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From:   Jernej =?utf-8?B?xaBrcmFiZWM=?= <jernej.skrabec@siol.net>
To:     Maxime Ripard <maxime.ripard@bootlin.com>
Cc:     wens@csie.org, robh+dt@kernel.org, mark.rutland@arm.com,
        dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-clk@vger.kernel.org, linux-sunxi@googlegroups.com
Subject: Re: [PATCH 05/15] drm/sun4i: Add TCON TOP driver
Date:   Mon, 21 May 2018 17:15:15 +0200
Message-ID: <5965231.6ucpJrPIQ5@jernej-laptop>
In-Reply-To: <20180521080517.3qmlfajqpn4uw7jv@flea>
References: <20180519183127.2718-1-jernej.skrabec@siol.net> <20180519183127.2718-6-jernej.skrabec@siol.net> <20180521080517.3qmlfajqpn4uw7jv@flea>
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Sender: linux-kernel-owner@vger.kernel.org
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Hi,

Dne ponedeljek, 21. maj 2018 ob 10:05:17 CEST je Maxime Ripard napisal(a):
> On Sat, May 19, 2018 at 08:31:17PM +0200, Jernej Skrabec wrote:
> > As already described in DT binding, TCON TOP is responsible for
> > configuring display pipeline. In this initial driver focus is on HDMI
> > pipeline, so TVE and LCD configuration is not implemented.
> > 
> > Implemented features:
> > - HDMI source selection
> > - clock driver (TCON and DSI gating)
> > - connecting mixers and TCONS
> > 
> > Something similar also existed in previous SoCs, except that it was part
> > of first TCON.
> > 
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> > ---
> > 
> >  drivers/gpu/drm/sun4i/Makefile             |   3 +-
> >  drivers/gpu/drm/sun4i/sun8i_tcon_top.c     | 256 +++++++++++++++++++++
> >  drivers/gpu/drm/sun4i/sun8i_tcon_top.h     |  20 ++
> >  include/dt-bindings/clock/sun8i-tcon-top.h |  11 +
> >  4 files changed, 289 insertions(+), 1 deletion(-)
> >  create mode 100644 drivers/gpu/drm/sun4i/sun8i_tcon_top.c
> >  create mode 100644 drivers/gpu/drm/sun4i/sun8i_tcon_top.h
> >  create mode 100644 include/dt-bindings/clock/sun8i-tcon-top.h
> > 
> > diff --git a/drivers/gpu/drm/sun4i/Makefile
> > b/drivers/gpu/drm/sun4i/Makefile index 2589f4acd5ae..09fbfd6304ba 100644
> > --- a/drivers/gpu/drm/sun4i/Makefile
> > +++ b/drivers/gpu/drm/sun4i/Makefile
> > @@ -16,7 +16,8 @@ sun8i-drm-hdmi-y		+= sun8i_hdmi_phy_clk.o
> > 
> >  sun8i-mixer-y			+= sun8i_mixer.o sun8i_ui_layer.o \
> >  
> >  				   sun8i_vi_layer.o sun8i_ui_scaler.o \
> > 
> > -				   sun8i_vi_scaler.o sun8i_csc.o
> > +				   sun8i_vi_scaler.o sun8i_csc.o \
> > +				   sun8i_tcon_top.o
> > 
> >  sun4i-tcon-y			+= sun4i_crtc.o
> >  sun4i-tcon-y			+= sun4i_dotclock.o
> > 
> > diff --git a/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
> > b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c new file mode 100644
> > index 000000000000..075a356a6dfa
> > --- /dev/null
