Hi Torsten,
On 5/28/2026 1:22 PM, Torsten Duwe wrote:
>
> Devicetree commit a198185b9b5 introduced a new type of clock,
> "gated-fixed-clock", for which Das U-Boot does not have
> a driver yet. The required code is similar to gpio-gate-clock,
> and can be added using little extra text space.
>
> Use this code e.g. to boot a Rock5 ITX from NVMe
>
> Signed-off-by: Torsten Duwe <[email protected]>
> ---
> Hi all,
>
> I have a Rock 5 ITX, too, and got struck by Heiko's change ;)
> Instead of Copy & Waste I merged the required changes into
> clk-gpio, which results in 121 extra code bytes and a driver
> which accepts a superset of both DT bindings.
>
> size clk-gated-fixed.o clk-gpio*.o
> text data bss dec hex filename
> 673 120 0 793 319 clk-gated-fixed.o
> 665 120 0 785 311 clk-gpio.o
> 544 120 0 664 298 clk-gpio-orig.o
>
> All I want to do here is present it as an alternative to Daniele's
> approach[1] and let the maintainers decide how to proceed. This is
> a "works for me" raw cut, feel free to review if we want to go this
> way.
>
> Torsten
>
> [1] https://lists.denx.de/pipermail/u-boot/2026-May/619110.html
> ---
> configs/rock-5-itx-rk3588_defconfig | 1 +
> drivers/clk/clk-gpio.c | 29 ++++++++++++++++++++++-------
> 2 files changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/configs/rock-5-itx-rk3588_defconfig
> b/configs/rock-5-itx-rk3588_defconfig
> index cb014de4188..adb20c2f3a0 100644
> --- a/configs/rock-5-itx-rk3588_defconfig
> +++ b/configs/rock-5-itx-rk3588_defconfig
> @@ -52,6 +52,7 @@ CONFIG_AHCI=y
> CONFIG_AHCI_PCI=y
> CONFIG_DWC_AHCI=y
> CONFIG_SPL_CLK=y
> +CONFIG_CLK_GPIO=y
> # CONFIG_USB_FUNCTION_FASTBOOT is not set
> CONFIG_ROCKCHIP_GPIO=y
> CONFIG_SYS_I2C_ROCKCHIP=y
> diff --git a/drivers/clk/clk-gpio.c b/drivers/clk/clk-gpio.c
> index 4ed14306575..b7abc891ed2 100644
> --- a/drivers/clk/clk-gpio.c
> +++ b/drivers/clk/clk-gpio.c
> @@ -6,6 +6,7 @@
> #include <clk.h>
> #include <clk-uclass.h>
> #include <dm.h>
> +#include <power/regulator.h>
> #include <linux/clk-provider.h>
>
> #include <asm/gpio.h>
> @@ -13,14 +14,18 @@
> struct clk_gpio_priv {
> struct gpio_desc enable; /* GPIO, controlling the gate */
> struct clk *clk; /* Gated clock */
> + struct udevice *vdd_supply;
> };
>
> static int clk_gpio_enable(struct clk *clk)
> {
> struct clk_gpio_priv *priv = dev_get_priv(clk->dev);
>
> - clk_enable(priv->clk);
> - dm_gpio_set_value(&priv->enable, 1);
> + if (priv->clk)
> + clk_enable(priv->clk);
> +
> + if (priv->enable.dev)
> + dm_gpio_set_value(&priv->enable, 1);
>
> return 0;
> }
> @@ -29,8 +34,11 @@ static int clk_gpio_disable(struct clk *clk)
> {
> struct clk_gpio_priv *priv = dev_get_priv(clk->dev);
>
> - dm_gpio_set_value(&priv->enable, 0);
> - clk_disable(priv->clk);
> + if (priv->enable.dev)
> + dm_gpio_set_value(&priv->enable, 0);
> +
> + if (priv->clk)
> + clk_disable(priv->clk);
>
> return 0;
> }
> @@ -39,7 +47,7 @@ static ulong clk_gpio_get_rate(struct clk *clk)
> {
> struct clk_gpio_priv *priv = dev_get_priv(clk->dev);
>
> - return clk_get_rate(priv->clk);
> + return (priv->clk) ? clk_get_rate(priv->clk) : -1;
> }
>
> const struct clk_ops clk_gpio_ops = {
> @@ -57,7 +65,7 @@ static int clk_gpio_probe(struct udevice *dev)
> if (IS_ERR(priv->clk)) {
> log_debug("%s: Could not get gated clock: %ld\n",
> __func__, PTR_ERR(priv->clk));
> - return PTR_ERR(priv->clk);
> + priv->clk = 0;
> }
>
> ret = gpio_request_by_name(dev, "enable-gpios", 0,
> @@ -65,9 +73,15 @@ static int clk_gpio_probe(struct udevice *dev)
> if (ret) {
> log_debug("%s: Could not decode enable-gpios (%d)\n",
> __func__, ret);
> - return ret;
> }
>
> + ret = device_get_supply_regulator(dev, "vdd-supply",
> + &priv->vdd_supply);
> + if (ret == 0)
> + ret = regulator_set_enable(priv->vdd_supply, true);
You should use regulator_set_enable_if_allowed() and also only enable
and disable the regulator in clk enable and disable ops to keep a
balanced enable ref-count of the regulator.
Regards,
Jonas
> +
> + log_debug("%s: %s regulator = %d\n", __func__, dev->name, ret);
> +
> return 0;
> }
>
> @@ -80,6 +94,7 @@ static int clk_gpio_probe(struct udevice *dev)
> */
> static const struct udevice_id clk_gpio_match[] = {
> { .compatible = "gpio-gate-clock" },
> + { .compatible = "gated-fixed-clock" },
> { /* sentinel */ }
> };
>
