Re: [PATCH v1] ASoC: rockchip: i2s: use regmap_read_poll_timeout to poll I2S_CLR

14 Sep 2022

Hi Judy,
On Thu, Sep 08, 2022 at 03:11:42PM +0000, Judy Hsiao wrote:
...
Use regmap_read_poll_timeout to poll I2S_CLR.
It also fixes the 'rockchip-i2s ff070000.i2s; fail to clear' and
return -EBUSY when the read of I2S_CLR exceeds the retry limit.
Fixes: 0ff9f8b9f592 ("ASoC: rockchip: i2s: Fix error code when fail
to read I2S_CLR")
Signed-off-by: Judy Hsiao judyhsiao@chromium.org
Thanks for the patch!
...

sound/soc/rockchip/rockchip_i2s.c | 39 +++++++++++++------------------
 1 file changed, 16 insertions(+), 23 deletions(-)

diff --git a/sound/soc/rockchip/rockchip_i2s.c b/sound/soc/rockchip/rockchip_i2s.c
index f5f3540a9e18..02905eec615e 100644
--- a/sound/soc/rockchip/rockchip_i2s.c
+++ b/sound/soc/rockchip/rockchip_i2s.c
@@ -163,18 +163,14 @@ static int rockchip_snd_txctrl(struct rk_i2s_dev *i2s, int on)
   					 I2S_CLR_TXC | I2S_CLR_RXC);
   		if (ret < 0)
   			goto end;

	regmap_read(i2s->regmap, I2S_CLR, &val);



	/* Should wait for clear operation to finish */


	while (val) {


		regmap_read(i2s->regmap, I2S_CLR, &val);


		retry--;



I think you're leaving |retry| as a "set but unused" variable now.
Presumably some compile-testing bots will eventually complain at you
about that.
...

		if (!retry) {


			dev_warn(i2s->dev, "fail to clear\n");


			ret = -EBUSY;


			break;


		}


	}




	ret = regmap_read_poll_timeout(i2s->regmap,


				       I2S_CLR,


				       val,


				       val != 0,


				       20,


				       200);


	if (ret < 0)


		dev_warn(i2s->dev, "fail to clear\n");



Now would be a good time to print the return code, I think:
dev_warn(i2s->dev, "fail to clear: %d\n", ret);
...
}

}
 end:
@@ -226,17 +222,14 @@ static int rockchip_snd_rxctrl(struct rk_i2s_dev *i2s, int on)
   					 I2S_CLR_TXC | I2S_CLR_RXC);
   		if (ret < 0)
   			goto end;

	regmap_read(i2s->regmap, I2S_CLR, &val);


	/* Should wait for clear operation to finish */


	while (val) {


		regmap_read(i2s->regmap, I2S_CLR, &val);


		retry--;


		if (!retry) {



Same.
...

			dev_warn(i2s->dev, "fail to clear\n");


			ret = -EBUSY;


			break;


		}


	}




	ret = regmap_read_poll_timeout(i2s->regmap,


				       I2S_CLR,


				       val,


				       val != 0,


				       20,


				       200);


	if (ret < 0)


		dev_warn(i2s->dev, "fail to clear\n");



Same.
...
}

}
 end:
Otherwise, this is definitely a good change, since we have no timing
guarantee on the existing retry loop, which will surely make it flaky.
So, with those fixups:
Reviewed-by: Brian Norris briannorris@chromium.org

    