[PATCHv2 3/3] clk: keystone: Add sci-clk driver support
Tero Kristo
t-kristo at ti.com
Thu Sep 1 05:40:35 PDT 2016
In K2G, the clock handling is done through firmware executing on a
separate core. Linux kernel needs to communicate to the firmware
through TI system control interface to access any power management
related resources, including clocks.
The keystone sci-clk driver does this, by communicating to the
firmware through the TI SCI driver. The driver adds support for
registering clocks through DT, and basic required clock operations
like prepare/get_rate, etc.
Signed-off-by: Tero Kristo <t-kristo at ti.com>
---
MAINTAINERS | 1 +
drivers/clk/Kconfig | 9 +
drivers/clk/keystone/Makefile | 1 +
drivers/clk/keystone/sci-clk.c | 537 +++++++++++++++++++++++++++++++++++++++++
4 files changed, 548 insertions(+)
create mode 100644 drivers/clk/keystone/sci-clk.c
diff --git a/MAINTAINERS b/MAINTAINERS
index bcb7b9e..2ed4d38 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11575,6 +11575,7 @@ F: drivers/firmware/ti_sci*
F: include/linux/soc/ti/ti_sci_protocol.h
F: Documentation/devicetree/bindings/clock/ti,sci-clk.txt
F: include/dt-bindings/clock/k2g.h
+F: drivers/clk/keystone/sci-clk.c
THANKO'S RAREMONO AM/FM/SW RADIO RECEIVER USB DRIVER
M: Hans Verkuil <hverkuil at xs4all.nl>
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index e2d9bd7..dbe792a7 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -179,6 +179,15 @@ config COMMON_CLK_NXP
---help---
Support for clock providers on NXP platforms.
+config TI_SCI_CLK
+ tristate "TI System Control Interface clock drivers"
+ depends on (TI_SCI_PROTOCOL && COMMON_CLK_KEYSTONE) || COMPILE_TEST
+ default TI_SCI_PROTOCOL
+ ---help---
+ This adds the clock driver support over TI System Control Interface.
+ If you wish to use clock resources from the PMMC firmware, say Y.
+ Otherwise, say N.
+
config COMMON_CLK_PALMAS
tristate "Clock driver for TI Palmas devices"
depends on MFD_PALMAS
diff --git a/drivers/clk/keystone/Makefile b/drivers/clk/keystone/Makefile
index 0477cf6..0e7993d 100644
--- a/drivers/clk/keystone/Makefile
+++ b/drivers/clk/keystone/Makefile
@@ -1 +1,2 @@
obj-y += pll.o gate.o
+obj-$(CONFIG_TI_SCI_CLK) += sci-clk.o
diff --git a/drivers/clk/keystone/sci-clk.c b/drivers/clk/keystone/sci-clk.c
new file mode 100644
index 0000000..852fc49
--- /dev/null
+++ b/drivers/clk/keystone/sci-clk.c
@@ -0,0 +1,537 @@
+/*
+ * SCI Clock driver for keystone based devices
+ *
+ * Copyright (C) 2015-2016 Texas Instruments Incorporated - http://www.ti.com/
+ * Tero Kristo <t-kristo at ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/soc/ti/ti_sci_protocol.h>
+
+#define SCI_CLK_SSC_ENABLE BIT(0)
+#define SCI_CLK_ALLOW_FREQ_CHANGE BIT(1)
+#define SCI_CLK_INPUT_TERMINATION BIT(2)
+
+/**
+ * struct sci_clk_provider - TI SCI clock provider representation
+ * @sci: Handle to the System Control Interface protocol handler
+ * @ops: Pointer to the SCI ops to be used by the clocks
+ * @dev: Device pointer for the clock provider
+ * @clocks: List of all registered clocks
+ * @lock: Mutex for locking access to the @clocks list
+ */
+struct sci_clk_provider {
+ const struct ti_sci_handle *sci;
+ const struct ti_sci_clk_ops *ops;
+ struct device *dev;
+ struct list_head clocks;
+ struct mutex lock; /* Protects access to the @clocks list */
+};
+
+/**
+ * struct sci_clk - TI SCI clock representation
+ * @hw: Hardware clock cookie for common clock framework
+ * @dev_id: Device index
+ * @clk_id: Clock index
+ * @node: Clocks list link
+ * @provider: Master clock provider
+ * @flags: Flags for the clock
+ */
+struct sci_clk {
+ struct clk_hw hw;
+ u16 dev_id;
+ u8 clk_id;
+ struct list_head node;
+ struct sci_clk_provider *provider;
+ u8 flags;
+};
+
+#define to_sci_clk(_hw) container_of(_hw, struct sci_clk, hw)
+
+/**
+ * sci_clk_prepare - Prepare (enable) a TI SCI clock
+ * @hw: clock to prepare
+ *
+ * Prepares a clock to be actively used. Returns the SCI protocol status.
