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Subject: Re: [PATCH v4 1/2] drm/bridge: sil_sii8620: make remote control
 optional.
To:     =?UTF-8?Q?Ronald_Tschal=c3=a4r?= <ronald@innovation.ch>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Henrik Rydberg <rydberg@bitmath.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Lukas Wunner <lukas@wunner.de>,
        Federico Lorenzi <federico@travelground.com>,
        linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
        Inki Dae <inki.dae@samsung.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>
From:   Andrzej Hajda <a.hajda@samsung.com>
Message-ID: <c861091d-f659-614d-65f4-6fe983885e09@samsung.com>
Date:   Wed, 10 Apr 2019 11:42:50 +0200
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References: <20190407050358.2976-1-ronald@innovation.ch>
        <CGME20190407050410epcas1p3ec1f887f8ccf8ff4495f4557437cd594@epcas1p3.samsung.com>
        <20190407050358.2976-2-ronald@innovation.ch>
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On 07.04.2019 07:03, Ronald Tschalär wrote:
> commit d6abe6df706c (drm/bridge: sil_sii8620: do not have a dependency
> of RC_CORE) changed the driver to select both RC_CORE and INPUT.
> However, this causes problems with other drivers, in particular an input
> driver that depends on MFD_INTEL_LPSS_PCI (to be added in a separate
> commit):
>
>   drivers/clk/Kconfig:9:error: recursive dependency detected!
>   drivers/clk/Kconfig:9:        symbol COMMON_CLK is selected by MFD_INTEL_LPSS
>   drivers/mfd/Kconfig:566:      symbol MFD_INTEL_LPSS is selected by MFD_INTEL_LPSS_PCI
>   drivers/mfd/Kconfig:580:      symbol MFD_INTEL_LPSS_PCI is implied by KEYBOARD_APPLESPI
>   drivers/input/keyboard/Kconfig:73:    symbol KEYBOARD_APPLESPI depends on INPUT
>   drivers/input/Kconfig:8:      symbol INPUT is selected by DRM_SIL_SII8620
>   drivers/gpu/drm/bridge/Kconfig:83:    symbol DRM_SIL_SII8620 depends on DRM_BRIDGE
>   drivers/gpu/drm/bridge/Kconfig:1:     symbol DRM_BRIDGE is selected by DRM_PL111
>   drivers/gpu/drm/pl111/Kconfig:1:      symbol DRM_PL111 depends on COMMON_CLK
>
> According to the docs and general consensus, select should only be used
> for non user-visible symbols, but both RC_CORE and INPUT are
> user-visible. Furthermore almost all other references to INPUT
> throughout the kernel config are depends, not selects. For this reason
> the first part of this change reverts commit d6abe6df706c.
>
> In order to address the original reason for commit d6abe6df706c, namely
> that not all boards use the remote controller functionality and hence
> should not need have to deal with RC_CORE, the second part of this
> change now makes the remote control support in the driver optional and
> contingent on RC_CORE being defined. And with this the hard dependency
> on INPUT also goes away as that is only needed if RC_CORE is defined
> (which in turn already depends on INPUT).
>
> CC: Inki Dae <inki.dae@samsung.com>
> CC: Andrzej Hajda <a.hajda@samsung.com>
> CC: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> CC: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Signed-off-by: Ronald Tschalär <ronald@innovation.ch>
> ---
>  drivers/gpu/drm/bridge/Kconfig       |  3 +--
>  drivers/gpu/drm/bridge/sil-sii8620.c | 21 +++++++++++++++++++++
>  2 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index 2fee47b0d50b..9cf07105b73a 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -85,8 +85,7 @@ config DRM_SIL_SII8620
>  	depends on OF
>  	select DRM_KMS_HELPER
>  	imply EXTCON
> -	select INPUT
> -	select RC_CORE
> +	imply RC_CORE
>  	help
>  	  Silicon Image SII8620 HDMI/MHL bridge chip driver.
>  
> diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
> index a6e8f4591e63..f8dfbf01caa8 100644
> --- a/drivers/gpu/drm/bridge/sil-sii8620.c
> +++ b/drivers/gpu/drm/bridge/sil-sii8620.c
> @@ -66,7 +66,9 @@ enum sii8620_mt_state {
>  struct sii8620 {
>  	struct drm_bridge bridge;
>  	struct device *dev;
> +#if IS_ENABLED(CONFIG_RC_CORE)
>  	struct rc_dev *rc_dev;
> +#endif
>  	struct clk *clk_xtal;
>  	struct gpio_desc *gpio_reset;
>  	struct gpio_desc *gpio_int;
> @@ -1757,6 +1759,7 @@ static void sii8620_send_features(struct sii8620 *ctx)
>  	sii8620_write_buf(ctx, REG_MDT_XMIT_WRITE_PORT, buf, ARRAY_SIZE(buf));
>  }
>  
> +#if IS_ENABLED(CONFIG_RC_CORE)
>  static bool sii8620_rcp_consume(struct sii8620 *ctx, u8 scancode)
>  {
>  	bool pressed = !(scancode & MHL_RCP_KEY_RELEASED_MASK);
> @@ -1775,6 +1778,12 @@ static bool sii8620_rcp_consume(struct sii8620 *ctx, u8 scancode)
>  
>  	return true;
>  }
> +#else
> +static bool sii8620_rcp_consume(struct sii8620 *ctx, u8 scancode)
> +{
> +	return false;
> +}
> +#endif
>  
>  static void sii8620_msc_mr_set_int(struct sii8620 *ctx)
>  {
> @@ -2098,6 +2107,7 @@ static void sii8620_cable_in(struct sii8620 *ctx)
>  	enable_irq(to_i2c_client(ctx->dev)->irq);
>  }
>  
> +#if IS_ENABLED(CONFIG_RC_CORE)
>  static void sii8620_init_rcp_input_dev(struct sii8620 *ctx)
>  {
>  	struct rc_dev *rc_dev;
> @@ -2127,6 +2137,11 @@ static void sii8620_init_rcp_input_dev(struct sii8620 *ctx)
>  	}
>  	ctx->rc_dev = rc_dev;
>  }
> +#else
> +static void sii8620_init_rcp_input_dev(struct sii8620 *ctx)
> +{
> +}
> +#endif
>  
>  static void sii8620_cable_out(struct sii8620 *ctx)
>  {
> @@ -2213,12 +2228,18 @@ static int sii8620_attach(struct drm_bridge *bridge)
>  	return sii8620_clear_error(ctx);
>  }
>  
> +#if IS_ENABLED(CONFIG_RC_CORE)
>  static void sii8620_detach(struct drm_bridge *bridge)
>  {
>  	struct sii8620 *ctx = bridge_to_sii8620(bridge);
>  
>  	rc_unregister_device(ctx->rc_dev);
>  }
> +#else
> +static void sii8620_detach(struct drm_bridge *bridge)
> +{
> +}
> +#endif
>  
>  static int sii8620_is_packing_required(struct sii8620 *ctx,
>  				       const struct drm_display_mode *mode)

