V4L/DVB (9311): s5h1411: bugfix: Setting serial or parallel mode could destroy bits

Adding a serialmode function to read/and/or/write the register for safety.

Signed-off-by: Steven Toth <stoth@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 16 insertions, 2 deletions

diff --git a/drivers/media/dvb/frontends/s5h1411.c b/drivers/media/dvb/frontends/s5h1411.c
index c79e23ded4d7..4cb056140767 100644
--- a/drivers/media/dvb/frontends/s5h1411.c
+++ b/drivers/media/dvb/frontends/s5h1411.c
@@ -470,6 +470,20 @@ static int s5h1411_set_spectralinversion(struct dvb_frontend *fe, int inversion)
         return s5h1411_writereg(state, S5H1411_I2C_TOP_ADDR, 0x24, val);
 }
 
+static int s5h1411_set_serialmode(struct dvb_frontend *fe, int serial)
+{
+        struct s5h1411_state *state = fe->demodulator_priv;
+        u16 val;
+
+        dprintk("%s(%d)\n", __func__, serial);
+        val = s5h1411_readreg(state, S5H1411_I2C_TOP_ADDR, 0xbd) & ~0x100;
+
+        if (serial == 1)
+                val |= 0x100;
+
+        return s5h1411_writereg(state, S5H1411_I2C_TOP_ADDR, 0xbd, val);
+}
+
 static int s5h1411_enable_modulation(struct dvb_frontend *fe,
                                      fe_modulation_t m)
 {
@@ -611,10 +625,10 @@ static int s5h1411_init(struct dvb_frontend *fe)
 
         if (state->config->output_mode == S5H1411_SERIAL_OUTPUT)
                 /* Serial */
-                s5h1411_writereg(state, S5H1411_I2C_TOP_ADDR, 0xbd, 0x1101);
+                s5h1411_set_serialmode(fe, 1);
         else
                 /* Parallel */
-                s5h1411_writereg(state, S5H1411_I2C_TOP_ADDR, 0xbd, 0x1001);
+                s5h1411_set_serialmode(fe, 0);
 
         s5h1411_set_spectralinversion(fe, state->config->inversion);
         s5h1411_set_if_freq(fe, state->config->vsb_if);