[PATCH v7 01/12] misc: add driver for sequencer serial port

[Cyril Chemparathy <cyril-l0cyMroinI0@public.gmane.org>]

TI's sequencer serial port (TI-SSP) is a jack-of-all-trades type of serial port
device.  It has a built-in programmable execution engine that can be programmed
to operate as almost any serial bus (I2C, SPI, EasyScale, and others).

This patch adds a driver for this controller device.  The driver does not
expose a user-land interface.  Protocol drivers built on top of this layer are
expected to remain in-kernel.

Signed-off-by: Cyril Chemparathy <cyril-l0cyMroinI0@public.gmane.org>
---
 drivers/mfd/Kconfig        |   11 +
 drivers/mfd/Makefile       |    1 +
 drivers/mfd/ti-ssp.c       |  476 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/ti_ssp.h |   87 ++++++++
 4 files changed, 575 insertions(+), 0 deletions(-)
 create mode 100644 drivers/mfd/ti-ssp.c
 create mode 100644 include/linux/mfd/ti_ssp.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 3a1493b..a4b4b70 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -81,6 +81,17 @@ config MFD_DM355EVM_MSP
 	  boards.  MSP430 firmware manages resets and power sequencing,
 	  inputs from buttons and the IR remote, LEDs, an RTC, and more.
 
+config MFD_TI_SSP
+	tristate "TI Sequencer Serial Port support"
+	depends on ARCH_DAVINCI_TNETV107X
+	select MFD_CORE
+	---help---
+	  Say Y here if you want support for the Sequencer Serial Port
+	  in a Texas Instruments TNETV107X SoC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ti-ssp.
+
 config HTC_EGPIO
 	bool "HTC EGPIO support"
 	depends on GENERIC_HARDIRQS && GPIOLIB && ARM
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index f54b365..f64cf13 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_HTC_I2CPLD)	+= htc-i2cpld.o
 
 obj-$(CONFIG_MFD_DAVINCI_VOICECODEC)	+= davinci_voicecodec.o
 obj-$(CONFIG_MFD_DM355EVM_MSP)	+= dm355evm_msp.o
+obj-$(CONFIG_MFD_TI_SSP)	+= ti-ssp.o
 
 obj-$(CONFIG_MFD_STMPE)		+= stmpe.o
 obj-$(CONFIG_MFD_TC35892)	+= tc35892.o
diff --git a/drivers/mfd/ti-ssp.c b/drivers/mfd/ti-ssp.c
new file mode 100644
index 0000000..af9ab0e
--- /dev/null
+++ b/drivers/mfd/ti-ssp.c
@@ -0,0 +1,476 @@
+/*
+ * Sequencer Serial Port (SSP) driver for Texas Instruments' SoCs
+ *
+ * Copyright (C) 2010 Texas Instruments Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/spinlock.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/ti_ssp.h>
+
+/* Register Offsets */
+#define REG_REV		0x00
+#define REG_IOSEL_1	0x04
+#define REG_IOSEL_2	0x08
+#define REG_PREDIV	0x0c
+#define REG_INTR_ST	0x10
+#define REG_INTR_EN	0x14
+#define REG_TEST_CTRL	0x18
+
+/* Per port registers */
+#define PORT_CFG_2	0x00
+#define PORT_ADDR	0x04
+#define PORT_DATA	0x08
+#define PORT_CFG_1	0x0c
+#define PORT_STATE	0x10
+
+#define SSP_PORT_CONFIG_MASK	(SSP_EARLY_DIN | SSP_DELAY_DOUT)
+#define SSP_PORT_CLKRATE_MASK	0x0f
+
+#define SSP_SEQRAM_WR_EN	BIT(4)
+#define SSP_SEQRAM_RD_EN	BIT(5)
+#define SSP_START		BIT(15)
+#define SSP_BUSY		BIT(10)
+#define SSP_PORT_ASL		BIT(7)
+#define SSP_PORT_CFO1		BIT(6)
+
+#define SSP_PORT_SEQRAM_SIZE	32
+
+static const int ssp_port_base[]   = {0x040, 0x080};
+static const int ssp_port_seqram[] = {0x100, 0x180};
+
+struct ti_ssp {
+	struct resource		*res;
+	struct device		*dev;
+	void __iomem		*regs;
+	spinlock_t		lock;
+	struct clk		*clk;
+	int			irq;
+	wait_queue_head_t	wqh;
+
+	/*
+	 * Some of the iosel2 register bits always read-back as 0, we need to
+	 * remember these values so that we don't clobber previously set
+	 * values.
