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Message-ID: <20200831090859.GF31019@paasikivi.fi.intel.com>
Date: Mon, 31 Aug 2020 12:08:59 +0300
From: Sakari Ailus <sakari.ailus@...ux.intel.com>
To: Krzysztof Kozlowski <krzk@...nel.org>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Shawn Guo <shawnguo@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
Pengutronix Kernel Team <kernel@...gutronix.de>,
Fabio Estevam <festevam@...il.com>,
NXP Linux Team <linux-imx@....com>,
linux-media@...r.kernel.org, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
"Yeh, Andy" <andy.yeh@...el.com>,
"Chiang, Alan" <alanx.chiang@...el.com>,
"Chen, Jason" <jasonx.z.chen@...el.com>
Subject: Re: [PATCH 3/3] media: imx258: Get clock from device properties and
enable it
Hi Krzysztof,
Thanks for the patchset.
On Fri, Aug 28, 2020 at 06:00:53PM +0200, Krzysztof Kozlowski wrote:
> The IMX258 sensor driver checked in device properties for a
> clock-frequency property which actually does not mean that the clock is
> really running such frequency or is it even enabled.
>
> Get the provided clock and check it frequency. If none is provided,
> fall back to old property.
>
> Enable the clock when accessing the IMX258 registers and when streaming
> starts.
>
> Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
> ---
> drivers/media/i2c/imx258.c | 107 ++++++++++++++++++++++++++++++-------
> 1 file changed, 87 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/media/i2c/imx258.c b/drivers/media/i2c/imx258.c
> index c20bac9b00ec..4d763dcabb1d 100644
> --- a/drivers/media/i2c/imx258.c
> +++ b/drivers/media/i2c/imx258.c
> @@ -2,6 +2,7 @@
> // Copyright (C) 2018 Intel Corporation
>
> #include <linux/acpi.h>
> +#include <linux/clk.h>
> #include <linux/delay.h>
> #include <linux/i2c.h>
> #include <linux/module.h>
> @@ -68,6 +69,9 @@
> #define REG_CONFIG_MIRROR_FLIP 0x03
> #define REG_CONFIG_FLIP_TEST_PATTERN 0x02
>
> +/* Input clock frequency in Hz */
> +#define IMX258_INPUT_CLOCK_FREQ 19200000
> +
> struct imx258_reg {
> u16 address;
> u8 val;
> @@ -610,6 +614,8 @@ struct imx258 {
>
> /* Streaming on/off */
> bool streaming;
> +
> + struct clk *clk;
> };
>
> static inline struct imx258 *to_imx258(struct v4l2_subdev *_sd)
> @@ -747,6 +753,12 @@ static int imx258_set_ctrl(struct v4l2_ctrl *ctrl)
> if (pm_runtime_get_if_in_use(&client->dev) == 0)
> return 0;
>
> + ret = clk_prepare_enable(imx258->clk);
> + if (ret) {
> + dev_err(&client->dev, "failed to enable clock\n");
> + goto out;
> + }
> +
> switch (ctrl->id) {
> case V4L2_CID_ANALOGUE_GAIN:
> ret = imx258_write_reg(imx258, IMX258_REG_ANALOG_GAIN,
> @@ -779,6 +791,8 @@ static int imx258_set_ctrl(struct v4l2_ctrl *ctrl)
> break;
> }
>
> +out:
> + clk_disable_unprepare(imx258->clk);
> pm_runtime_put(&client->dev);
>
> return ret;
> @@ -972,10 +986,40 @@ static int imx258_stop_streaming(struct imx258 *imx258)
> return 0;
> }
>
> +static int imx258_power_on(struct imx258 *imx258)
> +{
> + struct i2c_client *client = v4l2_get_subdevdata(&imx258->sd);
> + int ret;
> +
> + ret = pm_runtime_get_sync(&client->dev);
> + if (ret < 0)
> + goto err;
Please continue to use runtime PM directly, and move the clock control to
runtime PM callbacks (apart from probe and remove).
