[STLinux Kernel] [PATCH v3 1/4] spi: Add new driver for STMicroelectronics' SPI Controller
Patrice Chotard
patrice.chotard at st.com
Mon Dec 8 05:12:19 PST 2014
Hi Lee
Acked-by: Patrice Chotard <patrice.chotard at st.com>
Thanks
On 12/08/2014 01:53 PM, Lee Jones wrote:
> This patch adds support for the SPI portion of ST's SSC device.
>
> Signed-off-by: Lee Jones <lee.jones at linaro.org>
> ---
> drivers/spi/Kconfig | 7 +
> drivers/spi/Makefile | 1 +
> drivers/spi/spi-st-ssc4.c | 509 ++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 517 insertions(+)
> create mode 100644 drivers/spi/spi-st-ssc4.c
>
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index 84e7c9e..0d42362 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -488,6 +488,13 @@ config SPI_SIRF
> help
> SPI driver for CSR SiRFprimaII SoCs
>
> +config SPI_ST_SSC4
> + tristate "STMicroelectronics SPI SSC-based driver"
> + depends on ARCH_STI
> + help
> + STMicroelectronics SoCs support for SPI. If you say yes to
> + this option, support will be included for the SSC driven SPI.
> +
> config SPI_SUN4I
> tristate "Allwinner A10 SoCs SPI controller"
> depends on ARCH_SUNXI || COMPILE_TEST
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index 78f24ca..c38e28c 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -74,6 +74,7 @@ obj-$(CONFIG_SPI_SH_HSPI) += spi-sh-hspi.o
> obj-$(CONFIG_SPI_SH_MSIOF) += spi-sh-msiof.o
> obj-$(CONFIG_SPI_SH_SCI) += spi-sh-sci.o
> obj-$(CONFIG_SPI_SIRF) += spi-sirf.o
> +obj-$(CONFIG_SPI_ST_SSC4) += spi-st-ssc4.o
> obj-$(CONFIG_SPI_SUN4I) += spi-sun4i.o
> obj-$(CONFIG_SPI_SUN6I) += spi-sun6i.o
> obj-$(CONFIG_SPI_TEGRA114) += spi-tegra114.o
> diff --git a/drivers/spi/spi-st-ssc4.c b/drivers/spi/spi-st-ssc4.c
> new file mode 100644
> index 0000000..3fd3e85
> --- /dev/null
> +++ b/drivers/spi/spi-st-ssc4.c
> @@ -0,0 +1,509 @@
> +/*
> + * Copyright (c) 2008-2014 STMicroelectronics Limited
> + *
> + * Author: Angus Clark <Angus.Clark at st.com>
> + * Patrice Chotard <patrice.chotard at st.com>
> + * Lee Jones <lee.jones at linaro.org>
> + *
> + * SPI master mode controller driver, used in STMicroelectronics devices.
> + *
> + * May be copied or modified under the terms of the GNU General Public
> + * License Version 2.0 only. See linux/COPYING for more information.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/of_irq.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/spi/spi.h>
> +#include <linux/spi/spi_bitbang.h>
> +
> +/* SSC registers */
> +#define SSC_BRG 0x000
> +#define SSC_TBUF 0x004
> +#define SSC_RBUF 0x008
> +#define SSC_CTL 0x00C
> +#define SSC_IEN 0x010
> +#define SSC_I2C 0x018
> +
> +/* SSC Control */
> +#define SSC_CTL_DATA_WIDTH_9 0x8
> +#define SSC_CTL_DATA_WIDTH_MSK 0xf
> +#define SSC_CTL_BM 0xf
> +#define SSC_CTL_HB BIT(4)
> +#define SSC_CTL_PH BIT(5)
> +#define SSC_CTL_PO BIT(6)
> +#define SSC_CTL_SR BIT(7)
> +#define SSC_CTL_MS BIT(8)
> +#define SSC_CTL_EN BIT(9)
> +#define SSC_CTL_LPB BIT(10)
> +#define SSC_CTL_EN_TX_FIFO BIT(11)
> +#define SSC_CTL_EN_RX_FIFO BIT(12)
> +#define SSC_CTL_EN_CLST_RX BIT(13)
> +
> +/* SSC Interrupt Enable */
> +#define SSC_IEN_TEEN BIT(2)
> +
> +#define FIFO_SIZE 8
> +
> +struct spi_st {
> + /* SSC SPI Controller */
> + void __iomem *base;
> + struct clk *clk;
> + struct device *dev;
> +
> + /* SSC SPI current transaction */
> + const u8 *tx_ptr;
> + u8 *rx_ptr;
> + u16 bytes_per_word;
> + unsigned int words_remaining;
> + unsigned int baud;
> + struct completion done;
> +};
> +
> +static int spi_st_clk_enable(struct spi_st *spi_st)
> +{
> + /*
> + * Current platforms use one of the core clocks for SPI and I2C.
