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@@ -1,7 +1,7 @@
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-/* ------------------------------------------------------------------------- */
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-/* i2c-algo-bit.c i2c driver algorithms for bit-shift adapters */
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-/* ------------------------------------------------------------------------- */
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-/* Copyright (C) 1995-2000 Simon G. Vogl
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+/* -------------------------------------------------------------------------
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+ * i2c-algo-bit.c i2c driver algorithms for bit-shift adapters
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+ * -------------------------------------------------------------------------
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+ * Copyright (C) 1995-2000 Simon G. Vogl
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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@@ -15,8 +15,8 @@
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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- Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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-/* ------------------------------------------------------------------------- */
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+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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+ * ------------------------------------------------------------------------- */
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/* With some changes from Frodo Looijaard <frodol@dds.nl>, Kyösti Mälkki
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<kmalkki@cc.hut.fi> and Jean Delvare <khali@linux-fr.org> */
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@@ -60,26 +60,26 @@ MODULE_PARM_DESC(i2c_debug,
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/* --- setting states on the bus with the right timing: --------------- */
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-#define setsda(adap,val) adap->setsda(adap->data, val)
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-#define setscl(adap,val) adap->setscl(adap->data, val)
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-#define getsda(adap) adap->getsda(adap->data)
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-#define getscl(adap) adap->getscl(adap->data)
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+#define setsda(adap, val) adap->setsda(adap->data, val)
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+#define setscl(adap, val) adap->setscl(adap->data, val)
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+#define getsda(adap) adap->getsda(adap->data)
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+#define getscl(adap) adap->getscl(adap->data)
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static inline void sdalo(struct i2c_algo_bit_data *adap)
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{
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- setsda(adap,0);
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+ setsda(adap, 0);
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udelay((adap->udelay + 1) / 2);
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}
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static inline void sdahi(struct i2c_algo_bit_data *adap)
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{
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- setsda(adap,1);
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+ setsda(adap, 1);
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udelay((adap->udelay + 1) / 2);
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}
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static inline void scllo(struct i2c_algo_bit_data *adap)
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{
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- setscl(adap,0);
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+ setscl(adap, 0);
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udelay(adap->udelay / 2);
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}
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@@ -91,22 +91,21 @@ static int sclhi(struct i2c_algo_bit_data *adap)
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{
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unsigned long start;
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- setscl(adap,1);
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+ setscl(adap, 1);
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/* Not all adapters have scl sense line... */
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if (!adap->getscl)
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goto done;
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- start=jiffies;
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- while (! getscl(adap) ) {
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- /* the hw knows how to read the clock line,
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- * so we wait until it actually gets high.
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- * This is safer as some chips may hold it low
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- * while they are processing data internally.
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- */
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- if (time_after_eq(jiffies, start+adap->timeout)) {
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+ start = jiffies;
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+ while (!getscl(adap)) {
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+ /* This hw knows how to read the clock line, so we wait
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+ * until it actually gets high. This is safer as some
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+ * chips may hold it low ("clock stretching") while they
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+ * are processing data internally.
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+ */
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+ if (time_after_eq(jiffies, start + adap->timeout))
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return -ETIMEDOUT;
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- }
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cond_resched();
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}
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#ifdef DEBUG
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@@ -118,11 +117,11 @@ static int sclhi(struct i2c_algo_bit_data *adap)
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done:
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udelay(adap->udelay);
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return 0;
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-}
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+}
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/* --- other auxiliary functions -------------------------------------- */
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-static void i2c_start(struct i2c_algo_bit_data *adap)
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+static void i2c_start(struct i2c_algo_bit_data *adap)
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{
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/* assert: scl, sda are high */
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setsda(adap, 0);
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@@ -130,7 +129,7 @@ static void i2c_start(struct i2c_algo_bit_data *adap)
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scllo(adap);
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}
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-static void i2c_repstart(struct i2c_algo_bit_data *adap)
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+static void i2c_repstart(struct i2c_algo_bit_data *adap)
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{
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/* assert: scl is low */
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sdahi(adap);
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@@ -141,18 +140,18 @@ static void i2c_repstart(struct i2c_algo_bit_data *adap)
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}
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-static void i2c_stop(struct i2c_algo_bit_data *adap)
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+static void i2c_stop(struct i2c_algo_bit_data *adap)
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{
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/* assert: scl is low */
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sdalo(adap);
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- sclhi(adap);
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+ sclhi(adap);
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setsda(adap, 1);
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udelay(adap->udelay);
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}
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-/* send a byte without start cond., look for arbitration,
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+/* send a byte without start cond., look for arbitration,
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check ackn. from slave */
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/* returns:
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* 1 if the device acknowledged
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@@ -167,27 +166,33 @@ static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c)
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struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
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/* assert: scl is low */
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- for ( i=7 ; i>=0 ; i-- ) {
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+ for (i = 7; i >= 0; i--) {
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sb = (c >> i) & 1;
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- setsda(adap,sb);
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+ setsda(adap, sb);
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udelay((adap->udelay + 1) / 2);
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- if (sclhi(adap)<0) { /* timed out */
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+ if (sclhi(adap) < 0) { /* timed out */
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bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
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"timeout at bit #%d\n", (int)c, i);
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return -ETIMEDOUT;
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- };
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- /* do arbitration here:
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- * if ( sb && ! getsda(adap) ) -> ouch! Get out of here.
