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    SubjectRe: [PATCH 05/15] drm/sun4i: Add TCON TOP driver
    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.

    > + 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?

    > + 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.

    Thanks!
    Maxime

    --
    Maxime Ripard, Bootlin (formerly Free Electrons)
    Embedded Linux and Kernel engineering
    https://bootlin.com
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