X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Fi2c%2Falgos%2Fi2c-algo-pca.c;fp=kernel%2Fdrivers%2Fi2c%2Falgos%2Fi2c-algo-pca.c;h=580dbf05c1487c46e7ef504c18cfc8f128ced4cc;hb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;hp=0000000000000000000000000000000000000000;hpb=98260f3884f4a202f9ca5eabed40b1354c489b29;p=kvmfornfv.git diff --git a/kernel/drivers/i2c/algos/i2c-algo-pca.c b/kernel/drivers/i2c/algos/i2c-algo-pca.c new file mode 100644 index 000000000..580dbf05c --- /dev/null +++ b/kernel/drivers/i2c/algos/i2c-algo-pca.c @@ -0,0 +1,561 @@ +/* + * i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters + * Copyright (C) 2004 Arcom Control Systems + * Copyright (C) 2008 Pengutronix + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define DEB1(fmt, args...) do { if (i2c_debug >= 1) \ + printk(KERN_DEBUG fmt, ## args); } while (0) +#define DEB2(fmt, args...) do { if (i2c_debug >= 2) \ + printk(KERN_DEBUG fmt, ## args); } while (0) +#define DEB3(fmt, args...) do { if (i2c_debug >= 3) \ + printk(KERN_DEBUG fmt, ## args); } while (0) + +static int i2c_debug; + +#define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val) +#define pca_inw(adap, reg) adap->read_byte(adap->data, reg) + +#define pca_status(adap) pca_inw(adap, I2C_PCA_STA) +#define pca_clock(adap) adap->i2c_clock +#define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val) +#define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON) +#define pca_wait(adap) adap->wait_for_completion(adap->data) + +static void pca_reset(struct i2c_algo_pca_data *adap) +{ + if (adap->chip == I2C_PCA_CHIP_9665) { + /* Ignore the reset function from the module, + * we can use the parallel bus reset. + */ + pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET); + pca_outw(adap, I2C_PCA_IND, 0xA5); + pca_outw(adap, I2C_PCA_IND, 0x5A); + } else { + adap->reset_chip(adap->data); + } +} + +/* + * Generate a start condition on the i2c bus. + * + * returns after the start condition has occurred + */ +static int pca_start(struct i2c_algo_pca_data *adap) +{ + int sta = pca_get_con(adap); + DEB2("=== START\n"); + sta |= I2C_PCA_CON_STA; + sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI); + pca_set_con(adap, sta); + return pca_wait(adap); +} + +/* + * Generate a repeated start condition on the i2c bus + * + * return after the repeated start condition has occurred + */ +static int pca_repeated_start(struct i2c_algo_pca_data *adap) +{ + int sta = pca_get_con(adap); + DEB2("=== REPEATED START\n"); + sta |= I2C_PCA_CON_STA; + sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI); + pca_set_con(adap, sta); + return pca_wait(adap); +} + +/* + * Generate a stop condition on the i2c bus + * + * returns after the stop condition has been generated + * + * STOPs do not generate an interrupt or set the SI flag, since the + * part returns the idle state (0xf8). Hence we don't need to + * pca_wait here. + */ +static void pca_stop(struct i2c_algo_pca_data *adap) +{ + int sta = pca_get_con(adap); + DEB2("=== STOP\n"); + sta |= I2C_PCA_CON_STO; + sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI); + pca_set_con(adap, sta); +} + +/* + * Send the slave address and R/W bit + * + * returns after the address has been sent + */ +static int pca_address(struct i2c_algo_pca_data *adap, + struct i2c_msg *msg) +{ + int sta = pca_get_con(adap); + int addr; + + addr = ((0x7f & msg->addr) << 1); + if (msg->flags & I2C_M_RD) + addr |= 1; + DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n", + msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr); + + pca_outw(adap, I2C_PCA_DAT, addr); + + sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); + pca_set_con(adap, sta); + + return pca_wait(adap); +} + +/* + * Transmit a byte. + * + * Returns after the byte has been transmitted + */ +static int pca_tx_byte(struct i2c_algo_pca_data *adap, + __u8 b) +{ + int sta = pca_get_con(adap); + DEB2("=== WRITE %#04x\n", b); + pca_outw(adap, I2C_PCA_DAT, b); + + sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI); + pca_set_con(adap, sta); + + return pca_wait(adap); +} + +/* + * Receive a byte + * + * returns immediately. + */ +static void pca_rx_byte(struct i2c_algo_pca_data *adap, + __u8 *b, int ack) +{ + *b = pca_inw(adap, I2C_PCA_DAT); + DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK"); +} + +/* + * Setup ACK or NACK for next received byte and wait for it to arrive. + * + * Returns after next byte has arrived. + */ +static int pca_rx_ack(struct i2c_algo_pca_data *adap, + int ack) +{ + int sta = pca_get_con(adap); + + sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA); + + if (ack) + sta |= I2C_PCA_CON_AA; + + pca_set_con(adap, sta); + return