diff options
Diffstat (limited to 'drivers/i2c/algos/i2c-algo-pca.c')
-rw-r--r-- | drivers/i2c/algos/i2c-algo-pca.c | 250 |
1 files changed, 207 insertions, 43 deletions
diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c index d50b329..f68e5f8 100644 --- a/drivers/i2c/algos/i2c-algo-pca.c +++ b/drivers/i2c/algos/i2c-algo-pca.c @@ -22,14 +22,18 @@ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/delay.h> +#include <linux/jiffies.h> #include <linux/init.h> #include <linux/errno.h> #include <linux/i2c.h> #include <linux/i2c-algo-pca.h> -#define DEB1(fmt, args...) do { if (i2c_debug>=1) printk(fmt, ## args); } while(0) -#define DEB2(fmt, args...) do { if (i2c_debug>=2) printk(fmt, ## args); } while(0) -#define DEB3(fmt, args...) do { if (i2c_debug>=3) printk(fmt, ## args); } while(0) +#define DEB1(fmt, args...) do { if (i2c_debug >= 1) \ + printk(KERN_DEBUG fmt, ## args); } while (0) +#define DEB2(fmt, args...) do { if (i2c_debug >= 2) \ + printk(KERN_DEBUG fmt, ## args); } while (0) +#define DEB3(fmt, args...) do { if (i2c_debug >= 3) \ + printk(KERN_DEBUG fmt, ## args); } while (0) static int i2c_debug; @@ -43,19 +47,27 @@ 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. * * returns after the start condition has occurred */ -static void pca_start(struct i2c_algo_pca_data *adap) +static int pca_start(struct i2c_algo_pca_data *adap) { int sta = pca_get_con(adap); DEB2("=== START\n"); sta |= I2C_PCA_CON_STA; sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI); pca_set_con(adap, sta); - pca_wait(adap); + return pca_wait(adap); } /* @@ -63,14 +75,14 @@ static void pca_start(struct i2c_algo_pca_data *adap) * * return after the repeated start condition has occurred */ -static void pca_repeated_start(struct i2c_algo_pca_data *adap) +static int pca_repeated_start(struct i2c_algo_pca_data *adap) { int sta = pca_get_con(adap); DEB2("=== REPEATED START\n"); sta |= I2C_PCA_CON_STA; sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI); pca_set_con(adap, sta); - pca_wait(adap); + return pca_wait(adap); } /* @@ -96,7 +108,7 @@ static void pca_stop(struct i2c_algo_pca_data *adap) * * returns after the address has been sent */ -static void pca_address(struct i2c_algo_pca_data *adap, +static int pca_address(struct i2c_algo_pca_data *adap, struct i2c_msg *msg) { int sta = pca_get_con(adap); @@ -113,7 +125,7 @@ static void pca_address(struct i2c_algo_pca_data *adap, sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); pca_set_con(adap, sta); - pca_wait(adap); + return pca_wait(adap); } /* @@ -121,7 +133,7 @@ static void pca_address(struct i2c_algo_pca_data *adap, * * Returns after the byte has been transmitted */ -static void pca_tx_byte(struct i2c_algo_pca_data *adap, +static int pca_tx_byte(struct i2c_algo_pca_data *adap, __u8 b) { int sta = pca_get_con(adap); @@ -131,7 +143,7 @@ static void pca_tx_byte(struct i2c_algo_pca_data *adap, sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); pca_set_con(adap, sta); - pca_wait(adap); + return pca_wait(adap); } /* @@ -151,7 +163,7 @@ static void pca_rx_byte(struct i2c_algo_pca_data *adap, * * Returns after next byte has arrived. */ -static void pca_rx_ack(struct i2c_algo_pca_data *adap, +static int pca_rx_ack(struct i2c_algo_pca_data *adap, int ack) { int sta = pca_get_con(adap); @@ -162,7 +174,7 @@ static void pca_rx_ack(struct i2c_algo_pca_data *adap, sta |= I2C_PCA_CON_AA; pca_set_con(adap, sta); - pca_wait(adap); + return pca_wait(adap); } static int pca_xfer(struct i2c_adapter *i2c_adap, @@ -175,14 +187,17 @@ static int pca_xfer(struct i2c_adapter *i2c_adap, int numbytes = 0; int state; int