From mboxrd@z Thu Jan  1 00:00:00 1970
From: jacopo mondi <jacopo@jmondi.org>
Date: Thu, 21 Dec 2017 20:31:25 +0000
Subject: Re: [PATCH v1 05/10] arch: sh: migor: Use new renesas-ceu camera driver
Message-Id: <20171221203125.GH27115@w540>
List-Id: <linux-sh.vger.kernel.org>
References: <1510743363-25798-1-git-send-email-jacopo+renesas@jmondi.org>
 <1510743363-25798-6-git-send-email-jacopo+renesas@jmondi.org>
 <1742042.6TTT7UTHfg@avalon>
In-Reply-To: <1742042.6TTT7UTHfg@avalon>
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To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Jacopo Mondi <jacopo+renesas@jmondi.org>, magnus.damm@gmail.com, geert@glider.be, linux-renesas-soc@vger.kernel.org, linux-sh@vger.kernel.org

Hi Laurent,

On Tue, Dec 12, 2017 at 12:00:43PM +0200, Laurent Pinchart wrote:
> Hi Jacopo,
>
> Thank you for the patch.
>
> On Wednesday, 15 November 2017 12:55:58 EET Jacopo Mondi wrote:
> > Migo-R platform uses sh_mobile_ceu camera driver, which is now being
> > replaced by a proper V4L2 camera driver named 'renesas-ceu'.
> >
> > Move Migo-R platform to use the v4l2 renesas-ceu camera driver
> > interface and get rid of soc_camera defined components used to register
> > sensor drivers.
> >
> > Also, memory for CEU video buffers is now reserved with membocks APIs,
> > and need to be declared as dma_coherent during machine initialization to
> > remove that architecture specific part from CEU driver.
> >
> > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > ---
> >  arch/sh/boards/mach-migor/setup.c | 164 ++++++++++++++++------------------
> >  1 file changed, 76 insertions(+), 88 deletions(-)
> >
> > diff --git a/arch/sh/boards/mach-migor/setup.c
> > b/arch/sh/boards/mach-migor/setup.c index 98aa094..10a9b3c 100644
> > --- a/arch/sh/boards/mach-migor/setup.c
> > +++ b/arch/sh/boards/mach-migor/setup.c
> > @@ -27,7 +27,7 @@
> >  #include <linux/videodev2.h>
> >  #include <linux/sh_intc.h>
> >  #include <video/sh_mobile_lcdc.h>
> > -#include <media/drv-intf/sh_mobile_ceu.h>
> > +#include <media/drv-intf/renesas-ceu.h>
> >  #include <media/i2c/ov772x.h>
> >  #include <media/soc_camera.h>
> >  #include <media/i2c/tw9910.h>
> > @@ -308,62 +308,80 @@ static struct platform_device migor_lcdc_device = {
> >  static struct clk *camera_clk;
> >  static DEFINE_MUTEX(camera_lock);
> >
> > -static void camera_power_on(int is_tw)
> > +static void camera_vio_clk_on(void)
> >  {
> > -	mutex_lock(&camera_lock);
> > -
> >  	/* Use 10 MHz VIO_CKO instead of 24 MHz to work
> >  	 * around signal quality issues on Panel Board V2.1.
> >  	 */
> >  	camera_clk = clk_get(NULL, "video_clk");
> >  	clk_set_rate(camera_clk, 10000000);
> >  	clk_enable(camera_clk);	/* start VIO_CKO */
> > -
> > -	/* use VIO_RST to take camera out of reset */
> > -	mdelay(10);
> > -	if (is_tw) {
> > -		gpio_set_value(GPIO_PTT2, 0);
> > -		gpio_set_value(GPIO_PTT0, 0);
> > -	} else {
> > -		gpio_set_value(GPIO_PTT0, 1);
> > -	}
> > -	gpio_set_value(GPIO_PTT3, 0);
> > -	mdelay(10);
> > -	gpio_set_value(GPIO_PTT3, 1);
> > -	mdelay(10); /* wait to let chip come out of reset */
> >  }
> >
> > -static void camera_power_off(void)
> > +static void camera_disable(void)
> >  {
> > -	clk_disable(camera_clk); /* stop VIO_CKO */
> > +	/* stop VIO_CKO */
> > +	clk_disable(camera_clk);
> >  	clk_put(camera_clk);
> >
> > +	gpio_set_value(GPIO_PTT0, 0);
> > +	gpio_set_value(GPIO_PTT2, 1);
> >  	gpio_set_value(GPIO_PTT3, 0);
> > +
> >  	mutex_unlock(&camera_lock);
> >  }
> >
> > -static int ov7725_power(struct device *dev, int mode)
> > +static void camera_reset(void)
> >  {
> > -	if (mode)
> > -		camera_power_on(0);
> > -	else
> > -		camera_power_off();
> > +	/* use VIO_RST to take camera out of reset */
> > +	gpio_set_value(GPIO_PTT3, 0);
> > +	mdelay(10);
> > +	gpio_set_value(GPIO_PTT3, 1);
> > +	mdelay(10);
> > +}
> > +
> > +static int ov7725_enable(void)
> > +{
> > +	mutex_lock(&camera_lock);
> > +	camera_vio_clk_on();
> > +	mdelay(10);
> > +	gpio_set_value(GPIO_PTT0, 1);
> > +
> > +	camera_reset();
> >
> >  	return 0;
> >  }
> >
> > -static int tw9910_power(struct device *dev, int mode)
> > +static int tw9910_enable(void)
> >  {
> > -	if (mode)
> > -		camera_power_on(1);
> > -	else
> > -		camera_power_off();
> > +	mutex_lock(&camera_lock);
> > +	camera_vio_clk_on();
> > +	mdelay(10);
> > +	gpio_set_value(GPIO_PTT2, 0);
> > +
> > +	camera_reset();
> >
> >  	return 0;
> >  }
>
> After studying the schematics, and if you can confirm that R26 is not mounted
> on the panel board, I think all this could be handled by the OV7720 and TW9910
> drivers.
>
> The clock is easy, it's used by the OV7720 only, just expose it as the input
> clock for that device. On a side note, your ov772x driver in this series tries
> to get a clock named "mclk", but it should be named "xclk" as that's how the
> chip's input signal is named. The TW9910 has its own crystal oscillator so it
> won't be affected. As a bonus point the clock will remain off when capturing
> from the TW9910.