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+ }
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+ /* FIXME do arbitration here:
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+ * if (sb && !getsda(adap)) -> ouch! Get out of here.
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+ *
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+ * Report a unique code, so higher level code can retry
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+ * the whole (combined) message and *NOT* issue STOP.
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*/
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scllo(adap);
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}
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sdahi(adap);
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- if (sclhi(adap)<0){ /* timeout */
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+ if (sclhi(adap) < 0) { /* timeout */
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bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
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"timeout at ack\n", (int)c);
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return -ETIMEDOUT;
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- };
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- /* read ack: SDA should be pulled down by slave */
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+ }
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+
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+ /* read ack: SDA should be pulled down by slave, or it may
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+ * NAK (usually to report problems with the data we wrote).
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+ */
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ack = !getsda(adap); /* ack: sda is pulled low -> success */
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bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c,
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ack ? "A" : "NA");
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@@ -198,24 +203,24 @@ static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c)
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}
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-static int i2c_inb(struct i2c_adapter *i2c_adap)
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+static int i2c_inb(struct i2c_adapter *i2c_adap)
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{
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/* read byte via i2c port, without start/stop sequence */
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/* acknowledge is sent in i2c_read. */
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int i;
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- unsigned char indata=0;
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+ unsigned char indata = 0;
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struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
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/* assert: scl is low */
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sdahi(adap);
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- for (i=0;i<8;i++) {
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- if (sclhi(adap)<0) { /* timeout */
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+ for (i = 0; i < 8; i++) {
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+ if (sclhi(adap) < 0) { /* timeout */
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bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit "
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"#%d\n", 7 - i);
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return -ETIMEDOUT;
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- };
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+ }
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indata *= 2;
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- if ( getsda(adap) )
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+ if (getsda(adap))
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indata |= 0x01;
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setscl(adap, 0);
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udelay(i == 7 ? adap->udelay / 2 : adap->udelay);
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@@ -228,66 +233,67 @@ static int i2c_inb(struct i2c_adapter *i2c_adap)
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* Sanity check for the adapter hardware - check the reaction of
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* the bus lines only if it seems to be idle.
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*/
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-static int test_bus(struct i2c_algo_bit_data *adap, char* name) {
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- int scl,sda;
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+static int test_bus(struct i2c_algo_bit_data *adap, char *name)
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+{
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+ int scl, sda;
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- if (adap->getscl==NULL)
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+ if (adap->getscl == NULL)
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pr_info("%s: Testing SDA only, SCL is not readable\n", name);
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- sda=getsda(adap);
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- scl=(adap->getscl==NULL?1:getscl(adap));
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- if (!scl || !sda ) {
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+ sda = getsda(adap);
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+ scl = (adap->getscl == NULL) ? 1 : getscl(adap);
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+ if (!scl || !sda) {
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printk(KERN_WARNING "%s: bus seems to be busy\n", name);
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goto bailout;
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}
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sdalo(adap);
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- sda=getsda(adap);
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- scl=(adap->getscl==NULL?1:getscl(adap));
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- if ( 0 != sda ) {
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+ sda = getsda(adap);
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+ scl = (adap->getscl == NULL) ? 1 : getscl(adap);
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+ if (sda) {
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printk(KERN_WARNING "%s: SDA stuck high!\n", name);
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goto bailout;
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}
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- if ( 0 == scl ) {
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+ if (!scl) {
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printk(KERN_WARNING "%s: SCL unexpected low "
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"while pulling SDA low!\n", name);
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goto bailout;
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- }
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+ }
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sdahi(adap);
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- sda=getsda(adap);
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- scl=(adap->getscl==NULL?1:getscl(adap));
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- if ( 0 == sda ) {
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+ sda = getsda(adap);
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+ scl = (adap->getscl == NULL) ? 1 : getscl(adap);
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+ if (!sda) {
