V4L/DVB (10190): cx88: Fix some Kbuild troubles

As Randy Dunlap <randy.dunlap@oracle.com> reported, cx88 has some compilation issues:

drivers/built-in.o: In function `cx88_call_i2c_clients':
(.text+0x20af17): undefined reference to `videobuf_dvb_get_frontend'
drivers/built-in.o: In function `cx8802_probe':
cx88-mpeg.c:(.devinit.text+0x268c4): undefined reference to `videobuf_dvb_alloc_frontend'
cx88-mpeg.c:(.devinit.text+0x268ea): undefined reference to `videobuf_dvb_dealloc_frontends'

With those configs:

CONFIG_VIDEO_CX88=y
CONFIG_VIDEO_CX88_BLACKBIRD=y
CONFIG_VIDEO_CX88_DVB=m
CONFIG_DVB_CORE=m

After carefully examining the code, with the current code, several cx88 drivers
(cx8800, cx8802, cx88_dvb and cx88_blackbird) should be compiled as a module,
if one of them is marked as such. Just fixing Kconfig could create a very complex
set of rules. Also, this hides a problem with the current approach where the dvb
functionality weren't confined inside dvb module.

What happens is that:
	- cx88-i2c (part of cx8800) has some special rules if DVB;
	- cx88-mpeg (cx8802 module) has also part of DVB init code;
	- cx88-dvb has the rest of the dvb code;
	- cx88-blackbird can be used with cx88-mpeg, having cx88-dvb or not.

So, instead of doing some tricks at Kconfig and wait for a next breakage,
this patch moves the dvb code inside cx88-i2c and cx88-mpeg into cx88-dvb.

Another problem is that cx8802 were being compiled, even without cx88-dvb
and cx88-blackbird modules.

While on this code, let's fix also a reported problem:
http://www.linuxtv.org/pipermail/linux-dvb/2009-January/031225.html

A solution for the issue were proposed here:
http://www.mail-archive.com/linux-media@vger.kernel.org/msg00021.html

Thanks to Randy, Andy, Gregoire and Thomas for helping us to detect
and solve the issues.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

6 files changed, 65 insertions, 47 deletions

diff --git a/drivers/media/video/cx88/Kconfig b/drivers/media/video/cx88/Kconfig
index b0f837588e01..2d250a2a7bc3 100644
--- a/drivers/media/video/cx88/Kconfig
+++ b/drivers/media/video/cx88/Kconfig
@@ -69,6 +69,11 @@ config VIDEO_CX88_DVB
           To compile this driver as a module, choose M here: the
           module will be called cx88-dvb.
 
+config VIDEO_CX88_MPEG
+        tristate
+        depends on VIDEO_CX88_DVB || VIDEO_CX88_BLACKBIRD
+        default y
+
 config VIDEO_CX88_VP3054
         tristate "VP-3054 Secondary I2C Bus Support"
         default m
diff --git a/drivers/media/video/cx88/Makefile b/drivers/media/video/cx88/Makefile
index 6ec30f242578..b06b1275a9ec 100644
--- a/drivers/media/video/cx88/Makefile
+++ b/drivers/media/video/cx88/Makefile
@@ -3,7 +3,8 @@ cx88xx-objs	:= cx88-cards.o cx88-core.o cx88-i2c.o cx88-tvaudio.o \
 cx8800-objs     := cx88-video.o cx88-vbi.o
 cx8802-objs     := cx88-mpeg.o
 
-obj-$(CONFIG_VIDEO_CX88) += cx88xx.o cx8800.o cx8802.o
+obj-$(CONFIG_VIDEO_CX88) += cx88xx.o cx8800.o
+obj-$(CONFIG_VIDEO_CX88_MPEG) += cx8802.o
 obj-$(CONFIG_VIDEO_CX88_ALSA) += cx88-alsa.o
 obj-$(CONFIG_VIDEO_CX88_BLACKBIRD) += cx88-blackbird.o
 obj-$(CONFIG_VIDEO_CX88_DVB) += cx88-dvb.o
diff --git a/drivers/media/video/cx88/cx88-dvb.c b/drivers/media/video/cx88/cx88-dvb.c
index da4dd4913d9f..613dfea4ff3e 100644
--- a/drivers/media/video/cx88/cx88-dvb.c
+++ b/drivers/media/video/cx88/cx88-dvb.c
@@ -138,6 +138,28 @@ static int cx88_dvb_bus_ctrl(struct dvb_frontend* fe, int acquire)
         return ret;
 }
 
