Message-ID: <CAGb2v6465Upen-aFiLXDrSPLDGLh+2REjaZ_91W39=E1DffHeA@mail.gmail.com>
Date:   Thu, 28 Jun 2018 09:47:20 +0800
From:   Chen-Yu Tsai <wens@...e.org>
To:     Jernej Skrabec <jernej.skrabec@...l.net>
Cc:     Maxime Ripard <maxime.ripard@...tlin.com>,
        Rob Herring <robh+dt@...nel.org>,
        David Airlie <airlied@...ux.ie>,
        Gustavo Padovan <gustavo@...ovan.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Sean Paul <seanpaul@...omium.org>,
        Mark Rutland <mark.rutland@....com>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        devicetree <devicetree@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-clk <linux-clk@...r.kernel.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>
Subject: Re: [PATCH v3 05/24] drm/sun4i: Add TCON TOP driver

Hi,

So I'm late to the party, but...

On Mon, Jun 25, 2018 at 8:02 PM, Jernej Skrabec <jernej.skrabec@...l.net> 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@...l.net>
> ---
>  drivers/gpu/drm/sun4i/Makefile         |   3 +-
>  drivers/gpu/drm/sun4i/sun8i_tcon_top.c | 300 +++++++++++++++++++++++++
>  drivers/gpu/drm/sun4i/sun8i_tcon_top.h |  40 ++++
>  3 files changed, 342 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
>
> 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..8da0460e0028
> --- /dev/null
> +++ b/drivers/gpu/drm/sun4i/sun8i_tcon_top.c
> @@ -0,0 +1,300 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/* Copyright (c) 2018 Jernej Skrabec <jernej.skrabec@...l.net> */
> +
> +#include <drm/drmP.h>
> +
> +#include <dt-bindings/clock/sun8i-tcon-top.h>
> +
> +#include <linux/bitfield.h>
> +#include <linux/component.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/of_graph.h>
> +#include <linux/platform_device.h>
> +
> +#include "sun8i_tcon_top.h"
> +
> +static int sun8i_tcon_top_get_connected_ep_id(struct device_node *node,
> +                                             int port_id)
> +{
> +       struct device_node *ep, *remote, *port;
> +       struct of_endpoint endpoint;
> +
> +       port = of_graph_get_port_by_id(node, port_id);
> +       if (!port)
> +               return -ENOENT;
> +
> +       for_each_available_child_of_node(port, ep) {
> +               remote = of_graph_get_remote_port_parent(ep);
> +               if (!remote)
> +                       continue;
> +
> +               if (of_device_is_available(remote)) {
> +                       of_graph_parse_endpoint(ep, &endpoint);
> +
> +                       of_node_put(remote);
> +
> +                       return endpoint.id;
> +               }
> +
> +               of_node_put(remote);
> +       }
> +
> +       return -ENOENT;
> +}
> +
> +static struct clk_hw *sun8i_tcon_top_register_gate(struct device *dev,
> +                                                  struct clk *parent,
> +                                                  void __iomem *regs,
> +                                                  spinlock_t *lock,
> +                                                  u8 bit, int name_index)
> +{
> +       const char *clk_name, *parent_name;
> +       int ret;
> +
> +       parent_name = __clk_get_name(parent);

You can simply pass in the binding clock name, and have

    index = of_property_match_string(np, "clock-names", name);
    parent_name = of_clk_get_parent_name(dev->of_node, index);

