Re: [PATCH 03/11] drm: add driver for simple vga encoders

From: Rob Herring <robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>
Cc: David Airlie <airlied-cv59FeDIM0c@public.gmane.org>,
	mark.yao-TNX95d0MmH7DzftRWevZcw@public.gmane.org,
	Rob Clark <robdclark-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	djkurtz-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org,
	dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org,
	linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>,
	Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	Ian Campbell
	<ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>,
	Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	"devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>
Subject: Re: [PATCH 03/11] drm: add driver for simple vga encoders
Date: Thu, 26 Feb 2015 14:35:36 -0600	[thread overview]
Message-ID: <CAL_Jsq+dv5ZmAX8Y_x8eFPdHyKeM72bM35Mg3+mVF8Ut1KiHgg@mail.gmail.com> (raw)
In-Reply-To: <1422721984-27782-4-git-send-email-heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>

On Sat, Jan 31, 2015 at 10:32 AM, Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org> wrote:
> There exist simple vga encoders without any type of management interface
> and just maybe a simple gpio for turning it on or off. Examples for these
> are the Analog Devices ADV7123, Chipsea CS7123 or Micronas SDA7123.
>
> Add a generic encoder driver for those that can be used by drm drivers
> using the component framework.

What makes this specific to VGA other than DRM_MODE_CONNECTOR_VGA?
Seems like with match data you could generalize this to any simple
encoder chip.