pca_wait(adap); +} + +static int pca_xfer(struct i2c_adapter *i2c_adap, + struct i2c_msg *msgs, + int num) +{ + struct i2c_algo_pca_data *adap = i2c_adap->algo_data; + struct i2c_msg *msg = NULL; + int curmsg; + int numbytes = 0; + int state; + int ret; + int completed = 1; + unsigned long timeout = jiffies + i2c_adap->timeout; + + while ((state = pca_status(adap)) != 0xf8) { + if (time_before(jiffies, timeout)) { + msleep(10); + } else { + dev_dbg(&i2c_adap->dev, "bus is not idle. status is " + "%#04x\n", state); + return -EBUSY; + } + } + + DEB1("{{{ XFER %d messages\n", num); + + if (i2c_debug >= 2) { + for (curmsg = 0; curmsg < num; curmsg++) { + int addr, i; + msg = &msgs[curmsg]; + + addr = (0x7f & msg->addr) ; + + if (msg->flags & I2C_M_RD) + printk(KERN_INFO " [%02d] RD %d bytes from %#02x [%#02x, ...]\n", + curmsg, msg->len, addr, (addr << 1) | 1); + else { + printk(KERN_INFO " [%02d] WR %d bytes to %#02x [%#02x%s", + curmsg, msg->len, addr, addr << 1, + msg->len == 0 ? "" : ", "); + for (i = 0; i < msg->len; i++) + printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", "); + printk("]\n"); + } + } + } + + curmsg = 0; + ret = -EIO; + while (curmsg < num) { + state = pca_status(adap); + + DEB3("STATE is 0x%02x\n", state); + msg = &msgs[curmsg]; + + switch (state) { + case 0xf8: /* On reset or stop the bus is idle */ + completed = pca_start(adap); + break; + + case 0x08: /* A START condition has been transmitted */ + case 0x10: /* A repeated start condition has been transmitted */ + completed = pca_address(adap, msg); + break; + + case 0x18: /* SLA+W has been transmitted; ACK has been received */ + case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */ + if (numbytes < msg->len) { + completed = pca_tx_byte(adap, + msg->buf[numbytes]); + numbytes++; + break; + } + curmsg++; numbytes = 0; + if (curmsg == num) + pca_stop(adap); + else + completed = pca_repeated_start(adap); + break; + + case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */ + DEB2("NOT ACK received after SLA+W\n"); + pca_stop(adap); + ret = -ENXIO; + goto out; + + case 0x40: /* SLA+R has been transmitted; ACK has been received */ + completed = pca_rx_ack(adap, msg->len > 1); + break; + + case 0x50: /* Data bytes has been received; ACK has been returned */ + if (numbytes < msg->len) { + pca_rx_byte(adap, &msg->buf[numbytes], 1); + numbytes++; + completed = pca_rx_ack(adap, + numbytes < msg->len - 1); + break; + } + curmsg++; numbytes = 0; + if (curmsg == num) + pca_stop(adap); + else + completed = pca_repeated_start(adap); + break; + + case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */ + DEB2("NOT ACK received after SLA+R\n"); + pca_stop(adap); + ret = -ENXIO; + goto out; + + case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */ + DEB2("NOT ACK received after data byte\n"); + pca_stop(adap); + goto out; + + case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */ + DEB2("Arbitration lost\n"); + /* + * The PCA9564 data sheet (2006-09-01) says "A + * START condition will be transmitted when the + * bus becomes free (STOP or SCL and SDA high)" + * when the STA bit is set (p. 11). + * + * In case this won't work, try pca_reset() + * instead. + */ + pca_start(adap); + goto out; + + case 0x58: /* Data byte has been received; NOT ACK has been returned */ + if (numbytes == msg->len - 1) { + pca_rx_byte(adap, &msg->buf[numbytes], 0); + curmsg++; numbytes = 0; + if (curmsg == num) + pca_stop(adap); + else + completed = pca_repeated_start(adap); + } else { + DEB2("NOT ACK sent after data byte received. " + "Not final byte. numbytes %d. len %d\n", + numbytes, msg->len); + pca_stop(adap); + goto out; + } + break; + case 0x70: /* Bus error - SDA stuck low */ + DEB2("BUS ERROR - SDA Stuck low\n"); + pca_reset(adap); + goto out; + case 0x90: /* Bus error - SCL stuck low */ + DEB2("BUS ERROR - SCL Stuck low\n"); + pca_reset(adap); + goto out; + case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */ + DEB2("BUS ERROR - Illegal START or STOP\n"); + pca_reset(adap); + goto out; + default: + dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state); + break; + } + + if (!completed) + goto out; + } + + ret = curmsg; + out: + DEB1("}}} transferred %d/%d messages. " + "status is %#04x. control is %#04x\n", + curmsg, num, pca_status(adap), + pca_get_con(adap)); + return ret; +} + +static u32 pca_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm pca_algo = { + .master_xfer = pca_xfer, + .functionality = pca_func, +}; + +static unsigned int pca_probe_chip(struct i2c_adapter *adap) +{ + struct i2c_algo_pca_data *pca_data = adap->algo_data; + /* The trick here is to check if there is an indirect