> +       ret = of_property_read_string_index(dev->of_node,
> +                                           "clock-output-names", name_index,
> +                                           &clk_name);
> +       if (ret)
> +               return ERR_PTR(ret);
> +
> +       return clk_hw_register_gate(dev, clk_name, parent_name,
> +                                   CLK_SET_RATE_PARENT,
> +                                   regs + TCON_TOP_GATE_SRC_REG,
> +                                   bit, 0, lock);
> +};
> +
> +static int sun8i_tcon_top_bind(struct device *dev, struct device *master,
> +                              void *data)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct clk *dsi, *tcon_tv0, *tcon_tv1, *tve0, *tve1;
> +       struct clk_hw_onecell_data *clk_data;
> +       struct sun8i_tcon_top *tcon_top;
> +       bool mixer0_unused = false;
> +       struct resource *res;
> +       void __iomem *regs;
> +       int ret, i, id;
> +       u32 val;
> +
> +       tcon_top = devm_kzalloc(dev, sizeof(*tcon_top), GFP_KERNEL);
> +       if (!tcon_top)
> +               return -ENOMEM;
> +
> +       clk_data = devm_kzalloc(dev, sizeof(*clk_data) +
> +                               sizeof(*clk_data->hws) * CLK_NUM,
> +                               GFP_KERNEL);
> +       if (!clk_data)
> +               return -ENOMEM;
> +       tcon_top->clk_data = clk_data;
> +
> +       spin_lock_init(&tcon_top->reg_lock);
> +
> +       tcon_top->rst = devm_reset_control_get(dev, NULL);
> +       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);
> +       }
> +
> +       dsi = devm_clk_get(dev, "dsi");
> +       if (IS_ERR(dsi)) {
> +               dev_err(dev, "Couldn't get the dsi clock\n");
> +               return PTR_ERR(dsi);
> +       }
> +
> +       tcon_tv0 = devm_clk_get(dev, "tcon-tv0");
> +       if (IS_ERR(tcon_tv0)) {
> +               dev_err(dev, "Couldn't get the tcon-tv0 clock\n");
> +               return PTR_ERR(tcon_tv0);
> +       }
> +
> +       tcon_tv1 = devm_clk_get(dev, "tcon-tv1");
> +       if (IS_ERR(tcon_tv1)) {
> +               dev_err(dev, "Couldn't get the tcon-tv1 clock\n");
> +               return PTR_ERR(tcon_tv1);
> +       }
> +
> +       tve0 = devm_clk_get(dev, "tve0");
> +       if (IS_ERR(tve0)) {
> +               dev_err(dev, "Couldn't get the tve0 clock\n");
> +               return PTR_ERR(tve0);
> +       }
> +
> +       tve1 = devm_clk_get(dev, "tve1");
> +       if (IS_ERR(tve1)) {
> +               dev_err(dev, "Couldn't get the tve1 clock\n");
> +               return PTR_ERR(tve1);
> +       }

So you don't actually have to hold references to the parent clocks.

