Re: [PATCH v2 05/26] clk: sunxi: Add display and TCON0 clocks driver

Chen-Yu Tsai
2016-01-16T15:29:41Z

Hi,

On Thu, Jan 14, 2016 at 11:24 PM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:
> The A10 SoCs and its relatives has a special clock controller to drive the
> display engines (both frontend and backend), that have a lot in common with
> the clock to drive the first TCON channel.
>
> Add a driver to support both.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
> Documentation/devicetree/bindings/clock/sunxi.txt | 2 +
> drivers/clk/sunxi/Makefile | 1 +
> drivers/clk/sunxi/clk-sun4i-display.c | 241 ++++++++++++++++++++++
> 3 files changed, 244 insertions(+)
> create mode 100644 drivers/clk/sunxi/clk-sun4i-display.c
>
> diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
> index 8a47b77abfca..5360554a7d3f 100644
> --- a/Documentation/devicetree/bindings/clock/sunxi.txt
> +++ b/Documentation/devicetree/bindings/clock/sunxi.txt
> @@ -55,6 +55,7 @@ Required properties:
> "allwinner,sun9i-a80-apb1-gates-clk" - for the APB1 gates on A80
> "allwinner,sun6i-a31-apb2-gates-clk" - for the APB2 gates on A31
> "allwinner,sun8i-a23-apb2-gates-clk" - for the APB2 gates on A23
> + "allwinner,sun4i-a10-display-clk" - for the display clocks on the A10
> "allwinner,sun5i-a13-mbus-clk" - for the MBUS clock on A13
> "allwinner,sun4i-a10-mmc-clk" - for the MMC clock
> "allwinner,sun9i-a80-mmc-clk" - for mmc module clocks on A80
> @@ -64,6 +65,7 @@ Required properties:
> "allwinner,sun8i-a23-mbus-clk" - for the MBUS clock on A23
> "allwinner,sun7i-a20-out-clk" - for the external output clocks
> "allwinner,sun7i-a20-gmac-clk" - for the GMAC clock module on A20/A31
> + "allwinner,sun4i-a10-tcon-ch0-clk" - for the TCON channel 0 clock on the A10
> "allwinner,sun4i-a10-usb-clk" - for usb gates + resets on A10 / A20
> "allwinner,sun5i-a13-usb-clk" - for usb gates + resets on A13
> "allwinner,sun6i-a31-usb-clk" - for usb gates + resets on A31
> diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile
> index cb4c299214ce..a991cd8ca509 100644
> --- a/drivers/clk/sunxi/Makefile
> +++ b/drivers/clk/sunxi/Makefile
> @@ -10,6 +10,7 @@ obj-y += clk-a10-pll2.o
> obj-y += clk-a20-gmac.o
> obj-y += clk-mod0.o
> obj-y += clk-simple-gates.o
> +obj-y += clk-sun4i-display.o
> obj-y += clk-sun8i-mbus.o
> obj-y += clk-sun9i-core.o
> obj-y += clk-sun9i-mmc.o
> diff --git a/drivers/clk/sunxi/clk-sun4i-display.c b/drivers/clk/sunxi/clk-sun4i-display.c
> new file mode 100644
> index 000000000000..9dc6894f0934
> --- /dev/null
> +++ b/drivers/clk/sunxi/clk-sun4i-display.c
> @@ -0,0 +1,241 @@
> +/*
> + * Copyright 2015 Maxime Ripard
> + *
> + * Maxime Ripard <maxime.ripard@free-electrons.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/kernel.h>
> +#include <linux/of_address.h>
> +#include <linux/reset-controller.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +
> +struct sun4i_a10_display_clk_data {
> + bool has_div;
> + bool has_rst;
> + u8 parents;
> +
> + u8 offset_en;
> + u8 offset_div;
> + u8 offset_mux;
> + u8 offset_rst;
> +
> + u8 width_div;
> + u8 width_mux;
> +};
> +
> +struct reset_data {
> + void __iomem *reg;
> + spinlock_t *lock;
> + struct reset_controller_dev rcdev;
> + u8 offset;
> +};
> +
> +static DEFINE_SPINLOCK(sun4i_a10_display_lock);
> +
> +static inline struct reset_data *rcdev_to_reset_data(struct reset_controller_dev *rcdev)
> +{
> + return container_of(rcdev, struct reset_data, rcdev);
> +};
> +
> +static int sun4i_a10_display_assert(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct reset_data *data = rcdev_to_reset_data(rcdev);
> + unsigned long flags;
> + u32 reg;
> +
> + spin_lock_irqsave(data->lock, flags);
> +
> + reg = readl(data->reg);
> + writel(reg & ~BIT(data->offset), data->reg);
> +
> + spin_unlock_irqrestore(data->lock, flags);
> +
> + return 0;
> +}
> +
> +static int sun4i_a10_display_deassert(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct reset_data *data = rcdev_to_reset_data(rcdev);
> + unsigned long flags;
> + u32 reg;
> +
> + spin_lock_irqsave(data->lock, flags);
> +
> + reg = readl(data->reg);
> + writel(reg | BIT(data->offset), data->reg);
> +
> + spin_unlock_irqrestore(data->lock, flags);
> +
> + return 0;
> +}
> +
> +static int sun4i_a10_display_status(struct reset_controller_dev *rcdev,
> + unsigned long id)
> +{
> + struct reset_data *data = rcdev_to_reset_data(rcdev);
> +
> + return !(readl(data->reg) & BIT(data->offset));
> +}
> +
> +static const struct reset_control_ops sun4i_a10_display_reset_ops = {
> + .assert = sun4i_a10_display_assert,
> + .deassert = sun4i_a10_display_deassert,
> + .status = sun4i_a10_display_status,
> +};
> +
> +static int sun4i_a10_display_reset_xlate(struct reset_controller_dev *rcdev,
> + const struct of_phandle_args *spec)
> +{
> + /* We only have a single reset signal */
> + return 0;
> +}
> +
> +static void __init sun4i_a10_display_init(struct device_node *node,
> + struct sun4i_a10_display_clk_data *data)
> +{
> + const char *parents[data->parents];
> + const char *clk_name = node->name;
> + struct reset_data *reset_data;
> + struct clk_divider *div = NULL;
> + struct clk_gate *gate;
> + struct clk_mux *mux;
> + void __iomem *reg;
> + struct clk *clk;
> + int i;
> +
> + of_property_read_string(node, "clock-output-names", &clk_name);
> +
> + reg = of_io_request_and_map(node, 0, of_node_full_name(node));
> + if (IS_ERR(reg)) {
> + pr_err("%s: Could not map the clock registers\n", clk_name);
> + return;
> + }
> +
> + of_clk_parent_fill(node, parents, data->parents);

