diff options
Diffstat (limited to 'drivers/w1/w1_io.c')
| -rw-r--r-- | drivers/w1/w1_io.c | 117 |
1 files changed, 105 insertions, 12 deletions
diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c index 02796b5a39f6..00f032220173 100644 --- a/drivers/w1/w1_io.c +++ b/drivers/w1/w1_io.c @@ -1,8 +1,8 @@ /* - * w1_io.c + * w1_io.c * * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru> - * + * * * 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 @@ -55,15 +55,29 @@ void w1_delay(unsigned long tm) udelay(tm * w1_delay_parm); } +static void w1_write_bit(struct w1_master *dev, int bit); +static u8 w1_read_bit(struct w1_master *dev); + +/** + * Generates a write-0 or write-1 cycle and samples the level. + */ u8 w1_touch_bit(struct w1_master *dev, int bit) { if (dev->bus_master->touch_bit) return dev->bus_master->touch_bit(dev->bus_master->data, bit); - else + else if (bit) return w1_read_bit(dev); + else { + w1_write_bit(dev, 0); + return(0); + } } -void w1_write_bit(struct w1_master *dev, int bit) +/** + * Generates a write-0 or write-1 cycle. + * Only call if dev->bus_master->touch_bit is NULL + */ +static void w1_write_bit(struct w1_master *dev, int bit) { if (bit) { dev->bus_master->write_bit(dev->bus_master->data, 0); @@ -78,6 +92,12 @@ void w1_write_bit(struct w1_master *dev, int bit) } } +/** + * Writes 8 bits. + * + * @param dev the master device + * @param byte the byte to write + */ void w1_write_8(struct w1_master *dev, u8 byte) { int i; @@ -86,10 +106,15 @@ void w1_write_8(struct w1_master *dev, u8 byte) dev->bus_master->write_byte(dev->bus_master->data, byte); else for (i = 0; i < 8; ++i) - w1_write_bit(dev, (byte >> i) & 0x1); + w1_touch_bit(dev, (byte >> i) & 0x1); } -u8 w1_read_bit(struct w1_master *dev) + +/** + * Generates a write-1 cycle and samples the level. + * Only call if dev->bus_master->touch_bit is NULL + */ +static u8 w1_read_bit(struct w1_master *dev) { int result; @@ -104,6 +129,53 @@ u8 w1_read_bit(struct w1_master *dev) return result & 0x1; } +/** + * Does a triplet - used for searching ROM addresses. + * Return bits: + * bit 0 = id_bit + * bit 1 = comp_bit + * bit 2 = dir_taken + * If both bits 0 & 1 are set, the search should be restarted. + * + * @param dev the master device + * @param bdir the bit to write if both id_bit and comp_bit are 0 + * @return bit fields - see above + */ +u8 w1_triplet(struct w1_master *dev, int bdir) +{ + if ( dev->bus_master->triplet ) + return(dev->bus_master->triplet(dev->bus_master->data, bdir)); + else { + u8 id_bit = w1_touch_bit(dev, 1); + u8 comp_bit = w1_touch_bit(dev, 1); + u8 retval; + + if ( id_bit && comp_bit ) + return(0x03); /* error */ + + if ( !id_bit && !comp_bit ) { + /* Both bits are valid, take the direction given */ + retval = bdir ? 0x04 : 0; + } else { + /* Only one bit is valid, take that direction */ + bdir = id_bit; + retval = id_bit ? 0x05 : 0x02; + } + + if ( dev->bus_master->touch_bit ) + w1_touch_bit(dev, bdir); + else + w1_write_bit(dev, bdir); + return(retval); + } +} + +/** + * Reads 8 bits. + * + * @param dev the master device + * @return the byte read + */ u8 w1_read_8(struct w1_master * dev) { int i; @@ -113,12 +185,20 @@ u8 w1_read_8(struct w1_master * dev) res = dev->bus_master->read_byte(dev->bus_master->data); else for (i = 0; i < 8; ++i) - res |= (w1_read_bit(dev) << i); + res |= (w1_touch_bit(dev,1) << i); return res; } -void w1_write_block(struct w1_master *dev, u8 *buf, int len) +/** + * Writes a series of bytes. + * + * @param dev the master device + * @param buf pointer to the data to write + * @param len the number of bytes to write + * @return the byte read + */ +void w1_write_block(struct w1_master *dev, const u8 *buf, int len) { int i; @@ -129,6 +209,14 @@ void w1_write_block(struct w1_master *dev, u8 *buf, int len) w1_write_8(dev, buf[i]); } +/** + * Reads a series of bytes. + * + * @param dev the master device + * @param buf pointer to the buffer to fill + * @param len the number of bytes to read + * @return the number of bytes read + */ u8 w1_read_block(struct w1_master *dev, u8 *buf, int len) { int i; @@ -145,9 +233,15 @@ u8 w1_read_block(struct w1_master *dev, u8 *buf, int len) return ret; } +/** + * Issues a reset bus sequence. + * + * @param dev The bus master pointer + * @return 0=Device present, 1=No device present or error + */ int w1_reset_bus(struct w1_master *dev) { - int result = 0; + int result; if (dev->bus_master->reset_bus) result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1; @@ -180,12 +274,11 @@ void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb) if (dev->bus_master->search) dev->bus_master->search(dev->bus_master->data, cb); else - w1_search(dev); + w1_search(dev, cb); } -EXPORT_SYMBOL(w1_write_bit); +EXPORT_SYMBOL(w1_touch_bit); EXPORT_SYMBOL(w1_write_8); -EXPORT_SYMBOL(w1_read_bit); EXPORT_SYMBOL(w1_read_8); EXPORT_SYMBOL(w1_reset_bus); EXPORT_SYMBOL(w1_calc_crc8); |