[media] tda18271: allow restricting max out to 4 bytes

By default, tda18271 tries to optimize I2C bus by updating all registers
at the same time. Unfortunately, some devices doesn't support it.

The current logic has a problem when small_i2c is equal to 8, since there
are some transfers using 11 + 1 bytes.

Fix the problem by enforcing the max size at the right place, and allows
reducing it to max = 3 + 1.

Acked-by: Michael Krufky <mkrufky@kernellabs.com>
Acked-by: Sri Deevi <Srinivasa.Deevi@conexant.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/common/tuners/tda18271-common.c b/drivers/media/common/tuners/tda18271-common.c
index e1f678281a58d327752dfcf24dc72ccf1d93ff79..195b30e3872dad36bfc9fda7d4e114cb46d26e12 100644 (file)
--- a/drivers/media/common/tuners/tda18271-common.c
+++ b/drivers/media/common/tuners/tda18271-common.c
@@ -193,20 +193,46 @@ int tda18271_write_regs(struct dvb_frontend *fe, int idx, int len)
        unsigned char *regs = priv->tda18271_regs;
        unsigned char buf[TDA18271_NUM_REGS + 1];
        struct i2c_msg msg = { .addr = priv->i2c_props.addr, .flags = 0,
-                              .buf = buf, .len = len + 1 };
-       int i, ret;
+                              .buf = buf };
+       int i, ret = 1, max;
 
        BUG_ON((len == 0) || (idx + len > sizeof(buf)));
 
-       buf[0] = idx;
-       for (i = 1; i <= len; i++)
-               buf[i] = regs[idx - 1 + i];
+
+       switch (priv->small_i2c) {
+       case TDA18271_03_BYTE_CHUNK_INIT:
+               max = 3;
+               break;
+       case TDA18271_08_BYTE_CHUNK_INIT:
+               max = 8;
+               break;
+       case TDA18271_16_BYTE_CHUNK_INIT:
+               max = 16;
+               break;
+       case TDA18271_39_BYTE_CHUNK_INIT:
+       default:
+               max = 39;
+       }
 
        tda18271_i2c_gate_ctrl(fe, 1);
+       while (len) {
+               if (max > len)
+                       max = len;
+
+               buf[0] = idx;
+               for (i = 1; i <= max; i++)
+                       buf[i] = regs[idx - 1 + i];
 
-       /* write registers */
-       ret = i2c_transfer(priv->i2c_props.adap, &msg, 1);
+               msg.len = max + 1;
 
+               /* write registers */
+               ret = i2c_transfer(priv->i2c_props.adap, &msg, 1);
+               if (ret != 1)
+                       break;
+
+               idx += max;
+               len -= max;
+       }
        tda18271_i2c_gate_ctrl(fe, 0);
 
        if (ret != 1)
@@ -326,24 +352,7 @@ int tda18271_init_regs(struct dvb_frontend *fe)
        regs[R_EB22] = 0x48;
        regs[R_EB23] = 0xb0;
 
-       switch (priv->small_i2c) {
-       case TDA18271_08_BYTE_CHUNK_INIT:
-               tda18271_write_regs(fe, 0x00, 0x08);
-               tda18271_write_regs(fe, 0x08, 0x08);
-               tda18271_write_regs(fe, 0x10, 0x08);
-               tda18271_write_regs(fe, 0x18, 0x08);
-               tda18271_write_regs(fe, 0x20, 0x07);
-               break;
-       case TDA18271_16_BYTE_CHUNK_INIT:
-               tda18271_write_regs(fe, 0x00, 0x10);
-               tda18271_write_regs(fe, 0x10, 0x10);
-               tda18271_write_regs(fe, 0x20, 0x07);
-               break;
-       case TDA18271_39_BYTE_CHUNK_INIT:
-       default:
-               tda18271_write_regs(fe, 0x00, TDA18271_NUM_REGS);
-               break;
-       }
+       tda18271_write_regs(fe, 0x00, TDA18271_NUM_REGS);
 
        /* setup agc1 gain */
        regs[R_EB17] = 0x00;

diff --git a/drivers/media/common/tuners/tda18271.h b/drivers/media/common/tuners/tda18271.h
index d7fcc36dc6e6a6e7e91fcc29764f91d51a5601c4..3abb221f3d0745ff5b57eaaff6f4ac28b19a1a45 100644 (file)
--- a/drivers/media/common/tuners/tda18271.h
+++ b/drivers/media/common/tuners/tda18271.h
@@ -80,8 +80,9 @@ enum tda18271_output_options {
 
 enum tda18271_small_i2c {
        TDA18271_39_BYTE_CHUNK_INIT = 0,
-       TDA18271_16_BYTE_CHUNK_INIT = 1,
-       TDA18271_08_BYTE_CHUNK_INIT = 2,
+       TDA18271_16_BYTE_CHUNK_INIT = 16,
+       TDA18271_08_BYTE_CHUNK_INIT = 8,
+       TDA18271_03_BYTE_CHUNK_INIT = 3,
 };
 
 struct tda18271_config {

diff --git a/drivers/media/video/tuner-core.c b/drivers/media/video/tuner-core.c
index d14f66f0cb3198af20e41eb7ecd2ad345dc077ed..1cec1224913f4c64f3a68b7a9de9d4a635d5d66a 100644 (file)
--- a/drivers/media/video/tuner-core.c
+++ b/drivers/media/video/tuner-core.c
@@ -427,7 +427,7 @@ static void set_type(struct i2c_client *c, unsigned int type,
        {
                struct tda18271_config cfg = {
                        .config = t->config,
-                       .small_i2c = TDA18271_08_BYTE_CHUNK_INIT,
+                       .small_i2c = TDA18271_03_BYTE_CHUNK_INIT,
                };
 
                if (!dvb_attach(tda18271_attach, &t->fe, t->i2c->addr,