+ */
+static int sci_clk_prepare(struct clk_hw *hw)
+{
+ struct sci_clk *clk = to_sci_clk(hw);
+ bool enable_ssc = clk->flags & SCI_CLK_SSC_ENABLE;
+ bool allow_freq_change = clk->flags & SCI_CLK_ALLOW_FREQ_CHANGE;
+ bool input_termination = clk->flags & SCI_CLK_INPUT_TERMINATION;
+
+ return clk->provider->ops->get_clock(clk->provider->sci, clk->dev_id,
+ clk->clk_id, enable_ssc,
+ allow_freq_change,
+ input_termination);
+}
+
+/**
+ * sci_clk_unprepare - Un-prepares (disables) a TI SCI clock
+ * @hw: clock to unprepare
+ *
+ * Un-prepares a clock from active state.
+ */
+static void sci_clk_unprepare(struct clk_hw *hw)
+{
+ struct sci_clk *clk = to_sci_clk(hw);
+ int ret;
+
+ ret = clk->provider->ops->put_clock(clk->provider->sci, clk->dev_id,
+ clk->clk_id);
+ if (ret)
+ dev_err(clk->provider->dev,
+ "unprepare failed for dev=%d, clk=%d, ret=%d\n",
+ clk->dev_id, clk->clk_id, ret);
+}
+
+/**
+ * sci_clk_is_prepared - Check if a TI SCI clock is prepared or not
+ * @hw: clock to check status for
+ *
+ * Checks if a clock is prepared (enabled) in hardware. Returns non-zero
+ * value if clock is enabled, zero otherwise.
+ */
+static int sci_clk_is_prepared(struct clk_hw *hw)
+{
+ struct sci_clk *clk = to_sci_clk(hw);
+ bool req_state, current_state;
+ int ret;
+
+ ret = clk->provider->ops->is_on(clk->provider->sci, clk->dev_id,
+ clk->clk_id, &req_state,
+ ¤t_state);
+ if (ret) {
+ dev_err(clk->provider->dev,
+ "is_prepared failed for dev=%d, clk=%d, ret=%d\n",
+ clk->dev_id, clk->clk_id, ret);
+ return 0;
+ }
+
+ return req_state;
+}
+
+/**
+ * sci_clk_recalc_rate - Get clock rate for a TI SCI clock
+ * @hw: clock to get rate for
+ * @parent_rate: parent rate provided by common clock framework, not used
+ *
+ * Gets the current clock rate of a TI SCI clock. Returns the current
+ * clock rate, or zero in failure.
+ */
+static unsigned long sci_clk_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct sci_clk *clk = to_sci_clk(hw);
+ u64 freq;
+ int ret;
+
+ ret = clk->provider->ops->get_freq(clk->provider->sci, clk->dev_id,
+ clk->clk_id, &freq);
+ if (ret) {
+ dev_err(clk->provider->dev,
+ "recalc-rate failed for dev=%d, clk=%d, ret=%d\n",
+ clk->dev_id, clk->clk_id, ret);
+ return 0;
+ }
+
+ return (u32)freq;
+}
+
+/**
+ * sci_clk_determine_rate - Determines a clock rate a clock can be set to
+ * @hw: clock to change rate for
+ * @req: requested rate configuration for the clock
+ *
+ * Determines a suitable clock rate and parent for a TI SCI clock.
+ * The parent handling is un-used, as generally the parent clock rates
+ * are not known by the kernel; instead these are internally handled
+ * by the firmware. Returns 0 on success, negative error value on failure.
