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SubjectRe: [PATCH v8 4/8] drm/ingenic: Add dw-hdmi driver for jz4780
Hi Nikolaus,

Le mer., nov. 24 2021 at 17:13:30 +0100, H. Nikolaus Schaller
<hns@goldelico.com> a écrit :
>
>
>> Am 23.11.2021 um 21:05 schrieb Paul Cercueil <paul@crapouillou.net>:
>>
>> Hi Nikolaus,
>>
>> I keep seeing a few things, sorry.
>
> no problem.
>
>>
>>
>> Le mar., nov. 23 2021 at 19:13:57 +0100, H. Nikolaus Schaller
>> <hns@goldelico.com> a écrit :
>>> From: Paul Boddie <paul@boddie.org.uk>
>>> A specialisation of the generic Synopsys HDMI driver is employed
>>> for
>>> JZ4780 HDMI support. This requires a new driver, plus device tree
>>> and
>>> configuration modifications.
>>> Here we add Kconfig DRM_INGENIC_DW_HDMI, Makefile and driver code.
>>> Signed-off-by: Paul Boddie <paul@boddie.org.uk>
>>> Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
>>> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
>>> ---
>>> drivers/gpu/drm/ingenic/Kconfig | 9 ++
>>> drivers/gpu/drm/ingenic/Makefile | 1 +
>>> drivers/gpu/drm/ingenic/ingenic-dw-hdmi.c | 129
>>> ++++++++++++++++++++++
>>> 3 files changed, 139 insertions(+)
>>> create mode 100644 drivers/gpu/drm/ingenic/ingenic-dw-hdmi.c
>>> diff --git a/drivers/gpu/drm/ingenic/Kconfig
>>> b/drivers/gpu/drm/ingenic/Kconfig
>>> index 3b57f8be007c4..4efc709d77b0a 100644
>>> --- a/drivers/gpu/drm/ingenic/Kconfig
>>> +++ b/drivers/gpu/drm/ingenic/Kconfig
>>> @@ -25,4 +25,13 @@ config DRM_INGENIC_IPU
>>> The Image Processing Unit (IPU) will appear as a second primary
>>> plane.
>>> +config DRM_INGENIC_DW_HDMI
>>> + tristate "Ingenic specific support for Synopsys DW HDMI"
>>> + depends on MACH_JZ4780
>>> + select DRM_DW_HDMI
>>> + help
>>> + Choose this option to enable Synopsys DesignWare HDMI based
>>> driver.
>>> + If you want to enable HDMI on Ingenic JZ4780 based SoC, you
>>> should
>>> + select this option..
>>> +
>>> endif
>>> diff --git a/drivers/gpu/drm/ingenic/Makefile
>>> b/drivers/gpu/drm/ingenic/Makefile
>>> index d313326bdddbb..f10cc1c5a5f22 100644
>>> --- a/drivers/gpu/drm/ingenic/Makefile
>>> +++ b/drivers/gpu/drm/ingenic/Makefile
>>> @@ -1,3 +1,4 @@
>>> obj-$(CONFIG_DRM_INGENIC) += ingenic-drm.o
>>> ingenic-drm-y = ingenic-drm-drv.o
>>> ingenic-drm-$(CONFIG_DRM_INGENIC_IPU) += ingenic-ipu.o
>>> +obj-$(CONFIG_DRM_INGENIC_DW_HDMI) += ingenic-dw-hdmi.o
>>> diff --git a/drivers/gpu/drm/ingenic/ingenic-dw-hdmi.c
>>> b/drivers/gpu/drm/ingenic/ingenic-dw-hdmi.c
>>> new file mode 100644
>>> index 0000000000000..c14890d6b9826
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/ingenic/ingenic-dw-hdmi.c
>>> @@ -0,0 +1,129 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/* Copyright (C) 2011-2013 Freescale Semiconductor, Inc.
>>> + * Copyright (C) 2019, 2020 Paul Boddie <paul@boddie.org.uk>
>>> + *
>>> + * Derived from dw_hdmi-imx.c with i.MX portions removed.
>>> + * Probe and remove operations derived from rcar_dw_hdmi.c.
>>> + */
>>> +
>>> +#include <linux/module.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/regmap.h>
>>> +
>>> +#include <drm/bridge/dw_hdmi.h>
>>> +#include <drm/drm_of.h>
>>> +#include <drm/drm_print.h>
>>> +
>>> +static const struct dw_hdmi_mpll_config ingenic_mpll_cfg[] = {
>>> + { 45250000, { { 0x01e0, 0x0000 }, { 0x21e1, 0x0000 }, { 0x41e2,
>>> 0x0000 } } },
>>> + { 92500000, { { 0x0140, 0x0005 }, { 0x2141, 0x0005 }, { 0x4142,
>>> 0x0005 } } },
