| Message ID | 20240715110251.261844-3-heiko@sntech.de (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Binding and driver for voltage controlled oscillators | expand |
Quoting Heiko Stuebner (2024-07-15 04:02:50) > diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile > index 4abe16c8ccdfe..ca7b7b7ddfd8d 100644 > --- a/drivers/clk/Makefile > +++ b/drivers/clk/Makefile > @@ -79,6 +79,7 @@ obj-$(CONFIG_COMMON_CLK_SI521XX) += clk-si521xx.o > obj-$(CONFIG_COMMON_CLK_VC3) += clk-versaclock3.o > obj-$(CONFIG_COMMON_CLK_VC5) += clk-versaclock5.o > obj-$(CONFIG_COMMON_CLK_VC7) += clk-versaclock7.o > +obj-$(CONFIG_COMMON_CLK_VCO) += clk-vco.o Wrong section. It's basically a common clk type. > obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o > obj-$(CONFIG_COMMON_CLK_XGENE) += clk-xgene.o > > diff --git a/drivers/clk/clk-vco.c b/drivers/clk/clk-vco.c > new file mode 100644 > index 0000000000000..f7fe2bc627f36 > --- /dev/null > +++ b/drivers/clk/clk-vco.c > @@ -0,0 +1,133 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2024 Heiko Stuebner <heiko@sntech.de> > + * > + * Generic voltage controlled oscillator > + */ > + > +#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_vco { > + struct device *dev; > + struct clk_hw hw; > + u32 rate; > + struct regulator *supply; > + struct gpio_desc *enable_gpio; > +}; > + > +#define to_clk_vco(_hw) container_of(_hw, struct clk_vco, hw) > + > +static int clk_vco_prepare(struct clk_hw *hw) > +{ > + return regulator_enable(to_clk_vco(hw)->supply); > +} > + > +static void clk_vco_unprepare(struct clk_hw *hw) > +{ > + regulator_disable(to_clk_vco(hw)->supply); > +} > + > +static int clk_vco_enable(struct clk_hw *hw) > +{ > + gpiod_set_value(to_clk_vco(hw)->enable_gpio, 1); > + return 0; > +} > + > +static void clk_vco_disable(struct clk_hw *hw) > +{ > + gpiod_set_value(to_clk_vco(hw)->enable_gpio, 0); > +} It looks similar to clk-gpio.c code, but not as complete because it assumes gpios can't sleep. Please look into reusing that code somehow, possibly exporting 'clk_gpio_gate_ops' and struct clk_gpio for use in this new driver. It would be good to fold the sleepable gpio bit as well somehow, maybe with a new function to get a device's gpiod along with returning a const pointer to the clk_ops that can be copied and amended with the regulator part. > + > +static unsigned long clk_vco_recalc_rate(struct clk_hw *hw, > + unsigned long parent_rate) > +{ > + return to_clk_vco(hw)->rate; > +} > + > +const struct clk_ops clk_vco_ops = { > + .prepare = clk_vco_prepare, > + .unprepare = clk_vco_unprepare, > + .enable = clk_vco_enable, > + .disable = clk_vco_disable, > + .recalc_rate = clk_vco_recalc_rate, > +}; > + > +static int clk_vco_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct clk_vco *clkgen; > + const char *clk_name; > + int ret; > + > + clkgen = devm_kzalloc(dev, sizeof(*clkgen), GFP_KERNEL); > + if (!clkgen) > + return -ENOMEM; > + > + clkgen->dev = dev; Is this used outside of probe? Why stash it? > + > + if (device_property_read_u32(dev, "clock-frequency", &clkgen->rate)) > + return dev_err_probe(dev, -EIO, "failed to get clock-frequency"); > + > + 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 dev_err_probe(dev, ret, "failed to set gpio output"); Missing newline. > + > + clkgen->hw.init = CLK_HW_INIT_NO_PARENT(clk_name, &clk_vco_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"); > +
