From: Arnd Bergmann <arnd@arndb.de>
Date: Tue, 7 Feb 2017 13:01:41 +0000 (-0200)
Subject: [media] zd1301: fix building interface driver without demodulator
X-Git-Tag: v4.11-rc2~21^2~8
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0d1270df836fe9f5cc7e8001b7372ca4fa3f00f6;p=platform%2Fkernel%2Flinux-exynos.git

[media] zd1301: fix building interface driver without demodulator

If the USB driver is enabled but the demodulator is not, we get a link error:

ERROR: "zd1301_demod_get_dvb_frontend" [drivers/media/usb/dvb-usb-v2/zd1301.ko] undefined!
ERROR: "zd1301_demod_get_i2c_adapter" [drivers/media/usb/dvb-usb-v2/zd1301.ko] undefined!

Such a configuration obviously makes no sense, but we should not fail
the build.  This tries to mimic what we have for other drivers by turning
the build failure into a runtime failure.

Alternatively we could use an unconditional 'select' or 'depends on' to enforce
a sane configuration.

Fixes: 47d65372b3b6 ("[media] zd1301_demod: ZyDAS ZD1301 DVB-T demodulator driver")
Fixes: 992b39872b80 ("[media] zd1301: ZyDAS ZD1301 DVB USB interface driver")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---

diff --git a/drivers/media/dvb-frontends/zd1301_demod.h b/drivers/media/dvb-frontends/zd1301_demod.h
index 78a3122..ceb2e05 100644
--- a/drivers/media/dvb-frontends/zd1301_demod.h
+++ b/drivers/media/dvb-frontends/zd1301_demod.h
@@ -34,6 +34,7 @@ struct zd1301_demod_platform_data {
 	int (*reg_write)(void *, u16, u8);
 };
 
+#if IS_REACHABLE(CONFIG_DVB_ZD1301_DEMOD)
 /**
  * zd1301_demod_get_dvb_frontend() - Get pointer to DVB frontend
  * @pdev: Pointer to platform device
@@ -52,4 +53,21 @@ struct dvb_frontend *zd1301_demod_get_dvb_frontend(struct platform_device *);
 
 struct i2c_adapter *zd1301_demod_get_i2c_adapter(struct platform_device *);
 
+#else
+
+static inline struct dvb_frontend *zd1301_demod_get_dvb_frontend(struct platform_device *dev)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+
+	return NULL;
+}
+static inline struct i2c_adapter *zd1301_demod_get_i2c_adapter(struct platform_device *dev)
+{
+	printk(KERN_WARNING "%s: driver disabled by Kconfig\n", __func__);
+
+	return NULL;
+}
+
+#endif
+
 #endif /* ZD1301_DEMOD_H */
diff --git a/drivers/media/usb/dvb-usb-v2/zd1301.c b/drivers/media/usb/dvb-usb-v2/zd1301.c
index 563e50c..d1eb4b7 100644
--- a/drivers/media/usb/dvb-usb-v2/zd1301.c
+++ b/drivers/media/usb/dvb-usb-v2/zd1301.c
@@ -168,6 +168,10 @@ static int zd1301_frontend_attach(struct dvb_usb_adapter *adap)
 
 	adapter = zd1301_demod_get_i2c_adapter(pdev);
 	frontend = zd1301_demod_get_dvb_frontend(pdev);
+	if (!adapter || !frontend) {
+		ret = -ENODEV;
+		goto err_module_put_demod;
+	}
 
 	/* Add I2C tuner */
 	dev->mt2060_pdata.i2c_write_max = 9;