Re: [PATCH v2 3/3] media: i2c: ak7375: Add regulator management

Le 11/07/2022 à 19:31, Jacopo Mondi a écrit :

Hi Yassine,

On Mon, Jul 11, 2022 at 06:40:39PM +0400, Yassine Oudjana wrote:

quoted

From: Yassine Oudjana <y.oudjana@protonmail.com>

Make the driver get needed regulators on probe and enable/disable
them on runtime PM callbacks.

Signed-off-by: Yassine Oudjana <y.oudjana@protonmail.com>
---
Changes since v1:
   - Reorganize variable declaration
   - Change the power-on delay range to 3000-3500 microseconds.

  drivers/media/i2c/ak7375.c | 39 ++++++++++++++++++++++++++++++++++++++
  1 file changed, 39 insertions(+)

diff --git a/drivers/media/i2c/ak7375.c b/drivers/media/i2c/ak7375.c
index 40b1a4aa846c..c2b2542a0056 100644
--- a/drivers/media/i2c/ak7375.c
+++ b/drivers/media/i2c/ak7375.c

@@ -6,6 +6,7 @@
  #include <linux/i2c.h>
  #include <linux/module.h>
  #include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
  #include <media/v4l2-ctrls.h>
  #include <media/v4l2-device.h>

@@ -23,17 +24,32 @@
   */
  #define AK7375_CTRL_STEPS	64
  #define AK7375_CTRL_DELAY_US	1000
+/*
+ * The vcm takes around 3 ms to power on and start taking
+ * I2C messages. This value was found experimentally due to
+ * lack of documentation.
+ */
+#define AK7375_POWER_DELAY_US	3000

  #define AK7375_REG_POSITION	0x0
  #define AK7375_REG_CONT		0x2
  #define AK7375_MODE_ACTIVE	0x0
  #define AK7375_MODE_STANDBY	0x40

+static const char * const ak7375_supply_names[] = {
+	"vdd",
+	"vio",
+};
+
+#define AK7375_NUM_SUPPLIES ARRAY_SIZE(ak7375_supply_names)
+
  /* ak7375 device structure */
  struct ak7375_device {
  	struct v4l2_ctrl_handler ctrls_vcm;
  	struct v4l2_subdev sd;
  	struct v4l2_ctrl *focus;
+	struct regulator_bulk_data supplies[AK7375_NUM_SUPPLIES];
+
  	/* active or standby mode */
  	bool active;
  };

@@ -133,12 +149,24 @@ static int ak7375_probe(struct i2c_client *client)
  {
  	struct ak7375_device *ak7375_dev;
  	int ret;
+	int i;

  	ak7375_dev = devm_kzalloc(&client->dev, sizeof(*ak7375_dev),
  				  GFP_KERNEL);
  	if (!ak7375_dev)
  		return -ENOMEM;

+	for (i = 0; i < AK7375_NUM_SUPPLIES; i++)
+		ak7375_dev->supplies[i].supply = ak7375_supply_names[i];
+
+	ret = devm_regulator_bulk_get(&client->dev, AK7375_NUM_SUPPLIES,
+				      ak7375_dev->supplies);
+	if (ret) {
+		dev_err(&client->dev, "Failed to get regulators: %pe",
+			ERR_PTR(ret));

Why are you using %pe here ? Your return value is not a pointer
(Also, missing \n at the end of the string)

 From Documentation/core-api/printk-formats.rst:
	%pe	-ENOSPC

For printing error pointers (i.e. a pointer for which IS_ERR() is true)
as a symbolic error name. Error values for which no symbolic name is
known are printed in decimal, while a non-ERR_PTR passed as the
argument to %pe gets treated as ordinary %p.

Nit: using:
+		return dev_err_probe(&client->dev, ret, "Failed to get regulators);

would be even simpler.

CJ

quoted

+		return ret;
+	}
+
  	v4l2_i2c_subdev_init(&ak7375_dev->sd, client, &ak7375_ops);
  	ak7375_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
  	ak7375_dev->sd.internal_ops = &ak7375_int_ops;

@@ -210,6 +238,10 @@ static int __maybe_unused ak7375_vcm_suspend(struct device *dev)
  	if (ret)
  		dev_err(dev, "%s I2C failure: %d\n", __func__, ret);

+	ret = regulator_bulk_disable(AK7375_NUM_SUPPLIES, ak7375_dev->supplies);
+	if (ret)
+		return ret;
+
  	ak7375_dev->active = false;

  	return 0;

@@ -230,6 +262,13 @@ static int __maybe_unused ak7375_vcm_resume(struct device *dev)
  	if (ak7375_dev->active)
  		return 0;

+	ret = regulator_bulk_enable(AK7375_NUM_SUPPLIES, ak7375_dev->supplies);
+	if (ret)
+		return ret;
+
+	/* Wait for vcm to become ready */
+	usleep_range(AK7375_POWER_DELAY_US, AK7375_POWER_DELAY_US + 500);
+
  	ret = ak7375_i2c_write(ak7375_dev, AK7375_REG_CONT,
  		AK7375_MODE_ACTIVE, 1);
  	if (ret) {
--

2.37.0