generic: backport gated-fixed-clk

Backport gated-fixed-clk driver from Linux v6.13.

Signed-off-by: FUKAUMI Naoki <naoki@radxa.com>
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
This commit is contained in:
FUKAUMI Naoki 2025-08-25 15:31:50 +00:00
parent 2029a1123f
commit 722560eefd
3 changed files with 300 additions and 0 deletions

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@ -0,0 +1,27 @@
From 6cb137c7e99f8307f1f0fcccb1896f2d3b0651d3 Mon Sep 17 00:00:00 2001
From: Heiko Stuebner <heiko@sntech.de>
Date: Fri, 6 Sep 2024 10:25:08 +0200
Subject: clk: clk-gpio: update documentation for gpio-gate clock
The main documentation block seems to be from a time before the driver
handled sleeping and non-sleeping gpios and with that change it seems
updating the doc was overlooked. So do that now.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20240906082511.2963890-3-heiko@sntech.de
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
--- a/drivers/clk/clk-gpio.c
+++ b/drivers/clk/clk-gpio.c
@@ -22,8 +22,9 @@
* DOC: basic gpio gated clock which can be enabled and disabled
* with gpio output
* Traits of this clock:
- * prepare - clk_(un)prepare only ensures parent is (un)prepared
- * enable - clk_enable and clk_disable are functional & control gpio
+ * prepare - clk_(un)prepare are functional and control a gpio that can sleep
+ * enable - clk_enable and clk_disable are functional & control
+ * non-sleeping gpio
* rate - inherits rate from parent. No clk_set_rate support
* parent - fixed parent. No clk_set_parent support
*/

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From 36abe81d9c3fa200a57ef2363e93a2991e387e19 Mon Sep 17 00:00:00 2001
From: Heiko Stuebner <heiko@sntech.de>
Date: Fri, 6 Sep 2024 10:25:09 +0200
Subject: clk: clk-gpio: use dev_err_probe for gpio-get failure
This is a real driver and dev_err_probe will hide the distinction between
EPROBE_DEFER and other errors automatically, so there is no need to
open-code this.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20240906082511.2963890-4-heiko@sntech.de
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
--- a/drivers/clk/clk-gpio.c
+++ b/drivers/clk/clk-gpio.c
@@ -200,7 +200,6 @@ static int gpio_clk_driver_probe(struct
struct gpio_desc *gpiod;
struct clk_hw *hw;
bool is_mux;
- int ret;
is_mux = of_device_is_compatible(node, "gpio-mux-clock");
@@ -212,17 +211,9 @@ static int gpio_clk_driver_probe(struct
gpio_name = is_mux ? "select" : "enable";
gpiod = devm_gpiod_get(dev, gpio_name, GPIOD_OUT_LOW);
- if (IS_ERR(gpiod)) {
- ret = PTR_ERR(gpiod);
- if (ret == -EPROBE_DEFER)
- pr_debug("%pOFn: %s: GPIOs not yet available, retry later\n",
- node, __func__);
- else
- pr_err("%pOFn: %s: Can't get '%s' named GPIO property\n",
- node, __func__,
- gpio_name);
- return ret;
- }
+ if (IS_ERR(gpiod))
+ return dev_err_probe(dev, PTR_ERR(gpiod),
+ "Can't get '%s' named GPIO property\n", gpio_name);
if (is_mux)
hw = clk_hw_register_gpio_mux(dev, gpiod);

