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561 lines
15 KiB
561 lines
15 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters |
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* Copyright (C) 2004 Arcom Control Systems |
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* Copyright (C) 2008 Pengutronix |
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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/moduleparam.h> |
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#include <linux/delay.h> |
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#include <linux/jiffies.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-pca.h> |
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#define DEB1(fmt, args...) do { if (i2c_debug >= 1) \ |
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printk(KERN_DEBUG fmt, ## args); } while (0) |
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#define DEB2(fmt, args...) do { if (i2c_debug >= 2) \ |
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printk(KERN_DEBUG fmt, ## args); } while (0) |
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#define DEB3(fmt, args...) do { if (i2c_debug >= 3) \ |
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printk(KERN_DEBUG fmt, ## args); } while (0) |
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static int i2c_debug; |
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#define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val) |
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#define pca_inw(adap, reg) adap->read_byte(adap->data, reg) |
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#define pca_status(adap) pca_inw(adap, I2C_PCA_STA) |
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#define pca_clock(adap) adap->i2c_clock |
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#define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val) |
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#define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON) |
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#define pca_wait(adap) adap->wait_for_completion(adap->data) |
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static void pca_reset(struct i2c_algo_pca_data *adap) |
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{ |
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if (adap->chip == I2C_PCA_CHIP_9665) { |
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/* Ignore the reset function from the module, |
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* we can use the parallel bus reset. |
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*/ |
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pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET); |
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pca_outw(adap, I2C_PCA_IND, 0xA5); |
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pca_outw(adap, I2C_PCA_IND, 0x5A); |
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|
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/* |
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* After a reset we need to re-apply any configuration |
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* (calculated in pca_init) to get the bus in a working state. |
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*/ |
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pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IMODE); |
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pca_outw(adap, I2C_PCA_IND, adap->bus_settings.mode); |
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pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_ISCLL); |
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pca_outw(adap, I2C_PCA_IND, adap->bus_settings.tlow); |
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pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_ISCLH); |
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pca_outw(adap, I2C_PCA_IND, adap->bus_settings.thi); |
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pca_set_con(adap, I2C_PCA_CON_ENSIO); |
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} else { |
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adap->reset_chip(adap->data); |
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pca_set_con(adap, I2C_PCA_CON_ENSIO | adap->bus_settings.clock_freq); |
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} |
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} |
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/* |
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* Generate a start condition on the i2c bus. |
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* |
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* returns after the start condition has occurred |
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*/ |
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static int pca_start(struct i2c_algo_pca_data *adap) |
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{ |
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int sta = pca_get_con(adap); |
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DEB2("=== START\n"); |
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sta |= I2C_PCA_CON_STA; |
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sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI); |
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pca_set_con(adap, sta); |
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return pca_wait(adap); |
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} |
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/* |
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* Generate a repeated start condition on the i2c bus |
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* |
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* return after the repeated start condition has occurred |
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*/ |
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static int pca_repeated_start(struct i2c_algo_pca_data *adap) |
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{ |
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int sta = pca_get_con(adap); |
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DEB2("=== REPEATED START\n"); |
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sta |= I2C_PCA_CON_STA; |
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sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI); |
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pca_set_con(adap, sta); |
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return pca_wait(adap); |
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} |
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/* |
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* Generate a stop condition on the i2c bus |
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* |
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* returns after the stop condition has been generated |
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* |
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* STOPs do not generate an interrupt or set the SI flag, since the |
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* part returns the idle state (0xf8). Hence we don't need to |
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* pca_wait here. |
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*/ |
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static void pca_stop(struct i2c_algo_pca_data *adap) |
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{ |
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int sta = pca_get_con(adap); |
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DEB2("=== STOP\n"); |
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sta |= I2C_PCA_CON_STO; |
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sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI); |
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pca_set_con(adap, sta); |
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} |
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/* |
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* Send the slave address and R/W bit |
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* |
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* returns after the address has been sent |
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*/ |
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static int pca_address(struct i2c_algo_pca_data *adap, |
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struct i2c_msg *msg) |
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{ |
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int sta = pca_get_con(adap); |
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int addr = i2c_8bit_addr_from_msg(msg); |
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DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n", |
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msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr); |
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pca_outw(adap, I2C_PCA_DAT, addr); |
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sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); |
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pca_set_con(adap, sta); |