> + * If we attempt to disable the clock, the system will hang.
> + *
> + * TODO: Remove this when platform supports power domains.
> + */
> + return 0;
> +
> + return clk_prepare_enable(spi_st->clk);
> +}
> +
> +static void spi_st_clk_disable(struct spi_st *spi_st)
> +{
> + /*
> + * Current platforms use one of the core clocks for SPI and I2C.
> + * If we attempt to disable the clock, the system will hang.
> + *
> + * TODO: Remove this when platform supports power domains.
> + */
> + return;
> +
> + clk_disable_unprepare(spi_st->clk);
> +}
> +
> +/* Load the TX FIFO */
> +static void ssc_write_tx_fifo(struct spi_st *spi_st)
> +{
> + unsigned int count, i;
> + uint32_t word = 0;
> +
> + if (spi_st->words_remaining > FIFO_SIZE)
> + count = FIFO_SIZE;
> + else
> + count = spi_st->words_remaining;
> +
> + for (i = 0; i < count; i++) {
> + if (spi_st->tx_ptr) {
> + if (spi_st->bytes_per_word == 1) {
> + word = *spi_st->tx_ptr++;
> + } else {
> + word = *spi_st->tx_ptr++;
> + word = *spi_st->tx_ptr++ | (word << 8);
> + }
> + }
> + writel_relaxed(word, spi_st->base + SSC_TBUF);
> + }
> +}
> +
> +/* Read the RX FIFO */
> +static void ssc_read_rx_fifo(struct spi_st *spi_st)
> +{
> + unsigned int count, i;
> + uint32_t word = 0;
> +
> + if (spi_st->words_remaining > FIFO_SIZE)
> + count = FIFO_SIZE;
> + else
> + count = spi_st->words_remaining;
> +
> + for (i = 0; i < count; i++) {
> + word = readl_relaxed(spi_st->base + SSC_RBUF);
> +
> + if (spi_st->rx_ptr) {
> + if (spi_st->bytes_per_word == 1) {
> + *spi_st->rx_ptr++ = (uint8_t)word;
> + } else {
> + *spi_st->rx_ptr++ = (word >> 8);
> + *spi_st->rx_ptr++ = word & 0xff;
> + }
> + }
> + }
> + spi_st->words_remaining -= count;
> +}
> +
> +static int spi_st_transfer_one(struct spi_master *master,
> + struct spi_device *spi, struct spi_transfer *t)
> +{
> + struct spi_st *spi_st = spi_master_get_devdata(master);
> + uint32_t ctl = 0;
> +
> + /* Setup transfer */
> + spi_st->tx_ptr = t->tx_buf;
> + spi_st->rx_ptr = t->rx_buf;
> +
> + if (spi->bits_per_word > 8) {
> + /*
> + * Anything greater than 8 bits-per-word requires 2
> + * bytes-per-word in the RX/TX buffers
> + */
> + spi_st->bytes_per_word = 2;
> + spi_st->words_remaining = t->len / 2;
> +
> + } else if (spi->bits_per_word == 8 && !(t->len & 0x1)) {
> + /*
> + * If transfer is even-length, and 8 bits-per-word, then
> + * implement as half-length 16 bits-per-word transfer
> + */
> + spi_st->bytes_per_word = 2;
> + spi_st->words_remaining = t->len / 2;
> +
> + /* Set SSC_CTL to 16 bits-per-word */
> + ctl = readl_relaxed(spi_st->base + SSC_CTL);
> + writel_relaxed((ctl | 0xf), spi_st->base + SSC_CTL);
> +
> + readl_relaxed(spi_st->base + SSC_RBUF);
> +
> + } else {
> + spi_st->bytes_per_word = 1;
> + spi_st->words_remaining = t->len;
> + }
> +