Rob

>
> Signed-off-by: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>
> ---
>  drivers/gpu/drm/i2c/Kconfig      |   6 +
>  drivers/gpu/drm/i2c/Makefile     |   2 +
>  drivers/gpu/drm/i2c/vga-simple.c | 325 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 333 insertions(+)
>  create mode 100644 drivers/gpu/drm/i2c/vga-simple.c
>
> diff --git a/drivers/gpu/drm/i2c/Kconfig b/drivers/gpu/drm/i2c/Kconfig
> index 22c7ed6..319f2cb 100644
> --- a/drivers/gpu/drm/i2c/Kconfig
> +++ b/drivers/gpu/drm/i2c/Kconfig
> @@ -31,4 +31,10 @@ config DRM_I2C_NXP_TDA998X
>         help
>           Support for NXP Semiconductors TDA998X HDMI encoders.
>
> +config DRM_VGA_SIMPLE
> +       tristate "Generic simple vga encoder"
> +       help
> +         Support for vga encoder chips without any special settings
> +         and at most a power-control gpio.
> +
>  endmenu
> diff --git a/drivers/gpu/drm/i2c/Makefile b/drivers/gpu/drm/i2c/Makefile
> index 2c72eb5..858961f 100644
> --- a/drivers/gpu/drm/i2c/Makefile
> +++ b/drivers/gpu/drm/i2c/Makefile
> @@ -10,3 +10,5 @@ obj-$(CONFIG_DRM_I2C_SIL164) += sil164.o
>
>  tda998x-y := tda998x_drv.o
>  obj-$(CONFIG_DRM_I2C_NXP_TDA998X) += tda998x.o
> +
> +obj-$(CONFIG_DRM_VGA_SIMPLE) += vga-simple.o
> diff --git a/drivers/gpu/drm/i2c/vga-simple.c b/drivers/gpu/drm/i2c/vga-simple.c
> new file mode 100644
> index 0000000..bb9d19c
> --- /dev/null
> +++ b/drivers/gpu/drm/i2c/vga-simple.c
> @@ -0,0 +1,325 @@
> +/*
> + * Simple vga encoder driver
> + *
> + * Copyright (C) 2014 Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/component.h>
> +#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/regulator/consumer.h>
> +#include <drm/drm_of.h>
> +#include <drm/drmP.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_edid.h>
> +
> +#define connector_to_vga_simple(x) container_of(x, struct vga_simple, connector)
> +#define encoder_to_vga_simple(x) container_of(x, struct vga_simple, encoder)
> +
> +struct vga_simple {
> +       struct drm_connector connector;
> +       struct drm_encoder encoder;
> +
> +       struct device *dev;
> +       struct i2c_adapter *ddc;
> +
> +       struct regulator *vaa_reg;
> +       struct gpio_desc *enable_gpio;
> +
> +       struct mutex enable_lock;
> +       bool enabled;
> +};
> +
> +/*
> + * Connector functions
> + */
> +
> +enum drm_connector_status vga_simple_detect(struct drm_connector *connector,
> +                                           bool force)
> +{
> +       struct vga_simple *vga = connector_to_vga_simple(connector);
> +
> +       if (!vga->ddc)
> +               return connector_status_unknown;
> +
> +       if (drm_probe_ddc(vga->ddc))
> +               return connector_status_connected;
> +
> +       return connector_status_disconnected;
> +}
> +
> +void vga_simple_connector_destroy(struct drm_connector *connector)
> +{
> +       drm_connector_unregister(connector);
> +       drm_connector_cleanup(connector);
> +}
> +
> +struct drm_connector_funcs vga_simple_connector_funcs = {
> +       .dpms = drm_helper_connector_dpms,
> +       .fill_modes = drm_helper_probe_single_connector_modes,
> +       .detect = vga_simple_detect,
> +       .destroy = vga_simple_connector_destroy,
> +};
> +
> +/*
> + * Connector helper functions
> + */
> +
> +static int vga_simple_connector_get_modes(struct drm_connector *connector)
> +{
> +       struct vga_simple *vga = connector_to_vga_simple(connector);
> +       struct edid *edid;
> +       int ret = 0;
> +
> +       if (!vga->ddc)
> +               return 0;
> +
> +       edid = drm_get_edid(connector, vga->ddc);
> +       if (edid) {
> +               drm_mode_connector_update_edid_property(connector, edid);
> +               ret = drm_add_edid_modes(connector, edid);
> +               kfree(edid);
> +       }
> +
> +       return ret;
> +}
> +
> +static int vga_simple_connector_mode_valid(struct drm_connector *connector,
> +                                       struct drm_display_mode *mode)
> +{
> +       return MODE_OK;
> +}
> +
> +static struct drm_encoder
> +*vga_simple_connector_best_encoder(struct drm_connector *connector)
> +{
> +       struct vga_simple *vga = connector_to_vga_simple(connector);
> +
> +       return &vga->encoder;
> +}
> +
> +static struct drm_connector_helper_funcs vga_simple_connector_helper_funcs = {
> +       .get_modes = vga_simple_connector_get_modes,
> +       .best_encoder = vga_simple_connector_best_encoder,
> +       .mode_valid = vga_simple_connector_mode_valid,
> +};
> +
> +/*
> + * Encoder functions
> + */
> +
> +static void vga_simple_encoder_destroy(struct drm_encoder *encoder)
> +{
> +       drm_encoder_cleanup(encoder);
> +}
> +
> +static const struct drm_encoder_funcs vga_simple_encoder_funcs = {
> +       .destroy = vga_simple_encoder_destroy,
> +};
> +
> +/*
> + * Encoder helper functions
> + */
> +
> +static void vga_simple_encoder_dpms(struct drm_encoder *encoder, int mode)
> +{
> +       struct vga_simple *vga = encoder_to_vga_simple(encoder);
> +
> +       mutex_lock(&vga->enable_lock);
> +
> +       switch (mode) {
> +       case DRM_MODE_DPMS_ON:
> +               if (vga->enabled)
> +                       goto out;
> +
> +               if (!IS_ERR(vga->vaa_reg))
> +                       regulator_enable(vga->vaa_reg);
> +
> +               if (vga->enable_gpio)
> +                       gpiod_set_value(vga->enable_gpio, 1);
> +
> +               vga->enabled = true;
> +               break;
> +       case DRM_MODE_DPMS_STANDBY:
> +       case DRM_MODE_DPMS_SUSPEND:
> +       case DRM_MODE_DPMS_OFF:
