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423 lines
11 KiB
423 lines
11 KiB
// 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 <[email protected]> and |
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* Frodo Looijaard <[email protected]>, and also from Martin Bailey |
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* <[email protected]> |
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* |
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* Partially rewriten by Oleg I. Vdovikin <[email protected]> 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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} |
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DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n", |
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i, msgs[i].addr, msgs[i].flags, msgs[i].len);) |
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if (pmsg->flags & I2C_M_RD) { |
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ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len, |
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(i + 1 == num)); |
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if (ret != pmsg->len) { |
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DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " |
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"only read %d bytes.\n",ret)); |
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} else { |
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DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: read %d bytes.\n",ret)); |
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} |
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} else { |
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ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len, |
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(i + 1 == num)); |
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if (ret != pmsg->len) { |
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DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " |
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"only wrote %d bytes.\n",ret)); |
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} else { |
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DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: wrote %d bytes.\n",ret)); |
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} |
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} |
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} |
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out: |
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if (adap->xfer_end) |
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adap->xfer_end(adap->data); |
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return i; |
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} |
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static u32 pcf_func(struct i2c_adapter *adap) |
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{ |
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return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | |
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I2C_FUNC_PROTOCOL_MANGLING; |
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} |
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/* exported algorithm data: */ |
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static const struct i2c_algorithm pcf_algo = { |
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.master_xfer = pcf_xfer, |
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.functionality = pcf_func, |
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}; |
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/* |
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* registering functions to load algorithms at runtime |
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*/ |
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int i2c_pcf_add_bus(struct i2c_adapter *adap) |
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{ |
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struct i2c_algo_pcf_data *pcf_adap = adap->algo_data; |
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int rval; |
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DEB2(dev_dbg(&adap->dev, "hw routines registered.\n")); |
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/* register new adapter to i2c module... */ |
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adap->algo = &pcf_algo; |
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if ((rval = pcf_init_8584(pcf_adap))) |
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return rval; |
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rval = i2c_add_adapter(adap); |
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return rval; |
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} |
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EXPORT_SYMBOL(i2c_pcf_add_bus); |
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MODULE_AUTHOR("Hans Berglund <[email protected]>"); |
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MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm"); |
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MODULE_LICENSE("GPL"); |
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module_param(i2c_debug, int, S_IRUGO | S_IWUSR); |
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MODULE_PARM_DESC(i2c_debug, |
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"debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol");
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