+	 */
+	u32			iosel2;
+};
+
+static inline struct ti_ssp *dev_to_ssp(struct device *dev)
+{
+	return dev_get_drvdata(dev->parent);
+}
+
+static inline int dev_to_port(struct device *dev)
+{
+	return to_platform_device(dev)->id;
+}
+
+/* Register Access Helpers, rmw() functions need to run locked */
+static inline u32 ssp_read(struct ti_ssp *ssp, int reg)
+{
+	return __raw_readl(ssp->regs + reg);
+}
+
+static inline void ssp_write(struct ti_ssp *ssp, int reg, u32 val)
+{
+	__raw_writel(val, ssp->regs + reg);
+}
+
+static inline void ssp_rmw(struct ti_ssp *ssp, int reg, u32 mask, u32 bits)
+{
+	ssp_write(ssp, reg, (ssp_read(ssp, reg) & ~mask) | bits);
+}
+
+static inline u32 ssp_port_read(struct ti_ssp *ssp, int port, int reg)
+{
+	return ssp_read(ssp, ssp_port_base[port] + reg);
+}
+
+static inline void ssp_port_write(struct ti_ssp *ssp, int port, int reg,
+				  u32 val)
+{
+	ssp_write(ssp, ssp_port_base[port] + reg, val);
+}
+
+static inline void ssp_port_rmw(struct ti_ssp *ssp, int port, int reg,
+				u32 mask, u32 bits)
+{
+	ssp_rmw(ssp, ssp_port_base[port] + reg, mask, bits);
+}
+
+static inline void ssp_port_clr_bits(struct ti_ssp *ssp, int port, int reg,
+				     u32 bits)
+{
+	ssp_port_rmw(ssp, port, reg, bits, 0);
+}
+
+static inline void ssp_port_set_bits(struct ti_ssp *ssp, int port, int reg,
+				     u32 bits)
+{
+	ssp_port_rmw(ssp, port, reg, 0, bits);
+}
+
+/* Called to setup port clock mode, caller must hold ssp->lock */
+static int __set_mode(struct ti_ssp *ssp, int port, int mode)
+{
+	mode &= SSP_PORT_CONFIG_MASK;
+	ssp_port_rmw(ssp, port, PORT_CFG_1, SSP_PORT_CONFIG_MASK, mode);
+
+	return 0;
+}
+
+int ti_ssp_set_mode(struct device *dev, int mode)
+{
+	struct ti_ssp *ssp = dev_to_ssp(dev);
+	int port = dev_to_port(dev);
+	int ret;
+
+	spin_lock(&ssp->lock);
+	ret = __set_mode(ssp, port, mode);
+	spin_unlock(&ssp->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(ti_ssp_set_mode);
+
+/* Called to setup iosel2, caller must hold ssp->lock */
+static void __set_iosel2(struct ti_ssp *ssp, u32 mask, u32 val)
+{
+	ssp->iosel2 = (ssp->iosel2 & ~mask) | val;
+	ssp_write(ssp, REG_IOSEL_2, ssp->iosel2);
+}
+
+/* Called to setup port iosel, caller must hold ssp->lock */
+static void __set_iosel(struct ti_ssp *ssp, int port, u32 iosel)
+{
+	unsigned val, shift = port ? 16 : 0;
+
+	/* IOSEL1 gets the least significant 16 bits */
+	val = ssp_read(ssp, REG_IOSEL_1);
+	val &= 0xffff << (port ? 0 : 16);
+	val |= (iosel & 0xffff) << (port ? 16 : 0);
+	ssp_write(ssp, REG_IOSEL_1, val);
+
+	/* IOSEL2 gets the most significant 16 bits */
+	val = (iosel >> 16) & 0x7;
+	__set_iosel2(ssp, 0x7 << shift, val << shift);
+}
+
+int ti_ssp_set_iosel(struct device *dev, u32 iosel)
+{
+	struct ti_ssp *ssp = dev_to_ssp(dev);
+	int port = dev_to_port(dev);
+
+	spin_lock(&ssp->lock);
+	__set_iosel(ssp, port, iosel);
+	spin_unlock(&ssp->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(ti_ssp_set_iosel);
+
+int ti_ssp_load(struct device *dev, int offs, u32* prog, int len)
+{
+	struct ti_ssp *ssp = dev_to_ssp(dev);
+	int port = dev_to_port(dev);
+	int i;
+
+	if (len > SSP_PORT_SEQRAM_SIZE)
