i2c-algo-pca.rar_algo_algorithms_pca9564

/* * i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters * Copyright (C) 2004 Arcom Control Systems * Copyright (C) 2008 Pengutronix * * 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. */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/delay.h> #include <linux/jiffies.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(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; #define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val) #define pca_inw(adap, reg) adap->read_byte(adap->data, reg) #define pca_status(adap) pca_inw(adap, I2C_PCA_STA) #define pca_clock(adap) adap->i2c_clock #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_completion(adap->data) static void pca_reset(struct i2c_algo_pca_data *adap) { if (adap->chip == I2C_PCA_CHIP_9665) { /* Ignore the reset function from the module, * we can use the parallel bus reset. */ pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET); pca_outw(adap, I2C_PCA_IND, 0xA5); pca_outw(adap, I2C_PCA_IND, 0x5A); } else { adap->reset_chip(adap->data); } } /* * Generate a start condition on the i2c bus. * * returns after the start condition has occurred */ 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); return pca_wait(adap); } /* * Generate a repeated start condition on the i2c bus * * return after the repeated start condition has occurred */ 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); return 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 int 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); return pca_wait(adap); } /* * Transmit a byte. * * Returns after the byte has been transmitted */ static int 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); return 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 int 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); return pca_wait(adap); } 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 completed = 1; unsigned long timeout = jiffies + i2c_adap->timeout; while ((state = 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 -EBUSY; } } 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 = -EIO; 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 */ completed = pca_start(adap); break; case 0x08: /* A START condition has been transmitted */ case 0x10: /* A repeated start condition has been transmitted */ 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) { completed = pca_tx_byte(adap, msg->buf[numbytes]); numbytes++; break; } curmsg++; numbytes = 0; if (curmsg == num) pca_stop(adap); else completed = 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); ret = -ENXIO; goto out; case 0x40: /* SLA+R has been transmitted; ACK has been received */ 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++; completed = pca_rx_ack(adap, numbytes < msg->len - 1); break; } curmsg++; numbytes = 0; if (curmsg == num) pca_stop(adap); else completed = 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); ret = -ENXIO; goto out; case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */ DEB2("NOT ACK received after data byte\n"); pca_stop(adap); goto out; case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */ DEB2("Arbitration lost\n"); /* * The PCA9564 data sheet (2006-09-01) says "A * START condition will be transmitted when the * bus becomes free (STOP or SCL and SDA high)" * when the STA bit is set (p. 11). * * In case this won't wo