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index 3e9099504fad4..e93a380b6ee47 100644 --- a/drivers/clk/Kconfig +++ b/drivers/clk/Kconfig @@ -414,6 +414,16 @@ config COMMON_CLK_VC7 Renesas Versaclock7 is a family of configurable clock generator and jitter attenuator ICs with fractional and integer dividers. +config COMMON_CLK_VCO + tristate "Clock driver for voltage controlled oscillators" + depends on GPIOLIB && REGULATOR + help + This driver supports generic voltage controlled oscillators that + are not configurable but need supplies to be enabled to run. + Generally they need a supply voltage to be enabled and may also + require a separate enable pin, though in a lot of cases, vdd + and enable control might be tied to the same supply. + config COMMON_CLK_STM32F def_bool COMMON_CLK && (MACH_STM32F429 || MACH_STM32F469 || MACH_STM32F746) help diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 4abe16c8ccdfe..ca7b7b7ddfd8d 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -79,6 +79,7 @@ obj-$(CONFIG_COMMON_CLK_SI521XX) += clk-si521xx.o obj-$(CONFIG_COMMON_CLK_VC3) += clk-versaclock3.o obj-$(CONFIG_COMMON_CLK_VC5) += clk-versaclock5.o obj-$(CONFIG_COMMON_CLK_VC7) += clk-versaclock7.o +obj-$(CONFIG_COMMON_CLK_VCO) += clk-vco.o obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o obj-$(CONFIG_COMMON_CLK_XGENE) += clk-xgene.o diff --git a/drivers/clk/clk-vco.c b/drivers/clk/clk-vco.c new file mode 100644 index 0000000000000..f7fe2bc627f36 --- /dev/null +++ b/drivers/clk/clk-vco.c @@ -0,0 +1,133 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2024 Heiko Stuebner <heiko@sntech.de> + * + * Generic voltage controlled oscillator + */ + +#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_vco { + struct device *dev; + struct clk_hw hw; + u32 rate; + struct regulator *supply; + struct gpio_desc *enable_gpio; +}; + +#define to_clk_vco(_hw) container_of(_hw, struct clk_vco, hw) + +static int clk_vco_prepare(struct clk_hw *hw) +{ + return regulator_enable(to_clk_vco(hw)->supply); +} + +static void clk_vco_unprepare(struct clk_hw *hw) +{ + regulator_disable(to_clk_vco(hw)->supply); +} + +static int clk_vco_enable(struct clk_hw *hw) +{ + gpiod_set_value(to_clk_vco(hw)->enable_gpio, 1); + return 0; +} + +static void clk_vco_disable(struct clk_hw *hw) +{ + gpiod_set_value(to_clk_vco(hw)->enable_gpio, 0); +} + +static unsigned long clk_vco_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + return to_clk_vco(hw)->rate; +} + +const struct clk_ops clk_vco_ops = { + .prepare = clk_vco_prepare, + .unprepare = clk_vco_unprepare, + .enable = clk_vco_enable, + .disable = clk_vco_disable, + .recalc_rate = clk_vco_recalc_rate, +}; + +static int clk_vco_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct clk_vco *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 dev_err_probe(dev, -EIO, "failed to get clock-frequency"); + + 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 dev_err_probe(dev, ret, "failed to set gpio output"); + + clkgen->hw.init = CLK_HW_INIT_NO_PARENT(clk_name, &clk_vco_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_vco_ids[] = { + { .compatible = "voltage-oscillator" }, + { } +}; +MODULE_DEVICE_TABLE(of, clk_vco_ids); + +static struct platform_driver clk_vco_driver = { + .driver = { + .name = "clk_vco", + .of_match_table = clk_vco_ids, + }, + .probe = clk_vco_probe, +}; +module_platform_driver(clk_vco_driver); + +MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>"); +MODULE_DESCRIPTION("Voltage controlled oscillator driver"); +MODULE_LICENSE("GPL");
In contrast to fixed clocks that are described as ungateable, boards sometimes use additional oscillators 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 voltage controlled oscillators, that can show up in schematics looking like ---------------- Enable - | 100MHz,3.3V, | - VDD | 3225 | GND - | | - OUT ---------------- Signed-off-by: Heiko Stuebner <heiko@sntech.de> --- drivers/clk/Kconfig | 10 ++++ drivers/clk/Makefile | 1 + drivers/clk/clk-vco.c | 133 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 144 insertions(+) create mode 100644 drivers/clk/clk-vco.c