[PATCH 1/2] staging: iio: ad5933: attach life-cycle of kfifo buffer to parent device

[PATCH 1/2] staging: iio: ad5933: attach life-cycle of kfifo buffer to parent device

[Alexandru Ardelean]

This change makes the use of devm_iio_kfifo_allocate() to attach the
life-cycle of the kfifo buffer to the parent (client->dev) object.

This removes the need to explicitly free 'indio_dev->buffer' via
iio_kfifo_free(), which is the main intent.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 drivers/staging/iio/impedance-analyzer/ad5933.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
index af0bcf95ee8a..633adf1a08c1 100644
--- a/drivers/staging/iio/impedance-analyzer/ad5933.c
+++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
@@ -602,11 +602,12 @@ static const struct iio_buffer_setup_ops ad5933_ring_setup_ops = {
 	.postdisable = ad5933_ring_postdisable,
 };
 
-static int ad5933_register_ring_funcs_and_init(struct iio_dev *indio_dev)
+static int ad5933_register_ring_funcs_and_init(struct device *dev,
+					       struct iio_dev *indio_dev)
 {
 	struct iio_buffer *buffer;
 
-	buffer = iio_kfifo_allocate();
+	buffer = devm_iio_kfifo_allocate(dev);
 	if (!buffer)
 		return -ENOMEM;
 
@@ -742,7 +743,7 @@ static int ad5933_probe(struct i2c_client *client,
 	indio_dev->channels = ad5933_channels;
 	indio_dev->num_channels = ARRAY_SIZE(ad5933_channels);
 
-	ret = ad5933_register_ring_funcs_and_init(indio_dev);
+	ret = ad5933_register_ring_funcs_and_init(&client->dev, indio_dev);
 	if (ret)
 		goto error_disable_mclk;
 
@@ -756,8 +757,6 @@ static int ad5933_probe(struct i2c_client *client,
 
 	return 0;
 
-error_unreg_ring:
-	iio_kfifo_free(indio_dev->buffer);
 error_disable_mclk:
 	clk_disable_unprepare(st->mclk);
 error_disable_reg:
@@ -772,7 +771,6 @@ static int ad5933_remove(struct i2c_client *client)
 	struct ad5933_state *st = iio_priv(indio_dev);
 
 	iio_device_unregister(indio_dev);
-	iio_kfifo_free(indio_dev->buffer);
 	regulator_disable(st->reg);
 	clk_disable_unprepare(st->mclk);
 
-- 
2.17.1

[PATCH 2/2] staging: iio: ad5933: convert probe init to use device managed callbacks

[Alexandru Ardelean]

This change moves the clock & regulator disable to use the
devm_add_action_or_reset() callback and uses the devm_iio_device_register()
to register the IIO device.

With this, it should be now possible to get rid of the remove callback.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
 .../staging/iio/impedance-analyzer/ad5933.c   | 67 +++++++++----------
 1 file changed, 33 insertions(+), 34 deletions(-)

diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
index 633adf1a08c1..c468355b0848 100644
--- a/drivers/staging/iio/impedance-analyzer/ad5933.c
+++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
@@ -677,6 +677,20 @@ static void ad5933_work(struct work_struct *work)
 	}
 }
 
+static void ad5933_reg_disable(void *data)
+{
+	struct ad5933_state *st = data;
+
+	regulator_disable(st->reg);
+}
+
+static void ad5933_clk_disable(void *data)
+{
+	struct ad5933_state *st = data;
+
+	clk_disable_unprepare(st->mclk);
+}
+
 static int ad5933_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
@@ -704,23 +718,32 @@ static int ad5933_probe(struct i2c_client *client,
 		dev_err(&client->dev, "Failed to enable specified VDD supply\n");
 		return ret;
 	}
-	ret = regulator_get_voltage(st->reg);
 
+	ret = devm_add_action_or_reset(&client->dev, ad5933_reg_disable, st);
+	if (ret)
+		return ret;
+
+	ret = regulator_get_voltage(st->reg);
 	if (ret < 0)
-		goto error_disable_reg;
+		return ret;
 
 	st->vref_mv = ret / 1000;
 
 	st->mclk = devm_clk_get(&client->dev, "mclk");
-	if (IS_ERR(st->mclk) && PTR_ERR(st->mclk) != -ENOENT) {
-		ret = PTR_ERR(st->mclk);
-		goto error_disable_reg;
-	}
+	if (IS_ERR(st->mclk) && PTR_ERR(st->mclk) != -ENOENT)
+		return PTR_ERR(st->mclk);
 
 	if (!IS_ERR(st->mclk)) {
 		ret = clk_prepare_enable(st->mclk);
 		if (ret < 0)
-			goto error_disable_reg;
+			return ret;
+
+		ret = devm_add_action_or_reset(&client->dev,
+					       ad5933_clk_disable,
+					       st);
+		if (ret)
+			return ret;
+
 		ext_clk_hz = clk_get_rate(st->mclk);
 	}
 
