[PATCH v3 0/4] spi: st: New driver for ST's SPI Controller

[PATCH v3 0/4] spi: st: New driver for ST's SPI Controller

[Lee Jones]

This is a new driver which controls the SPI component of ST's
Synchronous Serial Controller (SSC).
 
v2 => v3:
- Fixes Patrice's review comments
- Removed COMPILE_TEST (at least until Will Deacon's patch lands)

v1 => v2:
- New, more specific CONFIG symbol
- Increased Runtime PM functionality
- Make use of new Pinctrl API
- Convert from SPI Bitbang => Transfer One
- Omit functionality which Core can handle
- Removal of *cough* debug code

Lee Jones (4):
  spi: Add new driver for STMicroelectronics' SPI Controller
  spi: st: Provide Device Tree binding documentation
  ARM: sti: Provide DT nodes for SSC[0..4]
  ARM: sti: Provide DT nodes for SBC SSC[0..2]

 Documentation/devicetree/bindings/spi/spi-st.txt |  40 ++
 arch/arm/boot/dts/stih407.dtsi                   |  85 ++++
 drivers/spi/Kconfig                              |   7 +
 drivers/spi/Makefile                             |   1 +
 drivers/spi/spi-st-ssc4.c                        | 509 +++++++++++++++++++++++
 5 files changed, 642 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/spi-st.txt
 create mode 100644 drivers/spi/spi-st-ssc4.c

-- 
1.9.1

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[PATCH v3 0/4] spi: st: New driver for ST's SPI Controller

[Lee Jones]

This is a new driver which controls the SPI component of ST's
Synchronous Serial Controller (SSC).
 
v2 => v3:
- Fixes Patrice's review comments
- Removed COMPILE_TEST (at least until Will Deacon's patch lands)

v1 => v2:
- New, more specific CONFIG symbol
- Increased Runtime PM functionality
- Make use of new Pinctrl API
- Convert from SPI Bitbang => Transfer One
- Omit functionality which Core can handle
- Removal of *cough* debug code

Lee Jones (4):
  spi: Add new driver for STMicroelectronics' SPI Controller
  spi: st: Provide Device Tree binding documentation
  ARM: sti: Provide DT nodes for SSC[0..4]
  ARM: sti: Provide DT nodes for SBC SSC[0..2]

 Documentation/devicetree/bindings/spi/spi-st.txt |  40 ++
 arch/arm/boot/dts/stih407.dtsi                   |  85 ++++
 drivers/spi/Kconfig                              |   7 +
 drivers/spi/Makefile                             |   1 +
 drivers/spi/spi-st-ssc4.c                        | 509 +++++++++++++++++++++++
 5 files changed, 642 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/spi-st.txt
 create mode 100644 drivers/spi/spi-st-ssc4.c

-- 
1.9.1

[PATCH v3 0/4] spi: st: New driver for ST's SPI Controller

[Lee Jones]

This is a new driver which controls the SPI component of ST's
Synchronous Serial Controller (SSC).
 
v2 => v3:
- Fixes Patrice's review comments
- Removed COMPILE_TEST (at least until Will Deacon's patch lands)

v1 => v2:
- New, more specific CONFIG symbol
- Increased Runtime PM functionality
- Make use of new Pinctrl API
- Convert from SPI Bitbang => Transfer One
- Omit functionality which Core can handle
- Removal of *cough* debug code

Lee Jones (4):
  spi: Add new driver for STMicroelectronics' SPI Controller
  spi: st: Provide Device Tree binding documentation
  ARM: sti: Provide DT nodes for SSC[0..4]
  ARM: sti: Provide DT nodes for SBC SSC[0..2]

 Documentation/devicetree/bindings/spi/spi-st.txt |  40 ++
 arch/arm/boot/dts/stih407.dtsi                   |  85 ++++
 drivers/spi/Kconfig                              |   7 +
 drivers/spi/Makefile                             |   1 +
 drivers/spi/spi-st-ssc4.c                        | 509 +++++++++++++++++++++++
 5 files changed, 642 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/spi-st.txt
 create mode 100644 drivers/spi/spi-st-ssc4.c

-- 
1.9.1

[PATCH v3 1/4] spi: Add new driver for STMicroelectronics' SPI Controller

[Lee Jones]

This patch adds support for the SPI portion of ST's SSC device.

Signed-off-by: Lee Jones <lee.jones@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@st.com>
+ *          Patrice Chotard <patrice.chotard@st.com>
+ *          Lee Jones <lee.jones@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@st.com>");
+MODULE_DESCRIPTION("STM SSC SPI driver");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

[PATCH v3 1/4] spi: Add new driver for STMicroelectronics' SPI Controller

[Lee Jones]

This patch adds support for the SPI portion of ST's SSC device.