> + reinit_completion(&spi_st->done);
> +
> + /* Start transfer by writing to the TX FIFO */
> + ssc_write_tx_fifo(spi_st);
> + writel_relaxed(SSC_IEN_TEEN, spi_st->base + SSC_IEN);
> +
> + /* Wait for transfer to complete */
> + wait_for_completion(&spi_st->done);
> +
> + /* Restore SSC_CTL if necessary */
> + if (ctl)
> + writel_relaxed(ctl, spi_st->base + SSC_CTL);
> +
> + spi_finalize_current_transfer(spi->master);
> +
> + return t->len;
> +}
> +
> +static void spi_st_cleanup(struct spi_device *spi)
> +{
> + int cs = spi->cs_gpio;
> +
> + if (gpio_is_valid(cs))
> + devm_gpio_free(&spi->dev, cs);
> +}
> +
> +/* the spi->mode bits understood by this driver: */
> +#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_LOOP | SPI_CS_HIGH)
> +static int spi_st_setup(struct spi_device *spi)
> +{
> + struct spi_st *spi_st = spi_master_get_devdata(spi->master);
> + u32 spi_st_clk, sscbrg, var;
> + u32 hz = spi->max_speed_hz;
> + int cs = spi->cs_gpio;
> + int ret;
> +
> + if (spi->mode & ~MODEBITS) {
> + dev_err(&spi->dev, "unsupported mode bits 0x%x\n",
> + spi->mode & ~MODEBITS);
> + return -EINVAL;
> + }
> +
> + if (!hz) {
> + dev_err(&spi->dev, "max_speed_hz unspecified\n");
> + return -EINVAL;
> + }
> +
> + if (!gpio_is_valid(cs)) {
> + dev_err(&spi->dev, "%d is not a valid gpio\n", cs);
> + return -EINVAL;
> + }
> +
> + if (devm_gpio_request(&spi->dev, cs, dev_name(&spi->dev))) {
> + dev_err(&spi->dev, "could not request gpio:%d\n", cs);
> + return -EINVAL;
> + }
> +
> + ret = gpio_direction_output(cs, spi->mode & SPI_CS_HIGH);
> + if (ret)
> + return ret;
> +
> + spi_st_clk = clk_get_rate(spi_st->clk);
> +
> + /* Set SSC_BRF */
> + sscbrg = spi_st_clk / (2 * hz);
> + if (sscbrg < 0x07 || sscbrg > BIT(16)) {
> + dev_err(&spi->dev,
> + "baudrate %d outside valid range %d\n", sscbrg, hz);
> + return -EINVAL;
> + }
> +
> + spi_st->baud = spi_st_clk / (2 * sscbrg);
> + if (sscbrg == BIT(16)) /* 16-bit counter wraps */
> + sscbrg = 0x0;
> +
> + writel_relaxed(sscbrg, spi_st->base + SSC_BRG);
> +
> + dev_dbg(&spi->dev,
> + "setting baudrate:target= %u hz, actual= %u hz, sscbrg= %u\n",
> + hz, spi_st->baud, sscbrg);
> +
> + /* Set SSC_CTL and enable SSC */
> + var = readl_relaxed(spi_st->base + SSC_CTL);
> + var |= SSC_CTL_MS;
> +
> + if (spi->mode & SPI_CPOL)
> + var |= SSC_CTL_PO;
> + else
> + var &= ~SSC_CTL_PO;
> +
> + if (spi->mode & SPI_CPHA)
> + var |= SSC_CTL_PH;
> + else
> + var &= ~SSC_CTL_PH;
> +
> + if ((spi->mode & SPI_LSB_FIRST) == 0)
> + var |= SSC_CTL_HB;
> + else
> + var &= ~SSC_CTL_HB;
> +
> + if (spi->mode & SPI_LOOP)
> + var |= SSC_CTL_LPB;
> + else
> + var &= ~SSC_CTL_LPB;
> +
> + var &= ~SSC_CTL_DATA_WIDTH_MSK;
> + var |= (spi->bits_per_word - 1);
> +
> + var |= SSC_CTL_EN_TX_FIFO | SSC_CTL_EN_RX_FIFO;
> + var |= SSC_CTL_EN;
> +
