +
> + if (write)
> + writel(SSP_CTRL0_READ, mxs->regs + HW_SSP_CTRL0 + BIT_CLR);
> + else
> + writel(SSP_CTRL0_READ, mxs->regs + HW_SSP_CTRL0 + BIT_SET);
> +
> + writel(SSP_CTRL0_RUN, mxs->regs + HW_SSP_CTRL0 + BIT_SET);
> +
> + if (wait_on_timeout(MXS_SPI_MAX_TIMEOUT,
> + (readl(mxs->regs + HW_SSP_CTRL0) & SSP_CTRL0_RUN) == SSP_CTRL0_RUN)) {
> + dev_err(master->dev, "MXS SPI: Timeout waiting for start\n");
> + return -ETIMEDOUT;
> + }
> +
> + if (write)
> + writel(*data++, mxs->regs + HW_SSP_DATA);
> +
> + writel(SSP_CTRL0_DATA_XFER, mxs->regs + HW_SSP_CTRL0 + BIT_SET);
> +
> + if (!write) {
> + if (wait_on_timeout(MXS_SPI_MAX_TIMEOUT,
> + !(readl(mxs->regs + HW_SSP_STATUS) & SSP_STATUS_FIFO_EMPTY))) {
> + dev_err(master->dev, "MXS SPI: Timeout waiting for data\n");
> + return -ETIMEDOUT;
> + }
> +
> + *data++ = readl(mxs->regs + HW_SSP_DATA) & 0xff;
> + }
> +
> + if (wait_on_timeout(MXS_SPI_MAX_TIMEOUT,
> + !(readl(mxs->regs + HW_SSP_CTRL0) & SSP_CTRL0_RUN))) {
> + dev_err(master->dev, "MXS SPI: Timeout waiting for finish\n");
> + return -ETIMEDOUT;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int mxs_spi_transfer(struct spi_device *spi, struct spi_message *mesg)
> +{
> + struct mxs_spi *mxs = to_mxs(spi->master);
> + struct spi_master *master = spi->master;
> + struct spi_transfer *t = NULL;
> + char dummy;
> + unsigned long flags = 0;
> + int write = 0;
> + char *data = NULL;
> + int ret;
> + mesg->actual_length = 0;
> +
> + list_for_each_entry(t, &mesg->transfers, transfer_list) {
> + flags = 0;
> +
> + if (t->tx_buf) {
> + data = (char *) t->tx_buf;
> + write = 1;
> + } else if (t->rx_buf) {
> + data = (char *) t->rx_buf;
> + write = 0;
> + }
> +
> + if (&t->transfer_list == mesg->transfers.next)
> + flags |= SPI_XFER_BEGIN;
> +
> + if (&t->transfer_list == mesg->transfers.prev)
> + flags |= SPI_XFER_END;
> +
> + if ((t->rx_buf && t->tx_buf)) {
> + dev_err(master->dev, "Cannot send and receive simultaneously\n");
> + return -EIO;
> + }
> +
> + if ((!t->rx_buf && !t->tx_buf)) {
unnessecary bracktes
> + dev_err(master->dev, "No Data\n");
> + return -EIO;
> + }
I am not so happy with that. Can we check this at first of this loop?
With handle in the first if like that:
if (t->tx_buf)
...
else if (r->rx_buf)
...
else if (t->tx_buf && t->rx_buf)
...
else if (!t->tx_buf && !t->rx_buf)
...
> +
> + if (t->len == 0) {
> + if (flags == SPI_XFER_END) {
> + t->len = 1;
> + t->rx_buf = (void *) &dummy;
> + } else {
> + return 0;
> + }
> + }
> +
> + writel(SSP_CTRL1_DMA_ENABLE, mxs->regs + HW_SSP_CTRL1 + BIT_CLR);
> + ret = mxs_spi_xfer_pio(spi, data, t->len, write, flags);
> + if (ret < 0)
> + return ret;
> + mesg->actual_length += t->len;
> + }
> +
> + return 0;
> +}
> +
> +static int mxs_spi_probe(struct device_d *dev)
> +{
> + struct spi_master *master;
> + struct mxs_spi *mxs;
> +
> + mxs = xzalloc(sizeof(*mxs));
> +
> + master = &mxs->master;
> + master->dev = dev;
> +
> + master->bus_num = dev->id;
> + master->setup = mxs_spi_setup;
> + master->transfer = mxs_spi_transfer;
> + master->num_chipselect = 3;
> + mxs->mode = SPI_CPOL | SPI_CPHA;
> +
> + mxs->regs = dev_request_mem_region(dev, 0);
> +
> + spi_register_master(master);
> +
> + return 0;
> +}
> +
> +static struct driver_d mxs_spi_driver = {
> + .name = "mxs_spi",
> + .probe = mxs_spi_probe,
> +};
> +
> +static int __init mxs_spi_init(void)
> +{
> + return platform_driver_register(&mxs_spi_driver);
> +}
> +
> +device_initcall(mxs_spi_init);
> +
> +MODULE_AUTHOR("Denx Software Engeneering and Michael Grzeschik");
> +MODULE_DESCRIPTION("MXS SPI driver");
> +MODULE_LICENSE("GPL");
> --
> 1.7.10.4
>
>
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