* [PATCH 4/5] compat: Backport i2c_bit_algo structure
2012-07-02 14:22 [PATCH 1/5] compat: Make use of the vga_switcheroo_register_client Ozan Çağlayan
2012-07-02 14:22 ` [PATCH 2/5] compat: Backport shmem_read_mapping_page() Ozan Çağlayan
2012-07-02 14:22 ` [PATCH 3/5] compat: Define I2C_FUNC_NOSTART Ozan Çağlayan
@ 2012-07-02 14:22 ` Ozan Çağlayan
2012-07-02 14:22 ` [PATCH 5/5] compat: Backport DIV_ROUND_UP_DLL macro Ozan Çağlayan
3 siblings, 0 replies; 6+ messages in thread
From: Ozan Çağlayan @ 2012-07-02 14:22 UTC (permalink / raw)
To: mcgrof; +Cc: linux-wireless, Ozan Çağlayan
This backports all the necessary helpers for being able to export
i2c-bit_algo structure.
This is currently only used by drivers/gpu/drm/i915/intel_i2c.c.
This is only enabled for kernels >= 2.6.34.
Trying kernel 3.4.0-030400-generic [OK]
Trying kernel 3.3.7-030307-generic [OK]
Trying kernel 3.2.2-030202-generic [OK]
Trying kernel 3.1.10-030110-generic [OK]
Trying kernel 3.0.18-030018-generic [OK]
Trying kernel 2.6.39-02063904-generic [OK]
Trying kernel 2.6.38-02063808-generic [OK]
Trying kernel 2.6.37-02063706-generic [OK]
Trying kernel 2.6.36-02063604-generic [OK]
Trying kernel 2.6.35-02063512-generic [OK]
Trying kernel 2.6.34-02063410-generic [OK]
Trying kernel 2.6.33-02063305-generic [OK]
Trying kernel 2.6.32-02063255-generic [OK]
Trying kernel 2.6.31-02063113-generic [OK]
Trying kernel 2.6.30-02063010-generic [OK]
Trying kernel 2.6.29-02062906-generic [OK]
Trying kernel 2.6.28-02062810-generic [OK]
Trying kernel 2.6.27-020627-generic [OK]
Trying kernel 2.6.26-020626-generic [OK]
Trying kernel 2.6.25-020625-generic [OK]
Trying kernel 2.6.24-020624-generic [OK]
Signed-off-by: Ozan Çağlayan <ozancag@gmail.com>
---
compat/compat-3.4.c | 442 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/compat-3.4.h | 4 +
2 files changed, 446 insertions(+)
diff --git a/compat/compat-3.4.c b/compat/compat-3.4.c
index 4721fa2..4ff439b 100644
--- a/compat/compat-3.4.c
+++ b/compat/compat-3.4.c
@@ -11,6 +11,448 @@
#include <linux/fs.h>
#include <linux/module.h>
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,34))
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+#include <linux/delay.h>
+
+#define setsda(adap, val) adap->setsda(adap->data, val)
+#define setscl(adap, val) adap->setscl(adap->data, val)
+#define getsda(adap) adap->getsda(adap->data)
+#define getscl(adap) adap->getscl(adap->data)
+
+#define bit_dbg(level, dev, format, args...) \
+ do {} while (0)
+
+static inline void sdalo(struct i2c_algo_bit_data *adap)
+{
+ setsda(adap, 0);
+ udelay((adap->udelay + 1) / 2);
+}
+
+static inline void sdahi(struct i2c_algo_bit_data *adap)
+{
+ setsda(adap, 1);
+ udelay((adap->udelay + 1) / 2);
+}
+
+static inline void scllo(struct i2c_algo_bit_data *adap)
+{
+ setscl(adap, 0);
+ udelay(adap->udelay / 2);
+}
+
+static int sclhi(struct i2c_algo_bit_data *adap)
+{
+ unsigned long start;
+
+ setscl(adap, 1);
+
+ /* Not all adapters have scl sense line... */
+ if (!adap->getscl)
+ goto done;
+
+ start = jiffies;
+ while (!getscl(adap)) {
+ /* This hw knows how to read the clock line, so we wait
+ * until it actually gets high. This is safer as some
+ * chips may hold it low ("clock stretching") while they
+ * are processing data internally.