Signed-off-by: Lee Jones <lee.jones@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@st.com>
+ *          Patrice Chotard <patrice.chotard@st.com>
+ *          Lee Jones <lee.jones@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@st.com>");
+MODULE_DESCRIPTION("STM SSC SPI driver");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

Re: [STLinux Kernel] [PATCH v3 1/4] spi: Add new driver for STMicroelectronics' SPI Controller

[Patrice Chotard]

Hi Lee

Acked-by: Patrice Chotard <patrice.chotard@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@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@st.com>
> + *          Patrice Chotard <patrice.chotard@st.com>
> + *          Lee Jones <lee.jones@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@st.com>");
> +MODULE_DESCRIPTION("STM SSC SPI driver");
> +MODULE_LICENSE("GPL v2");

Re: [STLinux Kernel] [PATCH v3 1/4] spi: Add new driver for STMicroelectronics' SPI Controller

[Patrice Chotard]

Hi Lee

Acked-by: Patrice Chotard <patrice.chotard@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@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@st.com>
> + *          Patrice Chotard <patrice.chotard@st.com>
> + *          Lee Jones <lee.jones@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@st.com>");
> +MODULE_DESCRIPTION("STM SSC SPI driver");
> +MODULE_LICENSE("GPL v2");

[STLinux Kernel] [PATCH v3 1/4] spi: Add new driver for STMicroelectronics' SPI Controller

[Patrice Chotard]

Hi Lee

Acked-by: Patrice Chotard <patrice.chotard@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@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@st.com>
> + *          Patrice Chotard <patrice.chotard@st.com>
> + *          Lee Jones <lee.jones@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@st.com>");
> +MODULE_DESCRIPTION("STM SSC SPI driver");
> +MODULE_LICENSE("GPL v2");

[PATCH v3 2/4] spi: st: Provide Device Tree binding documentation

[Lee Jones]

This patch adds DT documentation for the SPI portion of ST's SSC device.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 Documentation/devicetree/bindings/spi/spi-st.txt | 40 ++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/spi-st.txt

diff --git a/Documentation/devicetree/bindings/spi/spi-st.txt b/Documentation/devicetree/bindings/spi/spi-st.txt
new file mode 100644
index 0000000..fe54959
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/spi-st.txt
@@ -0,0 +1,40 @@
+STMicroelectronics SSC (SPI) Controller
+---------------------------------------
+
+Required properties:
+- compatible	: "st,comms-ssc4-spi"
+- reg		: Offset and length of the device's register set
+- interrupts	: The interrupt specifier
+- clock-names	: Must contain "ssc"
+- clocks	: Must contain an entry for each name in clock-names
+		    See ../clk/*
+- pinctrl-names	: Uses "default", can use "sleep" if provided
+		    See ../pinctrl/pinctrl-binding.txt
+
+Optional properties:
+- cs-gpios	: List of GPIO chip selects
+		    See ../spi/spi-bus.txt
+
+Child nodes represent devices on the SPI bus
+  See ../spi/spi-bus.txt
+
+Example:
+	spi@9840000 {
+		compatible	= "st,comms-ssc4-spi";
+		reg		= <0x9840000 0x110>;
+		interrupts	= <GIC_SPI 112 IRQ_TYPE_LEVEL_HIGH>;
+		clocks		= <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+		clock-names	= "ssc";
+		pinctrl-0	= <&pinctrl_spi0_default>;
+		pinctrl-names	= "default";
+		cs-gpios	= <&pio17 5 0>;
+		#address-cells	= <1>;
+		#size-cells	= <0>;
+
+		st95hf@0{
+			compatible		= "st,st95hf";
+			reg			= <0>;
+			spi-max-frequency	= <1000000>;
+			interrupts		= <2 IRQ_TYPE_EDGE_FALLING>;
+		};
+	};
-- 
1.9.1

[PATCH v3 2/4] spi: st: Provide Device Tree binding documentation

[Lee Jones]