> > +++ b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
> > @@ -0,0 +1,256 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/* Copyright (c) 2018 Jernej Skrabec <jernej.skrabec@siol.net> */
> > +
> > +#include <drm/drmP.h>
> > +
> > +#include <dt-bindings/clock/sun8i-tcon-top.h>
> > +
> > +#include <linux/bitfield.h>
> > +#include <linux/clk.h>
> > +#include <linux/clk-provider.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/reset.h>
> > +#include <linux/spinlock.h>
> > +
> > +#include "sun8i_tcon_top.h"
> > +
> > +#define TCON_TOP_PORT_SEL_REG		0x1C
> > +#define TCON_TOP_PORT_DE0_MSK			GENMASK(1, 0)
> > +#define TCON_TOP_PORT_DE1_MSK			GENMASK(5, 4)
> > +#define TCON_TOP_PORT_TCON_LCD0			0
> > +#define TCON_TOP_PORT_TCON_LCD1			1
> > +#define TCON_TOP_PORT_TCON_TV0			2
> > +#define TCON_TOP_PORT_TCON_TV1			3
> > +
> > +#define TCON_TOP_GATE_SRC_REG		0x20
> > +#define TCON_TOP_HDMI_SRC_MSK			GENMASK(29, 28)
> > +#define TCON_TOP_HDMI_SRC_NONE			0
> > +#define TCON_TOP_HDMI_SRC_TCON_TV0		1
> > +#define TCON_TOP_HDMI_SRC_TCON_TV1		2
> > +#define TCON_TOP_TCON_TV1_GATE			24
> > +#define TCON_TOP_TCON_TV0_GATE			20
> > +#define TCON_TOP_TCON_DSI_GATE			16
> > +
> > +#define CLK_NUM					3
> > +
> > +struct sun8i_tcon_top {
> > +	struct clk		*bus;
> > +	void __iomem		*regs;
> > +	struct reset_control	*rst;
> > +
> > +	/*
> > +	 * spinlock is used for locking access to registers from different
> > +	 * places - tcon driver and clk subsystem.
> > +	 */
> > +	spinlock_t		reg_lock;
> > +};
> > +
> > +struct sun8i_tcon_top_gate {
> > +	const char	*name;
> > +	u8		bit;
> > +	int		index;
> > +};
> > +
> > +static const struct sun8i_tcon_top_gate gates[] = {
> > +	{"bus-tcon-top-dsi", TCON_TOP_TCON_DSI_GATE, CLK_BUS_TCON_TOP_DSI},
> > +	{"bus-tcon-top-tv0", TCON_TOP_TCON_TV0_GATE, CLK_BUS_TCON_TOP_TV0},
> > +	{"bus-tcon-top-tv1", TCON_TOP_TCON_TV1_GATE, CLK_BUS_TCON_TOP_TV1},
> > +};
> > +
> > +void sun8i_tcon_top_set_hdmi_src(struct sun8i_tcon_top *tcon_top, int
> > tcon) +{
> > +	unsigned long flags;
> > +	u32 val;
> > +
> > +	if (tcon > 1) {
> > +		DRM_ERROR("TCON index is too high!\n");
> > +		return;
> > +	}
> > +
> > +	spin_lock_irqsave(&tcon_top->reg_lock, flags);
> > +
> > +	val = readl(tcon_top->regs + TCON_TOP_GATE_SRC_REG);
> > +	val &= ~TCON_TOP_HDMI_SRC_MSK;
> > +	val |= FIELD_PREP(TCON_TOP_HDMI_SRC_MSK,
> > +			  TCON_TOP_HDMI_SRC_TCON_TV0 + tcon);
> > +	writel(val, tcon_top->regs + TCON_TOP_GATE_SRC_REG);
> > +
> > +	spin_unlock_irqrestore(&tcon_top->reg_lock, flags);
> > +}
> > +
> > +void sun8i_tcon_top_de_config(struct sun8i_tcon_top *tcon_top,
> > +			      int mixer, enum tcon_type tcon_type, int tcon)
> > +{
> > +	unsigned long flags;
> > +	u32 val, reg;
> > +
> > +	if (mixer > 1) {
> > +		DRM_ERROR("Mixer index is too high!\n");
> > +		return;
> > +	}
> > +
