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i2c-algo-pca: Add PCA9665 support

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Add support for the PCA9665 I2C controller.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Marco Aurelio da Costa
2009-03-28 21:34:44 +01:00
committed by Jean Delvare
parent bac3e7c2aa
commit eff9ec95ef
5 changed files with 216 additions and 28 deletions
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180
drivers/i2c/algos/i2c-algo-pca.c
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@ -46,6 +46,14 @@ static int i2c_debug;
#define pca_wait(adap) adap->wait_for_completion(adap->data)
#define pca_reset(adap) adap->reset_chip(adap->data)
static void pca9665_reset(void *pd)
{
struct i2c_algo_pca_data *adap = pd;
pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);
pca_outw(adap, I2C_PCA_IND, 0xA5);
pca_outw(adap, I2C_PCA_IND, 0x5A);
}
/*
* Generate a start condition on the i2c bus.
*
@ -333,27 +341,171 @@ static const struct i2c_algorithm pca_algo = {
.functionality = pca_func,
};
static unsigned int pca_probe_chip(struct i2c_adapter *adap)
{
struct i2c_algo_pca_data *pca_data = adap->algo_data;
/* The trick here is to check if there is an indirect register
* available. If there is one, we will read the value we first
* wrote on I2C_PCA_IADR. Otherwise, we will read the last value
* we wrote on I2C_PCA_ADR
*/
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
pca_outw(pca_data, I2C_PCA_IND, 0xAA);
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO);
pca_outw(pca_data, I2C_PCA_IND, 0x00);
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) {
printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name);
return I2C_PCA_CHIP_9665;
} else {
printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name);
return I2C_PCA_CHIP_9564;
}
}
static int pca_init(struct i2c_adapter *adap)
{
static int freqs[] = {330,288,217,146,88,59,44,36};
int clock;
struct i2c_algo_pca_data *pca_data = adap->algo_data;
if (pca_data->i2c_clock > 7) {
printk(KERN_WARNING "%s: Invalid I2C clock speed selected. Trying default.\n",
adap->name);
pca_data->i2c_clock = I2C_PCA_CON_59kHz;
}
adap->algo = &pca_algo;
pca_reset(pca_data);
if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) {
static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36};
int clock;
clock = pca_clock(pca_data);
printk(KERN_INFO "%s: Clock frequency is %dkHz\n", adap->name,
freqs[clock]);
if (pca_data->i2c_clock > 7) {
switch (pca_data->i2c_clock) {
case 330000:
pca_data->i2c_clock = I2C_PCA_CON_330kHz;
break;
case 288000:
pca_data->i2c_clock = I2C_PCA_CON_288kHz;
break;
case 217000:
pca_data->i2c_clock = I2C_PCA_CON_217kHz;
break;
case 146000:
pca_data->i2c_clock = I2C_PCA_CON_146kHz;
break;
case 88000:
pca_data->i2c_clock = I2C_PCA_CON_88kHz;
break;
case 59000:
pca_data->i2c_clock = I2C_PCA_CON_59kHz;
break;
case 44000:
pca_data->i2c_clock = I2C_PCA_CON_44kHz;
break;
case 36000:
pca_data->i2c_clock = I2C_PCA_CON_36kHz;
break;
default:
printk(KERN_WARNING
"%s: Invalid I2C clock speed selected."
" Using default 59kHz.\n", adap->name);
pca_data->i2c_clock = I2C_PCA_CON_59kHz;
}
} else {
printk(KERN_WARNING "%s: "
"Choosing the clock frequency based on "
"index is deprecated."
" Use the nominal frequency.\n", adap->name);
}
pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock);
pca_reset(pca_data);
clock = pca_clock(pca_data);
printk(KERN_INFO "%s: Clock frequency is %dkHz\n",
adap->name, freqs[clock]);
pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock);
} else {
int clock;
int mode;
int tlow, thi;
/* Values can be found on PCA9665 datasheet section 7.3.2.6 */
int min_tlow, min_thi;
/* These values are the maximum raise and fall values allowed
* by the I2C operation mode (Standard, Fast or Fast+)
* They are used (added) below to calculate the clock dividers
* of PCA9665. Note that they are slightly different of the
* real maximum, to allow the change on mode exactly on the
* maximum clock rate for each mode
*/
int raise_fall_time;
struct i2c_algo_pca_data *pca_data = adap->algo_data;
/* Ignore the reset function from the module,
* we can use the parallel bus reset
*/
pca_data->reset_chip = pca9665_reset;
if (pca_data->i2c_clock > 1265800) {
printk(KERN_WARNING "%s: I2C clock speed too high."
" Using 1265.8kHz.\n", adap->name);
pca_data->i2c_clock = 1265800;
}
if (pca_data->i2c_clock < 60300) {
printk(KERN_WARNING "%s: I2C clock speed too low."
" Using 60.3kHz.\n", adap->name);
pca_data->i2c_clock = 60300;
}
/* To avoid integer overflow, use clock/100 for calculations */
clock = pca_clock(pca_data) / 100;
if (pca_data->i2c_clock > 10000) {
mode = I2C_PCA_MODE_TURBO;
min_tlow = 14;
min_thi = 5;
raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
} else if (pca_data->i2c_clock > 4000) {
mode = I2C_PCA_MODE_FASTP;
min_tlow = 17;
min_thi = 9;
raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
} else if (pca_data->i2c_clock > 1000) {
mode = I2C_PCA_MODE_FAST;
min_tlow = 44;
min_thi = 20;
raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */
} else {
mode = I2C_PCA_MODE_STD;
min_tlow = 157;
min_thi = 134;
raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */
}
/* The minimum clock that respects the thi/tlow = 134/157 is
* 64800 Hz. Below that, we have to fix the tlow to 255 and
* calculate the thi factor.
*/
if (clock < 648) {
tlow = 255;
thi = 1000000 - clock * raise_fall_time;
thi /= (I2C_PCA_OSC_PER * clock) - tlow;
} else {
tlow = (1000000 - clock * raise_fall_time) * min_tlow;
tlow /= I2C_PCA_OSC_PER * clock * (min_thi + min_tlow);
thi = tlow * min_thi / min_tlow;
}
pca_reset(pca_data);
printk(KERN_INFO
"%s: Clock frequency is %dHz\n", adap->name, clock * 100);
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IMODE);
pca_outw(pca_data, I2C_PCA_IND, mode);
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLL);
pca_outw(pca_data, I2C_PCA_IND, tlow);
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLH);
pca_outw(pca_data, I2C_PCA_IND, thi);
pca_set_con(pca_data, I2C_PCA_CON_ENSIO);
}
udelay(500); /* 500 us for oscilator to stabilise */
return 0;
@ -388,7 +540,7 @@ EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
"Wolfram Sang <w.sang@pengutronix.de>");
MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm");
MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
MODULE_LICENSE("GPL");
module_param(i2c_debug, int, 0);