/* * i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters * Copyright (C) 2004 Arcom Control Systems * * 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include #include #include #include #include #include #include "i2c-algo-pca.h" #define DRIVER "i2c-algo-pca" #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) static int i2c_debug; #define pca_outw(adap, reg, val) adap->write_byte(adap, reg, val) #define pca_inw(adap, reg) adap->read_byte(adap, reg) #define pca_status(adap) pca_inw(adap, I2C_PCA_STA) #define pca_clock(adap) adap->get_clock(adap) #define pca_own(adap) adap->get_own(adap) #define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val) #define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON) #define pca_wait(adap) adap->wait_for_interrupt(adap) /* * 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) { 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); } /* * Generate a repeated start condition on the i2c bus * * return after the repeated start condition has occurred */ static void 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); } /* * Generate a stop condition on the i2c bus * * returns after the stop condition has been generated * * STOPs do not generate an interrupt or set the SI flag, since the * part returns the idle state (0xf8). Hence we don't need to * pca_wait here. */ static void pca_stop(struct i2c_algo_pca_data *adap) { int sta = pca_get_con(adap); DEB2("=== STOP\n"); sta |= I2C_PCA_CON_STO; sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI); pca_set_con(adap, sta); } /* * Send the slave address and R/W bit * * returns after the address has been sent */ static void pca_address(struct i2c_algo_pca_data *adap, struct i2c_msg *msg) { int sta = pca_get_con(adap); int addr; addr = ( (0x7f & msg->addr) << 1 ); if (msg->flags & I2C_M_RD ) addr |= 1; DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n", msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr); pca_outw(adap, I2C_PCA_DAT, addr); sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); pca_set_con(adap, sta); pca_wait(adap); } /* * Transmit a byte. * * Returns after the byte has been transmitted */ static void pca_tx_byte(struct i2c_algo_pca_data *adap, __u8 b) { int sta = pca_get_con(adap); DEB2("=== WRITE %#04x\n", b); pca_outw(adap, I2C_PCA_DAT, b); sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); pca_set_con(adap, sta); pca_wait(adap); } /* * Receive a byte * * returns immediately. */ static void pca_rx_byte(struct i2c_algo_pca_data *adap, __u8 *b, int ack) { *b = pca_inw(adap, I2C_PCA_DAT); DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK"); } /* * Setup ACK or NACK for next received byte and wait for it to arrive. * * Returns after next byte has arrived. */ static void pca_rx_ack(struct i2c_algo_pca_data *adap, int ack) { int sta = pca_get_con(adap); sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA); if ( ack ) sta |= I2C_PCA_CON_AA; pca_set_con(adap, sta); pca_wait(adap); } /* * Reset the i2c bus / SIO */ static void pca_reset(struct i2c_algo_pca_data *adap) { /* apparently only an external reset will do it. not a lot can be done */ printk(KERN_ERR DRIVER ": Haven't figured out how to do a reset yet\n"); } static int pca_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num) { struct i2c_algo_pca_data *adap = i2c_adap->algo_data; struct i2c_msg *msg = NULL; int curmsg; int numbytes = 0; int state; int ret; int timeout = 100; 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 -EIO; } DEB1("{{{ XFER %d messages\n", num); if (i2c_debug>=2) { for (curmsg = 0; curmsg < num; curmsg++) { int addr, i; msg = &msgs[curmsg]; addr = (0x7f & msg->addr) ; if (msg->flags & I2C_M_RD ) printk(KERN_INFO " [%02d] RD %d bytes from %#02x [%#02x, ...]\n", curmsg, msg->len, addr, (addr<<1) | 1); else { printk(KERN_INFO " [%02d] WR %d bytes to %#02x [%#02x%s", curmsg, msg->len, addr, addr<<1, msg->len == 0 ? "" : ", "); for(i=0; i < msg->len; i++) printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", "); printk("]\n"); } } } curmsg = 0; ret = -EREMOTEIO; while (curmsg < num) { state = pca_status(adap); DEB3("STATE is 0x%02x\n", state); msg = &msgs[curmsg]; switch (state) { case 0xf8: /* On reset or stop the bus is idle */ 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); 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]); numbytes++; break; } curmsg++; numbytes = 0; if (curmsg == num) pca_stop(adap); else pca_repeated_start(adap); break; case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */ DEB2("NOT ACK received after SLA+W\n"); pca_stop(adap); goto out; case 0x40: /* SLA+R has been transmitted; ACK has been received */ 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); break; } curmsg++; numbytes = 0; if (curmsg == num) pca_stop(adap); else pca_repeated_start(adap); break; case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */ DEB2("NOT ACK received after SLA+R\n"); pca_stop(adap); goto out; case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */ DEB2("NOT ACK received after data byte\n"); goto out; case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */ DEB2("Arbitration lost\n"); goto out; case 0x58: /* Data byte has been received; NOT ACK has been returned */ if ( numbytes == msg->len - 1 ) { pca_rx_byte(adap, &msg->buf[numbytes], 0); curmsg++; numbytes = 0; if (curmsg == num) pca_stop(adap); else pca_repeated_start(adap); } else { DEB2("NOT ACK sent after data byte received. " "Not final byte. numbytes %d. len %d\n", numbytes, msg->len); pca_stop(adap); goto out; } break; case 0x70: /* Bus error - SDA stuck low */ DEB2("BUS ERROR - SDA Stuck low\n"); pca_reset(adap); goto out; case 0x90: /* Bus error - SCL stuck low */ DEB2("BUS ERROR - SCL Stuck low\n"); pca_reset(adap); goto out; case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */ DEB2("BUS ERROR - Illegal START or STOP\n"); pca_reset(adap); goto out; default: printk(KERN_ERR DRIVER ": unhandled SIO state 0x%02x\n", state); break; } } ret = curmsg; out: DEB1(KERN_CRIT "}}} transfered %d/%d messages. " "status is %#04x. control is %#04x\n", curmsg, num, pca_status(adap), pca_get_con(adap)); return ret; } static u32 pca_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } static int pca_init(struct i2c_algo_pca_data *adap) { static int freqs[] = {330,288,217,146,88,59,44,36}; int own, clock; own = pca_own(adap); clock = pca_clock(adap); DEB1(KERN_INFO DRIVER ": own address is %#04x\n", own); DEB1(KERN_INFO DRIVER ": clock freqeuncy is %dkHz\n", freqs[clock]); pca_outw(adap, I2C_PCA_ADR, own << 1); pca_set_con(adap, I2C_PCA_CON_ENSIO | clock); udelay(500); /* 500 µs for oscilator to stabilise */ return 0; } static struct i2c_algorithm pca_algo = { .master_xfer = pca_xfer, .functionality = pca_func, }; /* * registering functions to load algorithms at runtime */ int i2c_pca_add_bus(struct i2c_adapter *adap) { struct i2c_algo_pca_data *pca_adap = adap->algo_data; int rval; /* register new adapter to i2c module... */ adap->algo = &pca_algo; adap->timeout = 100; /* default values, should */ adap->retries = 3; /* be replaced by defines */ rval = pca_init(pca_adap); if (!rval) i2c_add_adapter(adap); return rval; } int i2c_pca_del_bus(struct i2c_adapter *adap) { return i2c_del_adapter(adap); } EXPORT_SYMBOL(i2c_pca_add_bus); EXPORT_SYMBOL(i2c_pca_del_bus); MODULE_AUTHOR("Ian Campbell "); MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm"); MODULE_LICENSE("GPL"); module_param(i2c_debug, int, 0);