424 lines
11 KiB
C
424 lines
11 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* i2c-algo-pcf.c i2c driver algorithms for PCF8584 adapters
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*
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* Copyright (C) 1995-1997 Simon G. Vogl
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* 1998-2000 Hans Berglund
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*
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* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
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* Frodo Looijaard <frodol@dds.nl>, and also from Martin Bailey
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* <mbailey@littlefeet-inc.com>
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*
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* Partially rewriten by Oleg I. Vdovikin <vdovikin@jscc.ru> to handle multiple
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* messages, proper stop/repstart signaling during receive, added detect code
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/errno.h>
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#include <linux/i2c.h>
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#include <linux/i2c-algo-pcf.h>
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#include "i2c-algo-pcf.h"
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#define DEB2(x) if (i2c_debug >= 2) x
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#define DEB3(x) if (i2c_debug >= 3) x /* print several statistical values */
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#define DEBPROTO(x) if (i2c_debug >= 9) x;
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/* debug the protocol by showing transferred bits */
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#define DEF_TIMEOUT 16
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/*
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* module parameters:
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*/
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static int i2c_debug;
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/* setting states on the bus with the right timing: */
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#define set_pcf(adap, ctl, val) adap->setpcf(adap->data, ctl, val)
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#define get_pcf(adap, ctl) adap->getpcf(adap->data, ctl)
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#define get_own(adap) adap->getown(adap->data)
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#define get_clock(adap) adap->getclock(adap->data)
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#define i2c_outb(adap, val) adap->setpcf(adap->data, 0, val)
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#define i2c_inb(adap) adap->getpcf(adap->data, 0)
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/* other auxiliary functions */
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static void i2c_start(struct i2c_algo_pcf_data *adap)
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{
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DEBPROTO(printk(KERN_DEBUG "S "));
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set_pcf(adap, 1, I2C_PCF_START);
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}
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static void i2c_repstart(struct i2c_algo_pcf_data *adap)
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{
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DEBPROTO(printk(" Sr "));
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set_pcf(adap, 1, I2C_PCF_REPSTART);
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}
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static void i2c_stop(struct i2c_algo_pcf_data *adap)
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{
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DEBPROTO(printk("P\n"));
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set_pcf(adap, 1, I2C_PCF_STOP);
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}
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static void handle_lab(struct i2c_algo_pcf_data *adap, const int *status)
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{
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DEB2(printk(KERN_INFO
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"i2c-algo-pcf.o: lost arbitration (CSR 0x%02x)\n",
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*status));
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/*
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* Cleanup from LAB -- reset and enable ESO.
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* This resets the PCF8584; since we've lost the bus, no
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* further attempts should be made by callers to clean up
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* (no i2c_stop() etc.)
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*/
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set_pcf(adap, 1, I2C_PCF_PIN);
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set_pcf(adap, 1, I2C_PCF_ESO);
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/*
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* We pause for a time period sufficient for any running
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* I2C transaction to complete -- the arbitration logic won't
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* work properly until the next START is seen.
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* It is assumed the bus driver or client has set a proper value.
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*
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* REVISIT: should probably use msleep instead of mdelay if we
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* know we can sleep.
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*/
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if (adap->lab_mdelay)
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mdelay(adap->lab_mdelay);
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DEB2(printk(KERN_INFO
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"i2c-algo-pcf.o: reset LAB condition (CSR 0x%02x)\n",
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get_pcf(adap, 1)));
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}
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static int wait_for_bb(struct i2c_algo_pcf_data *adap)
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{
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int timeout = DEF_TIMEOUT;
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int status;
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status = get_pcf(adap, 1);
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while (!(status & I2C_PCF_BB) && --timeout) {
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udelay(100); /* wait for 100 us */
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status = get_pcf(adap, 1);
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}
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if (timeout == 0) {
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printk(KERN_ERR "Timeout waiting for Bus Busy\n");
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return -ETIMEDOUT;
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}
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return 0;
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}
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static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status)
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{
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int timeout = DEF_TIMEOUT;
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*status = get_pcf(adap, 1);
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while ((*status & I2C_PCF_PIN) && --timeout) {
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adap->waitforpin(adap->data);
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*status = get_pcf(adap, 1);
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}
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if (*status & I2C_PCF_LAB) {
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handle_lab(adap, status);
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return -EINTR;
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}
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if (timeout == 0)
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return -ETIMEDOUT;
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return 0;
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}
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/*
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* This should perform the 'PCF8584 initialization sequence' as described
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* in the Philips IC12 data book (1995, Aug 29).