+		return -ENOSPC;
+
+	spin_lock(&ssp->lock);
+
+	/* Enable SeqRAM access */
+	ssp_port_set_bits(ssp, port, PORT_CFG_2, SSP_SEQRAM_WR_EN);
+
+	/* Copy code */
+	for (i = 0; i < len; i++) {
+		__raw_writel(prog[i], ssp->regs + offs + 4*i +
+			     ssp_port_seqram[port]);
+	}
+
+	/* Disable SeqRAM access */
+	ssp_port_clr_bits(ssp, port, PORT_CFG_2, SSP_SEQRAM_WR_EN);
+
+	spin_unlock(&ssp->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(ti_ssp_load);
+
+int ti_ssp_raw_read(struct device *dev)
+{
+	struct ti_ssp *ssp = dev_to_ssp(dev);
+	int port = dev_to_port(dev);
+	int shift = port ? 27 : 11;
+
+	return (ssp_read(ssp, REG_IOSEL_2) >> shift) & 0xf;
+}
+EXPORT_SYMBOL(ti_ssp_raw_read);
+
+int ti_ssp_raw_write(struct device *dev, u32 val)
+{
+	struct ti_ssp *ssp = dev_to_ssp(dev);
+	int port = dev_to_port(dev), shift;
+
+	spin_lock(&ssp->lock);
+
+	shift = port ? 22 : 6;
+	val &= 0xf;
+	__set_iosel2(ssp, 0xf << shift, val << shift);
+
+	spin_unlock(&ssp->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL(ti_ssp_raw_write);
+
+static inline int __xfer_done(struct ti_ssp *ssp, int port)
+{
+	return !(ssp_port_read(ssp, port, PORT_CFG_1) & SSP_BUSY);
+}
+
+int ti_ssp_run(struct device *dev, u32 pc, u32 input, u32 *output)
+{
+	struct ti_ssp *ssp = dev_to_ssp(dev);
+	int port = dev_to_port(dev);
+	int ret;
+
+	if (pc & ~(0x3f))
+		return -EINVAL;
+
+	/* Grab ssp->lock to serialize rmw on ssp registers */
+	spin_lock(&ssp->lock);
+
+	ssp_port_write(ssp, port, PORT_ADDR, input >> 16);
+	ssp_port_write(ssp, port, PORT_DATA, input & 0xffff);
+	ssp_port_rmw(ssp, port, PORT_CFG_1, 0x3f, pc);
+
+	/* grab wait queue head lock to avoid race with the isr */
+	spin_lock_irq(&ssp->wqh.lock);
+
+	/* kick off sequence execution in hardware */
+	ssp_port_set_bits(ssp, port, PORT_CFG_1, SSP_START);
+
+	/* drop ssp lock; no register writes beyond this */
+	spin_unlock(&ssp->lock);
+
+	ret = wait_event_interruptible_locked_irq(ssp->wqh,
+						  __xfer_done(ssp, port));
+	spin_unlock_irq(&ssp->wqh.lock);
+
+	if (ret < 0)
+		return ret;
+
+	if (output) {
+		*output = (ssp_port_read(ssp, port, PORT_ADDR) << 16) |
+			  (ssp_port_read(ssp, port, PORT_DATA) &  0xffff);
+	}
+
+	ret = ssp_port_read(ssp, port, PORT_STATE) & 0x3f; /* stop address */
+
+	return ret;
+}
+EXPORT_SYMBOL(ti_ssp_run);
+
+static irqreturn_t ti_ssp_interrupt(int irq, void *dev_data)
+{
+	struct ti_ssp *ssp = dev_data;
+
+	spin_lock(&ssp->wqh.lock);
+
+	ssp_write(ssp, REG_INTR_ST, 0x3);
+	wake_up_locked(&ssp->wqh);
+
+	spin_unlock(&ssp->wqh.lock);
+
+	return IRQ_HANDLED;
+}
+
+static int __devinit ti_ssp_probe(struct platform_device *pdev)
+{
+	static struct ti_ssp *ssp;
+	const struct ti_ssp_data *pdata = pdev->dev.platform_data;
+	int error = 0, prediv = 0xff, id;
+	unsigned long sysclk;
+	struct device *dev = &pdev->dev;
+	struct mfd_cell cells[2];
+
+	ssp = kzalloc(sizeof(*ssp), GFP_KERNEL);
+	if (!ssp) {
+		dev_err(dev, "cannot allocate device info\n");
+		return -ENOMEM;
+	}
+
+	ssp->dev = dev;
+	dev_set_drvdata(dev, ssp);
+
+	ssp->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!ssp->res) {