> + writel_relaxed(var, spi_st->base + SSC_CTL);
> +
> + /* Clear the status register */
> + readl_relaxed(spi_st->base + SSC_RBUF);
> +
> + return 0;
> +}
> +
> +/* Interrupt fired when TX shift register becomes empty */
> +static irqreturn_t spi_st_irq(int irq, void *dev_id)
> +{
> + struct spi_st *spi_st = (struct spi_st *)dev_id;
> +
> + /* Read RX FIFO */
> + ssc_read_rx_fifo(spi_st);
> +
> + /* Fill TX FIFO */
> + if (spi_st->words_remaining) {
> + ssc_write_tx_fifo(spi_st);
> + } else {
> + /* TX/RX complete */
> + writel_relaxed(0x0, spi_st->base + SSC_IEN);
> + /*
> + * read SSC_IEN to ensure that this bit is set
> + * before re-enabling interrupt
> + */
> + readl(spi_st->base + SSC_IEN);
> + complete(&spi_st->done);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int spi_st_probe(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct spi_master *master;
> + struct resource *res;
> + struct spi_st *spi_st;
> + int irq, ret = 0;
> + u32 var;
> +
> + master = spi_alloc_master(&pdev->dev, sizeof(*spi_st));
> + if (!master)
> + return -ENOMEM;
> +
> + master->dev.of_node = np;
> + master->mode_bits = MODEBITS;
> + master->setup = spi_st_setup;
> + master->cleanup = spi_st_cleanup;
> + master->transfer_one = spi_st_transfer_one;
> + master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
> + master->auto_runtime_pm = true;
> + master->bus_num = pdev->id;
> + spi_st = spi_master_get_devdata(master);
> +
> + spi_st->clk = devm_clk_get(&pdev->dev, "ssc");
> + if (IS_ERR(spi_st->clk)) {
> + dev_err(&pdev->dev, "Unable to request clock\n");
> + return PTR_ERR(spi_st->clk);
> + }
> +
> + ret = spi_st_clk_enable(spi_st);
> + if (ret)
> + return ret;
> +
> + init_completion(&spi_st->done);
> +
> + /* Get resources */
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + spi_st->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(spi_st->base)) {
> + ret = PTR_ERR(spi_st->base);
> + goto clk_disable;
> + }
> +
> + /* Disable I2C and Reset SSC */
> + writel_relaxed(0x0, spi_st->base + SSC_I2C);
> + var = readw_relaxed(spi_st->base + SSC_CTL);
> + var |= SSC_CTL_SR;
> + writel_relaxed(var, spi_st->base + SSC_CTL);
> +
> + udelay(1);
> + var = readl_relaxed(spi_st->base + SSC_CTL);
> + var &= ~SSC_CTL_SR;
> + writel_relaxed(var, spi_st->base + SSC_CTL);
> +
> + /* Set SSC into slave mode before reconfiguring PIO pins */
> + var = readl_relaxed(spi_st->base + SSC_CTL);
> + var &= ~SSC_CTL_MS;
> + writel_relaxed(var, spi_st->base + SSC_CTL);
> +
> + irq = irq_of_parse_and_map(np, 0);
> + if (!irq) {
> + dev_err(&pdev->dev, "IRQ missing or invalid\n");
> + ret = -EINVAL;
> + goto clk_disable;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, irq, spi_st_irq, 0,
> + pdev->name, spi_st);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to request irq %d\n", irq);