+ */
+ if (time_after(jiffies, start + adap->timeout)) {
+ /* Test one last time, as we may have been preempted
+ * between last check and timeout test.
+ */
+ if (getscl(adap))
+ break;
+ return -ETIMEDOUT;
+ }
+ cpu_relax();
+ }
+#ifdef DEBUG
+ if (jiffies != start && i2c_debug >= 3)
+ pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go "
+ "high\n", jiffies - start);
+#endif
+
+done:
+ udelay(adap->udelay);
+ return 0;
+}
+
+static void i2c_start(struct i2c_algo_bit_data *adap)
+{
+ /* assert: scl, sda are high */
+ setsda(adap, 0);
+ udelay(adap->udelay);
+ scllo(adap);
+}
+
+static void i2c_repstart(struct i2c_algo_bit_data *adap)
+{
+ /* assert: scl is low */
+ sdahi(adap);
+ sclhi(adap);
+ setsda(adap, 0);
+ udelay(adap->udelay);
+ scllo(adap);
+}
+
+
+static void i2c_stop(struct i2c_algo_bit_data *adap)
+{
+ /* assert: scl is low */
+ sdalo(adap);
+ sclhi(adap);
+ setsda(adap, 1);
+ udelay(adap->udelay);
+}
+
+static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c)
+{
+ int i;
+ int sb;
+ int ack;
+ struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
+
+ /* assert: scl is low */
+ for (i = 7; i >= 0; i--) {
+ sb = (c >> i) & 1;
+ setsda(adap, sb);
+ udelay((adap->udelay + 1) / 2);
+ if (sclhi(adap) < 0) { /* timed out */
+ bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
+ "timeout at bit #%d\n", (int)c, i);
+ return -ETIMEDOUT;
+ }
+ /* FIXME do arbitration here:
+ * if (sb && !getsda(adap)) -> ouch! Get out of here.
+ *
+ * Report a unique code, so higher level code can retry
+ * the whole (combined) message and *NOT* issue STOP.
+ */
+ scllo(adap);
+ }
+ sdahi(adap);
+ if (sclhi(adap) < 0) { /* timeout */
+ bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
+ "timeout at ack\n", (int)c);
+ return -ETIMEDOUT;
+ }
+
+ /* read ack: SDA should be pulled down by slave, or it may
+ * NAK (usually to report problems with the data we wrote).
+ */
+ ack = !getsda(adap); /* ack: sda is pulled low -> success */
+ bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c,
+ ack ? "A" : "NA");
+
+ scllo(adap);
+ return ack;
+ /* assert: scl is low (sda undef) */
+}
+
+static int i2c_inb(struct i2c_adapter *i2c_adap)
+{
+ /* read byte via i2c port, without start/stop sequence */
+ /* acknowledge is sent in i2c_read. */
+ int i;
+ unsigned char indata = 0;
+ struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
+
+ /* assert: scl is low */
+ sdahi(adap);
+ for (i = 0; i < 8; i++) {
+ if (sclhi(adap) < 0) { /* timeout */
+ bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit "
+ "#%d\n", 7 - i);
+ return -ETIMEDOUT;
+ }
+ indata *= 2;
+ if (getsda(adap))
+ indata |= 0x01;
+ setscl(adap, 0);
+ udelay(i == 7 ? adap->udelay / 2 : adap->udelay);
+ }
+ /* assert: scl is low */
+ return indata;
+}
+
+static int try_address(struct i2c_adapter *i2c_adap,
+ unsigned char addr, int retries)
+{
+ struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
+ int i, ret = 0;
+
+ for (i = 0; i <= retries; i++) {
+ ret = i2c_outb(i2c_adap, addr);
+ if (ret == 1 || i == retries)
+ break;
+ bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
+ i2c_stop(adap);
+ udelay(adap->udelay);
+ yield();
+ bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
+ i2c_start(adap);
+ }
+ if (i && ret)
