On Tue, Sep 28, 2010 at 2:46 PM, Mauro Carvalho Chehab
<mchehab@xxxxxxxxxx> wrote:
> 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.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
>
> diff --git a/drivers/media/common/tuners/tda18271-common.c b/drivers/media/common/tuners/tda18271-common.c
> index e1f6782..195b30e 100644
> --- 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;
>
> - /* write registers */
> - ret = i2c_transfer(priv->i2c_props.adap, &msg, 1);
> + buf[0] = idx;
> + for (i = 1; i <= max; i++)
> + buf[i] = regs[idx - 1 + i];
>
> + 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 d7fcc36..3abb221 100644
> --- 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 fa406b9..1a047c5 100644
> --- a/drivers/media/video/tuner-core.c
> +++ b/drivers/media/video/tuner-core.c
> @@ -428,7 +428,7 @@ 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,
> --
> 1.7.1
>
>
>
Adding the maintainer for the 18271 driver to the CC.
Devin
--
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com
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