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linux/drivers/i2c/busses/i2c-mpc.c
Wolfgang Grandegger 1904b03430 i2c-mpc: bug fix for MPC52xx clock setting and printout 
The clock setting did not work for the MPC52xx due to a stupid bug.
Furthermore, the dev info output "clock=0" for old device trees was
misleading. This patch fixes both issues.

Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-05-12 00:35:56 +01:00

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/*
* (C) Copyright 2003-2004
* Humboldt Solutions Ltd, adrian@humboldt.co.uk.
* This is a combined i2c adapter and algorithm driver for the
* MPC107/Tsi107 PowerPC northbridge and processors that include
* the same I2C unit (8240, 8245, 85xx).
*
* Release 0.8
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/of_platform.h>
#include <linux/of_i2c.h>
#include <linux/io.h>
#include <linux/fsl_devices.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <asm/mpc52xx.h>
#include <sysdev/fsl_soc.h>
#define DRV_NAME "mpc-i2c"
#define MPC_I2C_FDR 0x04
#define MPC_I2C_CR 0x08
#define MPC_I2C_SR 0x0c
#define MPC_I2C_DR 0x10
#define MPC_I2C_DFSRR 0x14
#define CCR_MEN 0x80
#define CCR_MIEN 0x40
#define CCR_MSTA 0x20
#define CCR_MTX 0x10
#define CCR_TXAK 0x08
#define CCR_RSTA 0x04
#define CSR_MCF 0x80
#define CSR_MAAS 0x40
#define CSR_MBB 0x20
#define CSR_MAL 0x10
#define CSR_SRW 0x04
#define CSR_MIF 0x02
#define CSR_RXAK 0x01
struct mpc_i2c {
struct device *dev;
void __iomem *base;
u32 interrupt;
wait_queue_head_t queue;
struct i2c_adapter adap;
int irq;
};
struct mpc_i2c_divider {
u16 divider;
u16 fdr; /* including dfsrr */
};
struct mpc_i2c_match_data {
void (*setclock)(struct device_node *node,
struct mpc_i2c *i2c,
u32 clock, u32 prescaler);
u32 prescaler;
};
static inline void writeccr(struct mpc_i2c *i2c, u32 x)
{
writeb(x, i2c->base + MPC_I2C_CR);
}
static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
{
struct mpc_i2c *i2c = dev_id;
if (readb(i2c->base + MPC_I2C_SR) & CSR_MIF) {
/* Read again to allow register to stabilise */
i2c->interrupt = readb(i2c->base + MPC_I2C_SR);
writeb(0, i2c->base + MPC_I2C_SR);
wake_up(&i2c->queue);
}
return IRQ_HANDLED;
}
/* Sometimes 9th clock pulse isn't generated, and slave doesn't release
* the bus, because it wants to send ACK.
* Following sequence of enabling/disabling and sending start/stop generates
* the pulse, so it's all OK.
*/
static void mpc_i2c_fixup(struct mpc_i2c *i2c)
{
writeccr(i2c, 0);
udelay(30);
writeccr(i2c, CCR_MEN);
udelay(30);
writeccr(i2c, CCR_MSTA | CCR_MTX);
udelay(30);
writeccr(i2c, CCR_MSTA | CCR_MTX | CCR_MEN);
udelay(30);
writeccr(i2c, CCR_MEN);
udelay(30);
}
static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
{