What if someone uses an incorrect DT that has less parents described?

> +
> + mux = kzalloc(sizeof(*mux), GFP_KERNEL);
> + if (!mux)
> + return;
> +
> + mux->reg = reg;
> + mux->shift = data->offset_mux;
> + mux->mask = (1 << data->width_mux) - 1;
> + mux->lock = &sun4i_a10_display_lock;
> +
> + gate = kzalloc(sizeof(*gate), GFP_KERNEL);
> + if (!gate)
> + goto free_mux;
> +
> + gate->reg = reg;
> + gate->bit_idx = data->offset_en;
> + gate->lock = &sun4i_a10_display_lock;
> +
> + if (data->has_div) {
> + div = kzalloc(sizeof(*div), GFP_KERNEL);
> + if (!div)
> + goto free_gate;
> +
> + div->reg = reg;
> + div->shift = data->offset_div;
> + div->width = data->width_div;
> + div->lock = &sun4i_a10_display_lock;
> + }
> +
> + clk = clk_register_composite(NULL, clk_name,
> + parents, data->parents,
> + &mux->hw, &clk_mux_ops,
> + data->has_div ? &div->hw : NULL,
> + data->has_div ? &clk_divider_ops : NULL,
> + &gate->hw, &clk_gate_ops,
> + 0);
> + if (IS_ERR(clk)) {
> + pr_err("%s: Couldn't register the clock\n", clk_name);
> + goto free_div;
> + }
> +
> + of_clk_add_provider(node, of_clk_src_simple_get, clk);

Check for errors?

> +
> + if (!data->has_rst)
> + return;
> +
> + reset_data = kzalloc(sizeof(*reset_data), GFP_KERNEL);
> + if (!reset_data)
> + goto free_clk;
> +
> + reset_data->reg = reg;
> + reset_data->offset = data->offset_rst;
> + reset_data->lock = &sun4i_a10_display_lock;
> + reset_data->rcdev.nr_resets = 1;
> + reset_data->rcdev.ops = &sun4i_a10_display_reset_ops;
> + reset_data->rcdev.of_node = node;
> + reset_data->rcdev.of_reset_n_cells = 0;
> + reset_data->rcdev.of_xlate = &sun4i_a10_display_reset_xlate;
> +
> + if (reset_controller_register(&reset_data->rcdev)) {
> + pr_err("%s: Couldn't register the reset controller\n",
> + clk_name);
> + goto free_reset;
> + }
> +
> + return;
> +
> +free_reset:
> + kfree(reset_data);
> +free_clk:
> + clk_unregister(clk);
> +free_div:
> + if (data->has_div)
> + kfree(div);
> +free_gate:
> + kfree(gate);
> +free_mux:
> + kfree(mux);

Cleanup after of_io_request_and_map()?

> +}
> +
> +static struct sun4i_a10_display_clk_data sun4i_a10_tcon_ch0_data = {
> + .has_rst = true,
> + .parents = 4,
> + .offset_en = 31,
> + .offset_rst = 29,

My datasheets (A10 v1.5, A20 v1.4), say bit 30 for LCD0 ch0 reset.

A13 and R8 manuals do not list this clock, but A10s does, which has
bit 30 for LCD reset and bit 29 for TV encoder reset.

I suggest changing has_rst to int, and for sun5i variant, have
has_rst = 2, reset_cells = 1, for 2 separate reset controls.
The tcon and tv encoder bits of the DTSI should be updated as
well.

I assume your tests work because U-boot already de-asserted the
resets (both if you're using composite output).

> + .offset_mux = 24,
> + .width_mux = 2,
> +};
> +
> +static void __init sun4i_a10_tcon_ch0_setup(struct device_node *node)
> +{
> + sun4i_a10_display_init(node, &sun4i_a10_tcon_ch0_data);
> +}
> +CLK_OF_DECLARE(sun4i_a10_tcon_ch0, "allwinner,sun4i-a10-tcon-ch0-clk",
> + sun4i_a10_tcon_ch0_setup);
> +
> +static struct sun4i_a10_display_clk_data sun4i_a10_display_data = {
> + .has_div = true,

Missing .has_rst = true.

> + .parents = 3,
> + .offset_en = 31,
> + .offset_rst = 30,
> + .offset_mux = 24,
> + .offset_div = 0,

This is already implied.

> + .width_mux = 2,
> + .width_div = 4,
> +};
> +
> +static void __init sun4i_a10_display_setup(struct device_node *node)
> +{
> + sun4i_a10_display_init(node, &sun4i_a10_display_data);
> +}
> +CLK_OF_DECLARE(sun4i_a10_display, "allwinner,sun4i-a10-display-clk",
> + sun4i_a10_display_setup);
> --
> 2.6.4

Thanks for working on this!

Regards
ChenYu