@@ -745,36 +768,13 @@ static int ad5933_probe(struct i2c_client *client,
 
 	ret = ad5933_register_ring_funcs_and_init(&client->dev, indio_dev);
 	if (ret)
-		goto error_disable_mclk;
+		return ret;
 
 	ret = ad5933_setup(st);
 	if (ret)
-		goto error_unreg_ring;
-
-	ret = iio_device_register(indio_dev);
-	if (ret)
-		goto error_unreg_ring;
-
-	return 0;
-
-error_disable_mclk:
-	clk_disable_unprepare(st->mclk);
-error_disable_reg:
-	regulator_disable(st->reg);
-
-	return ret;
-}
-
-static int ad5933_remove(struct i2c_client *client)
-{
-	struct iio_dev *indio_dev = i2c_get_clientdata(client);
-	struct ad5933_state *st = iio_priv(indio_dev);
-
-	iio_device_unregister(indio_dev);
-	regulator_disable(st->reg);
-	clk_disable_unprepare(st->mclk);
+		return ret;
 
-	return 0;
+	return devm_iio_device_register(&client->dev, indio_dev);
 }
 
 static const struct i2c_device_id ad5933_id[] = {
@@ -799,7 +799,6 @@ static struct i2c_driver ad5933_driver = {
 		.of_match_table = ad5933_of_match,
 	},
 	.probe = ad5933_probe,
-	.remove = ad5933_remove,
 	.id_table = ad5933_id,
 };
 module_i2c_driver(ad5933_driver);
-- 
2.17.1

Re: [PATCH 1/2] staging: iio: ad5933: attach life-cycle of kfifo buffer to parent device

[Jonathan Cameron]

On Fri, 8 May 2020 17:39:35 +0300
Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:

> This change makes the use of devm_iio_kfifo_allocate() to attach the
> life-cycle of the kfifo buffer to the parent (client->dev) object.
> 
> This removes the need to explicitly free 'indio_dev->buffer' via
> iio_kfifo_free(), which is the main intent.
> 
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
*mutters darkly*.  Technically this patch adds a non obvious ordering
issue in remove, but then you fix it in the next one so I'll let that go.

However, you've not tried building patch 1 on it's own..

drivers/staging/iio/impedance-analyzer/ad5933.c:752:17: error: label 'error_unreg_ring' was not declared
drivers/staging/iio/impedance-analyzer/ad5933.c:756:17: error: label 'error_unreg_ring' was not declared
  CC [M]  drivers/staging/iio/impedance-analyzer/ad5933.o
drivers/staging/iio/impedance-analyzer/ad5933.c: In function ‘ad5933_probe’:
drivers/staging/iio/impedance-analyzer/ad5933.c:756:3: error: label ‘error_unreg_ring’ used but not defined
  756 |   goto error_unreg_ring;
      |   ^~~~
make[4]: *** [scripts/Makefile.build:267: drivers/staging/iio/impedance-analyzer/ad5933.o] Error 1
make[3]: *** [scripts/Makefile.build:488: drivers/staging/iio/impedance-analyzer] Error 2
make[2]: *** [scripts/Makefile.build:488: drivers/staging/iio] Error 2
make[1]: *** [scripts/Makefile.build:488: drivers/staging] Error 2
make: *** [Makefile:1722: drivers] Error 2

Easiest option here is just to merge the two patches into one. I've
done that and mashed the two commit messages into one semi-coherent whole.

Applied both patches as one to the togreg branch of iio.git and pushed out
as testing for the autobuilders to play with it.

thanks,

Jonathan

> ---
>  drivers/staging/iio/impedance-analyzer/ad5933.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
> index af0bcf95ee8a..633adf1a08c1 100644
> --- a/drivers/staging/iio/impedance-analyzer/ad5933.c
> +++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
> @@ -602,11 +602,12 @@ static const struct iio_buffer_setup_ops ad5933_ring_setup_ops = {
>  	.postdisable = ad5933_ring_postdisable,
>  };
>  
> -static int ad5933_register_ring_funcs_and_init(struct iio_dev *indio_dev)
> +static int ad5933_register_ring_funcs_and_init(struct device *dev,
> +					       struct iio_dev *indio_dev)
>  {
>  	struct iio_buffer *buffer;
>  
> -	buffer = iio_kfifo_allocate();
> +	buffer = devm_iio_kfifo_allocate(dev);
>  	if (!buffer)
>  		return -ENOMEM;
>  
> @@ -742,7 +743,7 @@ static int ad5933_probe(struct i2c_client *client,
>  	indio_dev->channels = ad5933_channels;
>  	indio_dev->num_channels = ARRAY_SIZE(ad5933_channels);
>  
> -	ret = ad5933_register_ring_funcs_and_init(indio_dev);
> +	ret = ad5933_register_ring_funcs_and_init(&client->dev, indio_dev);
>  	if (ret)
>  		goto error_disable_mclk;
>  
> @@ -756,8 +757,6 @@ static int ad5933_probe(struct i2c_client *client,
>  
>  	return 0;
>  
> -error_unreg_ring:
> -	iio_kfifo_free(indio_dev->buffer);
>  error_disable_mclk:
>  	clk_disable_unprepare(st->mclk);
>  error_disable_reg:
> @@ -772,7 +771,6 @@ static int ad5933_remove(struct i2c_client *client)
>  	struct ad5933_state *st = iio_priv(indio_dev);
>  
>  	iio_device_unregister(indio_dev);
> -	iio_kfifo_free(indio_dev->buffer);
>  	regulator_disable(st->reg);
>  	clk_disable_unprepare(st->mclk);
>