unsigned long orig_jiffies = jiffies;
u32 x;
int result = 0;
if (i2c->irq == NO_IRQ) {
while (!(readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
schedule();
if (time_after(jiffies, orig_jiffies + timeout)) {
dev_dbg(i2c->dev, "timeout\n");
writeccr(i2c, 0);
result = -EIO;
break;
}
}
x = readb(i2c->base + MPC_I2C_SR);
writeb(0, i2c->base + MPC_I2C_SR);
} else {
/* Interrupt mode */
result = wait_event_timeout(i2c->queue,
(i2c->interrupt & CSR_MIF), timeout);
if (unlikely(!(i2c->interrupt & CSR_MIF))) {
dev_dbg(i2c->dev, "wait timeout\n");
writeccr(i2c, 0);
result = -ETIMEDOUT;
}
x = i2c->interrupt;
i2c->interrupt = 0;
}
if (result < 0)
return result;
if (!(x & CSR_MCF)) {
dev_dbg(i2c->dev, "unfinished\n");
return -EIO;
}
if (x & CSR_MAL) {
dev_dbg(i2c->dev, "MAL\n");
return -EIO;
}
if (writing && (x & CSR_RXAK)) {
dev_dbg(i2c->dev, "No RXAK\n");
/* generate stop */
writeccr(i2c, CCR_MEN);
return -EIO;
}
return 0;
}
#ifdef CONFIG_PPC_MPC52xx
static const struct mpc_i2c_divider mpc_i2c_dividers_52xx[] = {
{20, 0x20}, {22, 0x21}, {24, 0x22}, {26, 0x23},
{28, 0x24}, {30, 0x01}, {32, 0x25}, {34, 0x02},
{36, 0x26}, {40, 0x27}, {44, 0x04}, {48, 0x28},
{52, 0x63}, {56, 0x29}, {60, 0x41}, {64, 0x2a},
{68, 0x07}, {72, 0x2b}, {80, 0x2c}, {88, 0x09},
{96, 0x2d}, {104, 0x0a}, {112, 0x2e}, {120, 0x81},
{128, 0x2f}, {136, 0x47}, {144, 0x0c}, {160, 0x30},
{176, 0x49}, {192, 0x31}, {208, 0x4a}, {224, 0x32},
{240, 0x0f}, {256, 0x33}, {272, 0x87}, {288, 0x10},
{320, 0x34}, {352, 0x89}, {384, 0x35}, {416, 0x8a},
{448, 0x36}, {480, 0x13}, {512, 0x37}, {576, 0x14},
{640, 0x38}, {768, 0x39}, {896, 0x3a}, {960, 0x17},
{1024, 0x3b}, {1152, 0x18}, {1280, 0x3c}, {1536, 0x3d},
{1792, 0x3e}, {1920, 0x1b}, {2048, 0x3f}, {2304, 0x1c},
{2560, 0x1d}, {3072, 0x1e}, {3584, 0x7e}, {3840, 0x1f},
{4096, 0x7f}, {4608, 0x5c}, {5120, 0x5d}, {6144, 0x5e},
{7168, 0xbe}, {7680, 0x5f}, {8192, 0xbf}, {9216, 0x9c},
{10240, 0x9d}, {12288, 0x9e}, {15360, 0x9f}
};
int mpc_i2c_get_fdr_52xx(struct device_node *node, u32 clock, int prescaler)
{
const struct mpc_i2c_divider *div = NULL;
unsigned int pvr = mfspr(SPRN_PVR);
u32 divider;
int i;
if (!clock)
return -EINVAL;
/* Determine divider value */
divider = mpc52xx_find_ipb_freq(node) / clock;
/*
* We want to choose an FDR/DFSR that generates an I2C bus speed that
* is equal to or lower than the requested speed.
*/
for (i = 0; i < ARRAY_SIZE(mpc_i2c_dividers_52xx); i++) {
div = &mpc_i2c_dividers_52xx[i];
/* Old MPC5200 rev A CPUs do not support the high bits */
if (div->fdr & 0xc0 && pvr == 0x80822011)
continue;
if (div->divider >= divider)
break;
}
return div ? (int)div->fdr : -EINVAL;
}
static void mpc_i2c_setclock_52xx(struct device_node *node,
struct mpc_i2c *i2c,
