Re: [PATCH 2/2] V4L/DVB: Use custom I2C probing function mechanism

[Jean Delvare <khali@linux-fr.org>]

Hi Mauro,

On Tue, 06 Apr 2010 02:34:46 -0300, Mauro Carvalho Chehab wrote:
> Jean Delvare wrote:
> > On Mon, 05 Apr 2010 15:26:32 -0300, Mauro Carvalho Chehab wrote:
> >> Please, don't add new things at ir-common module. It basically contains the
> >> decoding functions for RC5 and pulse/distance, plus several IR keymaps. With
> >> the IR rework I'm doing, this module will go away, after having all the current 
> >> IR decoders implemented via ir-raw-input binding. 
> >>
> >> The keymaps were already removed from it, on my experimental tree 
> >> (http://git.linuxtv.org/mchehab/ir.git), and rc5 decoder is already written
> >> (but still needs a few fixes). 
> >>
> >> The new ir-core is creating an abstract way to deal with Remote Controllers,
> >> meant to be used not only by IR's, but also for other types of RC, like, 
> >> bluetooth and USB HID. It will also export a raw event interface, for use
> >> with lirc. As this is the core of the RC subsystem, a i2c-specific binding
> >> method also doesn't seem to belong there. SO, IMO, the better place is to add 
> >> it as a static inline function at ir-kbd-i2c.h.
> > 
> > Ever tried to pass the address of an inline function as another
> > function's parameter? :)
> 
> :) Never tried... maybe gcc would to the hard thing, de-inlining it ;)
> 
> Well, we need to put this code somewhere. Where are the other probing
> codes? Probably the better is to put them together.

There are no other probing functions yet, this is the first one. I have
added the mechanism to i2c-core for these very IR chips.

Putting all probe functions together would mean moving them to
i2c-core. This wasn't my original intent, but after all, it makes some
sense. Would you be happy with the following?

* * * * *

From: Jean Delvare <khali@linux-fr.org>
Subject: V4L/DVB: Use custom I2C probing function mechanism

Now that i2c-core offers the possibility to provide custom probing
function for I2C devices, let's make use of it.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
---
 drivers/i2c/i2c-core.c                    |    7 +++++++
 drivers/media/video/cx23885/cx23885-i2c.c |   15 ++++-----------
 drivers/media/video/cx88/cx88-i2c.c       |   19 ++++---------------
 include/linux/i2c.h                       |    3 +++
 4 files changed, 18 insertions(+), 26 deletions(-)

--- linux-2.6.34-rc3.orig/drivers/media/video/cx23885/cx23885-i2c.c	2010-04-06 11:31:20.000000000 +0200
+++ linux-2.6.34-rc3/drivers/media/video/cx23885/cx23885-i2c.c	2010-04-06 12:28:09.000000000 +0200
@@ -365,17 +365,10 @@ int cx23885_i2c_register(struct cx23885_
 
 		memset(&info, 0, sizeof(struct i2c_board_info));
 		strlcpy(info.type, "ir_video", I2C_NAME_SIZE);
-		/*
-		 * We can't call i2c_new_probed_device() because it uses
-		 * quick writes for probing and the IR receiver device only
-		 * replies to reads.
-		 */
-		if (i2c_smbus_xfer(&bus->i2c_adap, addr_list[0], 0,
-				   I2C_SMBUS_READ, 0, I2C_SMBUS_QUICK,
-				   NULL) >= 0) {
-			info.addr = addr_list[0];
-			i2c_new_device(&bus->i2c_adap, &info);
-		}
+		/* Use quick read command for probe, some IR chips don't
+		 * support writes */
+		i2c_new_probed_device(&bus->i2c_adap, &info, addr_list,
+				      i2c_probe_func_quick_read);
 	}
 
 	return bus->i2c_rc;
--- linux-2.6.34-rc3.orig/drivers/media/video/cx88/cx88-i2c.c	2010-04-06 11:31:20.000000000 +0200
+++ linux-2.6.34-rc3/drivers/media/video/cx88/cx88-i2c.c	2010-04-06 12:28:06.000000000 +0200
@@ -188,24 +188,13 @@ int cx88_i2c_init(struct cx88_core *core
 			0x18, 0x6b, 0x71,
 			I2C_CLIENT_END
 		};
-		const unsigned short *addrp;
 
 		memset(&info, 0, sizeof(struct i2c_board_info));
 		strlcpy(info.type, "ir_video", I2C_NAME_SIZE);
-		/*
-		 * We can't call i2c_new_probed_device() because it uses
-		 * quick writes for probing and at least some R receiver
-		 * devices only reply to reads.
-		 */
-		for (addrp = addr_list; *addrp != I2C_CLIENT_END; addrp++) {
-			if (i2c_smbus_xfer(&core->i2c_adap, *addrp, 0,
-					   I2C_SMBUS_READ, 0,
-					   I2C_SMBUS_QUICK, NULL) >= 0) {
-				info.addr = *addrp;
-				i2c_new_device(&core->i2c_adap, &info);
-				break;
-			}
-		}
+		/* Use quick read command for probe, some IR chips don't
+		 * support writes */
+		i2c_new_probed_device(&core->i2c_adap, &info, addr_list,
+				      i2c_probe_func_quick_read);
 	}
 	return core->i2c_rc;
 }
--- linux-2.6.34-rc3.orig/drivers/i2c/i2c-core.c	2010-04-06 10:15:02.000000000 +0200
+++ linux-2.6.34-rc3/drivers/i2c/i2c-core.c	2010-04-06 12:25:31.000000000 +0200
@@ -1460,6 +1460,13 @@ static int i2c_default_probe(struct i2c_
 	return err >= 0;
 }
 
+int i2c_probe_func_quick_read(struct i2c_adapter *i2c, unsigned short addr)
+{
+	return i2c_smbus_xfer(i2c, addr, 0, I2C_SMBUS_READ, 0,
+			      I2C_SMBUS_QUICK, NULL) >= 0;
+}
+EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
+
 struct i2c_client *
 i2c_new_probed_device(struct i2c_adapter *adap,
 		      struct i2c_board_info *info,
--- linux-2.6.34-rc3.orig/include/linux/i2c.h	2010-04-06 10:15:02.000000000 +0200
+++ linux-2.6.34-rc3/include/linux/i2c.h	2010-04-06 12:26:29.000000000 +0200
@@ -288,6 +288,9 @@ i2c_new_probed_device(struct i2c_adapter
 		      unsigned short const *addr_list,
 		      int (*probe)(struct i2c_adapter *, unsigned short addr));
 
+/* common custom probe functions */
+extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
+
 /* For devices that use several addresses, use i2c_new_dummy() to make
  * client handles for the extra addresses.
  */



-- 
Jean Delvare