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linux/drivers/mfd/ti-ssp.c
Cyril Chemparathy 03df0f6294 mfd: add driver for sequencer serial port 
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@ti.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
2011-03-15 08:17:22 -07:00

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/*
* 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");
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