ret; - int timeout = i2c_adap->timeout; - - while ((state = pca_status(adap)) != 0xf8 && timeout--) { - msleep(10); - } - if (state != 0xf8) { - dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state); - return -EAGAIN; + int completed = 1; + unsigned long timeout = jiffies + i2c_adap->timeout; + + while (pca_status(adap) != 0xf8) { + if (time_before(jiffies, timeout)) { + msleep(10); + } else { + dev_dbg(&i2c_adap->dev, "bus is not idle. status is " + "%#04x\n", state); + return -EAGAIN; + } } DEB1("{{{ XFER %d messages\n", num); @@ -218,18 +233,19 @@ static int pca_xfer(struct i2c_adapter *i2c_adap, switch (state) { case 0xf8: /* On reset or stop the bus is idle */ - pca_start(adap); + completed = pca_start(adap); break; case 0x08: /* A START condition has been transmitted */ case 0x10: /* A repeated start condition has been transmitted */ - pca_address(adap, msg); + completed = pca_address(adap, msg); break; case 0x18: /* SLA+W has been transmitted; ACK has been received */ case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */ if (numbytes < msg->len) { - pca_tx_byte(adap, msg->buf[numbytes]); + completed = pca_tx_byte(adap, + msg->buf[numbytes]); numbytes++; break; } @@ -237,7 +253,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap, if (curmsg == num) pca_stop(adap); else - pca_repeated_start(adap); + completed = pca_repeated_start(adap); break; case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */ @@ -246,21 +262,22 @@ static int pca_xfer(struct i2c_adapter *i2c_adap, goto out; case 0x40: /* SLA+R has been transmitted; ACK has been received */ - pca_rx_ack(adap, msg->len > 1); + completed = pca_rx_ack(adap, msg->len > 1); break; case 0x50: /* Data bytes has been received; ACK has been returned */ if (numbytes < msg->len) { pca_rx_byte(adap, &msg->buf[numbytes], 1); numbytes++; - pca_rx_ack(adap, numbytes < msg->len - 1); + completed = pca_rx_ack(adap, + numbytes < msg->len - 1); break; } curmsg++; numbytes = 0; if (curmsg == num) pca_stop(adap); else - pca_repeated_start(adap); + completed = pca_repeated_start(adap); break; case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */ @@ -283,7 +300,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap, if (curmsg == num) pca_stop(adap); else - pca_repeated_start(adap); + completed = pca_repeated_start(adap); } else { DEB2("NOT ACK sent after data byte received. " "Not final byte. numbytes %d. len %d\n", @@ -309,11 +326,13 @@ static int pca_xfer(struct i2c_adapter *i2c_adap, break; } + if (!completed) + goto out; } ret = curmsg; out: - DEB1(KERN_CRIT "}}} transfered %d/%d messages. " + DEB1("}}} transfered %d/%d messages. " "status is %#04x. control is %#04x\n", curmsg, num, pca_status(adap), pca_get_con(adap)); @@ -330,26 +349,171 @@ static const struct i2c_algorithm pca_algo = { .functionality = pca_func, }; -static int pca_init(struct i2c_adapter *adap) +static unsigned int pca_probe_chip(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; + /* 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) +{ + struct i2c_algo_pca_data *pca_data = adap->algo_data; 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; + + 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_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; + } - clock = pca_clock(pca_data); - DEB1(KERN_INFO "%s: Clock frequency is %dkHz\n", adap->name, freqs[clock]); + /* 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_set_con(pca_data, I2C_PCA_CON_ENSIO | clock); + 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; @@ -384,7 +548,7 @@ 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); |