clk: Add GPIO-controlled clock gate driver

Add driver which implements GPIO-controlled clock. The GPIO is used
as a gate to enable/disable the clock. This matches linux clk-gpio.c
driver, however this does not implement the GPIO mux part, which in
U-Boot DM would be better fit in separate driver.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Sean Anderson <seanga2@gmail.com>

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 29859cdfa15839c20f752386939571cb05b134c4..bfd23a990469e8debe8e172c607fd05cbcdad300 100644 (file)
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -83,6 +83,19 @@ config CLK_COMPOSITE_CCF
          Enable this option if you want to (re-)use the Linux kernel's Common
          Clock Framework [CCF] composite code in U-Boot's clock driver.
 
+config CLK_GPIO
+       bool "GPIO-controlled clock gate driver"
+       depends on CLK
+       help
+         Enable this option to add GPIO-controlled clock gate driver.
+
+config SPL_CLK_GPIO
+       bool "GPIO-controlled clock gate driver in SPL"
+       depends on SPL_CLK
+       help
+         Enable this option to add GPIO-controlled clock gate driver
+         in U-Boot SPL.
+
 config CLK_BCM6345
        bool "Clock controller driver for BCM6345"
        depends on CLK && ARCH_BMIPS

diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index e22c8cf291f6a0c6c8e7c3c70695ad41da524341..26bf429acbc0738c483a9f2ea1d6a9ec8e95f9ca 100644 (file)
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_$(SPL_TPL_)CLK) += clk_fixed_factor.o
 obj-$(CONFIG_$(SPL_TPL_)CLK_CCF) += clk.o clk-divider.o clk-mux.o clk-gate.o
 obj-$(CONFIG_$(SPL_TPL_)CLK_CCF) += clk-fixed-factor.o
 obj-$(CONFIG_$(SPL_TPL_)CLK_COMPOSITE_CCF) += clk-composite.o
+obj-$(CONFIG_$(SPL_TPL_)CLK_GPIO) += clk-gpio.o
 
 obj-y += analogbits/
 obj-y += imx/

diff --git a/drivers/clk/clk-gpio.c b/drivers/clk/clk-gpio.c
new file mode 100644 (file)
index 0000000..26d795b
--- /dev/null
+++ b/drivers/clk/clk-gpio.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2023 Marek Vasut <marek.vasut+renesas@mailbox.org>
+ */
+
+#include <asm/gpio.h>
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm.h>
+
+struct clk_gpio_priv {
+       struct gpio_desc        enable;
+};
+
+static int clk_gpio_enable(struct clk *clk)
+{
+       struct clk_gpio_priv *priv = dev_get_priv(clk->dev);
+
+       dm_gpio_set_value(&priv->enable, 1);
+
+       return 0;
+}
+
+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);
+
+       return 0;
+}
+
+const struct clk_ops clk_gpio_ops = {
+       .enable         = clk_gpio_enable,
+       .disable        = clk_gpio_disable,
+};
+
+static int clk_gpio_probe(struct udevice *dev)
+{
+       struct clk_gpio_priv *priv = dev_get_priv(dev);
+
+       return gpio_request_by_name(dev, "enable-gpios", 0,
+                                   &priv->enable, GPIOD_IS_OUT);
+}
+
+/*
+ * When implementing clk-mux-clock, use gpio_request_list_by_name
+ * and implement get_rate/set_rate/set_parent ops. This should be
+ * in a separate driver and with separate Kconfig option to enable
+ * that driver, since unlike Linux implementation, the U-Boot DM
+ * integration would be orthogonal to this driver.
+ */
+static const struct udevice_id clk_gpio_match[] = {
+       { .compatible = "gpio-gate-clock" },
+       { /* sentinel */ }
+};
+
+U_BOOT_DRIVER(gpio_gate_clock) = {
+       .name           = "gpio_clock",
+       .id             = UCLASS_CLK,
+       .of_match       = clk_gpio_match,
+       .probe          = clk_gpio_probe,
+       .priv_auto      = sizeof(struct clk_gpio_priv),
+       .ops            = &clk_gpio_ops,
+       .flags          = DM_FLAG_PRE_RELOC,
+};