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printk(KERN_WARNING "%s: SDA stuck low!\n", name);
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goto bailout;
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}
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- if ( 0 == scl ) {
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+ if (!scl) {
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printk(KERN_WARNING "%s: SCL unexpected low "
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"while pulling SDA high!\n", name);
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goto bailout;
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}
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scllo(adap);
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- sda=getsda(adap);
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- scl=(adap->getscl==NULL?0:getscl(adap));
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- if ( 0 != scl ) {
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+ sda = getsda(adap);
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+ scl = (adap->getscl == NULL) ? 0 : getscl(adap);
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+ if (scl) {
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printk(KERN_WARNING "%s: SCL stuck high!\n", name);
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goto bailout;
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}
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- if ( 0 == sda ) {
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+ if (!sda) {
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printk(KERN_WARNING "%s: SDA unexpected low "
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"while pulling SCL low!\n", name);
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goto bailout;
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}
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-
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+
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sclhi(adap);
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- sda=getsda(adap);
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- scl=(adap->getscl==NULL?1:getscl(adap));
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- if ( 0 == scl ) {
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+ sda = getsda(adap);
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+ scl = (adap->getscl == NULL) ? 1 : getscl(adap);
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+ if (!scl) {
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printk(KERN_WARNING "%s: SCL stuck low!\n", name);
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goto bailout;
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}
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- if ( 0 == sda ) {
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+ if (!sda) {
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printk(KERN_WARNING "%s: SDA unexpected low "
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"while pulling SCL high!\n", name);
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goto bailout;
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@@ -314,9 +320,10 @@ static int try_address(struct i2c_adapter *i2c_adap,
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unsigned char addr, int retries)
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{
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struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
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- int i,ret = -1;
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- for (i=0;i<=retries;i++) {
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- ret = i2c_outb(i2c_adap,addr);
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+ int i, ret = -1;
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+
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+ for (i = 0; i <= retries; i++) {
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+ ret = i2c_outb(i2c_adap, addr);
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if (ret == 1 || i == retries)
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break;
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bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
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@@ -338,14 +345,16 @@ static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
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{
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const unsigned char *temp = msg->buf;
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int count = msg->len;
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- unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
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+ unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
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int retval;
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- int wrcount=0;
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+ int wrcount = 0;
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while (count > 0) {
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retval = i2c_outb(i2c_adap, *temp);
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- if ((retval>0) || (nak_ok && (retval==0))) { /* ok or ignored NAK */
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- count--;
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+
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+ /* OK/ACK; or ignored NAK */
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+ if ((retval > 0) || (nak_ok && (retval == 0))) {
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+ count--;
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temp++;
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wrcount++;
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} else { /* arbitration or no acknowledge */
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@@ -376,14 +385,14 @@ static int acknak(struct i2c_adapter *i2c_adap, int is_ack)
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static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
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{
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int inval;
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- int rdcount=0; /* counts bytes read */
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+ int rdcount = 0; /* counts bytes read */
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unsigned char *temp = msg->buf;
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int count = msg->len;
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const unsigned flags = msg->flags;
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while (count > 0) {
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inval = i2c_inb(i2c_adap);
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- if (inval>=0) {
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+ if (inval >= 0) {
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*temp = inval;
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rdcount++;
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} else { /* read timed out */
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@@ -431,7 +440,7 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
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* returns:
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* 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set
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* -x an error occurred (like: -EREMOTEIO if the device did not answer, or
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- * -ETIMEDOUT, for example if the lines are stuck...)
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+ * -ETIMEDOUT, for example if the lines are stuck...)
