linux/drivers/i2c/busses/i2c-au1550.c
Sergei Shtylyov 8e07c2c6af [MIPS] Alchemy: SMBus resource fix
The Alchemy platform code registers the SMBus device using the virtual
address of its registers instead of the physical one -- fix this, taking
into account that actually the whole megabyte is decoded by any of the
programmable serial controllers (one of which is SMBus), and that all the
Alchemy peripherals are directly mappable into KSEG1 kernel space and
therefore ioremap() call would just boil down to CKSEG1ADDR() invocation.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-05-12 16:46:50 +01:00

479 lines
10 KiB
C

/*
* i2c-au1550.c: SMBus (i2c) adapter for Alchemy PSC interface
* Copyright (C) 2004 Embedded Edge, LLC <dan@embeddededge.com>
*
* 2.6 port by Matt Porter <mporter@kernel.crashing.org>
*
* The documentation describes this as an SMBus controller, but it doesn't
* understand any of the SMBus protocol in hardware. It's really an I2C
* controller that could emulate most of the SMBus in software.
*
* This is just a skeleton adapter to use with the Au1550 PSC
* algorithm. It was developed for the Pb1550, but will work with
* any Au1550 board that has a similar PSC configuration.
*
* 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/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <asm/mach-au1x00/au1xxx.h>
#include <asm/mach-au1x00/au1xxx_psc.h>
struct i2c_au1550_data {
u32 psc_base;
int xfer_timeout;
int ack_timeout;
struct i2c_adapter adap;
struct resource *ioarea;
};
static int
wait_xfer_done(struct i2c_au1550_data *adap)
{
u32 stat;
int i;
volatile psc_smb_t *sp;
sp = (volatile psc_smb_t *)(adap->psc_base);
/* Wait for Tx Buffer Empty
*/
for (i = 0; i < adap->xfer_timeout; i++) {
stat = sp->psc_smbstat;
au_sync();
if ((stat & PSC_SMBSTAT_TE) != 0)
return 0;
udelay(1);
}
return -ETIMEDOUT;
}
static int
wait_ack(struct i2c_au1550_data *adap)
{
u32 stat;
volatile psc_smb_t *sp;
if (wait_xfer_done(adap))
return -ETIMEDOUT;
sp = (volatile psc_smb_t *)(adap->psc_base);
stat = sp->psc_smbevnt;
au_sync();
if ((stat & (PSC_SMBEVNT_DN | PSC_SMBEVNT_AN | PSC_SMBEVNT_AL)) != 0)
return -ETIMEDOUT;
return 0;
}
static int
wait_master_done(struct i2c_au1550_data *adap)
{
u32 stat;
int i;
volatile psc_smb_t *sp;
sp = (volatile psc_smb_t *)(adap->psc_base);
/* Wait for Master Done.
*/
for (i = 0; i < adap->xfer_timeout; i++) {
stat = sp->psc_smbevnt;
au_sync();
if ((stat & PSC_SMBEVNT_MD) != 0)
return 0;
udelay(1);
}
return -ETIMEDOUT;
}
static int
do_address(struct i2c_au1550_data *adap, unsigned int addr, int rd, int q)
{
volatile psc_smb_t *sp;
u32 stat;
sp = (volatile psc_smb_t *)(adap->psc_base);
/* Reset the FIFOs, clear events.
*/
stat = sp->psc_smbstat;
sp->psc_smbevnt = PSC_SMBEVNT_ALLCLR;
au_sync();
if (!(stat & PSC_SMBSTAT_TE) || !(stat & PSC_SMBSTAT_RE)) {
sp->psc_smbpcr = PSC_SMBPCR_DC;
au_sync();
do {
stat = sp->psc_smbpcr;
au_sync();
} while ((stat & PSC_SMBPCR_DC) != 0);
udelay(50);
}
/* Write out the i2c chip address and specify operation
*/
addr <<= 1;
if (rd)
addr |= 1;
/* zero-byte xfers stop immediately */
if (q)
addr |= PSC_SMBTXRX_STP;
/* Put byte into fifo, start up master.