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@ -0,0 +1,229 @@
From 4940071d962827467f7297be3b874c96186ca0b7 Mon Sep 17 00:00:00 2001
From: Heiko Stuebner <heiko@sntech.de>
Date: Fri, 6 Sep 2024 10:25:10 +0200
Subject: clk: clk-gpio: add driver for gated-fixed-clocks
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 gated-fixed-clocks
that can show up in schematics looking like
----------------
Enable - | 100MHz,3.3V, | - VDD
| 3225 |
GND - | | - OUT
----------------
The new driver gets grouped together with the existing gpio-gate and
gpio-mux, as it for one re-uses a lot of the gpio-gate functions
and also in its core it's just another gpio-controlled clock, just
with a fixed rate and a regulator-supply added in.
The regulator-API provides function stubs for the !CONFIG_REGULATOR case,
so no special handling is necessary.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20240906082511.2963890-5-heiko@sntech.de
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
--- a/drivers/clk/clk-gpio.c
+++ b/drivers/clk/clk-gpio.c
@@ -17,6 +17,7 @@
#include <linux/device.h>
#include <linux/of.h>
#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
/**
* DOC: basic gpio gated clock which can be enabled and disabled
@@ -239,3 +240,187 @@ static struct platform_driver gpio_clk_d
},
};
builtin_platform_driver(gpio_clk_driver);
+
+/**
+ * DOC: gated fixed clock, controlled with a gpio output and a regulator
+ * Traits of this clock:
+ * prepare - clk_prepare and clk_unprepare are function & control regulator
+ * optionally a gpio that can sleep
+ * enable - clk_enable and clk_disable are functional & control gpio
+ * rate - rate is fixed and set on clock registration
+ * parent - fixed clock is a root clock and has no parent
+ */
+
+/**
+ * struct clk_gated_fixed - Gateable fixed rate clock
+ * @clk_gpio: instance of clk_gpio for gate-gpio
+ * @supply: supply regulator
+ * @rate: fixed rate
+ */
+struct clk_gated_fixed {
+ struct clk_gpio clk_gpio;
+ struct regulator *supply;
+ unsigned long rate;
+};
+
+#define to_clk_gated_fixed(_clk_gpio) container_of(_clk_gpio, struct clk_gated_fixed, clk_gpio)
+
+static unsigned long clk_gated_fixed_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ return to_clk_gated_fixed(to_clk_gpio(hw))->rate;
+}
+
+static int clk_gated_fixed_prepare(struct clk_hw *hw)
+{
+ struct clk_gated_fixed *clk = to_clk_gated_fixed(to_clk_gpio(hw));
+
+ if (!clk->supply)
+ return 0;
+
+ return regulator_enable(clk->supply);
+}
+
+static void clk_gated_fixed_unprepare(struct clk_hw *hw)
+{
+ struct clk_gated_fixed *clk = to_clk_gated_fixed(to_clk_gpio(hw));
+
+ if (!clk->supply)
+ return;
+
+ regulator_disable(clk->supply);
+}
+
+static int clk_gated_fixed_is_prepared(struct clk_hw *hw)
+{
+ struct clk_gated_fixed *clk = to_clk_gated_fixed(to_clk_gpio(hw));
+
+ if (!clk->supply)
+ return true;
+
+ return regulator_is_enabled(clk->supply);
+}
+
+/*
+ * Fixed gated clock with non-sleeping gpio.
+ *
+ * Prepare operation turns on the supply regulator
+ * and the enable operation switches the enable-gpio.
+ */
+static const struct clk_ops clk_gated_fixed_ops = {
+ .prepare = clk_gated_fixed_prepare,
+ .unprepare = clk_gated_fixed_unprepare,
+ .is_prepared = clk_gated_fixed_is_prepared,
+ .enable = clk_gpio_gate_enable,
+ .disable = clk_gpio_gate_disable,
+ .is_enabled = clk_gpio_gate_is_enabled,
+ .recalc_rate = clk_gated_fixed_recalc_rate,
+};
+
+static int clk_sleeping_gated_fixed_prepare(struct clk_hw *hw)
+{
+ int ret;
+
+ ret = clk_gated_fixed_prepare(hw);
+ if (ret)
+ return ret;
+
+ ret = clk_sleeping_gpio_gate_prepare(hw);
+ if (ret)
+ clk_gated_fixed_unprepare(hw);
+
+ return ret;
+}
+
+static void clk_sleeping_gated_fixed_unprepare(struct clk_hw *hw)
+{
+ clk_gated_fixed_unprepare(hw);
+ clk_sleeping_gpio_gate_unprepare(hw);
+}
+
+/*
+ * Fixed gated clock with non-sleeping gpio.
+ *
+ * Enabling the supply regulator and switching the enable-gpio happens
+ * both in the prepare step.
+ * is_prepared only needs to check the gpio state, as toggling the
+ * gpio is the last step when preparing.
+ */
+static const struct clk_ops clk_sleeping_gated_fixed_ops = {
+ .prepare = clk_sleeping_gated_fixed_prepare,
+ .unprepare = clk_sleeping_gated_fixed_unprepare,
+ .is_prepared = clk_sleeping_gpio_gate_is_prepared,
+ .recalc_rate = clk_gated_fixed_recalc_rate,
+};
+
+static int clk_gated_fixed_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct clk_gated_fixed *clk;
+ const struct clk_ops *ops;
+ const char *clk_name;
+ u32 rate;
+ int ret;
+
+ clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
+ if (!clk)
+ return -ENOMEM;
+
+ ret = device_property_read_u32(dev, "clock-frequency", &rate);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to get clock-frequency\n");
+ clk->rate = rate;
+
+ ret = device_property_read_string(dev, "clock-output-names", &clk_name);
+ if (ret)
+ clk_name = fwnode_get_name(dev->fwnode);
+
+ clk->supply = devm_regulator_get_optional(dev, "vdd");
+ if (IS_ERR(clk->supply)) {
+ if (PTR_ERR(clk->supply) != -ENODEV)
+ return dev_err_probe(dev, PTR_ERR(clk->supply),
+ "Failed to get regulator\n");
+ clk->supply = NULL;
+ }
+
+ clk->clk_gpio.gpiod = devm_gpiod_get_optional(dev, "enable",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(clk->clk_gpio.gpiod))
+ return dev_err_probe(dev, PTR_ERR(clk->clk_gpio.gpiod),
+ "Failed to get gpio\n");
+
+ if (gpiod_cansleep(clk->clk_gpio.gpiod))
+ ops = &clk_sleeping_gated_fixed_ops;
+ else
+ ops = &clk_gated_fixed_ops;
+
+ clk->clk_gpio.hw.init = CLK_HW_INIT_NO_PARENT(clk_name, ops, 0);
+
+ /* register the clock */
+ ret = devm_clk_hw_register(dev, &clk->clk_gpio.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,
+ &clk->clk_gpio.hw);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Failed to register clock provider\n");
+
+ return 0;
+}
+
+static const struct of_device_id gated_fixed_clk_match_table[] = {
+ { .compatible = "gated-fixed-clock" },
+ { /* sentinel */ }
+};
+
+static struct platform_driver gated_fixed_clk_driver = {
+ .probe = clk_gated_fixed_probe,
+ .driver = {
+ .name = "gated-fixed-clk",
+ .of_match_table = gated_fixed_clk_match_table,
+ },
+};
+builtin_platform_driver(gated_fixed_clk_driver);