+ */
+static int sci_clk_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ struct sci_clk *clk = to_sci_clk(hw);
+ int ret;
+ u64 new_rate;
+
+ ret = clk->provider->ops->get_best_match_freq(clk->provider->sci,
+ clk->dev_id,
+ clk->clk_id,
+ req->min_rate,
+ req->rate,
+ req->max_rate,
+ &new_rate);
+ if (ret) {
+ dev_err(clk->provider->dev,
+ "determine-rate failed for dev=%d, clk=%d, ret=%d\n",
+ clk->dev_id, clk->clk_id, ret);
+ return ret;
+ }
+
+ req->rate = new_rate;
+
+ return 0;
+}
+
+/**
+ * sci_clk_set_rate - Set rate for a TI SCI clock
+ * @hw: clock to change rate for
+ * @rate: target rate for the clock
+ * @parent_rate: rate of the clock parent, not used for TI SCI clocks
+ *
+ * Sets a clock frequency for a TI SCI clock. Returns the TI SCI
+ * protocol status.
+ */
+static int sci_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct sci_clk *clk = to_sci_clk(hw);
+
+ return clk->provider->ops->set_freq(clk->provider->sci, clk->dev_id,
+ clk->clk_id, rate, rate, rate);
+}
+
+/**
+ * sci_clk_get_parent - Get the current parent of a TI SCI clock
+ * @hw: clock to get parent for
+ *
+ * Returns the index of the currently selected parent for a TI SCI clock.
+ */
+static u8 sci_clk_get_parent(struct clk_hw *hw)
+{
+ struct sci_clk *clk = to_sci_clk(hw);
+ u8 parent_id;
+ int ret;
+
+ ret = clk->provider->ops->get_parent(clk->provider->sci, clk->dev_id,
+ clk->clk_id, &parent_id);
+ if (ret) {
+ dev_err(clk->provider->dev,
+ "get-parent failed for dev=%d, clk=%d, ret=%d\n",
+ clk->dev_id, clk->clk_id, ret);
+ return 0;
+ }
+
+ return parent_id - clk->clk_id - 1;
+}
+
+/**
+ * sci_clk_set_parent - Set the parent of a TI SCI clock
+ * @hw: clock to set parent for
+ * @index: new parent index for the clock
+ *
+ * Sets the parent of a TI SCI clock. Return TI SCI protocol status.
+ */
+static int sci_clk_set_parent(struct clk_hw *hw, u8 index)
+{
+ struct sci_clk *clk = to_sci_clk(hw);
+
+ return clk->provider->ops->set_parent(clk->provider->sci, clk->dev_id,
+ clk->clk_id,
+ index + 1 + clk->clk_id);
+}
+
+static const struct clk_ops sci_clk_ops = {
+ .prepare = sci_clk_prepare,
+ .unprepare = sci_clk_unprepare,
+ .is_prepared = sci_clk_is_prepared,
+ .recalc_rate = sci_clk_recalc_rate,
+ .determine_rate = sci_clk_determine_rate,
+ .set_rate = sci_clk_set_rate,
+ .get_parent = sci_clk_get_parent,
+ .set_parent = sci_clk_set_parent,
+};
+
+/**
+ * _sci_clk_get - Gets a handle for an SCI clock
+ * @provider: Handle to SCI clock provider
+ * @dev_id: device ID for the clock to register
+ * @clk_id: clock ID for the clock to register
+ * @parse_parents: indicator whether parents for this clock should be handled
+ *
+ * Gets a handle to an existing TI SCI hw clock, or builds a new clock
+ * entry and registers it with the common clock framework. Called from
+ * the common clock framework, when a corresponding of_clk_get call is
+ * executed, or recursively from itself when parsing parent clocks.
+ * Returns a pointer to the hw clock struct, or ERR_PTR value in failure.