*/
sp->psc_smbtxrx = addr;
au_sync();
sp->psc_smbpcr = PSC_SMBPCR_MS;
au_sync();
if (wait_ack(adap))
return -EIO;
return (q) ? wait_master_done(adap) : 0;
}
static u32
wait_for_rx_byte(struct i2c_au1550_data *adap, u32 *ret_data)
{
int j;
u32 data, stat;
volatile psc_smb_t *sp;
if (wait_xfer_done(adap))
return -EIO;
sp = (volatile psc_smb_t *)(adap->psc_base);
j = adap->xfer_timeout * 100;
do {
j--;
if (j <= 0)
return -EIO;
stat = sp->psc_smbstat;
au_sync();
if ((stat & PSC_SMBSTAT_RE) == 0)
j = 0;
else
udelay(1);
} while (j > 0);
data = sp->psc_smbtxrx;
au_sync();
*ret_data = data;
return 0;
}
static int
i2c_read(struct i2c_au1550_data *adap, unsigned char *buf,
unsigned int len)
{
int i;
u32 data;
volatile psc_smb_t *sp;
if (len == 0)
return 0;
/* A read is performed by stuffing the transmit fifo with
* zero bytes for timing, waiting for bytes to appear in the
* receive fifo, then reading the bytes.
*/
sp = (volatile psc_smb_t *)(adap->psc_base);
i = 0;
while (i < (len-1)) {
sp->psc_smbtxrx = 0;
au_sync();
if (wait_for_rx_byte(adap, &data))
return -EIO;
buf[i] = data;
i++;
}
/* The last byte has to indicate transfer done.
*/
sp->psc_smbtxrx = PSC_SMBTXRX_STP;
au_sync();
if (wait_master_done(adap))
return -EIO;
data = sp->psc_smbtxrx;
au_sync();
buf[i] = data;
return 0;
}
static int
i2c_write(struct i2c_au1550_data *adap, unsigned char *buf,
unsigned int len)
{
int i;
u32 data;
volatile psc_smb_t *sp;
if (len == 0)
return 0;
sp = (volatile psc_smb_t *)(adap->psc_base);
i = 0;
while (i < (len-1)) {
data = buf[i];
sp->psc_smbtxrx = data;
au_sync();
if (wait_ack(adap))
return -EIO;
i++;
}
/* The last byte has to indicate transfer done.
*/
data = buf[i];
data |= PSC_SMBTXRX_STP;
sp->psc_smbtxrx = data;
au_sync();
if (wait_master_done(adap))
return -EIO;
return 0;
}
static int
au1550_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
{
struct i2c_au1550_data *adap = i2c_adap->algo_data;
struct i2c_msg *p;
int i, err = 0;
for (i = 0; !err && i < num; i++) {
p = &msgs[i];
err = do_address(adap, p->addr, p->flags & I2C_M_RD,
(p->len == 0));
if (err || !p->len)
continue;
if (p->flags & I2C_M_RD)
err = i2c_read(adap, p->buf, p->len);
else
err = i2c_write(adap, p->buf, p->len);
}
/* Return the number of messages processed, or the error code.
*/
if (err == 0)
err = num;
return err;
}
static u32
au1550_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm au1550_algo = {
.master_xfer = au1550_xfer,
.functionality = au1550_func,
};
/*
* registering functions to load algorithms at runtime
* Prior to calling us, the 50MHz clock frequency and routing
* must have been set up for the PSC indicated by the adapter.
*/
static int __devinit
i2c_au1550_probe(struct platform_device *pdev)
{
struct i2c_au1550_data *priv;
volatile psc_smb_t *sp;
struct resource *r;
u32 stat;
int ret;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!r) {
ret = -ENODEV;
goto out;
}
priv = kzalloc(sizeof(struct i2c_au1550_data), GFP_KERNEL);
if (!priv) {
ret = -ENOMEM;
goto out;
}
priv->ioarea = request_mem_region(r->start, r->end - r->start + 1,
pdev->name);
if (!priv->ioarea) {
ret = -EBUSY;
goto out_mem;
}
priv->psc_base = CKSEG1ADDR(r->start);
priv->xfer_timeout = 200;
priv->ack_timeout = 200;
priv->adap.id = I2C_HW_AU1550_PSC;
priv->adap.nr = pdev->id;
priv->adap.algo = &au1550_algo;
priv->adap.algo_data = priv;
priv->adap.dev.parent = &pdev->dev;
strlcpy(priv->adap.name, "Au1xxx PSC I2C", sizeof(priv->adap.name));
/* Now, set up the PSC for SMBus PIO mode.
