Re: [PATCH v5 3/3] media: i2c: imx274: Add IMX274 power on and off sequence
From: Sowjanya Komatineni
Date: Thu Sep 03 2020 - 12:26:40 EST
On 9/3/20 8:03 AM, Jacopo Mondi wrote:
Hello,
On Tue, Sep 01, 2020 at 07:04:38PM -0700, Sowjanya Komatineni wrote:
IMX274 has VANA analog 2.8V supply, VDIG digital core 1.8V supply,
and VDDL digital io 1.2V supply which are optional based on camera
module design.
IMX274 also need external 24Mhz clock and is optional based on
camera module design.
This patch adds support for IMX274 power on and off to enable and
disable these supplies and external clock.
Reviewed-by: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>
Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
---
drivers/media/i2c/imx274.c | 134 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 131 insertions(+), 3 deletions(-)
diff --git a/drivers/media/i2c/imx274.c b/drivers/media/i2c/imx274.c
index a4b9dfd..79bfac3c6 100644
--- a/drivers/media/i2c/imx274.c
+++ b/drivers/media/i2c/imx274.c
@@ -18,7 +18,9 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
+#include <linux/pm_runtime.h>
#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/v4l2-mediabus.h>
#include <linux/videodev2.h>
@@ -131,6 +133,15 @@
#define IMX274_TABLE_WAIT_MS 0
#define IMX274_TABLE_END 1
+/* regulator supplies */
+static const char * const imx274_supply_names[] = {
+ "vddl", /* IF (1.2V) supply */
+ "vdig", /* Digital Core (1.8V) supply */
+ "vana", /* Analog (2.8V) supply */
+};
+
+#define IMX274_NUM_SUPPLIES ARRAY_SIZE(imx274_supply_names)
+
/*
* imx274 I2C operation related structure
*/
@@ -501,6 +512,8 @@ struct imx274_ctrls {
* @frame_rate: V4L2 frame rate structure
* @regmap: Pointer to regmap structure
* @reset_gpio: Pointer to reset gpio
+ * @supplies: List of analog and digital supply regulators
+ * @inck: Pointer to sensor input clock
* @lock: Mutex structure
* @mode: Parameters for the selected readout mode
*/
@@ -514,6 +527,8 @@ struct stimx274 {
struct v4l2_fract frame_interval;
struct regmap *regmap;
struct gpio_desc *reset_gpio;
+ struct regulator_bulk_data supplies[IMX274_NUM_SUPPLIES];
+ struct clk *inck;
struct mutex lock; /* mutex lock for operations */
const struct imx274_mode *mode;
};
@@ -767,6 +782,75 @@ static void imx274_reset(struct stimx274 *priv, int rst)
usleep_range(IMX274_RESET_DELAY1, IMX274_RESET_DELAY2);
}
+/*
+ * imx274_power_on - Function called to power on the sensor
+ * @imx274: Pointer to device structure
+ */
Can I say this does not bring much value ? :)
Also the parameter name is wrong
+static int imx274_power_on(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct v4l2_subdev *sd = i2c_get_clientdata(client);
+ struct stimx274 *imx274 = to_imx274(sd);
+ int ret;
+
+ /* keep sensor in reset before power on */
+ imx274_reset(imx274, 0);
+
+ ret = clk_prepare_enable(imx274->inck);
+ if (ret) {
+ dev_err(&imx274->client->dev,
+ "Failed to enable input clock: %d\n", ret);
+ return ret;
+ }
+
+ ret = regulator_bulk_enable(IMX274_NUM_SUPPLIES, imx274->supplies);
+ if (ret) {
+ dev_err(&imx274->client->dev,
+ "Failed to enable regulators: %d\n", ret);
+ goto fail_reg;
+ }
+
+ usleep_range(1, 2);
usleep_range() allows you to provide an interval in which your timeout
can be coalesced with others. Giving a [1usec, 2usec] range kind of
defeat the purpose. And most than everything, does sleeping for 2usec
serve any real purpose ?
Following delay recommendation from DS for power on sequence.
+ imx274_reset(imx274, 1);
+
+ return 0;
+
+fail_reg:
+ regulator_bulk_disable(IMX274_NUM_SUPPLIES, imx274->supplies);
regulator_bulk_enable() disables all the regulators that were enabled
before the one that failed, so I don't think you need this one here
+ clk_disable_unprepare(imx274->inck);
+ return ret;
+}
+
+/*
+ * imx274_power_off - Function called to power off the sensor
+ * @imx274: Pointer to device structure
+ */
Same as the above one
+static int imx274_power_off(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct v4l2_subdev *sd = i2c_get_clientdata(client);
+ struct stimx274 *imx274 = to_imx274(sd);
+
+ imx274_reset(imx274, 0);
+
Is reset before power-off necessary ?
Its recommended power off sequence as per data sheet.
Safe to keep sensor in reset before powering down one regulator at a time.
+ regulator_bulk_disable(IMX274_NUM_SUPPLIES, imx274->supplies);
+
+ clk_disable_unprepare(imx274->inck);
+
+ return 0;
+}
+
+static int imx274_get_regulators(struct device *dev, struct stimx274 *imx274)
For symmetry with the regulators API I would call this
imx274_regulators_get(). Up to you :)
+{
+ unsigned int i;
+
+ for (i = 0; i < IMX274_NUM_SUPPLIES; i++)
+ imx274->supplies[i].supply = imx274_supply_names[i];
+
+ return devm_regulator_bulk_get(dev, IMX274_NUM_SUPPLIES,
+ imx274->supplies);
^ not sure if it's my email
client but you might have a
wrong indent here
Also, the regulators are optional in the bindings, how do the
regulators API cope with that ? I had a look around and they seems to
assume regulators are provided. I might be mistaken though
Yes these are optional regulators and based on feedback from sakari
changed to use regulator_bulk_get() here.
regulator_bulk_get() uses NORMAL_GET and in case if supplies is not
found it will use dummy regulator.