+ */
+static struct clk_hw *_sci_clk_get(struct sci_clk_provider *provider,
+ u16 dev_id, u8 clk_id, bool parse_parents)
+{
+ struct clk_init_data init = { NULL };
+ struct sci_clk *sci_clk = NULL;
+ char *name = NULL;
+ char **parent_names = NULL;
+ int i;
+ int ret;
+
+ list_for_each_entry(sci_clk, &provider->clocks, node)
+ if (sci_clk->dev_id == dev_id && sci_clk->clk_id == clk_id)
+ return &sci_clk->hw;
+
+ sci_clk = devm_kzalloc(provider->dev, sizeof(*sci_clk), GFP_KERNEL);
+ if (!sci_clk) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ sci_clk->dev_id = dev_id;
+ sci_clk->clk_id = clk_id;
+ sci_clk->provider = provider;
+
+ if (parse_parents) {
+ ret = provider->ops->get_num_parents(provider->sci, dev_id,
+ clk_id,
+ &init.num_parents);
+ if (ret)
+ goto err;
+ }
+
+ name = kasprintf(GFP_KERNEL, "%s:%d:%d", dev_name(provider->dev),
+ sci_clk->dev_id, sci_clk->clk_id);
+
+ init.name = name;
+
+ if (init.num_parents < 2)
+ init.num_parents = 0;
+
+ if (init.num_parents) {
+ parent_names = devm_kcalloc(provider->dev, init.num_parents,
+ sizeof(char *), GFP_KERNEL);
+
+ if (!parent_names) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ for (i = 0; i < init.num_parents; i++) {
+ char *parent_name;
+
+ parent_name = devm_kzalloc(provider->dev, 20,
+ GFP_KERNEL);
+ if (!parent_name) {
+ ret = -ENOMEM;
+ goto err;
+ }
+ snprintf(parent_name, 20, "%s:%d:%d",
+ dev_name(provider->dev), sci_clk->dev_id,
+ sci_clk->clk_id + 1 + i);
+ parent_names[i] = parent_name;
+
+ _sci_clk_get(provider, dev_id, clk_id + 1 + i, false);
+ }
+ init.parent_names = (const char * const *)parent_names;
+ }
+
+ init.ops = &sci_clk_ops;
+ sci_clk->hw.init = &init;
+
+ ret = devm_clk_hw_register(provider->dev, &sci_clk->hw);
+ if (ret) {
+ dev_err(provider->dev, "failed clk register with %d\n", ret);
+ goto err;
+ } else {
+ list_add(&sci_clk->node, &provider->clocks);
+ }
+
+ kfree(name);
+
+ return &sci_clk->hw;
+
+err:
+ if (parent_names) {
+ for (i = 0; i < init.num_parents; i++)
+ devm_kfree(provider->dev, parent_names[i]);
+
+ devm_kfree(provider->dev, parent_names);
+ }
+
+ devm_kfree(provider->dev, sci_clk);
+
+ kfree(name);
+
+ return ERR_PTR(ret);
+}
+
+/**
+ * sci_clk_get - Xlate function for getting clock handles
+ * @clkspec: device tree clock specifier
+ * @data: pointer to the clock provider
+ *
+ * Xlate function for retrieving clock TI SCI hw clock handles based on
+ * device tree clock specifier. Called from the common clock framework,
+ * when a corresponding of_clk_get call is executed. Returns a pointer
+ * to the TI SCI hw clock struct, or ERR_PTR value in failure.
+ */
+static struct clk_hw *sci_clk_get(struct of_phandle_args *clkspec, void *data)
+{
+ struct sci_clk_provider *provider = data;
+ struct clk_hw *clk;
+ u16 dev_id;
+ u8 clk_id;
+
+ if (clkspec->args_count != 2)
+ return ERR_PTR(-EINVAL);
+
+ mutex_lock(&provider->lock);
+
+ dev_id = clkspec->args[0];
+ clk_id = clkspec->args[1];
+
+ clk = _sci_clk_get(provider, dev_id, clk_id, true);
+
+ mutex_unlock(&provider->lock);
+
+ return clk;
+}
+
+static const struct of_device_id ti_sci_clk_of_match[] = {
+ { .compatible = "ti,sci-clk" },
+ { /* Sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, ti_sci_clk_of_match);
+
+/**
+ * ti_sci_clk_parse_flags - Helper function to parse clock flag arrays
+ * @provider: clock provider handle
+ * @list_name: property name containing the clocks list
+ * @flag: flag to apply to the list of clocks
+ *
+ * Parses a DT list based on the provided data, and applies the flag value
+ * for each of the clocks identified by the list. Return 0 for success,
+ * negative error value for failure.