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return pca_wait(adap); |
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} |
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/* |
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* Transmit a byte. |
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* |
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* Returns after the byte has been transmitted |
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*/ |
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static int pca_tx_byte(struct i2c_algo_pca_data *adap, |
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__u8 b) |
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{ |
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int sta = pca_get_con(adap); |
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DEB2("=== WRITE %#04x\n", b); |
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pca_outw(adap, I2C_PCA_DAT, b); |
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sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); |
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pca_set_con(adap, sta); |
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return pca_wait(adap); |
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} |
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/* |
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* Receive a byte |
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* |
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* returns immediately. |
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*/ |
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static void pca_rx_byte(struct i2c_algo_pca_data *adap, |
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__u8 *b, int ack) |
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{ |
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*b = pca_inw(adap, I2C_PCA_DAT); |
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DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK"); |
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} |
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/* |
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* Setup ACK or NACK for next received byte and wait for it to arrive. |
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* |
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* Returns after next byte has arrived. |
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*/ |
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static int pca_rx_ack(struct i2c_algo_pca_data *adap, |
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int ack) |
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{ |
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int sta = pca_get_con(adap); |
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sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA); |
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if (ack) |
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sta |= I2C_PCA_CON_AA; |
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pca_set_con(adap, sta); |
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return pca_wait(adap); |
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} |
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static int pca_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_pca_data *adap = i2c_adap->algo_data; |
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struct i2c_msg *msg = NULL; |
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int curmsg; |
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int numbytes = 0; |
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int state; |
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int ret; |
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int completed = 1; |
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unsigned long timeout = jiffies + i2c_adap->timeout; |
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while ((state = pca_status(adap)) != 0xf8) { |
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if (time_before(jiffies, timeout)) { |
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msleep(10); |
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} else { |
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dev_dbg(&i2c_adap->dev, "bus is not idle. status is " |
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"%#04x\n", state); |
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return -EBUSY; |
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} |
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} |
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DEB1("{{{ XFER %d messages\n", num); |
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if (i2c_debug >= 2) { |
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for (curmsg = 0; curmsg < num; curmsg++) { |
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int addr, i; |
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msg = &msgs[curmsg]; |
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addr = (0x7f & msg->addr) ; |
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if (msg->flags & I2C_M_RD) |
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printk(KERN_INFO " [%02d] RD %d bytes from %#02x [%#02x, ...]\n", |
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curmsg, msg->len, addr, (addr << 1) | 1); |
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else { |
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printk(KERN_INFO " [%02d] WR %d bytes to %#02x [%#02x%s", |
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curmsg, msg->len, addr, addr << 1, |
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msg->len == 0 ? "" : ", "); |
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for (i = 0; i < msg->len; i++) |
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printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", "); |
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printk("]\n"); |
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} |
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} |
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} |
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curmsg = 0; |
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ret = -EIO; |
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while (curmsg < num) { |
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state = pca_status(adap); |
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DEB3("STATE is 0x%02x\n", state); |
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msg = &msgs[curmsg]; |
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switch (state) { |
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case 0xf8: /* On reset or stop the bus is idle */ |
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completed = pca_start(adap); |
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break; |
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case 0x08: /* A START condition has been transmitted */ |
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case 0x10: /* A repeated start condition has been transmitted */ |
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completed = pca_address(adap, msg); |
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break; |
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case 0x18: /* SLA+W has been transmitted; ACK has been received */ |
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case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */ |
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if (numbytes < msg->len) { |
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completed = pca_tx_byte(adap, |
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msg->buf[numbytes]); |
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numbytes++; |
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break; |
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} |
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curmsg++; numbytes = 0; |
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if (curmsg == num) |
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pca_stop(adap); |
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else |
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completed = pca_repeated_start(adap); |
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break; |
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case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */ |
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DEB2("NOT ACK received after SLA+W\n"); |
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pca_stop(adap); |
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ret = -ENXIO; |
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goto out; |
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case 0x40: /* SLA+R has been transmitted; ACK has been received */ |
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completed = pca_rx_ack(adap, msg->len > 1); |
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break; |
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case 0x50: /* Data bytes has been received; ACK has been returned */ |
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if (numbytes < msg->len) { |
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pca_rx_byte(adap, &msg->buf[numbytes], 1); |
