| /* | 
 |  *  i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters                 | 
 |  *    Copyright (C) 2004 Arcom Control Systems | 
 |  * | 
 |  *  This program is free software; you can redistribute it and/or modify | 
 |  *  it under the terms of the GNU General Public License as published by | 
 |  *  the Free Software Foundation; either version 2 of the License, or | 
 |  *  (at your option) any later version. | 
 |  * | 
 |  *  This program is distributed in the hope that it will be useful, | 
 |  *  but WITHOUT ANY WARRANTY; without even the implied warranty of | 
 |  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the | 
 |  *  GNU General Public License for more details. | 
 |  * | 
 |  *  You should have received a copy of the GNU General Public License | 
 |  *  along with this program; if not, write to the Free Software | 
 |  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | 
 |  */ | 
 |  | 
 | #include <linux/kernel.h> | 
 | #include <linux/module.h> | 
 | #include <linux/moduleparam.h> | 
 | #include <linux/delay.h> | 
 | #include <linux/slab.h> | 
 | #include <linux/init.h> | 
 | #include <linux/errno.h> | 
 | #include <linux/i2c.h> | 
 | #include <linux/i2c-algo-pca.h> | 
 | #include "i2c-algo-pca.h" | 
 |  | 
 | #define DRIVER "i2c-algo-pca" | 
 |  | 
 | #define DEB1(fmt, args...) do { if (i2c_debug>=1) printk(fmt, ## args); } while(0) | 
 | #define DEB2(fmt, args...) do { if (i2c_debug>=2) printk(fmt, ## args); } while(0) | 
 | #define DEB3(fmt, args...) do { if (i2c_debug>=3) printk(fmt, ## args); } while(0) | 
 |  | 
 | static int i2c_debug=0; | 
 |  | 
 | #define pca_outw(adap, reg, val) adap->write_byte(adap, reg, val) | 
 | #define pca_inw(adap, reg) adap->read_byte(adap, reg) | 
 |  | 
 | #define pca_status(adap) pca_inw(adap, I2C_PCA_STA) | 
 | #define pca_clock(adap) adap->get_clock(adap) | 
 | #define pca_own(adap) adap->get_own(adap) | 
 | #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_interrupt(adap) | 
 |  | 
 | /* | 
 |  * Generate a start condition on the i2c bus. | 
 |  * | 
 |  * returns after the start condition has occured | 
 |  */ | 
 | static void 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); | 
 | 	pca_wait(adap); | 
 | } | 
 |  | 
 | /* | 
 |  * Generate a repeated start condition on the i2c bus  | 
 |  * | 
 |  * return after the repeated start condition has occured | 
 |  */ | 
 | static void 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); | 
 | 	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 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 void 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); | 
 |  | 
 | 	pca_wait(adap); | 
 | } | 
 |  | 
 | /* | 
 |  * Transmit a byte. | 
 |  * | 
 |  * Returns after the byte has been transmitted | 
 |  */ | 
 | static void 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); | 
 |  | 
 | 	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 void 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); | 
 | 	pca_wait(adap); | 
 | } | 
 |  | 
 | /*  | 
 |  * Reset the i2c bus / SIO  | 
 |  */ | 
 | static void pca_reset(struct i2c_algo_pca_data *adap) | 
 | { | 
 | 	/* apparently only an external reset will do it. not a lot can be done */ | 
 | 	printk(KERN_ERR DRIVER ": Haven't figured out how to do a reset yet\n"); | 
 | } | 
 |  | 
 | 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; | 
 |  | 
 | 	state = pca_status(adap); | 
 | 	if ( state != 0xF8 ) { | 
 | 		dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state ); | 