register + * available. If there is one, we will read the value we first + * wrote on I2C_PCA_IADR. Otherwise, we will read the last value + * we wrote on I2C_PCA_ADR + */ + pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR); + pca_outw(pca_data, I2C_PCA_IND, 0xAA); + pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO); + pca_outw(pca_data, I2C_PCA_IND, 0x00); + pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR); + if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) { + printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name); + pca_data->chip = I2C_PCA_CHIP_9665; + } else { + printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name); + pca_data->chip = I2C_PCA_CHIP_9564; + } + return pca_data->chip; +} + +static int pca_init(struct i2c_adapter *adap) +{ + struct i2c_algo_pca_data *pca_data = adap->algo_data; + + adap->algo = &pca_algo; + + if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) { + static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36}; + int clock; + + if (pca_data->i2c_clock > 7) { + switch (pca_data->i2c_clock) { + case 330000: + pca_data->i2c_clock = I2C_PCA_CON_330kHz; + break; + case 288000: + pca_data->i2c_clock = I2C_PCA_CON_288kHz; + break; + case 217000: + pca_data->i2c_clock = I2C_PCA_CON_217kHz; + break; + case 146000: + pca_data->i2c_clock = I2C_PCA_CON_146kHz; + break; + case 88000: + pca_data->i2c_clock = I2C_PCA_CON_88kHz; + break; + case 59000: + pca_data->i2c_clock = I2C_PCA_CON_59kHz; + break; + case 44000: + pca_data->i2c_clock = I2C_PCA_CON_44kHz; + break; + case 36000: + pca_data->i2c_clock = I2C_PCA_CON_36kHz; + break; + default: + printk(KERN_WARNING + "%s: Invalid I2C clock speed selected." + " Using default 59kHz.\n", adap->name); + pca_data->i2c_clock = I2C_PCA_CON_59kHz; + } + } else { + printk(KERN_WARNING "%s: " + "Choosing the clock frequency based on " + "index is deprecated." + " Use the nominal frequency.\n", adap->name); + } + + pca_reset(pca_data); + + clock = pca_clock(pca_data); + printk(KERN_INFO "%s: Clock frequency is %dkHz\n", + adap->name, freqs[clock]); + + pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock); + } else { + int clock; + int mode; + int tlow, thi; + /* Values can be found on PCA9665 datasheet section 7.3.2.6 */ + int min_tlow, min_thi; + /* These values are the maximum raise and fall values allowed + * by the I2C operation mode (Standard, Fast or Fast+) + * They are used (added) below to calculate the clock dividers + * of PCA9665. Note that they are slightly different of the + * real maximum, to allow the change on mode exactly on the + * maximum clock rate for each mode + */ + int raise_fall_time; + + if (pca_data->i2c_clock > 1265800) { + printk(KERN_WARNING "%s: I2C clock speed too high." + " Using 1265.8kHz.\n", adap->name); + pca_data->i2c_clock = 1265800; + } + + if (pca_data->i2c_clock < 60300) { + printk(KERN_WARNING "%s: I2C clock speed too low." + " Using 60.3kHz.\n", adap->name); + pca_data->i2c_clock = 60300; + } + + /* To avoid integer overflow, use clock/100 for calculations */ + clock = pca_clock(pca_data) / 100; + + if (pca_data->i2c_clock > 1000000) { + mode = I2C_PCA_MODE_TURBO; + min_tlow = 14; + min_thi = 5; + raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */ + } else if (pca_data->i2c_clock > 400000) { + mode = I2C_PCA_MODE_FASTP; + min_tlow = 17; + min_thi = 9; + raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */ + } else if (pca_data->i2c_clock > 100000) { + mode = I2C_PCA_MODE_FAST; + min_tlow = 44; + min_thi = 20; + raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */ + } else { + mode = I2C_PCA_MODE_STD; + min_tlow = 157; + min_thi = 134; + raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */ + } + + /* The minimum clock that respects the thi/tlow = 134/157 is + * 64800 Hz. Below that, we have to fix the tlow to 255 and + * calculate the thi factor. + */ + if (clock < 648) { + 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; + } + + pca_reset(pca_data); + + printk(KERN_INFO + "%s: Clock frequency is %dHz\n", adap->name, clock * 100); + + pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IMODE); + pca_outw(pca_data, I2C_PCA_IND, mode); + pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLL); + pca_outw(pca_data, I2C_PCA_IND, tlow); + pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLH); + pca_outw(pca_data, I2C_PCA_IND, thi); + + pca_set_con(pca_data, I2C_PCA_CON_ENSIO); + } + udelay(500); /* 500 us for oscilator 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 , " + "Wolfram Sang "); +MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm"); +MODULE_LICENSE("GPL"); + +module_param(i2c_debug, int, 0);