[PATCH] [media] zd1301: fix building interface driver without demodulator

From: Arnd Bergmann
Date: Tue Feb 07 2017 - 08:03:12 EST


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@xxxxxxxx>
---
drivers/media/dvb-frontends/zd1301_demod.h | 18 ++++++++++++++++++
drivers/media/usb/dvb-usb-v2/zd1301.c | 4 ++++
2 files changed, 22 insertions(+)

diff --git a/drivers/media/dvb-frontends/zd1301_demod.h b/drivers/media/dvb-frontends/zd1301_demod.h
index 78a3122e4942..ceb2e05e873c 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 563e50c6a327..d1eb4b7bc051 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;
--
2.9.0