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* There should be a 30 clock cycle wait after reset, I assume this
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* has been fulfilled.
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* There should be a delay at the end equal to the longest I2C message
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* to synchronize the BB-bit (in multimaster systems). How long is
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* this? I assume 1 second is always long enough.
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*
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* vdovikin: added detect code for PCF8584
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*/
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static int pcf_init_8584 (struct i2c_algo_pcf_data *adap)
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{
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unsigned char temp;
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DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: PCF state 0x%02x\n",
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get_pcf(adap, 1)));
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/* S1=0x80: S0 selected, serial interface off */
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set_pcf(adap, 1, I2C_PCF_PIN);
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/*
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* check to see S1 now used as R/W ctrl -
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* PCF8584 does that when ESO is zero
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*/
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if (((temp = get_pcf(adap, 1)) & 0x7f) != (0)) {
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DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp));
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return -ENXIO; /* definitely not PCF8584 */
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}
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/* load own address in S0, effective address is (own << 1) */
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i2c_outb(adap, get_own(adap));
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/* check it's really written */
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if ((temp = i2c_inb(adap)) != get_own(adap)) {
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DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp));
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return -ENXIO;
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}
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/* S1=0xA0, next byte in S2 */
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set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1);
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/* check to see S2 now selected */
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if (((temp = get_pcf(adap, 1)) & 0x7f) != I2C_PCF_ES1) {
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DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp));
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return -ENXIO;
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}
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/* load clock register S2 */
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i2c_outb(adap, get_clock(adap));
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/* check it's really written, the only 5 lowest bits does matter */
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if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) {
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DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp));
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return -ENXIO;
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}
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/* Enable serial interface, idle, S0 selected */
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set_pcf(adap, 1, I2C_PCF_IDLE);
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/* check to see PCF is really idled and we can access status register */
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if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) {
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DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp));
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return -ENXIO;
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}
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printk(KERN_DEBUG "i2c-algo-pcf.o: detected and initialized PCF8584.\n");
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return 0;
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}
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static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf,
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int count, int last)
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{
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struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
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int wrcount, status, timeout;
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for (wrcount=0; wrcount<count; ++wrcount) {
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DEB2(dev_dbg(&i2c_adap->dev, "i2c_write: writing %2.2X\n",
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buf[wrcount] & 0xff));
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i2c_outb(adap, buf[wrcount]);
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timeout = wait_for_pin(adap, &status);
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if (timeout) {
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if (timeout == -EINTR)
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return -EINTR; /* arbitration lost */
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i2c_stop(adap);
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dev_err(&i2c_adap->dev, "i2c_write: error - timeout.\n");
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return -EREMOTEIO; /* got a better one ?? */
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}
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if (status & I2C_PCF_LRB) {
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i2c_stop(adap);
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dev_err(&i2c_adap->dev, "i2c_write: error - no ack.\n");
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return -EREMOTEIO; /* got a better one ?? */
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}
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}
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if (last)
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i2c_stop(adap);
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else
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i2c_repstart(adap);
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return wrcount;
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}
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static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf,
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int count, int last)
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{
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int i, status;
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struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
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int wfp;
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/* increment number of bytes to read by one -- read dummy byte */
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for (i = 0; i <= count; i++) {
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if ((wfp = wait_for_pin(adap, &status))) {
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if (wfp == -EINTR)
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return -EINTR; /* arbitration lost */
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i2c_stop(adap);
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dev_err(&i2c_adap->dev, "pcf_readbytes timed out.\n");
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return -1;