ChenYu

> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       regs = devm_ioremap_resource(dev, res);
> +       if (IS_ERR(regs))
> +               return PTR_ERR(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;
> +       }
> +
> +       val = 0;
> +
> +       /* check if HDMI mux output is connected */
> +       if (sun8i_tcon_top_get_connected_ep_id(dev->of_node, 5) >= 0) {
> +               /* find HDMI input endpoint id, if it is connected at all*/
> +               id = sun8i_tcon_top_get_connected_ep_id(dev->of_node, 4);
> +               if (id >= 0)
> +                       val = FIELD_PREP(TCON_TOP_HDMI_SRC_MSK, id + 1);
> +               else
> +                       DRM_DEBUG_DRIVER("TCON TOP HDMI input is not connected\n");
> +       } else {
> +               DRM_DEBUG_DRIVER("TCON TOP HDMI output is not connected\n");
> +       }
> +
> +       writel(val, regs + TCON_TOP_GATE_SRC_REG);
> +
> +       val = 0;
> +
> +       /* process mixer0 mux output */
> +       id = sun8i_tcon_top_get_connected_ep_id(dev->of_node, 1);
> +       if (id >= 0) {
> +               val = FIELD_PREP(TCON_TOP_PORT_DE0_MSK, id);
> +       } else {
> +               DRM_DEBUG_DRIVER("TCON TOP mixer0 output is not connected\n");
> +               mixer0_unused = true;
> +       }
> +
> +       /* process mixer1 mux output */
> +       id = sun8i_tcon_top_get_connected_ep_id(dev->of_node, 3);
> +       if (id >= 0) {
> +               val |= FIELD_PREP(TCON_TOP_PORT_DE1_MSK, id);
> +
> +               /*
> +                * mixer0 mux has priority over mixer1 mux. We have to
> +                * make sure mixer0 doesn't overtake TCON from mixer1.
> +                */
> +               if (mixer0_unused && id == 0)
> +                       val |= FIELD_PREP(TCON_TOP_PORT_DE0_MSK, 1);
> +       } else {
> +               DRM_DEBUG_DRIVER("TCON TOP mixer1 output is not connected\n");
> +       }
> +
> +       writel(val, regs + TCON_TOP_PORT_SEL_REG);
> +
> +       /*
> +        * TCON TOP has two muxes, which select parent clock for each TCON TV
> +        * channel clock. Parent could be either TCON TV or TVE clock. For now
> +        * we leave this fixed to TCON TV, since TVE driver for R40 is not yet
> +        * implemented. Once it is, graph needs to be traversed to determine
> +        * if TVE is active on each TCON TV. If it is, mux should be switched
> +        * to TVE clock parent.
> +        */
> +       clk_data->hws[CLK_TCON_TOP_TV0] =
> +               sun8i_tcon_top_register_gate(dev, tcon_tv0, regs,
> +                                            &tcon_top->reg_lock,
> +                                            TCON_TOP_TCON_TV0_GATE, 0);
> +
> +       clk_data->hws[CLK_TCON_TOP_TV1] =
> +               sun8i_tcon_top_register_gate(dev, tcon_tv1, regs,
> +                                            &tcon_top->reg_lock,
> +                                            TCON_TOP_TCON_TV1_GATE, 1);
> +
> +       clk_data->hws[CLK_TCON_TOP_DSI] =
> +               sun8i_tcon_top_register_gate(dev, dsi, regs,
> +                                            &tcon_top->reg_lock,
> +                                            TCON_TOP_TCON_DSI_GATE, 2);
> +
> +       for (i = 0; i < CLK_NUM; i++)
> +               if (IS_ERR(clk_data->hws[i])) {
> +                       ret = PTR_ERR(clk_data->hws[i]);
> +                       goto err_unregister_gates;
> +               }
> +
> +       clk_data->num = CLK_NUM;
> +
> +       ret = of_clk_add_hw_provider(dev->of_node, of_clk_hw_onecell_get,
> +                                    clk_data);
> +       if (ret)
> +               goto err_unregister_gates;
> +
> +       dev_set_drvdata(dev, tcon_top);
> +
> +       return 0;
> +
> +err_unregister_gates:
> +       for (i = 0; i < CLK_NUM; i++)
> +               if (clk_data->hws[i])
> +                       clk_hw_unregister_gate(clk_data->hws[i]);
> +       clk_disable_unprepare(tcon_top->bus);
> +err_assert_reset:
> +       reset_control_assert(tcon_top->rst);
> +
> +       return ret;
> +}
> +
> +static void sun8i_tcon_top_unbind(struct device *dev, struct device *master,
> +                                 void *data)
> +{
> +       struct sun8i_tcon_top *tcon_top = dev_get_drvdata(dev);
> +       struct clk_hw_onecell_data *clk_data = tcon_top->clk_data;
> +       int i;
> +
> +       of_clk_del_provider(dev->of_node);
> +       for (i = 0; i < CLK_NUM; i++)
> +               clk_hw_unregister_gate(clk_data->hws[i]);
> +
> +       clk_disable_unprepare(tcon_top->bus);
> +       reset_control_assert(tcon_top->rst);
> +}
> +
> +static const struct component_ops sun8i_tcon_top_ops = {
> +       .bind   = sun8i_tcon_top_bind,
> +       .unbind = sun8i_tcon_top_unbind,
> +};
> +
> +static int sun8i_tcon_top_probe(struct platform_device *pdev)
> +{
> +       return component_add(&pdev->dev, &sun8i_tcon_top_ops);
> +}
> +
> +static int sun8i_tcon_top_remove(struct platform_device *pdev)
> +{
> +       component_del(&pdev->dev, &sun8i_tcon_top_ops);
> +
> +       return 0;
> +}
> +
> +/* sun4i_drv uses this list to check if a device node is a TCON TOP */
> +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);
> +EXPORT_SYMBOL(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@...l.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..39838bbfeaee
> --- /dev/null
> +++ b/drivers/gpu/drm/sun4i/sun8i_tcon_top.h
> @@ -0,0 +1,40 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/* Copyright (c) 2018 Jernej Skrabec <jernej.skrabec@...l.net> */
> +
> +#ifndef _SUN8I_TCON_TOP_H_
> +#define _SUN8I_TCON_TOP_H_
> +
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/reset.h>
> +#include <linux/spinlock.h>
> +
> +#define TCON_TOP_TCON_TV_SETUP_REG     0x00
> +
> +#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_GATE_SRC_REG          0x20
> +#define TCON_TOP_HDMI_SRC_MSK                  GENMASK(29, 28)
> +#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;
> +       struct clk_hw_onecell_data      *clk_data;
> +       struct reset_control            *rst;
> +
> +       /*
> +        * spinlock is used to synchronize access to same
> +        * register where multiple clock gates can be set.
> +        */
> +       spinlock_t                      reg_lock;
> +};
> +
> +extern const struct of_device_id sun8i_tcon_top_of_table[];
> +
> +#endif /* _SUN8I_TCON_TOP_H_ */
> --
> 2.18.0
>

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