u32 clock, u32 prescaler)
{
int ret, fdr;
ret = mpc_i2c_get_fdr_52xx(node, clock, prescaler);
fdr = (ret >= 0) ? ret : 0x3f; /* backward compatibility */
writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
if (ret >= 0)
dev_info(i2c->dev, "clock %d Hz (fdr=%d)\n", clock, fdr);
}
#else /* !CONFIG_PPC_MPC52xx */
static void mpc_i2c_setclock_52xx(struct device_node *node,
struct mpc_i2c *i2c,
u32 clock, u32 prescaler)
{
}
#endif /* CONFIG_PPC_MPC52xx*/
#ifdef CONFIG_FSL_SOC
static const struct mpc_i2c_divider mpc_i2c_dividers_8xxx[] = {
{160, 0x0120}, {192, 0x0121}, {224, 0x0122}, {256, 0x0123},
{288, 0x0100}, {320, 0x0101}, {352, 0x0601}, {384, 0x0102},
{416, 0x0602}, {448, 0x0126}, {480, 0x0103}, {512, 0x0127},
{544, 0x0b03}, {576, 0x0104}, {608, 0x1603}, {640, 0x0105},
{672, 0x2003}, {704, 0x0b05}, {736, 0x2b03}, {768, 0x0106},
{800, 0x3603}, {832, 0x0b06}, {896, 0x012a}, {960, 0x0107},
{1024, 0x012b}, {1088, 0x1607}, {1152, 0x0108}, {1216, 0x2b07},
{1280, 0x0109}, {1408, 0x1609}, {1536, 0x010a}, {1664, 0x160a},
{1792, 0x012e}, {1920, 0x010b}, {2048, 0x012f}, {2176, 0x2b0b},
{2304, 0x010c}, {2560, 0x010d}, {2816, 0x2b0d}, {3072, 0x010e},
{3328, 0x2b0e}, {3584, 0x0132}, {3840, 0x010f}, {4096, 0x0133},
{4608, 0x0110}, {5120, 0x0111}, {6144, 0x0112}, {7168, 0x0136},
{7680, 0x0113}, {8192, 0x0137}, {9216, 0x0114}, {10240, 0x0115},
{12288, 0x0116}, {14336, 0x013a}, {15360, 0x0117}, {16384, 0x013b},
{18432, 0x0118}, {20480, 0x0119}, {24576, 0x011a}, {28672, 0x013e},
{30720, 0x011b}, {32768, 0x013f}, {36864, 0x011c}, {40960, 0x011d},
{49152, 0x011e}, {61440, 0x011f}
};
u32 mpc_i2c_get_sec_cfg_8xxx(void)
{
struct device_node *node = NULL;
u32 __iomem *reg;
u32 val = 0;
node = of_find_node_by_name(NULL, "global-utilities");
if (node) {
const u32 *prop = of_get_property(node, "reg", NULL);
if (prop) {
/*
* Map and check POR Device Status Register 2
* (PORDEVSR2) at 0xE0014
*/
reg = ioremap(get_immrbase() + *prop + 0x14, 0x4);
if (!reg)
printk(KERN_ERR
"Error: couldn't map PORDEVSR2\n");
else
val = in_be32(reg) & 0x00000080; /* sec-cfg */
iounmap(reg);
}
}
if (node)
of_node_put(node);
return val;
}
int mpc_i2c_get_fdr_8xxx(struct device_node *node, u32 clock, u32 prescaler)
{
const struct mpc_i2c_divider *div = NULL;
u32 divider;
int i;
if (!clock)
return -EINVAL;
/* Determine proper divider value */
if (of_device_is_compatible(node, "fsl,mpc8544-i2c"))
prescaler = mpc_i2c_get_sec_cfg_8xxx() ? 3 : 2;
if (!prescaler)
prescaler = 1;
divider = fsl_get_sys_freq() / clock / prescaler;
pr_debug("I2C: src_clock=%d clock=%d divider=%d\n",
fsl_get_sys_freq(), clock, divider);
/*
* We want to choose an FDR/DFSR that generates an I2C bus speed that
* is equal to or lower than the requested speed.