>>> + { 148500000, { { 0x00a0, 0x000a }, { 0x20a1, 0x000a }, { 0x40a2,
>>> 0x000a } } },
>>> + { 216000000, { { 0x00a0, 0x000a }, { 0x2001, 0x000f }, { 0x4002,
>>> 0x000f } } },
>>> + { ~0UL, { { 0x0000, 0x0000 }, { 0x0000, 0x0000 }, { 0x0000,
>>> 0x0000 } } }
>>> +};
>>> +
>>> +static const struct dw_hdmi_curr_ctrl ingenic_cur_ctr[] = {
>>> + /*pixelclk bpp8 bpp10 bpp12 */
>>> + { 54000000, { 0x091c, 0x091c, 0x06dc } },
>>> + { 58400000, { 0x091c, 0x06dc, 0x06dc } },
>>> + { 72000000, { 0x06dc, 0x06dc, 0x091c } },
>>> + { 74250000, { 0x06dc, 0x0b5c, 0x091c } },
>>> + { 118800000, { 0x091c, 0x091c, 0x06dc } },
>>> + { 216000000, { 0x06dc, 0x0b5c, 0x091c } },
>>> + { ~0UL, { 0x0000, 0x0000, 0x0000 } },
>>> +};
>>> +
>>> +/*
>>> + * Resistance term 133Ohm Cfg
>>> + * PREEMP config 0.00
>>> + * TX/CK level 10
>>> + */
>>> +static const struct dw_hdmi_phy_config ingenic_phy_config[] = {
>>> + /*pixelclk symbol term vlev */
>>> + { 216000000, 0x800d, 0x0005, 0x01ad},
>>> + { ~0UL, 0x0000, 0x0000, 0x0000}
>>> +};
>>> +
>>> +static enum drm_mode_status
>>> +ingenic_dw_hdmi_mode_valid(struct dw_hdmi *hdmi, void *data,
>>> + const struct drm_display_info *info,
>>> + const struct drm_display_mode *mode)
>>> +{
>>> + if (mode->clock < 13500)
>>> + return MODE_CLOCK_LOW;
>>> + /* FIXME: Hardware is capable of 270MHz, but setup data is
>>> missing. */
>>> + if (mode->clock > 216000)
>>> + return MODE_CLOCK_HIGH;
>>> +
>>> + return MODE_OK;
>>> +}
>>> +
>>> +static struct dw_hdmi_plat_data ingenic_dw_hdmi_plat_data = {
>>> + .mpll_cfg = ingenic_mpll_cfg,
>>> + .cur_ctr = ingenic_cur_ctr,
>>> + .phy_config = ingenic_phy_config,
>>> + .mode_valid = ingenic_dw_hdmi_mode_valid,
>>> + .output_port = 1,
>>> +};
>>> +
>>> +static const struct of_device_id ingenic_dw_hdmi_dt_ids[] = {
>>> + { .compatible = "ingenic,jz4780-dw-hdmi" },
>>> + { /* Sentinel */ },
>>> +};
>>> +MODULE_DEVICE_TABLE(of, ingenic_dw_hdmi_dt_ids);
>>> +
>>> +static int ingenic_dw_hdmi_probe(struct platform_device *pdev)
>>> +{
>>> + struct dw_hdmi *hdmi;
>>> + struct regulator *regulator;
>>> + int ret;
>>> +
>>> + hdmi = dw_hdmi_probe(pdev, &ingenic_dw_hdmi_plat_data);
>>> + if (IS_ERR(hdmi))
>>> + return PTR_ERR(hdmi);
>>> +
>>> + platform_set_drvdata(pdev, hdmi);
>>> +
>>> + regulator = devm_regulator_get_optional(&pdev->dev, "hdmi-5v");
>>> +
>>
>> Nit - you can remove this blank line.
>
> ok.
>
>>
>>> + if (IS_ERR(regulator)) {
>>> + ret = PTR_ERR(regulator);
>>> +
>>> + DRM_DEV_ERROR(&pdev->dev, "failed to get hpd regulator: %s
>>> (%d)\n",
>>> + "hdmi-5v", ret);
>>> + return ret;
>>> + }
>>> +
>>> + ret = regulator_enable(regulator);
>>
>> You used devm_regulator_get_optional(), so you are not guaranteed
>> to obtain anything; your "regulator" variable might be a NULL
>> pointer, so you can't just call regulator_enable() without checking
>> it first.
>
> right. I forgot about that.
>
>>
>>> + if (ret) {
>>> + DRM_DEV_ERROR(&pdev->dev, "Failed to enable hpd regulator:
>>> %d\n",
>>> + ret);
>>> + return ret;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int ingenic_dw_hdmi_remove(struct platform_device *pdev)
>>> +{
>>> + struct dw_hdmi *hdmi = platform_get_drvdata(pdev);
>>> +
>>> + dw_hdmi_remove(hdmi);
>>
>> You probably should disable the regulator (if not NULL) here.
>
> Indeed. Would it be ok to make struct regulator *regulator static
> or do we need dynamically allocated memory?