> > +	if (tcon > 1) {
> > +		DRM_ERROR("TCON index is too high!\n");
> > +		return;
> > +	}
> > +
> > +	switch (tcon_type) {
> > +	case tcon_type_lcd:
> > +		val = TCON_TOP_PORT_TCON_LCD0 + tcon;
> > +		break;
> > +	case tcon_type_tv:
> > +		val = TCON_TOP_PORT_TCON_TV0 + tcon;
> > +		break;
> > +	default:
> > +		DRM_ERROR("Invalid TCON type!\n");
> > +		return;
> > +	}
> > +
> > +	spin_lock_irqsave(&tcon_top->reg_lock, flags);
> > +
> > +	reg = readl(tcon_top->regs + TCON_TOP_PORT_SEL_REG);
> > +	if (mixer == 0) {
> > +		reg &= ~TCON_TOP_PORT_DE0_MSK;
> > +		reg |= FIELD_PREP(TCON_TOP_PORT_DE0_MSK, val);
> > +	} else {
> > +		reg &= ~TCON_TOP_PORT_DE1_MSK;
> > +		reg |= FIELD_PREP(TCON_TOP_PORT_DE1_MSK, val);
> > +	}
> > +	writel(reg, tcon_top->regs + TCON_TOP_PORT_SEL_REG);
> > +
> > +	spin_unlock_irqrestore(&tcon_top->reg_lock, flags);
> > +}
> > +
> > +static int sun8i_tcon_top_probe(struct platform_device *pdev)
> > +{
> > +	struct clk_hw_onecell_data *clk_data;
> > +	struct sun8i_tcon_top *tcon_top;
> > +	struct device *dev = &pdev->dev;
> > +	struct resource *res;
> > +	int ret, i;
> > +
> > +	tcon_top = devm_kzalloc(dev, sizeof(*tcon_top), GFP_KERNEL);
> > +	if (!tcon_top)
> > +		return -ENOMEM;
> > +
> > +	clk_data = devm_kzalloc(&pdev->dev, sizeof(*clk_data) +
> > +				sizeof(*clk_data->hws) * CLK_NUM,
> > +				GFP_KERNEL);
> > +	if (!clk_data)
> > +		return -ENOMEM;
> > +
> > +	spin_lock_init(&tcon_top->reg_lock);
> > +
> > +	tcon_top->rst = devm_reset_control_get(dev, "rst");
> > +	if (IS_ERR(tcon_top->rst)) {
> > +		dev_err(dev, "Couldn't get our reset line\n");
> > +		return PTR_ERR(tcon_top->rst);
> > +	}
> > +
> > +	tcon_top->bus = devm_clk_get(dev, "bus");
> > +	if (IS_ERR(tcon_top->bus)) {
> > +		dev_err(dev, "Couldn't get the bus clock\n");
> > +		return PTR_ERR(tcon_top->bus);
> > +	}
> > +
> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	tcon_top->regs = devm_ioremap_resource(dev, res);
> > +	if (IS_ERR(tcon_top->regs))
> > +		return PTR_ERR(tcon_top->regs);
> > +
> > +	ret = reset_control_deassert(tcon_top->rst);
> > +	if (ret) {
> > +		dev_err(dev, "Could not deassert ctrl reset control\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = clk_prepare_enable(tcon_top->bus);
> > +	if (ret) {
> > +		dev_err(dev, "Could not enable bus clock\n");
> > +		goto err_assert_reset;
> > +	}
> > +
> > +	/*
> > +	 * Default register values might have some reserved bits set, which
> > +	 * prevents TCON TOP from working properly. Set them to 0 here.
> > +	 */
> > +	writel(0, tcon_top->regs + TCON_TOP_PORT_SEL_REG);
> > +	writel(0, tcon_top->regs + TCON_TOP_GATE_SRC_REG);
> > +
> > +	for (i = 0; i < CLK_NUM; i++) {
> > +		const char *parent_name = "bus-tcon-top";
> 
> I guess retrieving the parent's clock name at runtime would be more
> flexible.
> 