 | 		/* FIXME: what to do. Force stop ? */ | 
 | 		return -EREMOTEIO; | 
 | 	} | 
 |  | 
 | 	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 = -EREMOTEIO; | 
 | 	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 */ | 
 | 			pca_start(adap); | 
 | 			break; | 
 |  | 
 | 		case 0x08: /* A START condition has been transmitted */ | 
 | 		case 0x10: /* A repeated start condition has been transmitted */ | 
 | 			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) { | 
 | 				pca_tx_byte(adap, msg->buf[numbytes]); | 
 | 				numbytes++; | 
 | 				break; | 
 | 			} | 
 | 			curmsg++; numbytes = 0; | 
 | 			if (curmsg == num) | 
 | 				pca_stop(adap); | 
 | 			else | 
 | 				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); | 
 | 			goto out; | 
 |  | 
 | 		case 0x40: /* SLA+R has been transmitted; ACK has been received */ | 
 | 			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++; | 
 | 				pca_rx_ack(adap, numbytes < msg->len - 1); | 
 | 				break; | 
 | 			} | 
 | 			curmsg++; numbytes = 0; | 
 | 			if (curmsg == num) | 
 | 				pca_stop(adap); | 
 | 			else | 
 | 				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); | 
 | 			goto out; | 
 |  | 
 | 		case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */ | 
 | 			DEB2("NOT ACK received after data byte\n"); | 
 | 			goto out; | 
 |  | 
 | 		case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */ | 
 | 			DEB2("Arbitration lost\n"); | 
 | 			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 | 
 | 					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: | 
 | 			printk(KERN_ERR DRIVER ": unhandled SIO state 0x%02x\n", state); | 
 | 			break; | 
 | 		} | 
 | 		 | 
 | 	} | 
 |  | 
 | 	ret = curmsg; | 
 |  out: | 
 | 	DEB1(KERN_CRIT "}}} transfered %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 int pca_init(struct i2c_algo_pca_data *adap) | 
 | { | 
 | 	static int freqs[] = {330,288,217,146,88,59,44,36}; | 
 | 	int own, clock; | 
 |  | 
 | 	own = pca_own(adap); | 
 | 	clock = pca_clock(adap); | 
 | 	DEB1(KERN_INFO DRIVER ": own address is %#04x\n", own); | 
 | 	DEB1(KERN_INFO DRIVER ": clock freqeuncy is %dkHz\n", freqs[clock]); | 
 |  | 
 | 	pca_outw(adap, I2C_PCA_ADR, own << 1); | 
 |  | 
 | 	pca_set_con(adap, I2C_PCA_CON_ENSIO | clock); | 
 | 	udelay(500); /* 500 µs for oscilator to stabilise */ | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static struct i2c_algorithm pca_algo = { | 
 | 	.name		= "PCA9564 algorithm", | 
 | 	.id		= I2C_ALGO_PCA, | 
 | 	.master_xfer	= pca_xfer, | 
 | 	.functionality	= pca_func, | 
 | }; | 
 |  | 
 | /*  | 
 |  * registering functions to load algorithms at runtime  | 
 |  */ | 
 | int i2c_pca_add_bus(struct i2c_adapter *adap) | 
 | { | 
 | 	struct i2c_algo_pca_data *pca_adap = adap->algo_data; | 
 | 	int rval; | 
 |  | 
 | 	/* register new adapter to i2c module... */ | 
 |  | 
 | 	adap->id |= pca_algo.id; | 
 | 	adap->algo = &pca_algo; | 
 |  | 
 | 	adap->timeout = 100;		/* default values, should	*/ | 
 | 	adap->retries = 3;		/* be replaced by defines	*/ | 
 |  | 
 | 	rval = pca_init(pca_adap); | 
 |  | 
 | 	if (!rval) | 
 | 		i2c_add_adapter(adap); | 
 |  | 
 | 	return rval; | 
 | } | 
 |  | 
 | int i2c_pca_del_bus(struct i2c_adapter *adap) | 
 | { | 
 | 	return i2c_del_adapter(adap); | 
 | } | 
 |  | 
 | EXPORT_SYMBOL(i2c_pca_add_bus); | 
 | EXPORT_SYMBOL(i2c_pca_del_bus); | 
 |  | 
 | MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>"); | 
 | MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm"); | 
 | MODULE_LICENSE("GPL"); | 
 |  | 
 | module_param(i2c_debug, int, 0); |