+ */
+static int ti_sci_clk_parse_flags(struct sci_clk_provider *provider,
+ const char *list_name, u8 flag)
+{
+ int num_clks;
+ int i;
+ struct device_node *np = provider->dev->of_node;
+ struct device *dev = provider->dev;
+
+ num_clks = of_count_phandle_with_args(np, list_name, "#clock-cells");
+
+ for (i = 0; i < num_clks; i++) {
+ struct of_phandle_args clkspec;
+ struct sci_clk *sci_clk;
+ struct clk_hw *clk;
+ int ret;
+
+ ret = of_parse_phandle_with_args(np, list_name, "#clock-cells",
+ i, &clkspec);
+ if (ret) {
+ dev_err(dev, "Failed to parse %s[%d] = %d\n", list_name,
+ i, ret);
+ return ret;
+ }
+ clk = sci_clk_get(&clkspec, provider);
+ if (IS_ERR(clk)) {
+ dev_err(dev, "clk_get failed for %s[%d] = %ld\n",
+ list_name, i, PTR_ERR(clk));
+ return PTR_ERR(clk);
+ }
+ sci_clk = to_sci_clk(clk);
+
+ sci_clk->flags |= flag;
+ }
+
+ return 0;
+}
+
+/**
+ * ti_sci_clk_probe - Probe function for the TI SCI clock driver
+ * @pdev: platform device pointer to be probed
+ *
+ * Probes the TI SCI clock device. Allocates a new clock provider
+ * and registers this to the common clock framework. Also applies
+ * any required flags to the identified clocks via clock lists
+ * supplied from DT. Returns 0 for success, negative error value
+ * for failure.
+ */
+static int ti_sci_clk_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct sci_clk_provider *provider;
+ const struct ti_sci_handle *handle;
+ int ret;
+
+ if (!np) {
+ dev_err(dev, "OF data missing\n");
+ return -EINVAL;
+ }
+
+ handle = devm_ti_sci_get_handle(dev);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+
+ provider = devm_kzalloc(dev, sizeof(*provider), GFP_KERNEL);
+ if (!provider)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&provider->clocks);
+ mutex_init(&provider->lock);
+
+ provider->sci = handle;
+ provider->ops = &handle->ops.clk_ops;
+ provider->dev = dev;
+
+ ret = of_clk_add_hw_provider(np, sci_clk_get, provider);
+ if (ret)
+ return ret;
+
+ ti_sci_clk_parse_flags(provider, "ti,ssc-clocks", SCI_CLK_SSC_ENABLE);
+ ti_sci_clk_parse_flags(provider, "ti,allow-freq-change-clocks",
+ SCI_CLK_ALLOW_FREQ_CHANGE);
+ ti_sci_clk_parse_flags(provider, "ti,input-term-clocks",
+ SCI_CLK_INPUT_TERMINATION);
+
+ return 0;
+}
+
+/**
+ * ti_sci_clk_remove - Remove TI SCI clock device
+ * @pdev: platform device pointer for the device to be removed
+ *
+ * Removes the TI SCI device. Unregisters the clock provider registered
+ * via common clock framework. Any memory allocated for the device will
+ * be free'd silently via the devm framework. Returns 0 always.
+ */
+static int ti_sci_clk_remove(struct platform_device *pdev)
+{
+ of_clk_del_provider(pdev->dev.of_node);
+
+ return 0;
+}
+
+static struct platform_driver ti_sci_clk_driver = {
+ .probe = ti_sci_clk_probe,
+ .remove = ti_sci_clk_remove,
+ .driver = {
+ .name = "ti-sci-clk",
+ .of_match_table = of_match_ptr(ti_sci_clk_of_match),
+ },
+};
+module_platform_driver(ti_sci_clk_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("TI System Control Interface(SCI) Clock driver");
+MODULE_AUTHOR("Tero Kristo");
+MODULE_ALIAS("platform:ti-sci-clk");
--
1.9.1
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