static non-const is almost always a bad idea, so avoid it.

You can either:

- create a "ingenic_dw_hdmi" struct that will contain a pointer to
dw_hdmi and a pointer to the regulator. Instanciate it in the probe
with devm_kzalloc() and set the pointers, then set it as the driver
data (platform_set_drvdata). In the remove function you can then obtain
the pointer to your ingenic_dw_hdmi struct with platform_get_drvdata(),
and you can remove the dw_hdmi and unregister the regulator.

- register cleanup functions, using devm_add_action_or_reset(dev, f,
priv). When it's time to cleanup, the kernel core will call f(priv)
automatically. So you can add a small wrapper around dw_hdmi_remove()
and another one around regulator_disable(), and those will be called
automatically if your probe function fails, or when the driver is
removed. Then you can completely remove the ".remove" callback. There
are a few examples of these in the ingenic-drm-drv.c if you want to
take a look.

Cheers,
-Paul

>>
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static struct platform_driver ingenic_dw_hdmi_driver = {
>>> + .probe = ingenic_dw_hdmi_probe,
>>> + .remove = ingenic_dw_hdmi_remove,
>>> + .driver = {
>>> + .name = "dw-hdmi-ingenic",
>>> + .of_match_table = ingenic_dw_hdmi_dt_ids,
>>> + },
>>> +};
>>> +
>>
>> Nit - remove this blank line too.
>
> ok.
>
>>
>> Cheers,
>> -Paul
>>
>>> +module_platform_driver(ingenic_dw_hdmi_driver);
>>> +
>>> +MODULE_DESCRIPTION("JZ4780 Specific DW-HDMI Driver Extension");
>>> +MODULE_LICENSE("GPL v2");
>>> +MODULE_ALIAS("platform:dwhdmi-ingenic");
>>> --
>>> 2.33.0
>>
>>
>


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