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numbytes++; |
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completed = pca_rx_ack(adap, |
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numbytes < msg->len - 1); |
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break; |
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} |
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curmsg++; numbytes = 0; |
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if (curmsg == num) |
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pca_stop(adap); |
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else |
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completed = pca_repeated_start(adap); |
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break; |
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case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */ |
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DEB2("NOT ACK received after SLA+R\n"); |
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pca_stop(adap); |
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ret = -ENXIO; |
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goto out; |
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case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */ |
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DEB2("NOT ACK received after data byte\n"); |
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pca_stop(adap); |
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goto out; |
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case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */ |
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DEB2("Arbitration lost\n"); |
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/* |
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* The PCA9564 data sheet (2006-09-01) says "A |
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* START condition will be transmitted when the |
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* bus becomes free (STOP or SCL and SDA high)" |
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* when the STA bit is set (p. 11). |
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* |
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* In case this won't work, try pca_reset() |
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* instead. |
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*/ |
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pca_start(adap); |
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goto out; |
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case 0x58: /* Data byte has been received; NOT ACK has been returned */ |
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if (numbytes == msg->len - 1) { |
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pca_rx_byte(adap, &msg->buf[numbytes], 0); |
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curmsg++; numbytes = 0; |
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if (curmsg == num) |
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pca_stop(adap); |
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else |
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completed = pca_repeated_start(adap); |
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} else { |
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DEB2("NOT ACK sent after data byte received. " |
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"Not final byte. numbytes %d. len %d\n", |
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numbytes, msg->len); |
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pca_stop(adap); |
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goto out; |
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} |
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break; |
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case 0x70: /* Bus error - SDA stuck low */ |
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DEB2("BUS ERROR - SDA Stuck low\n"); |
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pca_reset(adap); |
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goto out; |
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case 0x78: /* Bus error - SCL stuck low (PCA9665) */ |
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case 0x90: /* Bus error - SCL stuck low (PCA9564) */ |
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DEB2("BUS ERROR - SCL Stuck low\n"); |
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pca_reset(adap); |
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goto out; |
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case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */ |
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DEB2("BUS ERROR - Illegal START or STOP\n"); |
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pca_reset(adap); |
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goto out; |
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default: |
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dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state); |
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break; |
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} |
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if (!completed) |
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goto out; |
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} |
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ret = curmsg; |
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out: |
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DEB1("}}} transferred %d/%d messages. " |
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"status is %#04x. control is %#04x\n", |
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curmsg, num, pca_status(adap), |
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pca_get_con(adap)); |
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return ret; |
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} |
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static u32 pca_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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} |
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static const struct i2c_algorithm pca_algo = { |
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.master_xfer = pca_xfer, |
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.functionality = pca_func, |
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}; |
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static unsigned int pca_probe_chip(struct i2c_adapter *adap) |
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{ |
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struct i2c_algo_pca_data *pca_data = adap->algo_data; |
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/* The trick here is to check if there is an indirect register |
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* available. If there is one, we will read the value we first |
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* wrote on I2C_PCA_IADR. Otherwise, we will read the last value |
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* we wrote on I2C_PCA_ADR |
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*/ |
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pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR); |
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pca_outw(pca_data, I2C_PCA_IND, 0xAA); |
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pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO); |
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pca_outw(pca_data, I2C_PCA_IND, 0x00); |
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pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR); |
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if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) { |
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printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name); |
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pca_data->chip = I2C_PCA_CHIP_9665; |
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} else { |
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printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name); |
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pca_data->chip = I2C_PCA_CHIP_9564; |
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} |
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return pca_data->chip; |
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} |
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static int pca_init(struct i2c_adapter *adap) |
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{ |
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struct i2c_algo_pca_data *pca_data = adap->algo_data; |
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adap->algo = &pca_algo; |
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if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) { |
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static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36}; |
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int clock; |
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if (pca_data->i2c_clock > 7) { |
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switch (pca_data->i2c_clock) { |
