[PATCH V2] [media] V4L: soc-camera: add SPI device support

[PATCH V2] [media] V4L: soc-camera: add SPI device support

[Kassey Li]

From: Kassey Li <kasseyl@nvidia.com>

This adds support for spi interface sub device for
soc_camera.

Signed-off-by: Kassey Li <kasseyl@nvidia.com>
---
 drivers/media/platform/soc_camera/soc_camera.c |   94 ++++++++++++++++++++++++
 include/media/soc_camera.h                     |    4 +
 2 files changed, 98 insertions(+)

diff --git a/drivers/media/platform/soc_camera/soc_camera.c b/drivers/media/platform/soc_camera/soc_camera.c
index b3db51c..b01c075 100644
--- a/drivers/media/platform/soc_camera/soc_camera.c
+++ b/drivers/media/platform/soc_camera/soc_camera.c
@@ -27,6 +27,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
+#include <linux/spi/spi.h>
 #include <linux/vmalloc.h>
 
 #include <media/soc_camera.h>
@@ -1430,6 +1431,91 @@ static void soc_camera_i2c_free(struct soc_camera_device *icd)
 	icd->clk = NULL;
 }
 
+static int soc_camera_spi_init(struct soc_camera_device *icd,
+			       struct soc_camera_desc *sdesc)
+{
+	struct soc_camera_subdev_desc *ssdd;
+	struct spi_device *spi;
+	struct soc_camera_host *ici;
+	struct soc_camera_host_desc *shd = &sdesc->host_desc;
+	struct spi_master *spi_master;
+	struct v4l2_subdev *subdev;
+	char clk_name[V4L2_SUBDEV_NAME_SIZE];
+	int ret;
+
+	/* First find out how we link the main client */
+	if (icd->sasc) {
+		/* Async non-OF probing handled by the subdevice list */
+		return -EPROBE_DEFER;
+	}
+
+	ici = to_soc_camera_host(icd->parent);
+	spi_master = spi_busnum_to_master(shd->spi_bus_id);
+	if (!spi_master) {
+		dev_err(icd->pdev, "Cannot get SPI master #%d. No driver?\n",
+			shd->spi_bus_id);
+		return -ENODEV;
+	}
+
+	ssdd = kmemdup(&sdesc->subdev_desc, sizeof(*ssdd), GFP_KERNEL);
+	if (!ssdd)
+		return -ENOMEM;
+	/*
+	 * In synchronous case we request regulators ourselves in
+	 * soc_camera_pdrv_probe(), make sure the subdevice driver doesn't try
+	 * to allocate them again.
+	 */
+	ssdd->sd_pdata.num_regulators = 0;
+	ssdd->sd_pdata.regulators = NULL;
+	shd->board_info_spi->platform_data = ssdd;
+
+	snprintf(clk_name, sizeof(clk_name), "%d",
+		 shd->spi_bus_id);
+
+	icd->clk = v4l2_clk_register(&soc_camera_clk_ops, clk_name, "mclk", icd);
+	if (IS_ERR(icd->clk)) {
+		ret = PTR_ERR(icd->clk);
+		goto eclkreg;
+	}
+
+	subdev = v4l2_spi_new_subdev(&ici->v4l2_dev, spi_master,
+				shd->board_info_spi);
+	if (!subdev) {
+		ret = -ENODEV;
+		goto espind;
+	}
+
+	spi = v4l2_get_subdevdata(subdev);
+
+	icd->control = &spi->dev;
+
+	return 0;
+espind:
+	v4l2_clk_unregister(icd->clk);
+	icd->clk = NULL;
+eclkreg:
+	kfree(ssdd);
+	return ret;
+}
+
+static void soc_camera_spi_free(struct soc_camera_device *icd)
+{
+	struct spi_device *spi =
+		to_spi_device(to_soc_camera_control(icd));
+	struct soc_camera_subdev_desc *ssdd;
+	struct v4l2_subdev *sd = soc_camera_to_subdev(icd);
+
+	icd->control = NULL;
+	if (icd->sasc)
+		return;
+	ssdd = spi->dev.platform_data;
+	v4l2_device_unregister_subdev(sd);
+	spi_unregister_device(spi);
+	kfree(ssdd);
+	v4l2_clk_unregister(icd->clk);
+	icd->clk = NULL;
+}
+
 /*
  * V4L2 asynchronous notifier callbacks. They are all called under a v4l2-async
  * internal global mutex, therefore cannot race against other asynchronous
@@ -1762,6 +1848,10 @@ static int soc_camera_probe(struct soc_camera_host *ici,
 		ret = soc_camera_i2c_init(icd, sdesc);
 		if (ret < 0 && ret != -EPROBE_DEFER)
 			goto eadd;
+	} else if (shd->board_info_spi) {
+		ret = soc_camera_spi_init(icd, sdesc);
+		if (ret < 0)
+			goto eadd;
 	} else if (!shd->add_device || !shd->del_device) {
 		ret = -EINVAL;
 		goto eadd;
@@ -1803,6 +1893,8 @@ static int soc_camera_probe(struct soc_camera_host *ici,
 efinish:
 	if (shd->board_info) {
 		soc_camera_i2c_free(icd);
+	} else if (shd->board_info_spi) {
+		soc_camera_spi_free(icd);
 	} else {
 		shd->del_device(icd);
 		module_put(control->driver->owner);
@@ -1843,6 +1935,8 @@ static int soc_camera_remove(struct soc_camera_device *icd)
 