+static void cx88_dvb_gate_ctrl(struct cx88_core  *core, int open)
+{
+        struct videobuf_dvb_frontends *f;
+        struct videobuf_dvb_frontend *fe;
+
+        if (!core->dvbdev)
+                return;
+
+        f = &core->dvbdev->frontends;
+
+        if (!f)
+                return;
+
+        if (f->gate <= 1) /* undefined or fe0 */
+                fe = videobuf_dvb_get_frontend(f, 1);
+        else
+                fe = videobuf_dvb_get_frontend(f, f->gate);
+
+        if (fe && fe->dvb.frontend && fe->dvb.frontend->ops.i2c_gate_ctrl)
+                fe->dvb.frontend->ops.i2c_gate_ctrl(fe->dvb.frontend, open);
+}
+
 /* ------------------------------------------------------------------ */
 
 static int dvico_fusionhdtv_demod_init(struct dvb_frontend* fe)
@@ -597,12 +619,30 @@ static int dvb_register(struct cx8802_dev *dev)
         struct cx88_core *core = dev->core;
         struct videobuf_dvb_frontend *fe0, *fe1 = NULL;
         int mfe_shared = 0; /* bus not shared by default */
+        int i;
 
         if (0 != core->i2c_rc) {
                 printk(KERN_ERR "%s/2: no i2c-bus available, cannot attach dvb drivers\n", core->name);
                 goto frontend_detach;
         }
 
+        if (!core->board.num_frontends)
+                return -EINVAL;
+
+        mutex_init(&dev->frontends.lock);
+        INIT_LIST_HEAD(&dev->frontends.felist);
+
+        printk(KERN_INFO "%s() allocating %d frontend(s)\n", __func__,
+                         core->board.num_frontends);
+        for (i = 1; i <= core->board.num_frontends; i++) {
+                fe0 = videobuf_dvb_alloc_frontend(&dev->frontends, i);
+                if (!fe0) {
+                        printk(KERN_ERR "%s() failed to alloc\n", __func__);
+                        videobuf_dvb_dealloc_frontends(&dev->frontends);
+                        goto frontend_detach;
+                }
+        }
+
         /* Get the first frontend */
         fe0 = videobuf_dvb_get_frontend(&dev->frontends, 1);
         if (!fe0)
@@ -611,6 +651,9 @@ static int dvb_register(struct cx8802_dev *dev)
         /* multi-frontend gate control is undefined or defaults to fe0 */
         dev->frontends.gate = 0;
 
+        /* Sets the gate control callback to be used by i2c command calls */
+        core->gate_ctrl = cx88_dvb_gate_ctrl;
+
         /* init frontend(s) */
         switch (core->boardnr) {
         case CX88_BOARD_HAUPPAUGE_DVB_T1:
@@ -1109,6 +1152,7 @@ static int dvb_register(struct cx8802_dev *dev)
                 &dev->pci->dev, adapter_nr, mfe_shared);
 
 frontend_detach:
+        core->gate_ctrl = NULL;
         videobuf_dvb_dealloc_frontends(&dev->frontends);
         return -EINVAL;
 }
@@ -1270,6 +1314,8 @@ static int cx8802_dvb_remove(struct cx8802_driver *drv)
 
         vp3054_i2c_remove(dev);
 
+        core->gate_ctrl = NULL;
+
         return 0;
 }
 
diff --git a/drivers/media/video/cx88/cx88-i2c.c b/drivers/media/video/cx88/cx88-i2c.c
index 1ab691d20692..c0ff2305d804 100644
--- a/drivers/media/video/cx88/cx88-i2c.c
+++ b/drivers/media/video/cx88/cx88-i2c.c
@@ -116,30 +116,16 @@ static int detach_inform(struct i2c_client *client)
 
 void cx88_call_i2c_clients(struct cx88_core *core, unsigned int cmd, void *arg)
 {
-#if defined(CONFIG_VIDEO_CX88_DVB) || defined(CONFIG_VIDEO_CX88_DVB_MODULE)
-        struct videobuf_dvb_frontends *f = &core->dvbdev->frontends;
-        struct videobuf_dvb_frontend *fe = NULL;
-#endif
         if (0 != core->i2c_rc)
                 return;
 
-#if defined(CONFIG_VIDEO_CX88_DVB) || defined(CONFIG_VIDEO_CX88_DVB_MODULE)
-        if (core->dvbdev && f) {
-                if(f->gate <= 1) /* undefined or fe0 */
-                        fe = videobuf_dvb_get_frontend(f, 1);
-                else
-                        fe = videobuf_dvb_get_frontend(f, f->gate);
+        if (core->gate_ctrl)
+                core->gate_ctrl(core, 1);
 