+ bit_dbg(1, &i2c_adap->dev, "Used %d tries to %s client at "
+ "0x%02x: %s\n", i + 1,
+ addr & 1 ? "read from" : "write to", addr >> 1,
+ ret == 1 ? "success" : "failed, timeout?");
+ return ret;
+}
+
+static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
+{
+ unsigned short flags = msg->flags;
+ unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
+ struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
+
+ unsigned char addr;
+ int ret, retries;
+
+ retries = nak_ok ? 0 : i2c_adap->retries;
+
+ if (flags & I2C_M_TEN) {
+ /* a ten bit address */
+ addr = 0xf0 | ((msg->addr >> 7) & 0x06);
+ bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr);
+ /* try extended address code...*/
+ ret = try_address(i2c_adap, addr, retries);
+ if ((ret != 1) && !nak_ok) {
+ dev_err(&i2c_adap->dev,
+ "died at extended address code\n");
+ return -ENXIO;
+ }
+ /* the remaining 8 bit address */
+ ret = i2c_outb(i2c_adap, msg->addr & 0xff);
+ 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 -ENXIO;
+ }
+ 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) {
+ dev_err(&i2c_adap->dev,
+ "died at repeated address code\n");
+ return -EIO;
+ }
+ }
+ } else { /* normal 7bit address */
+ addr = msg->addr << 1;
+ if (flags & I2C_M_RD)
+ addr |= 1;
+ if (flags & I2C_M_REV_DIR_ADDR)
+ addr ^= 1;
+ ret = try_address(i2c_adap, addr, retries);
+ if ((ret != 1) && !nak_ok)
+ return -ENXIO;
+ }
+
+ return 0;
+}
+
+static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
+{
+ const unsigned char *temp = msg->buf;
+ int count = msg->len;
+ unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
+ int retval;
+ int wrcount = 0;
+
+ while (count > 0) {
+ retval = i2c_outb(i2c_adap, *temp);
+
+ /* OK/ACK; or ignored NAK */
+ if ((retval > 0) || (nak_ok && (retval == 0))) {
+ count--;
+ temp++;
+ wrcount++;
+
+ /* A slave NAKing the master means the slave didn't like
+ * something about the data it saw. For example, maybe
+ * the SMBus PEC was wrong.
+ */
+ } else if (retval == 0) {
+ dev_err(&i2c_adap->dev, "sendbytes: NAK bailout.\n");
+ return -EIO;
+
+ /* Timeout; or (someday) lost arbitration
+ *
+ * FIXME Lost ARB implies retrying the transaction from
+ * the first message, after the "winning" master issues
+ * its STOP. As a rule, upper layer code has no reason
+ * to know or care about this ... it is *NOT* an error.
+ */
+ } else {
+ dev_err(&i2c_adap->dev, "sendbytes: error %d\n",
+ retval);
+ return retval;
+ }
+ }
+ return wrcount;
+}
+
+static int acknak(struct i2c_adapter *i2c_adap, int is_ack)
+{
+ struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
+
+ /* assert: sda is high */
+ if (is_ack) /* send ack */
+ setsda(adap, 0);
+ udelay((adap->udelay + 1) / 2);
+ if (sclhi(adap) < 0) { /* timeout */
+ dev_err(&i2c_adap->dev, "readbytes: ack/nak timeout\n");
+ return -ETIMEDOUT;
+ }
+ scllo(adap);
+ return 0;
+}
+
+static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
+{
+ int inval;
+ int rdcount = 0; /* counts bytes read */
+ unsigned char *temp = msg->buf;
+ int count = msg->len;
+ const unsigned flags = msg->flags;
+
+ while (count > 0) {
+ inval = i2c_inb(i2c_adap);
+ if (inval >= 0) {
+ *temp = inval;
+ rdcount++;
+ } else { /* read timed out */
+ break;
+ }
+
+ temp++;
+ count--;
+
+ /* Some SMBus transactions require that we receive the