> +               if (!vga->enabled)
> +                       goto out;
> +
> +               if (vga->enable_gpio)
> +                       gpiod_set_value(vga->enable_gpio, 0);
> +
> +               if (!IS_ERR(vga->vaa_reg))
> +                       regulator_enable(vga->vaa_reg);
> +
> +               vga->enabled = false;
> +               break;
> +       default:
> +               break;
> +       }
> +
> +out:
> +       mutex_unlock(&vga->enable_lock);
> +}
> +
> +static bool vga_simple_mode_fixup(struct drm_encoder *encoder,
> +                                 const struct drm_display_mode *mode,
> +                                 struct drm_display_mode *adjusted_mode)
> +{
> +       return true;
> +}
> +
> +static void vga_simple_encoder_prepare(struct drm_encoder *encoder)
> +{
> +}
> +
> +static void vga_simple_encoder_mode_set(struct drm_encoder *encoder,
> +                                       struct drm_display_mode *mode,
> +                                       struct drm_display_mode *adjusted_mode)
> +{
> +}
> +
> +static void vga_simple_encoder_commit(struct drm_encoder *encoder)
> +{
> +       vga_simple_encoder_dpms(encoder, DRM_MODE_DPMS_ON);
> +}
> +
> +static void vga_simple_encoder_disable(struct drm_encoder *encoder)
> +{
> +       vga_simple_encoder_dpms(encoder, DRM_MODE_DPMS_OFF);
> +}
> +
> +static const struct drm_encoder_helper_funcs vga_simple_encoder_helper_funcs = {
> +       .dpms = vga_simple_encoder_dpms,
> +       .mode_fixup = vga_simple_mode_fixup,
> +       .prepare = vga_simple_encoder_prepare,
> +       .mode_set = vga_simple_encoder_mode_set,
> +       .commit = vga_simple_encoder_commit,
> +       .disable = vga_simple_encoder_disable,
> +};
> +
> +/*
> + * Component helper functions
> + */
> +
> +static int vga_simple_bind(struct device *dev, struct device *master,
> +                                void *data)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct drm_device *drm = data;
> +
> +       struct device_node *ddc_node, *np = pdev->dev.of_node;
> +       struct vga_simple *vga;
> +       int ret;
> +
> +       if (!np)
> +               return -ENODEV;
> +
> +       vga = devm_kzalloc(dev, sizeof(*vga), GFP_KERNEL);
> +       if (!vga)
> +               return -ENOMEM;
> +
> +       vga->dev = dev;
> +       dev_set_drvdata(dev, vga);
> +       mutex_init(&vga->enable_lock);
> +
> +       vga->enable_gpio = devm_gpiod_get_optional(dev, "enable",
> +                                                  GPIOD_OUT_LOW);
> +       if (IS_ERR(vga->enable_gpio)) {
> +               ret = PTR_ERR(vga->enable_gpio);
> +               dev_err(dev, "failed to request GPIO: %d\n", ret);
> +               return ret;
> +       }
> +
> +       vga->enabled = false;
> +
> +       ddc_node = of_parse_phandle(np, "ddc-i2c-bus", 0);
> +       if (ddc_node) {
> +               vga->ddc = of_find_i2c_adapter_by_node(ddc_node);
> +               of_node_put(ddc_node);
> +               if (!vga->ddc) {
> +                       dev_dbg(vga->dev, "failed to read ddc node\n");
> +                       return -EPROBE_DEFER;
> +               }
> +       } else {
> +               dev_dbg(vga->dev, "no ddc property found\n");
> +       }
> +
> +       vga->vaa_reg = devm_regulator_get_optional(dev, "vaa");
> +
> +       vga->encoder.possible_crtcs = drm_of_find_possible_crtcs(drm, np);
> +       vga->encoder.of_node = np;
> +       vga->connector.polled = DRM_CONNECTOR_POLL_CONNECT |
> +                               DRM_CONNECTOR_POLL_DISCONNECT;
> +
> +       drm_encoder_helper_add(&vga->encoder, &vga_simple_encoder_helper_funcs);
> +       drm_encoder_init(drm, &vga->encoder, &vga_simple_encoder_funcs,
> +                        DRM_MODE_ENCODER_DAC);
> +
> +       drm_connector_helper_add(&vga->connector,
> +                                &vga_simple_connector_helper_funcs);
> +       drm_connector_init(drm, &vga->connector, &vga_simple_connector_funcs,
> +                          DRM_MODE_CONNECTOR_VGA);
> +
> +       drm_mode_connector_attach_encoder(&vga->connector, &vga->encoder);
> +
> +       return 0;
> +}
> +
> +static void vga_simple_unbind(struct device *dev, struct device *master,
> +                                   void *data)
> +{
> +       struct vga_simple *vga = dev_get_drvdata(dev);
> +
> +       vga->connector.funcs->destroy(&vga->connector);
> +       vga->encoder.funcs->destroy(&vga->encoder);
> +}
> +
> +static const struct component_ops vga_simple_ops = {
> +       .bind = vga_simple_bind,
> +       .unbind = vga_simple_unbind,
> +};
> +
> +static int vga_simple_probe(struct platform_device *pdev)
> +{
> +       return component_add(&pdev->dev, &vga_simple_ops);
> +}
> +
> +static int vga_simple_remove(struct platform_device *pdev)
> +{
> +       component_del(&pdev->dev, &vga_simple_ops);
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id vga_simple_ids[] = {
> +       { .compatible = "adi,adv7123", },
> +       {},
> +};
> +MODULE_DEVICE_TABLE(of, vga_simple_ids);
> +
> +static struct platform_driver vga_simple_driver = {
> +       .probe  = vga_simple_probe,
> +       .remove = vga_simple_remove,
> +       .driver = {
> +               .name = "vga-simple",
> +               .of_match_table = vga_simple_ids,
> +       },
> +};
> +module_platform_driver(vga_simple_driver);
> +
> +MODULE_AUTHOR("Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>");
> +MODULE_DESCRIPTION("Simple vga converter");
> +MODULE_LICENSE("GPL");
> --
> 2.1.1
>
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