It is, but will it ever be anything else?

> > +		struct clk_init_data init;
> > +		struct clk_gate *gate;
> > +
> > +		gate = devm_kzalloc(dev, sizeof(*gate), GFP_KERNEL);
> > +		if (!gate) {
> > +			ret = -ENOMEM;
> > +			goto err_disable_clock;
> > +		}
> > +
> > +		init.name = gates[i].name;
> > +		init.ops = &clk_gate_ops;
> > +		init.flags = CLK_IS_BASIC;
> > +		init.parent_names = &parent_name;
> > +		init.num_parents = 1;
> > +
> > +		gate->reg = tcon_top->regs + TCON_TOP_GATE_SRC_REG;
> > +		gate->bit_idx = gates[i].bit;
> > +		gate->lock = &tcon_top->reg_lock;
> > +		gate->hw.init = &init;
> > +
> > +		ret = devm_clk_hw_register(dev, &gate->hw);
> > +		if (ret)
> > +			goto err_disable_clock;
> 
> Isn't it what clk_hw_register_gate is doing?
> 

Almost, but not exactly. My goal was to use devm_* functions, so there is no 
need to do any special cleanup.

> > +		clk_data->hws[gates[i].index] = &gate->hw;
> > +	}
> > +
> > +	clk_data->num = CLK_NUM;
> > +
> > +	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, 
clk_data);
> > +	if (ret)
> > +		goto err_disable_clock;
> > +
> > +	platform_set_drvdata(pdev, tcon_top);
> > +
> > +	return 0;
> > +
> > +err_disable_clock:
> > +	clk_disable_unprepare(tcon_top->bus);
> > +err_assert_reset:
> > +	reset_control_assert(tcon_top->rst);
> > +
> > +	return ret;
> > +}
> > +
> > +static int sun8i_tcon_top_remove(struct platform_device *pdev)
> > +{
> > +	struct sun8i_tcon_top *tcon_top = platform_get_drvdata(pdev);
> > +
> > +	clk_disable_unprepare(tcon_top->bus);
> > +	reset_control_assert(tcon_top->rst);
> > +
> > +	return 0;
> > +}
> > +
> > +const struct of_device_id sun8i_tcon_top_of_table[] = {
> > +	{ .compatible = "allwinner,sun8i-r40-tcon-top" },
> > +	{ /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, sun8i_tcon_top_of_table);
> > +
> > +static struct platform_driver sun8i_tcon_top_platform_driver = {
> > +	.probe		= sun8i_tcon_top_probe,
> > +	.remove		= sun8i_tcon_top_remove,
> > +	.driver		= {
> > +		.name		= "sun8i-tcon-top",
> > +		.of_match_table	= sun8i_tcon_top_of_table,
> > +	},
> > +};
> > +module_platform_driver(sun8i_tcon_top_platform_driver);
> > +
> > +MODULE_AUTHOR("Jernej Skrabec <jernej.skrabec@siol.net>");
> > +MODULE_DESCRIPTION("Allwinner R40 TCON TOP driver");
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/gpu/drm/sun4i/sun8i_tcon_top.h
> > b/drivers/gpu/drm/sun4i/sun8i_tcon_top.h new file mode 100644
> > index 000000000000..19126e07d2a6
> > --- /dev/null
> > +++ b/drivers/gpu/drm/sun4i/sun8i_tcon_top.h
> > @@ -0,0 +1,20 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ */
> > +/* Copyright (c) 2018 Jernej Skrabec <jernej.skrabec@siol.net> */
> > +
> > +#ifndef _SUN8I_TCON_TOP_H_
> > +#define _SUN8I_TCON_TOP_H_
> > +
> > +#include <linux/device.h>
> > +
> > +struct sun8i_tcon_top;
> > +
> > +enum tcon_type {
> > +	tcon_type_lcd,
> > +	tcon_type_tv,
> 
> The usual practice is to have the enum values upper-case.

Ok.

Best regards,
Jernej