-                if (fe && fe->dvb.frontend && fe->dvb.frontend->ops.i2c_gate_ctrl)
-                        fe->dvb.frontend->ops.i2c_gate_ctrl(fe->dvb.frontend, 1);
+        i2c_clients_command(&core->i2c_adap, cmd, arg);
 
-                i2c_clients_command(&core->i2c_adap, cmd, arg);
-
-                if (fe && fe->dvb.frontend && fe->dvb.frontend->ops.i2c_gate_ctrl)
-                        fe->dvb.frontend->ops.i2c_gate_ctrl(fe->dvb.frontend, 0);
-        } else
-#endif
-                i2c_clients_command(&core->i2c_adap, cmd, arg);
+        if (core->gate_ctrl)
+                core->gate_ctrl(core, 0);
 }
 
 static const struct i2c_algo_bit_data cx8800_i2c_algo_template = {
diff --git a/drivers/media/video/cx88/cx88-mpeg.c b/drivers/media/video/cx88/cx88-mpeg.c
index 59164fc94f5f..b295b76737e3 100644
--- a/drivers/media/video/cx88/cx88-mpeg.c
+++ b/drivers/media/video/cx88/cx88-mpeg.c
@@ -787,6 +787,9 @@ static int __devinit cx8802_probe(struct pci_dev *pci_dev,
         dev->pci = pci_dev;
         dev->core = core;
 
+        /* Maintain a reference so cx88-video can query the 8802 device. */
+        core->dvbdev = dev;
+
         err = cx8802_init_common(dev);
         if (err != 0)
                 goto fail_free;
@@ -794,32 +797,6 @@ static int __devinit cx8802_probe(struct pci_dev *pci_dev,
         INIT_LIST_HEAD(&dev->drvlist);
         list_add_tail(&dev->devlist,&cx8802_devlist);
 
-#if defined(CONFIG_VIDEO_CX88_DVB) || defined(CONFIG_VIDEO_CX88_DVB_MODULE)
-        mutex_init(&dev->frontends.lock);
-        INIT_LIST_HEAD(&dev->frontends.felist);
-
-        if (core->board.num_frontends) {
-                struct videobuf_dvb_frontend *fe;
-                int i;
-
-                printk(KERN_INFO "%s() allocating %d frontend(s)\n", __func__,
-                        core->board.num_frontends);
-                for (i = 1; i <= core->board.num_frontends; i++) {
-                        fe = videobuf_dvb_alloc_frontend(&dev->frontends, i);
-                        if(fe == NULL) {
-                                printk(KERN_ERR "%s() failed to alloc\n",
-                                        __func__);
-                                videobuf_dvb_dealloc_frontends(&dev->frontends);
-                                err = -ENOMEM;
-                                goto fail_free;
-                        }
-                }
-        }
-#endif
-
-        /* Maintain a reference so cx88-video can query the 8802 device. */
-        core->dvbdev = dev;
-
         /* now autoload cx88-dvb or cx88-blackbird */
         request_modules(dev);
         return 0;
@@ -827,6 +804,7 @@ static int __devinit cx8802_probe(struct pci_dev *pci_dev,
  fail_free:
         kfree(dev);
  fail_core:
+        core->dvbdev = NULL;
         cx88_core_put(core,pci_dev);
         return err;
 }
diff --git a/drivers/media/video/cx88/cx88.h b/drivers/media/video/cx88/cx88.h
index eb9ce30dc5e6..60a8b3187f14 100644
--- a/drivers/media/video/cx88/cx88.h
+++ b/drivers/media/video/cx88/cx88.h
@@ -302,6 +302,7 @@ struct cx88_dmaqueue {
         struct btcx_riscmem    stopper;
         u32                    count;
 };
+struct cx88_core;
 
 struct cx88_core {
         struct list_head           devlist;
@@ -334,7 +335,8 @@ struct cx88_core {
 
         /* config info -- dvb */
 #if defined(CONFIG_VIDEO_CX88_DVB) || defined(CONFIG_VIDEO_CX88_DVB_MODULE)
-        int                        (*prev_set_voltage)(struct dvb_frontend* fe, fe_sec_voltage_t voltage);
+        int                        (*prev_set_voltage)(struct dvb_frontend *fe, fe_sec_voltage_t voltage);
+        void                       (*gate_ctrl)(struct cx88_core  *core, int open);
 #endif
 
         /* state info */