In contrast to fixed clocks that are described as ungateable, boards
sometimes use additional clock generators for things like PCIe reference
clocks, that need actual supplies to get enabled and enable-gpios to be
toggled for them to work.
This adds a driver for those generic unconfigurable clock generators.
Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx>
---
drivers/clk/Kconfig | 7 ++
drivers/clk/Makefile | 1 +
drivers/clk/clk-generator.c | 133 ++++++++++++++++++++++++++++++++++++
3 files changed, 141 insertions(+)
create mode 100644 drivers/clk/clk-generator.c
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 3e9099504fad4..76c53ddc472ce 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -247,6 +247,13 @@ config COMMON_CLK_GEMINI
This driver supports the SoC clocks on the Cortina Systems Gemini
platform, also known as SL3516 or CS3516.
+config COMMON_CLK_GENERATOR
+ tristate "Clock driver for generic clock generators"
+ depends on GPIOLIB && REGULATOR
+ help
+ This driver supports generic clock generators that are not
+ configurable but need supplies to be enabled to run.
+
config COMMON_CLK_LAN966X
tristate "Generic Clock Controller driver for LAN966X SoC"
depends on HAS_IOMEM
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 4abe16c8ccdfe..9cb0801155771 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_COMMON_CLK_FIXED_MMIO) += clk-fixed-mmio.o
obj-$(CONFIG_COMMON_CLK_FSL_FLEXSPI) += clk-fsl-flexspi.o
obj-$(CONFIG_COMMON_CLK_FSL_SAI) += clk-fsl-sai.o
obj-$(CONFIG_COMMON_CLK_GEMINI) += clk-gemini.o
+obj-$(CONFIG_COMMON_CLK_GENERATOR) += clk-generator.o
obj-$(CONFIG_COMMON_CLK_ASPEED) += clk-aspeed.o
obj-$(CONFIG_MACH_ASPEED_G6) += clk-ast2600.o
obj-$(CONFIG_ARCH_HIGHBANK) += clk-highbank.o
diff --git a/drivers/clk/clk-generator.c b/drivers/clk/clk-generator.c
new file mode 100644
index 0000000000000..99737bab1f5ad
--- /dev/null
+++ b/drivers/clk/clk-generator.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Heiko Stuebner <heiko@xxxxxxxxx>
+ *
+ * Generic unconfigurable clock generators
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+struct clk_generator {
+ struct device *dev;
+ struct clk_hw hw;
+ u32 rate;
+ struct regulator *supply;
+ struct gpio_desc *enable_gpio;
+};
+
+#define to_clk_generator(_hw) container_of(_hw, struct clk_generator, hw)
+
+static int clk_generator_prepare(struct clk_hw *hw)
+{
+ return regulator_enable(to_clk_generator(hw)->supply);
+}
+
+static void clk_generator_unprepare(struct clk_hw *hw)
+{
+ regulator_disable(to_clk_generator(hw)->supply);
+}
+
+static int clk_generator_enable(struct clk_hw *hw)
+{
+ gpiod_set_value(to_clk_generator(hw)->enable_gpio, 1);
+ return 0;
+}
+
+static void clk_generator_disable(struct clk_hw *hw)
+{
+ gpiod_set_value(to_clk_generator(hw)->enable_gpio, 0);
+}
+
+static unsigned long clk_generator_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ return to_clk_generator(hw)->rate;
+}
+
+const struct clk_ops clk_generator_ops = {
+ .prepare = clk_generator_prepare,
+ .unprepare = clk_generator_unprepare,
+ .enable = clk_generator_enable,
+ .disable = clk_generator_disable,
+ .recalc_rate = clk_generator_recalc_rate,
+};
+
+static int clk_generator_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct clk_generator *clkgen;
+ const char *clk_name;
+ int ret;
+
+ clkgen = devm_kzalloc(dev, sizeof(*clkgen), GFP_KERNEL);
+ if (!clkgen)
+ return -ENOMEM;
+
+ clkgen->dev = dev;
+
+ if (device_property_read_u32(dev, "clock-frequency", &clkgen->rate))
+ return -EIO;
+
+ ret = device_property_read_string(dev, "clock-output-names", &clk_name);
+ if (ret)
+ clk_name = fwnode_get_name(dev->fwnode);
+
+ clkgen->supply = devm_regulator_get_optional(dev, "vdd");
+ if (IS_ERR(clkgen->supply)) {
+ if (PTR_ERR(clkgen->supply) != -ENODEV)
+ return dev_err_probe(dev, PTR_ERR(clkgen->supply),
+ "failed to get regulator\n");
+ clkgen->supply = NULL;
+ }
+
+ clkgen->enable_gpio = devm_gpiod_get_optional(dev, "enable",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(clkgen->enable_gpio))
+ return dev_err_probe(dev, PTR_ERR(clkgen->enable_gpio),
+ "failed to get gpio\n");
+
+ ret = gpiod_direction_output(clkgen->enable_gpio, 0);
+ if (ret < 0)
+ return ret;
+
+ clkgen->hw.init = CLK_HW_INIT_NO_PARENT(clk_name, &clk_generator_ops, 0);
+
+ /* register the clock */
+ ret = devm_clk_hw_register(dev, &clkgen->hw);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "failed to register clock\n");
+
+ ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
+ &clkgen->hw);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "failed to register clock provider\n");
+
+ return 0;
+}
+
+static const struct of_device_id clk_generator_ids[] = {
+ { .compatible = "clock-generator" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, clk_generator_ids);
+
+static struct platform_driver clk_generator_driver = {
+ .driver = {
+ .name = "clk_generator",
+ .of_match_table = clk_generator_ids,
+ },
+ .probe = clk_generator_probe,
+};
+module_platform_driver(clk_generator_driver);
+
+MODULE_AUTHOR("Heiko Stuebner <heiko@xxxxxxxxx>");
+MODULE_DESCRIPTION("Clock-generator driver");
+MODULE_LICENSE("GPL");
--
2.39.2
