Re: [RFC v2 3/4] drm/panel: Add new panel driver based on crystal cove pmic

[Jani Nikula <jani.nikula@intel.com>]

On Fri, 02 Jan 2015, Shobhit Kumar <shobhit.kumar@intel.com> wrote:
> This driver provides support for the "crystal_cove_panel" cell device.
> On BYT-T pmic has to be used to enable/disable panel.

This needs to be sent to dri-devel.

With the comments below addressed, and with the disclaimer that I have
no idea about the pmic registers or required sleeps, this is

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

>
> Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
> ---
>  drivers/gpu/drm/panel/Kconfig             |   7 ++
>  drivers/gpu/drm/panel/Makefile            |   1 +
>  drivers/gpu/drm/panel/panel-crystalcove.c | 191 ++++++++++++++++++++++++++++++
>  3 files changed, 199 insertions(+)
>  create mode 100644 drivers/gpu/drm/panel/panel-crystalcove.c
>
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 024e98e..d813bd1 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -40,4 +40,11 @@ config DRM_PANEL_SHARP_LQ101R1SX01
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called panel-sharp-lq101r1sx01.
>  
> +config DRM_PANEL_CRYSTALCOVE
> +	tristate "Crystalcove PMIC controlled panel"
> +	depends on INTEL_SOC_PMIC

INTEL_SOC_PMIC is still a bool (and requires I2C=y), and IMO should be
fixed to support tristate. Or are there fundamental reasons this can't
be done?

> +	help
> +	  Say Y here if you want to enable support for DSI panel and backlight
> +	  control using crystalcove pmic. This is used for BYT CR configurations
> +
>  endmenu
> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
> index 4b2a043..c05824e 100644
> --- a/drivers/gpu/drm/panel/Makefile
> +++ b/drivers/gpu/drm/panel/Makefile
> @@ -2,3 +2,4 @@ obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
>  obj-$(CONFIG_DRM_PANEL_LD9040) += panel-ld9040.o
>  obj-$(CONFIG_DRM_PANEL_S6E8AA0) += panel-s6e8aa0.o
>  obj-$(CONFIG_DRM_PANEL_SHARP_LQ101R1SX01) += panel-sharp-lq101r1sx01.o
> +obj-$(CONFIG_DRM_PANEL_CRYSTALCOVE) += panel-crystalcove.o
> diff --git a/drivers/gpu/drm/panel/panel-crystalcove.c b/drivers/gpu/drm/panel/panel-crystalcove.c
> new file mode 100644
> index 0000000..22f7ff5
> --- /dev/null
> +++ b/drivers/gpu/drm/panel/panel-crystalcove.c
> @@ -0,0 +1,191 @@
> +/*
> + * Copyright © 2006-2014 Intel Corporation

2006?!

> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
> + *
> + * Authors:
> + *	Shobhit Kumar <shobhit.kumar@intel.com>
> + */
> +
> +#include <drm/drmP.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_panel.h>
> +#include <linux/mfd/intel_soc_pmic.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#define PMIC_PANEL_EN		0x52
> +#define PMIC_PWM_EN		0x51
> +#define PMIC_BKL_EN		0x4B
> +#define PMIC_PWM_LEVEL		0x4E
> +
> +struct crystalcove_panel {
> +	struct drm_panel base;
> +	char name[NAME_MAX];

Unused.

> +	bool prepared;
> +	bool enabled;
> +
> +	struct mutex lock;

Unused.

> +
> +	/* crystal cove pmic regmap */
> +	struct regmap *regmap;
> +};
> +
> +static inline struct crystalcove_panel *to_crystalcove_panel(struct drm_panel *panel)
> +{
> +	return container_of(panel, struct crystalcove_panel, base);
> +}
> +
> +static int crystalcove_panel_disable(struct drm_panel *panel)
> +{
> +	struct crystalcove_panel *p = to_crystalcove_panel(panel);
> +
> +	if (!p->enabled)
> +		return 0;
> +
> +	DRM_DEBUG_KMS("\n");
> +
> +	/* invoke the pmic driver */
> +	regmap_write(p->regmap, PMIC_PANEL_EN, 0x00);
> +
> +	/* Disable backlight as well */
> +	regmap_write(p->regmap, PMIC_PWM_LEVEL, 0);
> +	msleep(20);

Seems like a long delay.