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case 330000: |
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pca_data->i2c_clock = I2C_PCA_CON_330kHz; |
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break; |
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case 288000: |
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pca_data->i2c_clock = I2C_PCA_CON_288kHz; |
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break; |
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case 217000: |
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pca_data->i2c_clock = I2C_PCA_CON_217kHz; |
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break; |
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case 146000: |
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pca_data->i2c_clock = I2C_PCA_CON_146kHz; |
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break; |
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case 88000: |
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pca_data->i2c_clock = I2C_PCA_CON_88kHz; |
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break; |
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case 59000: |
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pca_data->i2c_clock = I2C_PCA_CON_59kHz; |
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break; |
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case 44000: |
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pca_data->i2c_clock = I2C_PCA_CON_44kHz; |
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break; |
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case 36000: |
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pca_data->i2c_clock = I2C_PCA_CON_36kHz; |
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break; |
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default: |
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printk(KERN_WARNING |
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"%s: Invalid I2C clock speed selected." |
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" Using default 59kHz.\n", adap->name); |
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pca_data->i2c_clock = I2C_PCA_CON_59kHz; |
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} |
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} else { |
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printk(KERN_WARNING "%s: " |
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"Choosing the clock frequency based on " |
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"index is deprecated." |
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" Use the nominal frequency.\n", adap->name); |
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} |
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clock = pca_clock(pca_data); |
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printk(KERN_INFO "%s: Clock frequency is %dkHz\n", |
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adap->name, freqs[clock]); |
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/* Store settings as these will be needed when the PCA chip is reset */ |
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pca_data->bus_settings.clock_freq = clock; |
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pca_reset(pca_data); |
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} else { |
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int clock; |
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int mode; |
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int tlow, thi; |
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/* Values can be found on PCA9665 datasheet section 7.3.2.6 */ |
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int min_tlow, min_thi; |
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/* These values are the maximum raise and fall values allowed |
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* by the I2C operation mode (Standard, Fast or Fast+) |
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* They are used (added) below to calculate the clock dividers |
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* of PCA9665. Note that they are slightly different of the |
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* real maximum, to allow the change on mode exactly on the |
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* maximum clock rate for each mode |
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*/ |
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int raise_fall_time; |
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if (pca_data->i2c_clock > 1265800) { |
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printk(KERN_WARNING "%s: I2C clock speed too high." |
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" Using 1265.8kHz.\n", adap->name); |
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pca_data->i2c_clock = 1265800; |
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} |
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if (pca_data->i2c_clock < 60300) { |
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printk(KERN_WARNING "%s: I2C clock speed too low." |
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" Using 60.3kHz.\n", adap->name); |
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pca_data->i2c_clock = 60300; |
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} |
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/* To avoid integer overflow, use clock/100 for calculations */ |
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clock = pca_clock(pca_data) / 100; |
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if (pca_data->i2c_clock > I2C_MAX_FAST_MODE_PLUS_FREQ) { |
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mode = I2C_PCA_MODE_TURBO; |
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min_tlow = 14; |
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min_thi = 5; |
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raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */ |
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} else if (pca_data->i2c_clock > I2C_MAX_FAST_MODE_FREQ) { |
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mode = I2C_PCA_MODE_FASTP; |
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min_tlow = 17; |
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min_thi = 9; |
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raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */ |
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} else if (pca_data->i2c_clock > I2C_MAX_STANDARD_MODE_FREQ) { |
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mode = I2C_PCA_MODE_FAST; |
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min_tlow = 44; |
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min_thi = 20; |
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raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */ |
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} else { |
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mode = I2C_PCA_MODE_STD; |
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min_tlow = 157; |
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min_thi = 134; |
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raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */ |
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} |
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|
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/* The minimum clock that respects the thi/tlow = 134/157 is |
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* 64800 Hz. Below that, we have to fix the tlow to 255 and |
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* calculate the thi factor. |
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*/ |
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if (clock < 648) { |
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tlow = 255; |
|
thi = 1000000 - clock * raise_fall_time; |
|
thi /= (I2C_PCA_OSC_PER * clock) - tlow; |
|
} else { |
|
tlow = (1000000 - clock * raise_fall_time) * min_tlow; |
|
tlow /= I2C_PCA_OSC_PER * clock * (min_thi + min_tlow); |
|
thi = tlow * min_thi / min_tlow; |
|
} |
|
|
|
/* Store settings as these will be needed when the PCA chip is reset */ |
|
pca_data->bus_settings.mode = mode; |
|
pca_data->bus_settings.tlow = tlow; |
|
pca_data->bus_settings.thi = thi; |
|
|
|
pca_reset(pca_data); |
|
|
|
printk(KERN_INFO |
|
"%s: Clock frequency is %dHz\n", adap->name, clock * 100); |
|
} |
|
udelay(500); /* 500 us for oscillator to stabilise */ |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* registering functions to load algorithms at runtime |
|
*/ |
|
int i2c_pca_add_bus(struct i2c_adapter *adap) |
|
{ |
|
int rval; |
|
|
|
rval = pca_init(adap); |
|
if (rval) |
|
return rval; |
|
|
|
return i2c_add_adapter(adap); |
|
} |
|
EXPORT_SYMBOL(i2c_pca_add_bus); |
|
|
|
int i2c_pca_add_numbered_bus(struct i2c_adapter *adap) |
|
{ |
|
int rval; |
|
|
|
rval = pca_init(adap); |
|
if (rval) |
|
return rval; |
|
|
|
return i2c_add_numbered_adapter(adap); |
|
} |
|
EXPORT_SYMBOL(i2c_pca_add_numbered_bus); |
|
|
|
MODULE_AUTHOR("Ian Campbell <[email protected]>"); |
|
MODULE_AUTHOR("Wolfram Sang <[email protected]>"); |
|
MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm"); |
|
MODULE_LICENSE("GPL"); |
|
|
|
module_param(i2c_debug, int, 0);
|
|
|