What about:

---------

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 8840f396a7b6..298189067929 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -86,8 +86,7 @@ config DRM_SIL_SII8620
        depends on OF
        select DRM_KMS_HELPER
        imply EXTCON
-       select INPUT
-       select RC_CORE
+       imply RC_CORE
        help
          Silicon Image SII8620 HDMI/MHL bridge chip driver.
 
diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c
b/drivers/gpu/drm/bridge/sil-sii8620.c
index 0cc293a6ac24..df0f9dbbe839 100644
--- a/drivers/gpu/drm/bridge/sil-sii8620.c
+++ b/drivers/gpu/drm/bridge/sil-sii8620.c
@@ -1762,10 +1762,8 @@ static bool sii8620_rcp_consume(struct sii8620
*ctx, u8 scancode)
 
        scancode &= MHL_RCP_KEY_ID_MASK;
 
-       if (!ctx->rc_dev) {
-               dev_dbg(ctx->dev, "RCP input device not initialized\n");
+       if (!IS_ENABLED(RC_CORE) || !ctx->rc_dev)
                return false;
-       }
 
        if (pressed)
                rc_keydown(ctx->rc_dev, RC_PROTO_CEC, scancode, 0);
@@ -2102,6 +2100,9 @@ static void sii8620_init_rcp_input_dev(struct
sii8620 *ctx)
        struct rc_dev *rc_dev;
        int ret;
 
+       if (!IS_ENABLED(RC_CORE))
+               return;
+
        rc_dev = rc_allocate_device(RC_DRIVER_SCANCODE);
        if (!rc_dev) {
                dev_err(ctx->dev, "Failed to allocate RC device\n");
@@ -2216,6 +2217,9 @@ static void sii8620_detach(struct drm_bridge *bridge)
 {
        struct sii8620 *ctx = bridge_to_sii8620(bridge);
 
+       if (!IS_ENABLED(RC_CORE))
+               return;
+
        rc_unregister_device(ctx->rc_dev);
 }
-----------

Less changes, no conditional compilation - better compiler coverage,
more readable.


Regards

Andrzej