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*/
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static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
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{
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@@ -443,10 +452,10 @@ static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
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int ret, retries;
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retries = nak_ok ? 0 : i2c_adap->retries;
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-
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- if ( (flags & I2C_M_TEN) ) {
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+
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+ if (flags & I2C_M_TEN) {
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/* a ten bit address */
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- addr = 0xf0 | (( msg->addr >> 7) & 0x03);
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+ addr = 0xf0 | ((msg->addr >> 7) & 0x03);
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bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr);
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/* try extended address code...*/
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ret = try_address(i2c_adap, addr, retries);
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@@ -456,33 +465,33 @@ static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
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return -EREMOTEIO;
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}
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/* the remaining 8 bit address */
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- ret = i2c_outb(i2c_adap,msg->addr & 0x7f);
|
|
|
+ ret = i2c_outb(i2c_adap, msg->addr & 0x7f);
|
|
|
if ((ret != 1) && !nak_ok) {
|
|
|
/* the chip did not ack / xmission error occurred */
|
|
|
dev_err(&i2c_adap->dev, "died at 2nd address code\n");
|
|
|
return -EREMOTEIO;
|
|
|
}
|
|
|
- if ( flags & I2C_M_RD ) {
|
|
|
+ if (flags & I2C_M_RD) {
|
|
|
bit_dbg(3, &i2c_adap->dev, "emitting repeated "
|
|
|
"start condition\n");
|
|
|
i2c_repstart(adap);
|
|
|
/* okay, now switch into reading mode */
|
|
|
addr |= 0x01;
|
|
|
ret = try_address(i2c_adap, addr, retries);
|
|
|
- if ((ret!=1) && !nak_ok) {
|
|
|
+ if ((ret != 1) && !nak_ok) {
|
|
|
dev_err(&i2c_adap->dev,
|
|
|
"died at repeated address code\n");
|
|
|
return -EREMOTEIO;
|
|
|
}
|
|
|
}
|
|
|
} else { /* normal 7bit address */
|
|
|
- addr = ( msg->addr << 1 );
|
|
|
- if (flags & I2C_M_RD )
|
|
|
+ addr = msg->addr << 1;
|
|
|
+ if (flags & I2C_M_RD)
|
|
|
addr |= 1;
|
|
|
- if (flags & I2C_M_REV_DIR_ADDR )
|
|
|
+ if (flags & I2C_M_REV_DIR_ADDR)
|
|
|
addr ^= 1;
|
|
|
ret = try_address(i2c_adap, addr, retries);
|
|
|
- if ((ret!=1) && !nak_ok)
|
|
|
+ if ((ret != 1) && !nak_ok)
|
|
|
return -EREMOTEIO;
|
|
|
}
|
|
|
|
|
@@ -494,15 +503,14 @@ static int bit_xfer(struct i2c_adapter *i2c_adap,
|
|
|
{
|
|
|
struct i2c_msg *pmsg;
|
|
|
struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
|
|
|
-
|
|
|
- int i,ret;
|
|
|
+ int i, ret;
|
|
|
unsigned short nak_ok;
|
|
|
|
|
|
bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
|
|
|
i2c_start(adap);
|
|
|
- for (i=0;i<num;i++) {
|
|
|
+ for (i = 0; i < num; i++) {
|
|
|
pmsg = &msgs[i];
|
|
|
- nak_ok = pmsg->flags & I2C_M_IGNORE_NAK;
|
|
|
+ nak_ok = pmsg->flags & I2C_M_IGNORE_NAK;
|
|
|
if (!(pmsg->flags & I2C_M_NOSTART)) {
|
|
|
if (i) {
|
|
|
bit_dbg(3, &i2c_adap->dev, "emitting "
|
|
@@ -517,7 +525,7 @@ static int bit_xfer(struct i2c_adapter *i2c_adap,
|
|
|
goto bailout;
|
|
|
}
|
|
|
}
|
|
|
- if (pmsg->flags & I2C_M_RD ) {
|
|
|
+ if (pmsg->flags & I2C_M_RD) {
|
|
|
/* read bytes into buffer*/
|
|
|
ret = readbytes(i2c_adap, pmsg);
|
|
|
if (ret >= 1)
|
|
@@ -551,7 +559,7 @@ bailout:
|
|
|
|
|
|
static u32 bit_func(struct i2c_adapter *adap)
|
|
|
{
|
|
|
- return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
|
|
|
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
|
|
|
I2C_FUNC_SMBUS_READ_BLOCK_DATA |
|
|
|
I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
|
|
|
I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
|
|
@@ -565,8 +573,8 @@ static const struct i2c_algorithm i2c_bit_algo = {
|
|
|
.functionality = bit_func,
|
|
|
};
|
|
|
|
|
|
-/*
|
|
|
- * registering functions to load algorithms at runtime
|
|
|
+/*
|
|
|
+ * registering functions to load algorithms at runtime
|
|
|
*/
|
|
|
static int i2c_bit_prepare_bus(struct i2c_adapter *adap)
|
|
|
{
|
|
@@ -574,7 +582,7 @@ static int i2c_bit_prepare_bus(struct i2c_adapter *adap)
|
|
|
|
|
|
if (bit_test) {
|
|
|
int ret = test_bus(bit_adap, adap->name);
|
|
|
- if (ret<0)
|
|
|
+ if (ret < 0)
|
|
|
return -ENODEV;
|
|
|
}
|
|
|
|