 	if (sdesc->host_desc.board_info) {
 		soc_camera_i2c_free(icd);
+	} else if (sdesc->host_desc.board_info_spi) {
+		soc_camera_spi_free(icd);
 	} else {
 		struct device *dev = to_soc_camera_control(icd);
 		struct device_driver *drv = dev ? dev->driver : NULL;
diff --git a/include/media/soc_camera.h b/include/media/soc_camera.h
index 2f6261f..a948ff6 100644
--- a/include/media/soc_camera.h
+++ b/include/media/soc_camera.h
@@ -178,6 +178,8 @@ struct soc_camera_host_desc {
 	int i2c_adapter_id;
 	struct i2c_board_info *board_info;
 	const char *module_name;
+	struct spi_board_info *board_info_spi;
+	int spi_bus_id;
 
 	/*
 	 * For non-I2C devices platform has to provide methods to add a device
@@ -243,6 +245,8 @@ struct soc_camera_link {
 	int i2c_adapter_id;
 	struct i2c_board_info *board_info;
 	const char *module_name;
+	struct spi_board_info *board_info_spi;
+	int spi_bus_id;
 
 	/*
 	 * For non-I2C devices platform has to provide methods to add a device
-- 
1.7.9.5

Re: [PATCH V2] [media] V4L: soc-camera: add SPI device support

[Guennadi Liakhovetski]

Hi Kassey,

Thanks for updating your patch and addressing my comments! In your reply 
to v1 of this patch you said, that you would add DT support in v2, i.e. in 
this version, right? Is it now present in this patch? If yes - can you 
explain to me how it works? For I2C the soc_camera_host_register() 
function calls scan_of_host() always when an OF node is present in the 
camera hostdevice, i.e. it would also be called in your SPI case, but the 
soc_of_bind() function, called there, explicitly uses I2C binding, so, it 
won't work for SPI. Could you explain?

Besides, you place your SPI support functions under #ifdef 
CONFIG_I2C_BOARDINFO, which doesn't make much sense for SPI.

Thanks
Guennadi

On Mon, 2 Feb 2015, Kassey Li wrote:

> From: Kassey Li <kasseyl@nvidia.com>
> 
> This adds support for spi interface sub device for
> soc_camera.
> 
> Signed-off-by: Kassey Li <kasseyl@nvidia.com>
> ---
>  drivers/media/platform/soc_camera/soc_camera.c |   94 ++++++++++++++++++++++++
>  include/media/soc_camera.h                     |    4 +
>  2 files changed, 98 insertions(+)

[patch omitted]