*/
for (i = 0; i < ARRAY_SIZE(mpc_i2c_dividers_8xxx); i++) {
div = &mpc_i2c_dividers_8xxx[i];
if (div->divider >= divider)
break;
}
return div ? (int)div->fdr : -EINVAL;
}
static void mpc_i2c_setclock_8xxx(struct device_node *node,
struct mpc_i2c *i2c,
u32 clock, u32 prescaler)
{
int ret, fdr;
ret = mpc_i2c_get_fdr_8xxx(node, clock, prescaler);
fdr = (ret >= 0) ? ret : 0x1031; /* backward compatibility */
writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
writeb((fdr >> 8) & 0xff, i2c->base + MPC_I2C_DFSRR);
if (ret >= 0)
dev_info(i2c->dev, "clock %d Hz (dfsrr=%d fdr=%d)\n",
clock, fdr >> 8, fdr & 0xff);
}
#else /* !CONFIG_FSL_SOC */
static void mpc_i2c_setclock_8xxx(struct device_node *node,
struct mpc_i2c *i2c,
u32 clock, u32 prescaler)
{
}
#endif /* CONFIG_FSL_SOC */
static void mpc_i2c_start(struct mpc_i2c *i2c)
{
/* Clear arbitration */
writeb(0, i2c->base + MPC_I2C_SR);
/* Start with MEN */
writeccr(i2c, CCR_MEN);
}
static void mpc_i2c_stop(struct mpc_i2c *i2c)
{
writeccr(i2c, CCR_MEN);
}
static int mpc_write(struct mpc_i2c *i2c, int target,
const u8 *data, int length, int restart)
{
int i, result;
unsigned timeout = i2c->adap.timeout;
u32 flags = restart ? CCR_RSTA : 0;
/* Start with MEN */
if (!restart)
writeccr(i2c, CCR_MEN);
/* Start as master */
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
/* Write target byte */
writeb((target << 1), i2c->base + MPC_I2C_DR);
result = i2c_wait(i2c, timeout, 1);
if (result < 0)
return result;
for (i = 0; i < length; i++) {
/* Write data byte */
writeb(data[i], i2c->base + MPC_I2C_DR);
result = i2c_wait(i2c, timeout, 1);
if (result < 0)
return result;
}
return 0;
}
static int mpc_read(struct mpc_i2c *i2c, int target,
u8 *data, int length, int restart)
{
unsigned timeout = i2c->adap.timeout;
int i, result;
u32 flags = restart ? CCR_RSTA : 0;
/* Start with MEN */
if (!restart)
writeccr(i2c, CCR_MEN);
/* Switch to read - restart */
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
/* Write target address byte - this time with the read flag set */
writeb((target << 1) | 1, i2c->base + MPC_I2C_DR);
result = i2c_wait(i2c, timeout, 1);
if (result < 0)
return result;
if (length) {
if (length == 1)
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
else
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA);
/* Dummy read */
readb(i2c->base + MPC_I2C_DR);
}
for (i = 0; i < length; i++) {
result = i2c_wait(i2c, timeout, 0);
if (result < 0)
return result;
/* Generate txack on next to last byte */
if (i == length - 2)
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
/* Generate stop on last byte */
if (i == length - 1)
writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_TXAK);
data[i] = readb(i2c->base + MPC_I2C_DR);
}
return length;
}
static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
struct i2c_msg *pmsg;
int i;
int ret = 0;
unsigned long orig_jiffies = jiffies;
struct mpc_i2c *i2c = i2c_get_adapdata(adap);
mpc_i2c_start(i2c);
/* Allow bus up to 1s to become not busy */
while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
if (signal_pending(current)) {
dev_dbg(i2c->dev, "Interrupted\n");
writeccr(i2c, 0);
return -EINTR;
}
if (time_after(jiffies, orig_jiffies + HZ)) {
dev_dbg(i2c->dev, "timeout\n");
if (readb(i2c->base + MPC_I2C_SR) ==
(CSR_MCF | CSR_MBB | CSR_RXAK))
mpc_i2c_fixup(i2c);
return -EIO;
}
schedule();
}
for (i = 0; ret >= 0 && i < num; i++) {
pmsg = &msgs[i];
dev_dbg(i2c->dev,
"Doing %s %d bytes to 0x%02x - %d of %d messages\n",
pmsg->flags & I2C_M_RD ? "read" : "write",
pmsg->len, pmsg->addr, i + 1, num);
if (pmsg->flags & I2C_M_RD)
ret =
mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
else
ret =
mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
}
mpc_i2c_stop(i2c);
return (ret < 0) ? ret : num;
}
static u32 mpc_functionality(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm mpc_algo = {
