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tuner_r82xx: fix short-write in r82xx_read 

In r82xx_read, there is a 1-byte I2C write followed by the I2C read.  If
this I2C write fails, r82xx_read correctly bails out but may return 0.
Callers that check whether (rc < 0) will assume that the buffer was written
when it has not been, e.g. in r82xx_set_tv_standard where

	priv->fil_cal_code = data[4] & 0x0f;

consumes a garbage value for data[4].

This change resolves that issue by copying the error path from r82xx_write.
This commit is contained in:
Derrick Pallas 2020-03-18 14:54:48 -07:00 committed by Steve Markgraf
parent dc92af01bf
commit d794155ba6
1 changed files with 8 additions and 2 deletions
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10
src/tuner_r82xx.c
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@ -330,8 +330,14 @@ static int r82xx_read(struct r82xx_priv *priv, uint8_t reg, uint8_t *val, int le
priv->buf[0] = reg;
rc = rtlsdr_i2c_write_fn(priv->rtl_dev, priv->cfg->i2c_addr, priv->buf, 1);
if (rc < 1)
return rc;
if (rc != 1) {
fprintf(stderr, "%s: i2c wr failed=%d reg=%02x len=%d\n",
__FUNCTION__, rc, reg, 1);
if (rc < 0)
return rc;
return -1;
}
rc = rtlsdr_i2c_read_fn(priv->rtl_dev, priv->cfg->i2c_addr, p, len);