I'm sorry, this is surely naive, but I never really worked with board
files before. I see two options for achieving what you proposed here

1) clk_get("video_clk") in migor/setup.c and add the returned "struct
clk" to "struct ov7725_info" and in the sensor driver use that clock

2) clk_get("xclk") in drivers/../ov772x.c
   The only way I found to add that clock would be to register a
   "struct clk_lookup" with "clkdev_add()" in migor/setup.c

3) Something else I haven't learned yet

>
> The TV_IN_EN and CAM_EN signals (PTT2 and PTT0 GPIOs respectively) shouldn't
> be difficult either. You can expose them as the PDN and PWDN GPIOs for the
> OV7720 and TW9910 and handle them in the respective drivers. CAM_EN also
> controls the digital video bus multiplexing, and unless I'm mistaken it will
> just work as a side effect of power down signal control as long as you make
> sure that the OV7720 remains in power down when not selected as the CEU input.

Same as above, should I "gpio_request" or even better use the new
"gpiod_" APIs in setup.c and pass to driver the result of the request
or should I request the gpios in the drivers?

>
> The VIO_RST signal (PTT3 GPIO) is a bit more annoying, as it is shared by both
> the OV7720 and TW9910 as their reset signal, and as far as I know GPIOs can't
> be easily shared between drivers.
>
> Using a reset controller might be an option but I can't see any reset
> controller driver for GPIOs. https://patchwork.kernel.org/patch/3978091/ seems
> not to have been merged. This being said, having to instantiate a reset
> controller to share a GPIO is annoying, I wonder if it would make sense to add
> support for shared GPIOs in the GPIO core.
>
> Another option could be to only request the reset GPIO when needed instead of
> doing so at probe time.

So that implies passing to drivers the gpio index and request/release
everytime? Aren't we pushin a platform specific thing in sensor
drivers this way?