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}
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if ((status & I2C_PCF_LRB) && (i != count)) {
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i2c_stop(adap);
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dev_err(&i2c_adap->dev, "i2c_read: i2c_inb, No ack.\n");
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return -1;
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}
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if (i == count - 1) {
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set_pcf(adap, 1, I2C_PCF_ESO);
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} else if (i == count) {
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if (last)
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i2c_stop(adap);
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else
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i2c_repstart(adap);
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}
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if (i)
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buf[i - 1] = i2c_inb(adap);
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else
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i2c_inb(adap); /* dummy read */
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}
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return i - 1;
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}
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static int pcf_doAddress(struct i2c_algo_pcf_data *adap,
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struct i2c_msg *msg)
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{
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unsigned char addr = i2c_8bit_addr_from_msg(msg);
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if (msg->flags & I2C_M_REV_DIR_ADDR)
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addr ^= 1;
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i2c_outb(adap, addr);
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return 0;
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}
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static int pcf_xfer(struct i2c_adapter *i2c_adap,
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struct i2c_msg *msgs,
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int num)
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{
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struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
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struct i2c_msg *pmsg;
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int i;
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int ret=0, timeout, status;
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if (adap->xfer_begin)
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adap->xfer_begin(adap->data);
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/* Check for bus busy */
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timeout = wait_for_bb(adap);
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if (timeout) {
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DEB2(printk(KERN_ERR "i2c-algo-pcf.o: "
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"Timeout waiting for BB in pcf_xfer\n");)
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i = -EIO;
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goto out;
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}
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for (i = 0;ret >= 0 && i < num; i++) {
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pmsg = &msgs[i];
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DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n",
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pmsg->flags & I2C_M_RD ? "read" : "write",
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pmsg->len, pmsg->addr, i + 1, num);)
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ret = pcf_doAddress(adap, pmsg);
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/* Send START */
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if (i == 0)
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i2c_start(adap);
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/* Wait for PIN (pending interrupt NOT) */
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timeout = wait_for_pin(adap, &status);
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if (timeout) {
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if (timeout == -EINTR) {
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/* arbitration lost */
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i = -EINTR;
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goto out;
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}
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i2c_stop(adap);
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DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting "
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"for PIN(1) in pcf_xfer\n");)
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i = -EREMOTEIO;
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goto out;
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}
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/* Check LRB (last rcvd bit - slave ack) */
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if (status & I2C_PCF_LRB) {
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i2c_stop(adap);
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DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");)
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i = -EREMOTEIO;
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goto out;
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||
|
|
}
|
||
|
|
|
||
|
|
DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n",
|
||
|
|
i, msgs[i].addr, msgs[i].flags, msgs[i].len);)
|
||
|
|
|
||
|
|
if (pmsg->flags & I2C_M_RD) {
|
||
|
|
ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len,
|
||
|
|
(i + 1 == num));
|
||
|
|
|
||
|
|
if (ret != pmsg->len) {
|
||
|
|
DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: "
|
||
|
|
"only read %d bytes.\n",ret));
|
||
|
|
} else {
|
||
|
|
DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: read %d bytes.\n",ret));
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len,
|
||
|
|
(i + 1 == num));
|
||
|
|
|
||
|
|
if (ret != pmsg->len) {
|
||
|
|
DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: "
|
||
|
|
"only wrote %d bytes.\n",ret));
|
||
|
|
} else {
|
||
|
|
DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: wrote %d bytes.\n",ret));
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
out:
|
||
|
|
if (adap->xfer_end)
|
||
|
|
adap->xfer_end(adap->data);
|
||
|
|
return i;
|
||
|
|
}
|
||
|
|
|
||
|
|
static u32 pcf_func(struct i2c_adapter *adap)
|
||
|
|
{
|
||
|
|
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
|
||
|
|
I2C_FUNC_PROTOCOL_MANGLING;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* exported algorithm data: */
|
||
|
|
static const struct i2c_algorithm pcf_algo = {
|
||
|
|
.master_xfer = pcf_xfer,
|
||
|
|
.functionality = pcf_func,
|
||
|
|
};
|
||
|
|
|
||
|
|
/*
|
||
|
|
* registering functions to load algorithms at runtime
|
||
|
|
*/
|
||
|
|
int i2c_pcf_add_bus(struct i2c_adapter *adap)
|
||
|
|
{
|
||
|
|
struct i2c_algo_pcf_data *pcf_adap = adap->algo_data;
|
||
|
|
int rval;
|
||
|
|
|
||
|
|
DEB2(dev_dbg(&adap->dev, "hw routines registered.\n"));
|
||
|
|
|
||
|
|
/* register new adapter to i2c module... */
|
||
|
|
adap->algo = &pcf_algo;
|
||
|
|
|
||
|
|
if ((rval = pcf_init_8584(pcf_adap)))
|
||
|
|
return rval;
|
||
|
|
|
||
|
|
rval = i2c_add_adapter(adap);
|
||
|
|
|
||
|
|
return rval;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(i2c_pcf_add_bus);
|
||
|
|
|
||
|
|
MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
|
||
|
|
MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm");
|
||
|
|
MODULE_LICENSE("GPL");
|
||
|
|
|
||
|
|
module_param(i2c_debug, int, S_IRUGO | S_IWUSR);
|
||
|
|
MODULE_PARM_DESC(i2c_debug,
|
||
|
|
"debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol");
|