This patch adds DT documentation for the SPI portion of ST's SSC device.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 Documentation/devicetree/bindings/spi/spi-st.txt | 40 ++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/spi-st.txt

diff --git a/Documentation/devicetree/bindings/spi/spi-st.txt b/Documentation/devicetree/bindings/spi/spi-st.txt
new file mode 100644
index 0000000..fe54959
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/spi-st.txt
@@ -0,0 +1,40 @@
+STMicroelectronics SSC (SPI) Controller
+---------------------------------------
+
+Required properties:
+- compatible	: "st,comms-ssc4-spi"
+- reg		: Offset and length of the device's register set
+- interrupts	: The interrupt specifier
+- clock-names	: Must contain "ssc"
+- clocks	: Must contain an entry for each name in clock-names
+		    See ../clk/*
+- pinctrl-names	: Uses "default", can use "sleep" if provided
+		    See ../pinctrl/pinctrl-binding.txt
+
+Optional properties:
+- cs-gpios	: List of GPIO chip selects
+		    See ../spi/spi-bus.txt
+
+Child nodes represent devices on the SPI bus
+  See ../spi/spi-bus.txt
+
+Example:
+	spi at 9840000 {
+		compatible	= "st,comms-ssc4-spi";
+		reg		= <0x9840000 0x110>;
+		interrupts	= <GIC_SPI 112 IRQ_TYPE_LEVEL_HIGH>;
+		clocks		= <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+		clock-names	= "ssc";
+		pinctrl-0	= <&pinctrl_spi0_default>;
+		pinctrl-names	= "default";
+		cs-gpios	= <&pio17 5 0>;
+		#address-cells	= <1>;
+		#size-cells	= <0>;
+
+		st95hf at 0{
+			compatible		= "st,st95hf";
+			reg			= <0>;
+			spi-max-frequency	= <1000000>;
+			interrupts		= <2 IRQ_TYPE_EDGE_FALLING>;
+		};
+	};
-- 
1.9.1

[PATCH v3 3/4] ARM: sti: Provide DT nodes for SSC[0..4]

[Lee Jones]

The Synchronous Serial Controller is used to provide SPI.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 arch/arm/boot/dts/stih407.dtsi | 54 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/arch/arm/boot/dts/stih407.dtsi b/arch/arm/boot/dts/stih407.dtsi
index 50637f5..90bc090 100644
--- a/arch/arm/boot/dts/stih407.dtsi
+++ b/arch/arm/boot/dts/stih407.dtsi
@@ -275,5 +275,59 @@
 
 			status = "disabled";
 		};
+
+		spi@9840000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9840000 0x110>;
+			interrupts = <GIC_SPI 112 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+			clock-names = "ssc";
+			pinctrl-0 = <&pinctrl_spi0_default>;
+			pinctrl-names = "default";
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			status = "disabled";
+		};
+
+		spi@9841000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9841000 0x110>;
+			interrupts = <GIC_SPI 113 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
+
+		spi@9842000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9842000 0x110>;
+			interrupts = <GIC_SPI 114 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
+
+		spi@9843000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9843000 0x110>;
+			interrupts = <GIC_SPI 115 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
+
+		spi@9844000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9844000 0x110>;
+			interrupts = <GIC_SPI 116 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
 	};
 };
-- 
1.9.1

[PATCH v3 3/4] ARM: sti: Provide DT nodes for SSC[0..4]

[Lee Jones]

The Synchronous Serial Controller is used to provide SPI.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 arch/arm/boot/dts/stih407.dtsi | 54 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/arch/arm/boot/dts/stih407.dtsi b/arch/arm/boot/dts/stih407.dtsi
index 50637f5..90bc090 100644
--- a/arch/arm/boot/dts/stih407.dtsi
+++ b/arch/arm/boot/dts/stih407.dtsi
@@ -275,5 +275,59 @@
 
 			status = "disabled";
 		};
+
+		spi at 9840000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9840000 0x110>;
+			interrupts = <GIC_SPI 112 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+			clock-names = "ssc";
+			pinctrl-0 = <&pinctrl_spi0_default>;
+			pinctrl-names = "default";
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			status = "disabled";
+		};
+
+		spi at 9841000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9841000 0x110>;
+			interrupts = <GIC_SPI 113 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
+
+		spi at 9842000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9842000 0x110>;
+			interrupts = <GIC_SPI 114 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
+
+		spi at 9843000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9843000 0x110>;
+			interrupts = <GIC_SPI 115 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
+
+		spi at 9844000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9844000 0x110>;
+			interrupts = <GIC_SPI 116 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
 	};
 };
-- 
1.9.1

[PATCH v3 4/4] ARM: sti: Provide DT nodes for SBC SSC[0..2]

[Lee Jones]

The Synchronous Serial Controller is used to provide SPI.

These are the ports which are located on the Stand-By Controller (SBC).

