In certain machines, camera devices are supplied directly
by a number of regulators. This patch add the ability to drive
these regulators directly by the soc_camera driver.

What the machine code have to do to use this functionality is to:
1- Define a number of useful regulator supply descriptions such as:

static struct regulator_consumer_supply camera_reg1_consumers[] = {
        ...
        REGULATOR_SUPPLY("camera_reg1", "soc-camera-pdrv.0"),
        ...
};

(Pay attention at the .N suffix of "soc-camera-pdrv" in case of
a system with multiple cameras)

2- Define the list of regulators to bind to a specific instance of
   soc-camera-pdrv with their voltages:

static struct soc_camera_regulator_desc soc_camera_regs[] = {
        SOCAM_REG_DESC("camera_reg1", 1300000, 1300000),
        SOCAM_REG_DESC("camera_reg2",   2800000, 2800000),
        ...
};

3- Add the list to the corresponding soc_camera_link description:

static struct soc_camera_link iclink_my_camera = {
...
        .soc_regulator_descs            = soc_camera_regs,
        .num_soc_regulator_descs        = ARRAY_SIZE(soc_camera_regs),
};

4- And register it as usual with the platform device description:

static struct platform_device machine_my_camera = {
        .name   = "soc-camera-pdrv",
        .id     = 0,
        .dev    = {
                .platform_data = &iclink_my_camera,
        },
};

Signed-off-by: Alberto Panizzo <maramaopercheseimo...@gmail.com>
---
 drivers/media/video/soc_camera.c |  135 +++++++++++++++++++++++++++++++------
 include/media/soc_camera.h       |   16 +++++
 2 files changed, 129 insertions(+), 22 deletions(-)

diff --git a/drivers/media/video/soc_camera.c b/drivers/media/video/soc_camera.c
index 43848a7..8fc5831 100644
--- a/drivers/media/video/soc_camera.c
+++ b/drivers/media/video/soc_camera.c
@@ -43,6 +43,96 @@ static LIST_HEAD(hosts);
 static LIST_HEAD(devices);
 static DEFINE_MUTEX(list_lock);                /* Protects the list of hosts */
 
+static int soc_camera_setup_regulators(struct soc_camera_device *icd,
+                                       struct soc_camera_link *icl)
+{
+       int i, ret;
+
+       icd->soc_regulators = kzalloc(icl->num_soc_regulator_descs *
+               sizeof(struct regulator *), GFP_KERNEL);
+       if (!icd->soc_regulators) {
+               dev_err(icd->pdev, "Not enough memory.\n");
+               ret = -ENOMEM;
+               goto err;
+       }
+
+       for (i = 0; i < icl->num_soc_regulator_descs; i++) {
+               dev_dbg(icd->pdev, "Looking for reg:'%s' bound to dev:'%s'",
+                       icl->soc_regulator_descs[i].supply,
+                       dev_name(icd->pdev));
+               icd->soc_regulators[i] = regulator_get(icd->pdev,
+                                           icl->soc_regulator_descs[i].supply);
+               if (IS_ERR(icd->soc_regulators[i])) {
+                       icd->soc_regulators[i] = NULL;
+                       dev_err(icd->pdev, "Unable to get regulator: \"%s\".\n",
+                                       icl->soc_regulator_descs[i].supply);
+                       ret = -ENODEV;
+                       goto free_regs;
+               }
+       }
+
+       icd->num_soc_regulators = icl->num_soc_regulator_descs;
+
+       return 0;
+
+free_regs:
+       for (i--; i >= 0; i--)
+               regulator_put(icd->soc_regulators[i]);
+err:
+       return ret;
+}
+
+static int soc_camera_power_set(struct soc_camera_device *icd,
+                               struct soc_camera_link *icl,
+                               int power_on)
+{
+       int ret, i;
+
+       for (i = 0; i < icd->num_soc_regulators; i++) {
+               if (power_on) {
+                       ret = regulator_set_voltage(icd->soc_regulators[i],
+                               icl->soc_regulator_descs[i].value_on_min,
+                               icl->soc_regulator_descs[i].value_on_max);
+                       if (ret) {
+                               dev_err(icd->pdev, "Cannot set '%s' to %d:%d",
+                                 icl->soc_regulator_descs[i].supply,
+                                 icl->soc_regulator_descs[i].value_on_min,
+                                 icl->soc_regulator_descs[i].value_on_max);
+                               goto err;
+                       }
+
+                       ret = regulator_enable(icd->soc_regulators[i]);
+                       if (ret < 0) {
+                               dev_err(icd->pdev, "Cannot enable reg '%s'",
+                                       icl->soc_regulator_descs[i].supply);
+                               goto err;
+                       }
+               } else {
+                       ret = regulator_disable(icd->soc_regulators[i]);
+                       if (ret) {
+                               dev_err(icd->pdev, "Cannot disable reg '%s'",
+                                       icl->soc_regulator_descs[i].supply);
+                               goto err;
+                       }
+               }
+       }
+
+       if (icl->power) {
+               ret = icl->power(icd->pdev, power_on);
+               if (ret < 0) {
+                       dev_err(icd->pdev,
+                               "Platform failed to power-%s the camera.\n",
+                               power_on ? "ON" : "OFF");
+                       goto err;
+               }
+       }
+
+       return 0;
+
+err:
+       return ret;
+}
+
 const struct soc_camera_format_xlate *soc_camera_xlate_by_fourcc(
        struct soc_camera_device *icd, unsigned int fourcc)
 {
@@ -375,11 +465,9 @@ static int soc_camera_open(struct file *file)
                        },
                };
 