+ transaction length as the first read byte. */
+ if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) {
+ if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) {
+ if (!(flags & I2C_M_NO_RD_ACK))
+ acknak(i2c_adap, 0);
+ dev_err(&i2c_adap->dev, "readbytes: invalid "
+ "block length (%d)\n", inval);
+ return -EPROTO;
+ }
+ /* The original count value accounts for the extra
+ bytes, that is, either 1 for a regular transaction,
+ or 2 for a PEC transaction. */
+ count += inval;
+ msg->len += inval;
+ }
+
+ bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n",
+ inval,
+ (flags & I2C_M_NO_RD_ACK)
+ ? "(no ack/nak)"
+ : (count ? "A" : "NA"));
+
+ if (!(flags & I2C_M_NO_RD_ACK)) {
+ inval = acknak(i2c_adap, count);
+ if (inval < 0)
+ return inval;
+ }
+ }
+ return rdcount;
+}
+
+
+static u32 bit_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_EMUL |
+ I2C_FUNC_SMBUS_READ_BLOCK_DATA |
+ I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
+ I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
+}
+
+static int bit_xfer(struct i2c_adapter *i2c_adap,
+ struct i2c_msg msgs[], int num)
+{
+ struct i2c_msg *pmsg;
+ struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
+ int i, ret;
+ unsigned short nak_ok;
+
+ if (adap->pre_xfer) {
+ ret = adap->pre_xfer(i2c_adap);
+ if (ret < 0)
+ return ret;
+ }
+
+ bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
+ i2c_start(adap);
+ for (i = 0; i < num; i++) {
+ pmsg = &msgs[i];
+ nak_ok = pmsg->flags & I2C_M_IGNORE_NAK;
+ if (!(pmsg->flags & I2C_M_NOSTART)) {
+ if (i) {
+ bit_dbg(3, &i2c_adap->dev, "emitting "
+ "repeated start condition\n");
+ i2c_repstart(adap);
+ }
+ ret = bit_doAddress(i2c_adap, pmsg);
+ if ((ret != 0) && !nak_ok) {
+ bit_dbg(1, &i2c_adap->dev, "NAK from "
+ "device addr 0x%02x msg #%d\n",
+ msgs[i].addr, i);
+ goto bailout;
+ }
+ }
+ if (pmsg->flags & I2C_M_RD) {
+ /* read bytes into buffer*/
+ ret = readbytes(i2c_adap, pmsg);
+ if (ret >= 1)
+ bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n",
+ ret, ret == 1 ? "" : "s");
+ if (ret < pmsg->len) {
+ if (ret >= 0)
+ ret = -EIO;
+ goto bailout;
+ }
+ } else {
+ /* write bytes from buffer */
+ ret = sendbytes(i2c_adap, pmsg);
+ if (ret >= 1)
+ bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n",
+ ret, ret == 1 ? "" : "s");
+ if (ret < pmsg->len) {
+ if (ret >= 0)
+ ret = -EIO;
+ goto bailout;
+ }
+ }
+ }
+ ret = i;
+
+bailout:
+ bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
+ i2c_stop(adap);
+
+ if (adap->post_xfer)
+ adap->post_xfer(i2c_adap);
+ return ret;
+}
+
+
+const struct i2c_algorithm i2c_bit_algo = {
+ .master_xfer = bit_xfer,
+ .functionality = bit_func,
+};
+EXPORT_SYMBOL(i2c_bit_algo);
+#endif
+
int simple_open(struct inode *inode, struct file *file)
{
if (inode->i_private)
diff --git a/include/linux/compat-3.4.h b/include/linux/compat-3.4.h
index f343795..e603f4c 100644
--- a/include/linux/compat-3.4.h
+++ b/include/linux/compat-3.4.h
@@ -8,6 +8,10 @@
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,34))
+extern const struct i2c_algorithm i2c_bit_algo;
+#endif
+
extern int simple_open(struct inode *inode, struct file *file);
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28))
--
1.7.10.4
^ permalink raw reply related [flat|nested] 6+ messages in thread