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 arch/arm/boot/dts/stih407.dtsi | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/arch/arm/boot/dts/stih407.dtsi b/arch/arm/boot/dts/stih407.dtsi
index 90bc090..80e2407 100644
--- a/arch/arm/boot/dts/stih407.dtsi
+++ b/arch/arm/boot/dts/stih407.dtsi
@@ -329,5 +329,36 @@
 
 			status = "disabled";
 		};
+
+		/* SBC SSC */
+		spi@9540000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9540000 0x110>;
+			interrupts = <GIC_SPI 135 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_sysin>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
+
+		spi@9541000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9541000 0x110>;
+			interrupts = <GIC_SPI 136 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_sysin>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
+
+		spi@9542000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9542000 0x110>;
+			interrupts = <GIC_SPI 137 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_sysin>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
 	};
 };
-- 
1.9.1

[PATCH v3 4/4] ARM: sti: Provide DT nodes for SBC SSC[0..2]

[Lee Jones]

The Synchronous Serial Controller is used to provide SPI.

These are the ports which are located on the Stand-By Controller (SBC).

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 arch/arm/boot/dts/stih407.dtsi | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/arch/arm/boot/dts/stih407.dtsi b/arch/arm/boot/dts/stih407.dtsi
index 90bc090..80e2407 100644
--- a/arch/arm/boot/dts/stih407.dtsi
+++ b/arch/arm/boot/dts/stih407.dtsi
@@ -329,5 +329,36 @@
 
 			status = "disabled";
 		};
+
+		/* SBC SSC */
+		spi at 9540000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9540000 0x110>;
+			interrupts = <GIC_SPI 135 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_sysin>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
+
+		spi at 9541000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9541000 0x110>;
+			interrupts = <GIC_SPI 136 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_sysin>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
+
+		spi at 9542000 {
+			compatible = "st,comms-ssc4-spi";
+			reg = <0x9542000 0x110>;
+			interrupts = <GIC_SPI 137 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clk_sysin>;
+			clock-names = "ssc";
+
+			status = "disabled";
+		};
 	};
 };
-- 
1.9.1

Re: [STLinux Kernel] [PATCH v3 4/4] ARM: sti: Provide DT nodes for SBC SSC[0..2]

[Peter Griffin]

Hi Lee,

On Mon, 08 Dec 2014, Lee Jones wrote:

> The Synchronous Serial Controller is used to provide SPI.
> 
> These are the ports which are located on the Stand-By Controller (SBC).

After my series which adds stih410 SoC support, these nodes should now live in the
common stih407-family.dtsi file (common to both SoC's).

regards,

Peter.

[STLinux Kernel] [PATCH v3 4/4] ARM: sti: Provide DT nodes for SBC SSC[0..2]

[Peter Griffin]

Hi Lee,

On Mon, 08 Dec 2014, Lee Jones wrote:

> The Synchronous Serial Controller is used to provide SPI.
> 
> These are the ports which are located on the Stand-By Controller (SBC).

After my series which adds stih410 SoC support, these nodes should now live in the
common stih407-family.dtsi file (common to both SoC's).

regards,

Peter.

Re: [PATCH v3 0/4] spi: st: New driver for ST's SPI Controller

[Arnd Bergmann]

On Monday 08 December 2014 12:53:30 Lee Jones wrote:
> This is a new driver which controls the SPI component of ST's
> Synchronous Serial Controller (SSC).
> 

How does this related to the i2c driver for drivers/i2c/busses/i2c-st.c?
Could you have the same piece of hardware do one or the other mode
depending on pin configuration, or is each instance hardwired to
a particular mode?

Is there any code worth sharing between the two drivers?

	Arnd
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Re: [PATCH v3 0/4] spi: st: New driver for ST's SPI Controller

[Arnd Bergmann]

On Monday 08 December 2014 12:53:30 Lee Jones wrote:
> This is a new driver which controls the SPI component of ST's
> Synchronous Serial Controller (SSC).
> 

How does this related to the i2c driver for drivers/i2c/busses/i2c-st.c?
Could you have the same piece of hardware do one or the other mode
depending on pin configuration, or is each instance hardwired to
a particular mode?

Is there any code worth sharing between the two drivers?

	Arnd

[PATCH v3 0/4] spi: st: New driver for ST's SPI Controller

[Arnd Bergmann]

On Monday 08 December 2014 12:53:30 Lee Jones wrote:
> This is a new driver which controls the SPI component of ST's
> Synchronous Serial Controller (SSC).
> 

How does this related to the i2c driver for drivers/i2c/busses/i2c-st.c?
Could you have the same piece of hardware do one or the other mode
depending on pin configuration, or is each instance hardwired to
a particular mode?

Is there any code worth sharing between the two drivers?