-               if (icl->power) {
-                       ret = icl->power(icd->pdev, 1);
-                       if (ret < 0)
-                               goto epower;
-               }
+               ret = soc_camera_power_set(icd, icl, 1);
+               if (ret < 0)
+                       goto epower;
 
                /* The camera could have been already on, try to reset */
                if (icl->reset)
@@ -425,8 +513,7 @@ esfmt:
 eresume:
        ici->ops->remove(icd);
 eiciadd:
-       if (icl->power)
-               icl->power(icd->pdev, 0);
+       soc_camera_power_set(icd, icl, 0);
 epower:
        icd->use_count--;
        mutex_unlock(&icd->video_lock);
@@ -450,8 +537,7 @@ static int soc_camera_close(struct file *file)
 
                ici->ops->remove(icd);
 
-               if (icl->power)
-                       icl->power(icd->pdev, 0);
+               soc_camera_power_set(icd, icl, 0);
        }
 
        if (icd->streamer == file)
@@ -937,18 +1023,18 @@ static int soc_camera_probe(struct device *dev)
        struct device *control = NULL;
        struct v4l2_subdev *sd;
        struct v4l2_mbus_framefmt mf;
-       int ret;
+       int ret = 0, i;
 
        dev_info(dev, "Probing %s\n", dev_name(dev));
 
-       if (icl->power) {
-               ret = icl->power(icd->pdev, 1);
-               if (ret < 0) {
-                       dev_err(dev,
-                               "Platform failed to power-on the camera.\n");
-                       goto epower;
-               }
-       }
+       if (icl->num_soc_regulator_descs)
+               ret = soc_camera_setup_regulators(icd, icl);
+       if (ret)
+               goto err;
+
+       ret = soc_camera_power_set(icd, icl, 1);
+       if (ret < 0)
+               goto epower;
 
        /* The camera could have been already on, try to reset */
        if (icl->reset)
@@ -1021,8 +1107,7 @@ static int soc_camera_probe(struct device *dev)
 
        ici->ops->remove(icd);
 
-       if (icl->power)
-               icl->power(icd->pdev, 0);
+       soc_camera_power_set(icd, icl, 0);
 
        mutex_unlock(&icd->video_lock);
 
@@ -1044,9 +1129,11 @@ eadddev:
 evdc:
        ici->ops->remove(icd);
 eadd:
-       if (icl->power)
-               icl->power(icd->pdev, 0);
+       soc_camera_power_set(icd, icl, 0);
 epower:
+       for (i = icd->num_soc_regulators; i >= 0; i--)
+               regulator_put(icd->soc_regulators[i]);
+err:
        return ret;
 }
 
@@ -1059,6 +1146,7 @@ static int soc_camera_remove(struct device *dev)
        struct soc_camera_device *icd = to_soc_camera_dev(dev);
        struct soc_camera_link *icl = to_soc_camera_link(icd);
        struct video_device *vdev = icd->vdev;
+       int i;
 
        BUG_ON(!dev->parent);
 
@@ -1081,6 +1169,9 @@ static int soc_camera_remove(struct device *dev)
        }
        soc_camera_free_user_formats(icd);
 
+       for (i = icd->num_soc_regulators; i >= 0; i--)
+               regulator_put(icd->soc_regulators[i]);
+
        return 0;
 }
 
diff --git a/include/media/soc_camera.h b/include/media/soc_camera.h
index 86e3631..ae589a4 100644
--- a/include/media/soc_camera.h
+++ b/include/media/soc_camera.h
@@ -15,6 +15,7 @@
 #include <linux/device.h>
 #include <linux/mutex.h>
 #include <linux/pm.h>
+#include <linux/regulator/consumer.h>
 #include <linux/videodev2.h>
 #include <media/videobuf-core.h>
 #include <media/v4l2-device.h>
@@ -45,6 +46,8 @@ struct soc_camera_device {
        struct mutex video_lock;        /* Protects device data */
        struct file *streamer;          /* stream owner */
        struct videobuf_queue vb_vidq;
+       struct regulator **soc_regulators;
+       int num_soc_regulators;
 };
 
 struct soc_camera_host {
@@ -96,6 +99,15 @@ struct soc_camera_host_ops {
 #define SOCAM_SENSOR_INVERT_VSYNC      (1 << 3)
 #define SOCAM_SENSOR_INVERT_DATA       (1 << 4)
 
+struct soc_camera_regulator_desc {
+       const char *supply;
+       int value_on_min;
+       int value_on_max;
+};
+
+#define SOCAM_REG_DESC(s, min, max) \
+       { .supply = s , .value_on_min = min , .value_on_max = max }
+
 struct i2c_board_info;
 
 struct soc_camera_link {
@@ -108,6 +120,10 @@ struct soc_camera_link {
        const char *module_name;
        void *priv;
 
+       /* Optional regulators that have to be managed on power on/off events */
+       struct soc_camera_regulator_desc *soc_regulator_descs;
+       int num_soc_regulator_descs;
+
        /*
         * For non-I2C devices platform platform has to provide methods to
         * add a device to the system and to remove
-- 
1.6.3.3



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