*/
sp = (volatile psc_smb_t *)priv->psc_base;
sp->psc_ctrl = PSC_CTRL_DISABLE;
au_sync();
sp->psc_sel = PSC_SEL_PS_SMBUSMODE;
sp->psc_smbcfg = 0;
au_sync();
sp->psc_ctrl = PSC_CTRL_ENABLE;
au_sync();
do {
stat = sp->psc_smbstat;
au_sync();
} while ((stat & PSC_SMBSTAT_SR) == 0);
sp->psc_smbcfg = (PSC_SMBCFG_RT_FIFO8 | PSC_SMBCFG_TT_FIFO8 |
PSC_SMBCFG_DD_DISABLE);
/* Divide by 8 to get a 6.25 MHz clock. The later protocol
* timings are based on this clock.
*/
sp->psc_smbcfg |= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8);
sp->psc_smbmsk = PSC_SMBMSK_ALLMASK;
au_sync();
/* Set the protocol timer values. See Table 71 in the
* Au1550 Data Book for standard timing values.
*/
sp->psc_smbtmr = PSC_SMBTMR_SET_TH(0) | PSC_SMBTMR_SET_PS(15) | \
PSC_SMBTMR_SET_PU(15) | PSC_SMBTMR_SET_SH(15) | \
PSC_SMBTMR_SET_SU(15) | PSC_SMBTMR_SET_CL(15) | \
PSC_SMBTMR_SET_CH(15);
au_sync();
sp->psc_smbcfg |= PSC_SMBCFG_DE_ENABLE;
do {
stat = sp->psc_smbstat;
au_sync();
} while ((stat & PSC_SMBSTAT_DR) == 0);
ret = i2c_add_numbered_adapter(&priv->adap);
if (ret == 0) {
platform_set_drvdata(pdev, priv);
return 0;
}
/* disable the PSC */
sp->psc_smbcfg = 0;
sp->psc_ctrl = PSC_CTRL_DISABLE;
au_sync();
release_resource(priv->ioarea);
kfree(priv->ioarea);
out_mem:
kfree(priv);
out:
return ret;
}
static int __devexit
i2c_au1550_remove(struct platform_device *pdev)
{
struct i2c_au1550_data *priv = platform_get_drvdata(pdev);
volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base;
platform_set_drvdata(pdev, NULL);
i2c_del_adapter(&priv->adap);
sp->psc_smbcfg = 0;
sp->psc_ctrl = PSC_CTRL_DISABLE;
au_sync();
release_resource(priv->ioarea);
kfree(priv->ioarea);
kfree(priv);
return 0;
}
static int
i2c_au1550_suspend(struct platform_device *pdev, pm_message_t state)
{
struct i2c_au1550_data *priv = platform_get_drvdata(pdev);
volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base;
sp->psc_ctrl = PSC_CTRL_SUSPEND;
au_sync();
return 0;
}
static int
i2c_au1550_resume(struct platform_device *pdev)
{
struct i2c_au1550_data *priv = platform_get_drvdata(pdev);
volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base;
sp->psc_ctrl = PSC_CTRL_ENABLE;
au_sync();
while (!(sp->psc_smbstat & PSC_SMBSTAT_SR))
au_sync();
return 0;
}
static struct platform_driver au1xpsc_smbus_driver = {
.driver = {
.name = "au1xpsc_smbus",
.owner = THIS_MODULE,
},
.probe = i2c_au1550_probe,
.remove = __devexit_p(i2c_au1550_remove),
.suspend = i2c_au1550_suspend,
.resume = i2c_au1550_resume,
};
static int __init
i2c_au1550_init(void)
{
return platform_driver_register(&au1xpsc_smbus_driver);
}
static void __exit
i2c_au1550_exit(void)
{
platform_driver_unregister(&au1xpsc_smbus_driver);
}
MODULE_AUTHOR("Dan Malek, Embedded Edge, LLC.");
MODULE_DESCRIPTION("SMBus adapter Alchemy pb1550");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:au1xpsc_smbus");
module_init (i2c_au1550_init);
module_exit (i2c_au1550_exit);