Thanks
   j

>
> > -static struct sh_mobile_ceu_info sh_mobile_ceu_info = {
> > -	.flags = SH_CEU_FLAG_USE_8BIT_BUS,
> > +static struct ceu_info ceu_info = {
> > +	.num_subdevs		= 2,
> > +	.subdevs = {
> > +		{ /* [0] = ov772x */
> > +			.flags		= CEU_FLAG_PRIMARY_SENS,
> > +			.bus_width	= 8,
> > +			.bus_shift	= 0,
> > +			.i2c_adapter_id	= 0,
> > +			.i2c_address	= 0x21,
> > +		},
> > +		{ /* [1] = tw9910 */
> > +			.flags		= 0,
> > +			.bus_width	= 8,
> > +			.bus_shift	= 0,
> > +			.i2c_adapter_id	= 0,
> > +			.i2c_address	= 0x45,
> > +		},
> > +	},
> >  };
> >
> >  static struct resource migor_ceu_resources[] = {
> > @@ -377,18 +395,15 @@ static struct resource migor_ceu_resources[] = {
> >  		.start  = evt2irq(0x880),
> >  		.flags  = IORESOURCE_IRQ,
> >  	},
> > -	[2] = {
> > -		/* place holder for contiguous memory */
> > -	},
> >  };
> >
> >  static struct platform_device migor_ceu_device = {
> > -	.name		= "sh_mobile_ceu",
> > +	.name		= "renesas-ceu",
> >  	.id             = 0, /* "ceu0" clock */
> >  	.num_resources	= ARRAY_SIZE(migor_ceu_resources),
> >  	.resource	= migor_ceu_resources,
> >  	.dev	= {
> > -		.platform_data	= &sh_mobile_ceu_info,
> > +		.platform_data	= &ceu_info,
> >  	},
> >  };
> >
> > @@ -427,6 +442,19 @@ static struct platform_device sdhi_cn9_device = {
> >  	},
> >  };
> >
> > +static struct ov772x_camera_info ov7725_info = {
> > +	.platform_enable = ov7725_enable,
> > +	.platform_disable = camera_disable,
> > +};
> > +
> > +static struct tw9910_video_info tw9910_info = {
> > +	.buswidth       = TW9910_DATAWIDTH_8,
> > +	.mpout          = TW9910_MPO_FIELD,
> > +
> > +	.platform_enable = tw9910_enable,
> > +	.platform_disable = camera_disable,
> > +};
> > +
> >  static struct i2c_board_info migor_i2c_devices[] = {
> >  	{
> >  		I2C_BOARD_INFO("rs5c372b", 0x32),
> > @@ -438,51 +466,13 @@ static struct i2c_board_info migor_i2c_devices[] = {
> >  	{
> >  		I2C_BOARD_INFO("wm8978", 0x1a),
> >  	},
> > -};
> > -
> > -static struct i2c_board_info migor_i2c_camera[] = {
> >  	{
> >  		I2C_BOARD_INFO("ov772x", 0x21),
> > +		.platform_data = &ov7725_info,
> >  	},
> >  	{
> >  		I2C_BOARD_INFO("tw9910", 0x45),
> > -	},
> > -};
> > -
> > -static struct ov772x_camera_info ov7725_info;
> > -
> > -static struct soc_camera_link ov7725_link = {
> > -	.power		= ov7725_power,
> > -	.board_info	= &migor_i2c_camera[0],
> > -	.i2c_adapter_id	= 0,
> > -	.priv		= &ov7725_info,
> > -};
> > -
> > -static struct tw9910_video_info tw9910_info = {
> > -	.buswidth	= SOCAM_DATAWIDTH_8,
> > -	.mpout		= TW9910_MPO_FIELD,
> > -};
> > -
> > -static struct soc_camera_link tw9910_link = {
> > -	.power		= tw9910_power,
> > -	.board_info	= &migor_i2c_camera[1],
> > -	.i2c_adapter_id	= 0,
> > -	.priv		= &tw9910_info,
> > -};
> > -
> > -static struct platform_device migor_camera[] = {
> > -	{
> > -		.name	= "soc-camera-pdrv",
> > -		.id	= 0,
> > -		.dev	= {
> > -			.platform_data = &ov7725_link,
> > -		},
> > -	}, {
> > -		.name	= "soc-camera-pdrv",
> > -		.id	= 1,
> > -		.dev	= {
> > -			.platform_data = &tw9910_link,
> > -		},
> > +		.platform_data = &tw9910_info,
> >  	},
> >  };
> >
> > @@ -490,12 +480,9 @@ static struct platform_device *migor_devices[]
> > __initdata = { &smc91x_eth_device,
> >  	&sh_keysc_device,
> >  	&migor_lcdc_device,
> > -	&migor_ceu_device,
> >  	&migor_nor_flash_device,
> >  	&migor_nand_flash_device,
> >  	&sdhi_cn9_device,
> > -	&migor_camera[0],
> > -	&migor_camera[1],
> >  };
> >
> >  extern char migor_sdram_enter_start;
> > @@ -505,8 +492,6 @@ extern char migor_sdram_leave_end;
> >
> >  static int __init migor_devices_setup(void)
> >  {
> > -	struct resource *r;
> > -
> >  	/* register board specific self-refresh code */
> >  	sh_mobile_register_self_refresh(SUSP_SH_STANDBY | SUSP_SH_SF,
> >  					&migor_sdram_enter_start,
> > @@ -651,16 +636,19 @@ static int __init migor_devices_setup(void)
> >  	 */
> >  	__raw_writew(__raw_readw(PORT_MSELCRA) | 1, PORT_MSELCRA);
> >
> > -	/* Setup additional memory resource for CEU video buffers */
> > -	r = &migor_ceu_device.resource[2];
> > -	r->flags = IORESOURCE_MEM;
> > -	r->start = ceu_dma_membase;
> > -	r->end = r->start + CEU_BUFFER_MEMORY_SIZE - 1;
> > -	r->name = "ceu";
> > -
> >  	i2c_register_board_info(0, migor_i2c_devices,
> >  				ARRAY_SIZE(migor_i2c_devices));
> >
> > +	/* Initialize CEU platform device separately to map memory first */
> > +	device_initialize(&migor_ceu_device.dev);
> > +	arch_setup_pdev_archdata(&migor_ceu_device);
> > +	dma_declare_coherent_memory(&migor_ceu_device.dev,
> > +				    ceu_dma_membase, ceu_dma_membase,
> > +				    ceu_dma_membase + CEU_BUFFER_MEMORY_SIZE - 1,
> > +				    DMA_MEMORY_EXCLUSIVE);
> > +
> > +	platform_device_add(&migor_ceu_device);
> > +
> >  	return platform_add_devices(migor_devices, ARRAY_SIZE(migor_devices));
> >  }
> >  arch_initcall(migor_devices_setup);
>
> --
> Regards,
>
> Laurent Pinchart
>