There was a deadlock between master I2C adapter and muxed I2C
adapter. Implement two I2C muxed I2C adapters and leave master
alone, just only for offering I2C adapter for these mux adapters.

Reported-by: Luis Alves <lja...@gmail.com>
Reported-by: Benjamin Larsson <benja...@southpole.se>
Signed-off-by: Antti Palosaari <cr...@iki.fi>
---
 drivers/media/dvb-frontends/rtl2832.c      | 71 ++++++++++++++++++++++++------
 drivers/media/dvb-frontends/rtl2832_priv.h |  1 +
 2 files changed, 58 insertions(+), 14 deletions(-)

diff --git a/drivers/media/dvb-frontends/rtl2832.c 
b/drivers/media/dvb-frontends/rtl2832.c
index dc46cf0..c0366a8 100644
--- a/drivers/media/dvb-frontends/rtl2832.c
+++ b/drivers/media/dvb-frontends/rtl2832.c
@@ -180,7 +180,7 @@ static int rtl2832_wr(struct rtl2832_priv *priv, u8 reg, u8 
*val, int len)
        buf[0] = reg;
        memcpy(&buf[1], val, len);
 
-       ret = i2c_transfer(priv->i2c, msg, 1);
+       ret = i2c_transfer(priv->i2c_adapter, msg, 1);
        if (ret == 1) {
                ret = 0;
        } else {
@@ -210,7 +210,7 @@ static int rtl2832_rd(struct rtl2832_priv *priv, u8 reg, u8 
*val, int len)
                }
        };
 
-       ret = i2c_transfer(priv->i2c, msg, 2);
+       ret = i2c_transfer(priv->i2c_adapter, msg, 2);
        if (ret == 2) {
                ret = 0;
        } else {
@@ -891,26 +891,61 @@ static void rtl2832_release(struct dvb_frontend *fe)
        struct rtl2832_priv *priv = fe->demodulator_priv;
 
        dev_dbg(&priv->i2c->dev, "%s:\n", __func__);
+       i2c_del_mux_adapter(priv->i2c_adapter_tuner);
        i2c_del_mux_adapter(priv->i2c_adapter);
        kfree(priv);
 }
 
-static int rtl2832_select(struct i2c_adapter *adap, void *mux_priv, u32 chan)
+static int rtl2832_select(struct i2c_adapter *adap, void *mux_priv, u32 
chan_id)
 {
        struct rtl2832_priv *priv = mux_priv;
-       return rtl2832_i2c_gate_ctrl(&priv->fe, 1);
-}
+       int ret;
+       u8 buf[2];
+       struct i2c_msg msg[1] = {
+               {
+                       .addr = priv->cfg.i2c_addr,
+                       .flags = 0,
+                       .len = sizeof(buf),
+                       .buf = buf,
+               }
+       };
 
-static int rtl2832_deselect(struct i2c_adapter *adap, void *mux_priv, u32 chan)
-{
-       struct rtl2832_priv *priv = mux_priv;
-       return rtl2832_i2c_gate_ctrl(&priv->fe, 0);
+       if (priv->i2c_gate_state == chan_id)
+               return 0;
+
+       /* select reg bank 1 */
+       buf[0] = 0x00;
+       buf[1] = 0x01;
+
+       ret = i2c_transfer(adap, msg, 1);
+       if (ret != 1)
+               goto err;
+
+       priv->page = 1;
+
+       /* open or close I2C repeater gate */
+       buf[0] = 0x01;
+       if (chan_id == 1)
+               buf[1] = 0x18; /* open */
+       else
+               buf[1] = 0x10; /* close */
+
+       ret = i2c_transfer(adap, msg, 1);
+       if (ret != 1)
+               goto err;
+
+       priv->i2c_gate_state = chan_id;
+
+       return 0;
+err:
+       dev_dbg(&priv->i2c->dev, "%s: failed=%d\n", __func__, ret);
+       return -EREMOTEIO;
 }
 
 struct i2c_adapter *rtl2832_get_i2c_adapter(struct dvb_frontend *fe)
 {
        struct rtl2832_priv *priv = fe->demodulator_priv;
-       return priv->i2c_adapter;
+       return priv->i2c_adapter_tuner;
 }
 EXPORT_SYMBOL(rtl2832_get_i2c_adapter);
 
@@ -933,15 +968,21 @@ struct dvb_frontend *rtl2832_attach(const struct 
rtl2832_config *cfg,
        priv->tuner = cfg->tuner;
        memcpy(&priv->cfg, cfg, sizeof(struct rtl2832_config));
 
+       /* create muxed i2c adapter for demod itself */
+       priv->i2c_adapter = i2c_add_mux_adapter(i2c, &i2c->dev, priv, 0, 0, 0,
+                       rtl2832_select, NULL);
+       if (priv->i2c_adapter == NULL)
+               goto err;
+
        /* check if the demod is there */
        ret = rtl2832_rd_reg(priv, 0x00, 0x0, &tmp);
        if (ret)
                goto err;
 
-       /* create muxed i2c adapter */
-       priv->i2c_adapter = i2c_add_mux_adapter(i2c, &i2c->dev, priv, 0, 0, 0,
-                       rtl2832_select, rtl2832_deselect);
-       if (priv->i2c_adapter == NULL)
+       /* create muxed i2c adapter for demod tuner bus */
+       priv->i2c_adapter_tuner = i2c_add_mux_adapter(i2c, &i2c->dev, priv,
+                       0, 1, 0, rtl2832_select, NULL);
+       if (priv->i2c_adapter_tuner == NULL)
                goto err;
 
        /* create dvb_frontend */
@@ -954,6 +995,8 @@ struct dvb_frontend *rtl2832_attach(const struct 
rtl2832_config *cfg,
        return &priv->fe;
 err:
        dev_dbg(&i2c->dev, "%s: failed=%d\n", __func__, ret);
+       if (priv && priv->i2c_adapter)
+               i2c_del_mux_adapter(priv->i2c_adapter);
        kfree(priv);
        return NULL;
 }
diff --git a/drivers/media/dvb-frontends/rtl2832_priv.h 
b/drivers/media/dvb-frontends/rtl2832_priv.h
index ec26c92..8b7c1ae 100644
--- a/drivers/media/dvb-frontends/rtl2832_priv.h
+++ b/drivers/media/dvb-frontends/rtl2832_priv.h
@@ -28,6 +28,7 @@
 struct rtl2832_priv {
        struct i2c_adapter *i2c;
        struct i2c_adapter *i2c_adapter;
+       struct i2c_adapter *i2c_adapter_tuner;
        struct dvb_frontend fe;
        struct rtl2832_config cfg;
 
-- 
1.8.5.3

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