> + goto clk_disable;
> + }
> +
> + /* by default the device is on */
> + pm_runtime_set_active(&pdev->dev);
> + pm_runtime_enable(&pdev->dev);
> +
> + platform_set_drvdata(pdev, master);
> +
> + ret = devm_spi_register_master(&pdev->dev, master);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to register master\n");
> + goto clk_disable;
> + }
> +
> + return 0;
> +
> +clk_disable:
> + spi_st_clk_disable(spi_st);
> +
> + return ret;
> +}
> +
> +static int spi_st_remove(struct platform_device *pdev)
> +{
> + struct spi_master *master = platform_get_drvdata(pdev);
> + struct spi_st *spi_st = spi_master_get_devdata(master);
> +
> + spi_st_clk_disable(spi_st);
> +
> + pinctrl_pm_select_sleep_state(&pdev->dev);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int spi_st_runtime_suspend(struct device *dev)
> +{
> + struct spi_master *master = dev_get_drvdata(dev);
> + struct spi_st *spi_st = spi_master_get_devdata(master);
> +
> + writel_relaxed(0, spi_st->base + SSC_IEN);
> + pinctrl_pm_select_sleep_state(dev);
> +
> + spi_st_clk_disable(spi_st);
> +
> + return 0;
> +}
> +
> +static int spi_st_runtime_resume(struct device *dev)
> +{
> + struct spi_master *master = dev_get_drvdata(dev);
> + struct spi_st *spi_st = spi_master_get_devdata(master);
> + int ret;
> +
> + ret = spi_st_clk_enable(spi_st);
> + pinctrl_pm_select_default_state(dev);
> +
> + return ret;
> +}
> +#endif
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int spi_st_suspend(struct device *dev)
> +{
> + struct spi_master *master = dev_get_drvdata(dev);
> + int ret;
> +
> + ret = spi_master_suspend(master);
> + if (ret)
> + return ret;
> +
> + return pm_runtime_force_suspend(dev);
> +}
> +
> +static int spi_st_resume(struct device *dev)
> +{
> + struct spi_master *master = dev_get_drvdata(dev);
> + int ret;
> +
> + ret = spi_master_resume(master);
> + if (ret)
> + return ret;
> +
> + return pm_runtime_force_resume(dev);
> +}
> +#endif
> +
> +static const struct dev_pm_ops spi_st_pm = {
> + SET_SYSTEM_SLEEP_PM_OPS(spi_st_suspend, spi_st_resume)
> + SET_RUNTIME_PM_OPS(spi_st_runtime_suspend, spi_st_runtime_resume, NULL)
> +};
> +
> +static struct of_device_id stm_spi_match[] = {
> + { .compatible = "st,comms-ssc4-spi", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, stm_spi_match);
> +
> +static struct platform_driver spi_st_driver = {
> + .driver = {
> + .name = "spi-st",
> + .pm = &spi_st_pm,
> + .of_match_table = of_match_ptr(stm_spi_match),
> + },
> + .probe = spi_st_probe,
> + .remove = spi_st_remove,
> +};
> +module_platform_driver(spi_st_driver);
> +
> +MODULE_AUTHOR("Patrice Chotard <patrice.chotard at st.com>");
> +MODULE_DESCRIPTION("STM SSC SPI driver");
> +MODULE_LICENSE("GPL v2");
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