+		error = -ENODEV;
+		dev_err(dev, "cannot determine register area\n");
+		goto error_res;
+	}
+
+	if (!request_mem_region(ssp->res->start, resource_size(ssp->res),
+				pdev->name)) {
+		error = -ENOMEM;
+		dev_err(dev, "cannot claim register memory\n");
+		goto error_res;
+	}
+
+	ssp->regs = ioremap(ssp->res->start, resource_size(ssp->res));
+	if (!ssp->regs) {
+		error = -ENOMEM;
+		dev_err(dev, "cannot map register memory\n");
+		goto error_map;
+	}
+
+	ssp->clk = clk_get(dev, NULL);
+	if (IS_ERR(ssp->clk)) {
+		error = PTR_ERR(ssp->clk);
+		dev_err(dev, "cannot claim device clock\n");
+		goto error_clk;
+	}
+
+	ssp->irq = platform_get_irq(pdev, 0);
+	if (ssp->irq < 0) {
+		error = -ENODEV;
+		dev_err(dev, "unknown irq\n");
+		goto error_irq;
+	}
+
+	error = request_threaded_irq(ssp->irq, NULL, ti_ssp_interrupt, 0,
+				     dev_name(dev), ssp);
+	if (error < 0) {
+		dev_err(dev, "cannot acquire irq\n");
+		goto error_irq;
+	}
+
+	spin_lock_init(&ssp->lock);
+	init_waitqueue_head(&ssp->wqh);
+
+	/* Power on and initialize SSP */
+	error = clk_enable(ssp->clk);
+	if (error) {
+		dev_err(dev, "cannot enable device clock\n");
+		goto error_enable;
+	}
+
+	/* Reset registers to a sensible known state */
+	ssp_write(ssp, REG_IOSEL_1, 0);
+	ssp_write(ssp, REG_IOSEL_2, 0);
+	ssp_write(ssp, REG_INTR_EN, 0x3);
+	ssp_write(ssp, REG_INTR_ST, 0x3);
+	ssp_write(ssp, REG_TEST_CTRL, 0);
+	ssp_port_write(ssp, 0, PORT_CFG_1, SSP_PORT_ASL);
+	ssp_port_write(ssp, 1, PORT_CFG_1, SSP_PORT_ASL);
+	ssp_port_write(ssp, 0, PORT_CFG_2, SSP_PORT_CFO1);
+	ssp_port_write(ssp, 1, PORT_CFG_2, SSP_PORT_CFO1);
+
+	sysclk = clk_get_rate(ssp->clk);
+	if (pdata && pdata->out_clock)
+		prediv = (sysclk / pdata->out_clock) - 1;
+	prediv = clamp(prediv, 0, 0xff);
+	ssp_rmw(ssp, REG_PREDIV, 0xff, prediv);
+
+	memset(cells, 0, sizeof(cells));
+	for (id = 0; id < 2; id++) {
+		const struct ti_ssp_dev_data *data = &pdata->dev_data[id];
+
+		cells[id].id		= id;
+		cells[id].name		= data->dev_name;
+		cells[id].platform_data	= data->pdata;
+		cells[id].data_size	= data->pdata_size;
+	}
+
+	error = mfd_add_devices(dev, 0, cells, 2, NULL, 0);
+	if (error < 0) {
+		dev_err(dev, "cannot add mfd cells\n");
+		goto error_enable;
+	}
+
+	return 0;
+
+error_enable:
+	free_irq(ssp->irq, ssp);
+error_irq:
+	clk_put(ssp->clk);
+error_clk:
+	iounmap(ssp->regs);
+error_map:
+	release_mem_region(ssp->res->start, resource_size(ssp->res));
+error_res:
+	kfree(ssp);
+	return error;
+}
+
+static int __devexit ti_ssp_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ti_ssp *ssp = dev_get_drvdata(dev);
+
+	mfd_remove_devices(dev);
+	clk_disable(ssp->clk);
+	free_irq(ssp->irq, ssp);
+	clk_put(ssp->clk);
+	iounmap(ssp->regs);
+	release_mem_region(ssp->res->start, resource_size(ssp->res));
+	kfree(ssp);
+	dev_set_drvdata(dev, NULL);
+	return 0;
+}
+
+static struct platform_driver ti_ssp_driver = {
+	.probe		= ti_ssp_probe,
+	.remove		= __devexit_p(ti_ssp_remove),
+	.driver		= {
+		.name	= "ti-ssp",
+		.owner	= THIS_MODULE,
+	}
+};
+
+static int __init ti_ssp_init(void)
+{
+	return platform_driver_register(&ti_ssp_driver);
