V4L/DVB (6979): tda18271: use a mutex to protect state in critical sections

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/dvb/frontends/tda18271-fe.c

@@ -598,26 +598,36 @@ static int tda18271_init(struct dvb_frontend *fe)
 {
 	struct tda18271_priv *priv = fe->tuner_priv;
 
+	mutex_lock(&priv->lock);
+
 	/* initialization */
 	tda18271_ir_cal_init(fe);
 
 	if (priv->id == TDA18271HDC2)
 		tda18271_rf_cal_init(fe);
 
+	mutex_unlock(&priv->lock);
+
 	return 0;
 }
 
 static int tda18271c2_tune(struct dvb_frontend *fe,
 			   u32 ifc, u32 freq, u32 bw, u8 std)
 {
+	struct tda18271_priv *priv = fe->tuner_priv;
+
 	tda_dbg("freq = %d, ifc = %d\n", freq, ifc);
 
 	tda18271_init(fe);
 
+	mutex_lock(&priv->lock);
+
 	tda18271_rf_tracking_filters_correction(fe, freq);
 
 	tda18271_channel_configuration(fe, ifc, freq, bw, std);
 
+	mutex_unlock(&priv->lock);
+
 	return 0;
 }
 
@@ -632,6 +642,8 @@ static int tda18271c1_tune(struct dvb_frontend *fe,
 
 	tda18271_init(fe);
 
+	mutex_lock(&priv->lock);
+
 	tda_dbg("freq = %d, ifc = %d\n", freq, ifc);
 
 	/* RF tracking filter calibration */
@@ -766,6 +778,7 @@ static int tda18271c1_tune(struct dvb_frontend *fe,
 
 	tda18271_write_regs(fe, R_TM, 15);
 	msleep(5);
+	mutex_unlock(&priv->lock);
 
 	return 0;
 }
@@ -1012,7 +1025,9 @@ static int tda18271_get_id(struct dvb_frontend *fe)
 	char *name;
 	int ret = 0;
 
+	mutex_lock(&priv->lock);
 	tda18271_read_regs(fe);
+	mutex_unlock(&priv->lock);
 
 	switch (regs[R_ID] & 0x7f) {
 	case 3:
@@ -1065,6 +1080,7 @@ struct dvb_frontend *tda18271_attach(struct dvb_frontend *fe, u8 addr,
 	priv->i2c_adap = i2c;
 	priv->gate = (cfg) ? cfg->gate : TDA18271_GATE_AUTO;
 	priv->cal_initialized = false;
+	mutex_init(&priv->lock);
 
 	fe->tuner_priv = priv;
 
@@ -1084,8 +1100,12 @@ struct dvb_frontend *tda18271_attach(struct dvb_frontend *fe, u8 addr,
 	if (tda18271_debug & DBG_MAP)
 		tda18271_dump_std_map(fe);
 
+	mutex_lock(&priv->lock);
+
 	tda18271_init_regs(fe);
 
+	mutex_unlock(&priv->lock);
+
 	return fe;
 fail:
 	tda18271_release(fe);

drivers/media/dvb/frontends/tda18271-priv.h

@@ -23,6 +23,7 @@
 
 #include <linux/kernel.h>
 #include <linux/types.h>
+#include <linux/mutex.h>
 #include "tda18271.h"
 
 #define R_ID     0x00	/* ID byte                */
@@ -112,6 +113,8 @@ struct tda18271_priv {
 	struct tda18271_std_map std;
 	struct tda18271_rf_tracking_filter_cal rf_cal_state[8];
 
+	struct mutex lock;
+
 	u32 frequency;
 	u32 bandwidth;
 };