> +
> + ret = clk_prepare_enable(imx258->clk);
> + if (ret) {
> + dev_err(&client->dev, "failed to enable clock\n");
> + goto err;
> + }
> +
> + return 0;
> +
> +err:
> + pm_runtime_put_noidle(&client->dev);
> +
> + return ret;
> +}
> +
> +static void imx258_power_off(struct imx258 *imx258)
> +{
> + struct i2c_client *client = v4l2_get_subdevdata(&imx258->sd);
> +
> + clk_disable_unprepare(imx258->clk);
> + pm_runtime_put(&client->dev);
> +}
> +
> static int imx258_set_stream(struct v4l2_subdev *sd, int enable)
> {
> struct imx258 *imx258 = to_imx258(sd);
> - struct i2c_client *client = v4l2_get_subdevdata(sd);
> int ret = 0;
>
> mutex_lock(&imx258->mutex);
> @@ -985,11 +1029,9 @@ static int imx258_set_stream(struct v4l2_subdev *sd, int enable)
> }
>
> if (enable) {
> - ret = pm_runtime_get_sync(&client->dev);
> - if (ret < 0) {
> - pm_runtime_put_noidle(&client->dev);
> + ret = imx258_power_on(imx258);
> + if (ret < 0)
> goto err_unlock;
> - }
>
> /*
> * Apply default & customized values
> @@ -997,10 +1039,10 @@ static int imx258_set_stream(struct v4l2_subdev *sd, int enable)
> */
> ret = imx258_start_streaming(imx258);
> if (ret)
> - goto err_rpm_put;
> + goto err_power_off;
> } else {
> imx258_stop_streaming(imx258);
> - pm_runtime_put(&client->dev);
> + imx258_power_off(imx258);
> }
>
> imx258->streaming = enable;
> @@ -1008,8 +1050,8 @@ static int imx258_set_stream(struct v4l2_subdev *sd, int enable)
>
> return ret;
>
> -err_rpm_put:
> - pm_runtime_put(&client->dev);
> +err_power_off:
> + imx258_power_off(imx258);
> err_unlock:
> mutex_unlock(&imx258->mutex);
>
> @@ -1201,21 +1243,41 @@ static int imx258_probe(struct i2c_client *client)
> int ret;
> u32 val = 0;
>
> - device_property_read_u32(&client->dev, "clock-frequency", &val);
> - if (val != 19200000)
> - return -EINVAL;
> + imx258 = devm_kzalloc(&client->dev, sizeof(*imx258), GFP_KERNEL);
> + if (!imx258)
> + return -ENOMEM;
> +
> + imx258->clk = devm_clk_get_optional(&client->dev, NULL);
> + if (!imx258->clk) {
> + dev_info(&client->dev, "no clock provided, using clock-frequency property\n");
> +
> + device_property_read_u32(&client->dev, "clock-frequency", &val);
> + if (val != IMX258_INPUT_CLOCK_FREQ)
> + return -EINVAL;
> + } else if (IS_ERR(imx258->clk)) {
> + return dev_err_probe(&client->dev, PTR_ERR(imx258->clk), "error getting clock\n");
> + } else {
> + if (clk_get_rate(imx258->clk) != IMX258_INPUT_CLOCK_FREQ) {
> + dev_err(&client->dev, "input clock frequency not supported\n");
> + return -EINVAL;
> + }
> +
> + ret = clk_prepare_enable(imx258->clk);
> + if (ret) {
> + dev_err(&client->dev, "failed to enable clock\n");
> + return ret;
> + }
> + }
>
> /*
> * Check that the device is mounted upside down. The driver only
> * supports a single pixel order right now.
> */
> ret = device_property_read_u32(&client->dev, "rotation", &val);
> - if (ret || val != 180)
> - return -EINVAL;
> -
> - imx258 = devm_kzalloc(&client->dev, sizeof(*imx258), GFP_KERNEL);
> - if (!imx258)
> - return -ENOMEM;
> + if (ret || val != 180) {
> + ret = -EINVAL;
> + goto error_prop_read;
> + }
>
> /* Initialize subdev */
> v4l2_i2c_subdev_init(&imx258->sd, client, &imx258_subdev_ops);
> @@ -1223,14 +1285,14 @@ static int imx258_probe(struct i2c_client *client)
> /* Check module identity */
> ret = imx258_identify_module(imx258);
> if (ret)
> - return ret;
> + goto error_prop_read;
>
> /* Set default mode to max resolution */
> imx258->cur_mode = &supported_modes[0];
>
> ret = imx258_init_controls(imx258);
> if (ret)
> - return ret;
> + goto error_prop_read;
>
> /* Initialize subdev */
> imx258->sd.internal_ops = &imx258_internal_ops;
> @@ -1252,8 +1314,13 @@ static int imx258_probe(struct i2c_client *client)
> pm_runtime_enable(&client->dev);
> pm_runtime_idle(&client->dev);
>
> + clk_disable_unprepare(imx258->clk);
> +
> return 0;
>
> +error_prop_read:
> + clk_disable_unprepare(imx258->clk);
How about remove? Think of how this works when runtime PM is disabled.
> +
> error_media_entity:
> media_entity_cleanup(&imx258->sd.entity);
>
--
Kind regards,
Sakari Ailus
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