	Arnd

Re: [STLinux Kernel] [PATCH v3 0/4] spi: st: New driver for ST's SPI Controller

[Maxime Coquelin]

On 12/08/2014 02:22 PM, Arnd Bergmann wrote:
> On Monday 08 December 2014 12:53:30 Lee Jones wrote:
>> This is a new driver which controls the SPI component of ST's
>> Synchronous Serial Controller (SSC).
>>
> How does this related to the i2c driver for drivers/i2c/busses/i2c-st.c?
> Could you have the same piece of hardware do one or the other mode
> depending on pin configuration, or is each instance hardwired to
> a particular mode?
This is the same IP, that can be configured either in SPI or I2C.

>
> Is there any code worth sharing between the two drivers?
No, except a couple of registers, they are managed in a ways.

The way it is used, a single SSC instance can only be used either in SPI 
or I2C mode on a board,
so I think it wouldn't make sense to create a MFD driver to manage it.

Kr,
Maxime
>
> 	Arnd
>
> _______________________________________________
> Kernel mailing list
> Kernel-F5mvAk5X5gdBDgjK7y7TUQ@public.gmane.org
> http://www.stlinux.com/mailman/listinfo/kernel

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Re: [STLinux Kernel] [PATCH v3 0/4] spi: st: New driver for ST's SPI Controller

[Maxime Coquelin]

On 12/08/2014 02:22 PM, Arnd Bergmann wrote:
> On Monday 08 December 2014 12:53:30 Lee Jones wrote:
>> This is a new driver which controls the SPI component of ST's
>> Synchronous Serial Controller (SSC).
>>
> How does this related to the i2c driver for drivers/i2c/busses/i2c-st.c?
> Could you have the same piece of hardware do one or the other mode
> depending on pin configuration, or is each instance hardwired to
> a particular mode?
This is the same IP, that can be configured either in SPI or I2C.

>
> Is there any code worth sharing between the two drivers?
No, except a couple of registers, they are managed in a ways.

The way it is used, a single SSC instance can only be used either in SPI 
or I2C mode on a board,
so I think it wouldn't make sense to create a MFD driver to manage it.

Kr,
Maxime
>
> 	Arnd
>
> _______________________________________________
> Kernel mailing list
> Kernel@stlinux.com
> http://www.stlinux.com/mailman/listinfo/kernel

Re: [STLinux Kernel] [PATCH v3 0/4] spi: st: New driver for ST's SPI Controller

[Maxime Coquelin]

On 12/08/2014 02:22 PM, Arnd Bergmann wrote:
> On Monday 08 December 2014 12:53:30 Lee Jones wrote:
>> This is a new driver which controls the SPI component of ST's
>> Synchronous Serial Controller (SSC).
>>
> How does this related to the i2c driver for drivers/i2c/busses/i2c-st.c?
> Could you have the same piece of hardware do one or the other mode
> depending on pin configuration, or is each instance hardwired to
> a particular mode?
This is the same IP, that can be configured either in SPI or I2C.

>
> Is there any code worth sharing between the two drivers?
No, except a couple of registers, they are managed in a ways.

The way it is used, a single SSC instance can only be used either in SPI 
or I2C mode on a board,
so I think it wouldn't make sense to create a MFD driver to manage it.

Kr,
Maxime
>
> 	Arnd
>
> _______________________________________________
> Kernel mailing list
> Kernel-F5mvAk5X5gdBDgjK7y7TUQ@public.gmane.org
> http://www.stlinux.com/mailman/listinfo/kernel

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[STLinux Kernel] [PATCH v3 0/4] spi: st: New driver for ST's SPI Controller

[Maxime Coquelin]

On 12/08/2014 02:22 PM, Arnd Bergmann wrote:
> On Monday 08 December 2014 12:53:30 Lee Jones wrote:
>> This is a new driver which controls the SPI component of ST's
>> Synchronous Serial Controller (SSC).
>>
> How does this related to the i2c driver for drivers/i2c/busses/i2c-st.c?
> Could you have the same piece of hardware do one or the other mode
> depending on pin configuration, or is each instance hardwired to
> a particular mode?
This is the same IP, that can be configured either in SPI or I2C.

>
> Is there any code worth sharing between the two drivers?
No, except a couple of registers, they are managed in a ways.

The way it is used, a single SSC instance can only be used either in SPI 
or I2C mode on a board,
so I think it wouldn't make sense to create a MFD driver to manage it.

Kr,
Maxime
>
> 	Arnd
>
> _______________________________________________
> Kernel mailing list
> Kernel at stlinux.com
> http://www.stlinux.com/mailman/listinfo/kernel