+}
+module_init(ti_ssp_init);
+
+static void __exit ti_ssp_exit(void)
+{
+	platform_driver_unregister(&ti_ssp_driver);
+}
+module_exit(ti_ssp_exit);
+
+MODULE_DESCRIPTION("Sequencer Serial Port (SSP) Driver");
+MODULE_AUTHOR("Cyril Chemparathy");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ti-ssp");
diff --git a/include/linux/mfd/ti_ssp.h b/include/linux/mfd/ti_ssp.h
new file mode 100644
index 0000000..021fe09
--- /dev/null
+++ b/include/linux/mfd/ti_ssp.h
@@ -0,0 +1,87 @@
+/*
+ * Sequencer Serial Port (SSP) driver for Texas Instruments' SoCs
+ *
+ * Copyright (C) 2010 Texas Instruments Inc
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef __TI_SSP_H__
+#define __TI_SSP_H__
+
+struct ti_ssp_dev_data {
+	const char	*dev_name;
+	void		*pdata;
+	size_t		pdata_size;
+};
+
+struct ti_ssp_data {
+	unsigned long		out_clock;
+	struct ti_ssp_dev_data	dev_data[2];
+};
+
+/*
+ * Sequencer port IO pin configuration bits.  These do not correlate 1-1 with
+ * the hardware.  The iosel field in the port data combines iosel1 and iosel2,
+ * and is therefore not a direct map to register space.  It is best to use the
+ * macros below to construct iosel values.
+ *
+ * least significant 16 bits --> iosel1
+ * most significant 16 bits  --> iosel2
+ */
+
+#define SSP_IN			0x0000
+#define SSP_DATA		0x0001
+#define SSP_CLOCK		0x0002
+#define SSP_CHIPSEL		0x0003
+#define SSP_OUT			0x0004
+#define SSP_PIN_SEL(pin, v)	((v) << ((pin) * 3))
+#define SSP_PIN_MASK(pin)	SSP_PIN_SEL(pin, 0x7)
+#define SSP_INPUT_SEL(pin)	((pin) << 16)
+
+/* Sequencer port config bits */
+#define SSP_EARLY_DIN		BIT(8)
+#define SSP_DELAY_DOUT		BIT(9)
+
+/* Sequence map definitions */
+#define SSP_CLK_HIGH		BIT(0)
+#define SSP_CLK_LOW		0
+#define SSP_DATA_HIGH		BIT(1)
+#define SSP_DATA_LOW		0
+#define SSP_CS_HIGH		BIT(2)
+#define SSP_CS_LOW		0
+#define SSP_OUT_MODE		BIT(3)
+#define SSP_IN_MODE		0
+#define SSP_DATA_REG		BIT(4)
+#define SSP_ADDR_REG		0
+
+#define SSP_OPCODE_DIRECT	((0x0) << 5)
+#define SSP_OPCODE_TOGGLE	((0x1) << 5)
+#define SSP_OPCODE_SHIFT	((0x2) << 5)
+#define SSP_OPCODE_BRANCH0	((0x4) << 5)
+#define SSP_OPCODE_BRANCH1	((0x5) << 5)
+#define SSP_OPCODE_BRANCH	((0x6) << 5)
+#define SSP_OPCODE_STOP		((0x7) << 5)
+#define SSP_BRANCH(addr)	((addr) << 8)
+#define SSP_COUNT(cycles)	((cycles) << 8)
+
+int ti_ssp_raw_read(struct device *dev);
+int ti_ssp_raw_write(struct device *dev, u32 val);
+int ti_ssp_load(struct device *dev, int offs, u32* prog, int len);
+int ti_ssp_run(struct device *dev, u32 pc, u32 input, u32 *output);
+int ti_ssp_set_mode(struct device *dev, int mode);
+int ti_ssp_set_iosel(struct device *dev, u32 iosel);
+
+#endif /* __TI_SSP_H__ */
-- 
1.7.1


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What happens now with your Lotus Notes apps - do you make another costly 
upgrade, or settle for being marooned without product support? Time to move
off Lotus Notes and onto the cloud with Force.com, apps are easier to build,
use, and manage than apps on traditional platforms. Sign up for the Lotus 
Notes Migration Kit to learn more. http://p.sf.net/sfu/salesforce-d2d