i2c-algo-pcf.rar_algorithms

/* * i2c-algo-pcf.c i2c driver algorithms for PCF8584 adapters * * * 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. * * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and * Frodo Looijaard <frodol@dds.nl>, and also from Martin Bailey * <mbailey@littlefeet-inc.com> * * Partially rewriten by Oleg I. Vdovikin <vdovikin@jscc.ru> to handle multiple * messages, proper stop/repstart signaling during receive, added detect code */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/errno.h> #include <linux/i2c.h> #include <linux/i2c-algo-pcf.h> #include "i2c-algo-pcf.h" #define DEB2(x) if (i2c_debug >= 2) x #define DEB3(x) if (i2c_debug >= 3) x /* print several statistical values */ #define DEBPROTO(x) if (i2c_debug >= 9) x; /* debug the protocol by showing transferred bits */ #define DEF_TIMEOUT 16 /* * module parameters: */ static int i2c_debug; /* setting states on the bus with the right timing: */ #define set_pcf(adap, ctl, val) adap->setpcf(adap->data, ctl, val) #define get_pcf(adap, ctl) adap->getpcf(adap->data, ctl) #define get_own(adap) adap->getown(adap->data) #define get_clock(adap) adap->getclock(adap->data) #define i2c_outb(adap, val) adap->setpcf(adap->data, 0, val) #define i2c_inb(adap) adap->getpcf(adap->data, 0) /* other auxiliary functions */ static void i2c_start(struct i2c_algo_pcf_data *adap) { DEBPROTO(printk(KERN_DEBUG "S ")); set_pcf(adap, 1, I2C_PCF_START); } static void i2c_repstart(struct i2c_algo_pcf_data *adap) { DEBPROTO(printk(" Sr ")); set_pcf(adap, 1, I2C_PCF_REPSTART); } static void i2c_stop(struct i2c_algo_pcf_data *adap) { DEBPROTO(printk("P\n")); set_pcf(adap, 1, I2C_PCF_STOP); } static void handle_lab(struct i2c_algo_pcf_data *adap, const int *status) { DEB2(printk(KERN_INFO "i2c-algo-pcf.o: lost arbitration (CSR 0x%02x)\n", *status)); /* * Cleanup from LAB -- reset and enable ESO. * This resets the PCF8584; since we've lost the bus, no * further attempts should be made by callers to clean up * (no i2c_stop() etc.) */ set_pcf(adap, 1, I2C_PCF_PIN); set_pcf(adap, 1, I2C_PCF_ESO); /* * We pause for a time period sufficient for any running * I2C transaction to complete -- the arbitration logic won't * work properly until the next START is seen. * It is assumed the bus driver or client has set a proper value. * * REVISIT: should probably use msleep instead of mdelay if we * know we can sleep. */ if (adap->lab_mdelay) mdelay(adap->lab_mdelay); DEB2(printk(KERN_INFO "i2c-algo-pcf.o: reset LAB condition (CSR 0x%02x)\n", get_pcf(adap, 1))); } static int wait_for_bb(struct i2c_algo_pcf_data *adap) { int timeout = DEF_TIMEOUT; int status; status = get_pcf(adap, 1); while (!(status & I2C_PCF_BB) && --timeout) { udelay(100); /* wait for 100 us */ status = get_pcf(adap, 1); } if (timeout == 0) { printk(KERN_ERR "Timeout waiting for Bus Busy\n"); return -ETIMEDOUT; } return 0; } static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) { int timeout = DEF_TIMEOUT; *status = get_pcf(adap, 1); while ((*status & I2C_PCF_PIN) && --timeout) { adap->waitforpin(adap->data); *status = get_pcf(adap, 1); } if (*status & I2C_PCF_LAB) { handle_lab(adap, status); return -EINTR; } if (timeout == 0) return -ETIMEDOUT; return 0; } /* * This should perform the 'PCF8584 initialization sequence' as described * in the Philips IC12 data book (1995, Aug 29). * There should be a 30 clock cycle wait after reset, I assume this * has been fulfilled. * There should be a delay at the end equal to the longest I2C message * to synchronize the BB-bit (in multimaster systems). How long is * this? I assume 1 second is always long enough. * * vdovikin: added detect code for PCF8584 */ static int pcf_init_8584 (struct i2c_algo_pcf_data *adap) { unsigned char temp; DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: PCF state 0x%02x\n", get_pcf(adap, 1))); /* S1=0x80: S0 selected, serial interface off */ set_pcf(adap, 1, I2C_PCF_PIN); /* * check to see S1 now used as R/W ctrl - * PCF8584 does that when ESO is zero */ if (((temp = get_pcf(adap, 1)) & 0x7f) != (0)) { DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp)); return -ENXIO; /* definitely not PCF8584 */ } /* load own address in S0, effective address is (own << 1) */ i2c_outb(adap, get_own(adap)); /* check it's really written */ if ((temp = i2c_inb(adap)) != get_own(adap)) { DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp)); return -ENXIO; } /* S1=0xA0, next byte in S2 */ set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1); /* check to see S2 now selected */ if (((temp = get_pcf(adap, 1)) & 0x7f) != I2C_PCF_ES1) { DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp)); return -ENXIO; } /* load clock register S2 */ i2c_outb(adap, get_clock(adap)); /* check it's really written, the only 5 lowest bits does matter */ if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) { DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp)); return -ENXIO; } /* Enable serial interface, idle, S0 selected */ set_pcf(adap, 1, I2C_PCF_IDLE); /* check to see PCF is really idled and we can access status register */ if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) { DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp)); return -ENXIO; } printk(KERN_DEBUG "i2c-algo-pcf.o: detected and initialized PCF8584.\n"); return 0; } static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf, int count, int last) { struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; int wrcount, status, timeout; for (wrcount=0; wrcount<count; ++wrcount) { DEB2(dev_dbg(&i2c_adap->dev, "i2c_write: writing %2.2X\n", buf[wrcount] & 0xff)); i2c_outb(adap, buf[wrcount]); timeout = wait_for_pin(adap, &status); if (timeout) { if (timeout == -EINTR) return -EINTR; /* arbitration lost */ i2c_stop(adap); dev_err(&i2c_adap->dev, "i2c_write: error - timeout.\n"); return -EREMOTEIO; /* got a better one ?? */ } if (status & I2C_PCF_LRB) { i2c_stop(adap); dev_err(&i2c_adap->dev, "i2c_write: error - no ack.\n"); return -EREMOTEIO; /* got a better one ?? */ } } if (last) i2c_stop(adap); else i2c_repstart(adap); return wrcount; } static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf, int count, int last) { int i, status; struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; int wfp; /* increment number of bytes to read by one -- read dummy byte */ for (i = 0; i <= count; i++) { if ((wfp = wait_for_pin(adap, &status))) { if (wfp == -EINTR) return -EINTR; /* arbitration lost */ i2c_stop(adap); dev_err(&i2c_adap->dev, "pcf_readbytes timed out.\n"); return -1; } if ((status & I2C_PCF_LRB) && (i != count)) { i2c_stop(adap); dev_err(&i2c_adap->dev, "i2c_read: i2c_inb, No ack.\n"); return -1; } if (i == count - 1) { set_pcf(adap, 1, I2C_PCF_ESO); } else if (i == count) { if (last) i2c_stop(adap); else