+}
+
/**
* imx274_s_ctrl - This is used to set the imx274 V4L2 controls
* @ctrl: V4L2 control to be set
@@ -781,6 +865,9 @@ static int imx274_s_ctrl(struct v4l2_ctrl *ctrl)
struct stimx274 *imx274 = to_imx274(sd);
int ret = -EINVAL;
+ if (!pm_runtime_get_if_in_use(&imx274->client->dev))
+ return 0;
+
Right, but then you should call __v4l2_ctrl_handler_setup() in the
s_stream(1) call path to have controls updated (after
pm_runtime_get_sync() call for power on). I had a look at it seems
only exposure is updated.
Existing driver does v4l2_ctrl_handler_setup() in probe(). So, sensor
power on happens prior to that in probe() and then powers down during idle.
dev_dbg(&imx274->client->dev,
"%s : s_ctrl: %s, value: %d\n", __func__,
ctrl->name, ctrl->val);
@@ -811,6 +898,8 @@ static int imx274_s_ctrl(struct v4l2_ctrl *ctrl)
break;
}
+ pm_runtime_put(&imx274->client->dev);
+
return ret;
}
@@ -1327,6 +1416,13 @@ static int imx274_s_stream(struct v4l2_subdev *sd, int on)
mutex_lock(&imx274->lock);
if (on) {
+ ret = pm_runtime_get_sync(&imx274->client->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(&imx274->client->dev);
+ mutex_unlock(&imx274->lock);
+ return ret;
+ }
+
/* load mode registers */
ret = imx274_mode_regs(imx274);
if (ret)
@@ -1362,6 +1458,7 @@ static int imx274_s_stream(struct v4l2_subdev *sd, int on)
ret = imx274_write_table(imx274, imx274_stop);
if (ret)
goto fail;
+ pm_runtime_put(&imx274->client->dev);
}
mutex_unlock(&imx274->lock);
@@ -1369,6 +1466,7 @@ static int imx274_s_stream(struct v4l2_subdev *sd, int on)
return 0;
fail:
+ pm_runtime_put(&imx274->client->dev);
mutex_unlock(&imx274->lock);
dev_err(&imx274->client->dev, "s_stream failed\n");
return ret;
@@ -1834,6 +1932,14 @@ static int imx274_probe(struct i2c_client *client)
mutex_init(&imx274->lock);
+ imx274->inck = devm_clk_get_optional(&client->dev, "inck");
clk_get_optional() might return error. I would check this with IS_ERR
+ ret = imx274_get_regulators(&client->dev, imx274);
+ if (ret) {
+ dev_err(&client->dev,
+ "Failed to get power regulators, err: %d\n", ret);
+ return ret;
+ }
+
/* initialize format */
imx274->mode = &imx274_modes[IMX274_DEFAULT_BINNING];
imx274->crop.width = IMX274_MAX_WIDTH;
@@ -1881,15 +1987,23 @@ static int imx274_probe(struct i2c_client *client)
goto err_me;
}
- /* pull sensor out of reset */
- imx274_reset(imx274, 1);
+ /* power on the sensor */
+ ret = imx274_power_on(&client->dev);
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "%s : imx274 power on failed\n", __func__);
+ goto err_me;
+ }
Doesn't pm_runtime_get calls the poweron function for you ?
But anyway, I don't see the device being probed for, in example,
querying it's VID/PID for identification during the driver's probe
routine. Do you need to power on ?
existing driver does v4l2_ctrl handler setup and loads sensor default
control values during probe.
So doing sensor power_on here prior to setup. Power off happens during idle.
+
+ pm_runtime_set_active(&client->dev);
+ pm_runtime_enable(&client->dev);
/* initialize controls */
ret = v4l2_ctrl_handler_init(&imx274->ctrls.handler, 4);
if (ret < 0) {
dev_err(&client->dev,
"%s : ctrl handler init Failed\n", __func__);
- goto err_me;
+ goto err_disable_rpm;
}
imx274->ctrls.handler.lock = &imx274->lock;
@@ -1951,11 +2065,16 @@ static int imx274_probe(struct i2c_client *client)
goto err_ctrls;
}
+ pm_runtime_idle(&client->dev);
+
dev_info(&client->dev, "imx274 : imx274 probe success !\n");
return 0;
err_ctrls:
v4l2_ctrl_handler_free(&imx274->ctrls.handler);
+err_disable_rpm:
+ pm_runtime_disable(&client->dev);
+ pm_runtime_set_suspended(&client->dev);
err_me:
media_entity_cleanup(&sd->entity);
err_regmap:
@@ -1973,14 +2092,23 @@ static int imx274_remove(struct i2c_client *client)
v4l2_async_unregister_subdev(sd);
v4l2_ctrl_handler_free(&imx274->ctrls.handler);
+
+ pm_runtime_disable(&client->dev);
+ pm_runtime_set_suspended(&client->dev);
+
media_entity_cleanup(&sd->entity);
mutex_destroy(&imx274->lock);
return 0;
}
+static const struct dev_pm_ops imx274_pm_ops = {
+ SET_RUNTIME_PM_OPS(imx274_power_off, imx274_power_on, NULL)
+};
+
static struct i2c_driver imx274_i2c_driver = {
.driver = {
.name = DRIVER_NAME,
+ .pm = &imx274_pm_ops,
.of_match_table = imx274_of_id_table,
},
.probe_new = imx274_probe,
--
2.7.4