[media] rtl2832_sdr: Realtek RTL2832 SDR driver module

Implement SDR driver for Realtek RTL2832U chip as a DVB extension
module. SDR module is attached by DVB USB RTL28XXU driver as a DVB
SEC (satellite equipment controller) module. Abusing unused SEC here
has no harm as that is DVB-T only frontend.

SDR functionality is provided by RTL2832 DVB-T demodulator. I suspect
it is originally planned for DAB and FM, but it could be abused general
SDR, due to modern silicon tuners that has wide frequency range and a
lot of configurable parameters (filters, gains, ...).

http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/44461

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/staging/media/Kconfig

@@ -41,6 +41,8 @@ source "drivers/staging/media/solo6x10/Kconfig"
 
 source "drivers/staging/media/omap4iss/Kconfig"
 
+source "drivers/staging/media/rtl2832u_sdr/Kconfig"
+
 # Keep LIRC at the end, as it has sub-menus
 source "drivers/staging/media/lirc/Kconfig"
 

drivers/staging/media/Makefile

@@ -11,3 +11,5 @@ obj-$(CONFIG_VIDEO_OMAP4)	+= omap4iss/
 obj-$(CONFIG_USB_SN9C102)       += sn9c102/
 obj-$(CONFIG_VIDEO_OMAP2)       += omap24xx/
 obj-$(CONFIG_VIDEO_TCM825X)     += omap24xx/
+obj-$(CONFIG_DVB_RTL2832_SDR)	+= rtl2832u_sdr/
+

drivers/staging/media/rtl2832u_sdr/Kconfig

@@ -0,0 +1,7 @@
+config DVB_RTL2832_SDR
+	tristate "Realtek RTL2832 SDR"
+	depends on USB && DVB_CORE && I2C && VIDEO_V4L2 && DVB_USB_RTL28XXU
+	select DVB_RTL2832
+	select VIDEOBUF2_VMALLOC
+	default m if !MEDIA_SUBDRV_AUTOSELECT
+

drivers/staging/media/rtl2832u_sdr/Makefile

@@ -0,0 +1,6 @@
+obj-$(CONFIG_DVB_RTL2832_SDR) += rtl2832_sdr.o
+
+ccflags-y += -Idrivers/media/dvb-core
+ccflags-y += -Idrivers/media/dvb-frontends
+ccflags-y += -Idrivers/media/tuners
+ccflags-y += -Idrivers/media/usb/dvb-usb-v2

drivers/staging/media/rtl2832u_sdr/rtl2832_sdr.h

@@ -0,0 +1,54 @@
+/*
+ * Realtek RTL2832U SDR driver
+ *
+ * Copyright (C) 2013 Antti Palosaari <crope@iki.fi>
+ *
+ *    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
+ *    the Free Software Foundation; either version 2 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License along
+ *    with this program; if not, write to the Free Software Foundation, Inc.,
+ *    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * GNU Radio plugin "gr-kernel" for device usage will be on:
+ * http://git.linuxtv.org/anttip/gr-kernel.git
+ *
+ * TODO:
+ * Help is very highly welcome for these + all the others you could imagine:
+ * - move controls to V4L2 API
+ * - use libv4l2 for stream format conversions
+ * - gr-kernel: switch to v4l2_mmap (current read eats a lot of cpu)
+ * - SDRSharp support
+ */
+
+#ifndef RTL2832_SDR_H
+#define RTL2832_SDR_H
+
+#include <linux/kconfig.h>
+#include <media/v4l2-subdev.h>
+
+/* for config struct */
+#include "rtl2832.h"
+
+#if IS_ENABLED(CONFIG_DVB_RTL2832_SDR)
+extern struct dvb_frontend *rtl2832_sdr_attach(struct dvb_frontend *fe,
+	struct i2c_adapter *i2c, const struct rtl2832_config *cfg,
+	struct v4l2_subdev *sd);
+#else
+static inline struct dvb_frontend *rtl2832_sdr_attach(struct dvb_frontend *fe,
+	struct i2c_adapter *i2c, const struct rtl2832_config *cfg,
+	struct v4l2_subdev *sd)
+{
+	dev_warn(&i2c->dev, "%s: driver disabled by Kconfig\n", __func__);
+	return NULL;
+}
+#endif
+
+#endif /* RTL2832_SDR_H */