> +	regmap_write(p->regmap, PMIC_PWM_EN, 0x00);
> +	regmap_write(p->regmap, PMIC_BKL_EN, 0x7F);
> +
> +	p->enabled = false;
> +
> +	return 0;
> +}
> +
> +static int crystalcove_panel_unprepare(struct drm_panel *panel)
> +{
> +	struct crystalcove_panel *p = to_crystalcove_panel(panel);
> +
> +	if (!p->prepared)
> +		return 0;
> +
> +	/* Nothing needed */
> +	p->prepared = false;
> +
> +	return 0;
> +}
> +
> +static int crystalcove_panel_prepare(struct drm_panel *panel)
> +{
> +	struct crystalcove_panel *p = to_crystalcove_panel(panel);
> +
> +	if (p->prepared)
> +		return 0;
> +
> +	/* Nothing needed */
> +	p->prepared = true;
> +
> +	return 0;
> +}

If you don't need prepare/unprepare, you can just leave them out
altogether. It's easy to add them if you need them later.

> +
> +static int crystalcove_panel_enable(struct drm_panel *panel)
> +{
> +	struct crystalcove_panel *p = to_crystalcove_panel(panel);
> +
> +	if (p->enabled)
> +		return 0;
> +
> +	DRM_DEBUG_KMS("\n");
> +
> +	/* invoke the pmic driver */
> +	regmap_write(p->regmap, PMIC_PANEL_EN, 0x01);
> +
> +	/* Enable BKL as well */
> +	regmap_write(p->regmap, PMIC_BKL_EN, 0xFF);
> +	regmap_write(p->regmap, PMIC_PWM_EN, 0x01);
> +	msleep(20);
> +	regmap_write(p->regmap, PMIC_PWM_LEVEL, 255);
> +
> +	p->enabled = true;
> +
> +	return 0;
> +}
> +
> +static const struct drm_panel_funcs crystalcove_panel_funcs = {
> +	.disable = crystalcove_panel_disable,
> +	.unprepare = crystalcove_panel_unprepare,
> +	.prepare = crystalcove_panel_prepare,
> +	.enable = crystalcove_panel_enable,
> +};
> +
> +static int crystalcove_panel_probe(struct platform_device *pdev)
> +{
> +	struct crystalcove_panel *panel;
> +	int retval;
> +	struct device *dev = pdev->dev.parent;
> +	struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
> +
> +	panel = devm_kzalloc(&pdev->dev, sizeof(*panel), GFP_KERNEL);
> +	if (!panel)
> +		return -ENOMEM;
> +
> +	DRM_DEBUG_KMS("\n");
> +
> +	platform_set_drvdata(pdev, panel);
> +
> +	strcpy(panel->base.name, "crystal_cove_panel");
> +	panel->regmap = pmic->regmap;
> +
> +	regmap_read(panel->regmap, PMIC_PANEL_EN, &retval);
> +	panel->enabled = panel->prepared = retval ? true : false;

For bools you can just assign retval, or if you want to emphasis it's a
bool you can use !!retval.

> +
> +	drm_panel_init(&panel->base);
> +	panel->base.dev = dev;
> +	panel->base.funcs = &crystalcove_panel_funcs;
> +
> +	drm_panel_add(&panel->base);
> +
> +	return 0;
> +}
> +
> +static int crystalcove_panel_remove(struct platform_device *pdev)
> +{
> +	struct crystalcove_panel *panel = platform_get_drvdata(pdev);
> +
> +	DRM_DEBUG_KMS("\n");
> +
> +	drm_panel_detach(&panel->base);
> +	drm_panel_remove(&panel->base);
> +
> +	crystalcove_panel_disable(&panel->base);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver crystalcove_panel_driver = {
> +	.probe = crystalcove_panel_probe,
> +	.remove = crystalcove_panel_remove,
> +	.driver = {
> +		.name = "crystal_cove_panel",
> +	},
> +};
> +
> +module_platform_driver(crystalcove_panel_driver);
> +
> +MODULE_AUTHOR("Shobhit Kumar <shobhit.kumar@linux.intel.com");
> +MODULE_DESCRIPTION("Intel Crystal Cove Panel Driver");
> +MODULE_LICENSE("GPL v2");

This conflicts with the copyright header of the file.


> -- 
> 1.9.1
>

-- 
Jani Nikula, Intel Open Source Technology Center
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