.master_xfer = mpc_xfer,
.functionality = mpc_functionality,
};
static struct i2c_adapter mpc_ops = {
.owner = THIS_MODULE,
.name = "MPC adapter",
.algo = &mpc_algo,
.timeout = HZ,
};
static int __devinit fsl_i2c_probe(struct of_device *op,
const struct of_device_id *match)
{
struct mpc_i2c *i2c;
const u32 *prop;
u32 clock = 0;
int result = 0;
int plen;
i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
if (!i2c)
return -ENOMEM;
i2c->dev = &op->dev; /* for debug and error output */
init_waitqueue_head(&i2c->queue);
i2c->base = of_iomap(op->node, 0);
if (!i2c->base) {
dev_err(i2c->dev, "failed to map controller\n");
result = -ENOMEM;
goto fail_map;
}
i2c->irq = irq_of_parse_and_map(op->node, 0);
if (i2c->irq != NO_IRQ) { /* i2c->irq = NO_IRQ implies polling */
result = request_irq(i2c->irq, mpc_i2c_isr,
IRQF_SHARED, "i2c-mpc", i2c);
if (result < 0) {
dev_err(i2c->dev, "failed to attach interrupt\n");
goto fail_request;
}
}
if (!of_get_property(op->node, "fsl,preserve-clocking", NULL)) {
prop = of_get_property(op->node, "clock-frequency", &plen);
if (prop && plen == sizeof(u32))
clock = *prop;
if (match->data) {
struct mpc_i2c_match_data *data =
(struct mpc_i2c_match_data *)match->data;
data->setclock(op->node, i2c, clock, data->prescaler);
} else {
/* Backwards compatibility */
if (of_get_property(op->node, "dfsrr", NULL))
mpc_i2c_setclock_8xxx(op->node, i2c,
clock, 0);
}
}
dev_set_drvdata(&op->dev, i2c);
i2c->adap = mpc_ops;
i2c_set_adapdata(&i2c->adap, i2c);
i2c->adap.dev.parent = &op->dev;
result = i2c_add_adapter(&i2c->adap);
if (result < 0) {
dev_err(i2c->dev, "failed to add adapter\n");
goto fail_add;
}
of_register_i2c_devices(&i2c->adap, op->node);
return result;
fail_add:
dev_set_drvdata(&op->dev, NULL);
free_irq(i2c->irq, i2c);
fail_request:
irq_dispose_mapping(i2c->irq);
iounmap(i2c->base);
fail_map:
kfree(i2c);
return result;
};
static int __devexit fsl_i2c_remove(struct of_device *op)
{
struct mpc_i2c *i2c = dev_get_drvdata(&op->dev);
i2c_del_adapter(&i2c->adap);
dev_set_drvdata(&op->dev, NULL);
if (i2c->irq != NO_IRQ)
free_irq(i2c->irq, i2c);
irq_dispose_mapping(i2c->irq);
iounmap(i2c->base);
kfree(i2c);
return 0;
};
static const struct of_device_id mpc_i2c_of_match[] = {
{.compatible = "mpc5200-i2c",
.data = &(struct mpc_i2c_match_data) {
.setclock = mpc_i2c_setclock_52xx,
},
},
{.compatible = "fsl,mpc5200b-i2c",
.data = &(struct mpc_i2c_match_data) {
.setclock = mpc_i2c_setclock_52xx,
},
},
{.compatible = "fsl,mpc5200-i2c",
.data = &(struct mpc_i2c_match_data) {
.setclock = mpc_i2c_setclock_52xx,
},
},
{.compatible = "fsl,mpc8313-i2c",
.data = &(struct mpc_i2c_match_data) {
.setclock = mpc_i2c_setclock_8xxx,
},
},
{.compatible = "fsl,mpc8543-i2c",
.data = &(struct mpc_i2c_match_data) {
.setclock = mpc_i2c_setclock_8xxx,
.prescaler = 2,
},
},
{.compatible = "fsl,mpc8544-i2c",
.data = &(struct mpc_i2c_match_data) {
.setclock = mpc_i2c_setclock_8xxx,
.prescaler = 3,
},
/* Backward compatibility */
},
{.compatible = "fsl-i2c", },
{},
};
MODULE_DEVICE_TABLE(of, mpc_i2c_of_match);
/* Structure for a device driver */
static struct of_platform_driver mpc_i2c_driver = {
.match_table = mpc_i2c_of_match,
.probe = fsl_i2c_probe,
.remove = __devexit_p(fsl_i2c_remove),
.driver = {
.owner = THIS_MODULE,
.name = DRV_NAME,
},
};
static int __init fsl_i2c_init(void)
{
int rv;
rv = of_register_platform_driver(&mpc_i2c_driver);
if (rv)
printk(KERN_ERR DRV_NAME
" of_register_platform_driver failed (%i)\n", rv);
return rv;
}
static void __exit fsl_i2c_exit(void)
{
of_unregister_platform_driver(&mpc_i2c_driver);
}
module_init(fsl_i2c_init);
module_exit(fsl_i2c_exit);
MODULE_AUTHOR("Adrian Cox <adrian@humboldt.co.uk>");
MODULE_DESCRIPTION("I2C-Bus adapter for MPC107 bridge and "
"MPC824x/85xx/52xx processors");
MODULE_LICENSE("GPL");
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