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- // SPDX-License-Identifier: GPL-2.0
- /*
- * System Control and Power Interface (SCMI) Protocol based clock driver
- *
- * Copyright (C) 2018-2022 ARM Ltd.
- */
- #include <linux/clk-provider.h>
- #include <linux/device.h>
- #include <linux/err.h>
- #include <linux/of.h>
- #include <linux/module.h>
- #include <linux/scmi_protocol.h>
- #include <asm/div64.h>
- static const struct scmi_clk_proto_ops *scmi_proto_clk_ops;
- struct scmi_clk {
- u32 id;
- struct clk_hw hw;
- const struct scmi_clock_info *info;
- const struct scmi_protocol_handle *ph;
- };
- #define to_scmi_clk(clk) container_of(clk, struct scmi_clk, hw)
- static unsigned long scmi_clk_recalc_rate(struct clk_hw *hw,
- unsigned long parent_rate)
- {
- int ret;
- u64 rate;
- struct scmi_clk *clk = to_scmi_clk(hw);
- ret = scmi_proto_clk_ops->rate_get(clk->ph, clk->id, &rate);
- if (ret)
- return 0;
- return rate;
- }
- static long scmi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
- unsigned long *parent_rate)
- {
- u64 fmin, fmax, ftmp;
- struct scmi_clk *clk = to_scmi_clk(hw);
- /*
- * We can't figure out what rate it will be, so just return the
- * rate back to the caller. scmi_clk_recalc_rate() will be called
- * after the rate is set and we'll know what rate the clock is
- * running at then.
- */
- if (clk->info->rate_discrete)
- return rate;
- fmin = clk->info->range.min_rate;
- fmax = clk->info->range.max_rate;
- if (rate <= fmin)
- return fmin;
- else if (rate >= fmax)
- return fmax;
- ftmp = rate - fmin;
- ftmp += clk->info->range.step_size - 1; /* to round up */
- do_div(ftmp, clk->info->range.step_size);
- return ftmp * clk->info->range.step_size + fmin;
- }
- static int scmi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
- unsigned long parent_rate)
- {
- struct scmi_clk *clk = to_scmi_clk(hw);
- return scmi_proto_clk_ops->rate_set(clk->ph, clk->id, rate);
- }
- static int scmi_clk_enable(struct clk_hw *hw)
- {
- struct scmi_clk *clk = to_scmi_clk(hw);
- return scmi_proto_clk_ops->enable(clk->ph, clk->id);
- }
- static void scmi_clk_disable(struct clk_hw *hw)
- {
- struct scmi_clk *clk = to_scmi_clk(hw);
- scmi_proto_clk_ops->disable(clk->ph, clk->id);
- }
- static int scmi_clk_atomic_enable(struct clk_hw *hw)
- {
- struct scmi_clk *clk = to_scmi_clk(hw);
- return scmi_proto_clk_ops->enable_atomic(clk->ph, clk->id);
- }
- static void scmi_clk_atomic_disable(struct clk_hw *hw)
- {
- struct scmi_clk *clk = to_scmi_clk(hw);
- scmi_proto_clk_ops->disable_atomic(clk->ph, clk->id);
- }
- /*
- * We can provide enable/disable atomic callbacks only if the underlying SCMI
- * transport for an SCMI instance is configured to handle SCMI commands in an
- * atomic manner.
- *
- * When no SCMI atomic transport support is available we instead provide only
- * the prepare/unprepare API, as allowed by the clock framework when atomic
- * calls are not available.
- *
- * Two distinct sets of clk_ops are provided since we could have multiple SCMI
- * instances with different underlying transport quality, so they cannot be
- * shared.
- */
- static const struct clk_ops scmi_clk_ops = {
- .recalc_rate = scmi_clk_recalc_rate,
- .round_rate = scmi_clk_round_rate,
- .set_rate = scmi_clk_set_rate,
- .prepare = scmi_clk_enable,
- .unprepare = scmi_clk_disable,
- };
- static const struct clk_ops scmi_atomic_clk_ops = {
- .recalc_rate = scmi_clk_recalc_rate,
- .round_rate = scmi_clk_round_rate,
- .set_rate = scmi_clk_set_rate,
- .enable = scmi_clk_atomic_enable,
- .disable = scmi_clk_atomic_disable,
- };
- static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk,
- const struct clk_ops *scmi_ops)
- {
- int ret;
- unsigned long min_rate, max_rate;
- struct clk_init_data init = {
- .flags = CLK_GET_RATE_NOCACHE,
- .num_parents = 0,
- .ops = scmi_ops,
- .name = sclk->info->name,
- };
- sclk->hw.init = &init;
- ret = devm_clk_hw_register(dev, &sclk->hw);
- if (ret)
- return ret;
- if (sclk->info->rate_discrete) {
- int num_rates = sclk->info->list.num_rates;
- if (num_rates <= 0)
- return -EINVAL;
- min_rate = sclk->info->list.rates[0];
- max_rate = sclk->info->list.rates[num_rates - 1];
- } else {
- min_rate = sclk->info->range.min_rate;
- max_rate = sclk->info->range.max_rate;
- }
- clk_hw_set_rate_range(&sclk->hw, min_rate, max_rate);
- return ret;
- }
- static int scmi_clocks_probe(struct scmi_device *sdev)
- {
- int idx, count, err;
- unsigned int atomic_threshold;
- bool is_atomic;
- struct clk_hw **hws;
- struct clk_hw_onecell_data *clk_data;
- struct device *dev = &sdev->dev;
- struct device_node *np = dev->of_node;
- const struct scmi_handle *handle = sdev->handle;
- struct scmi_protocol_handle *ph;
- if (!handle)
- return -ENODEV;
- scmi_proto_clk_ops =
- handle->devm_protocol_get(sdev, SCMI_PROTOCOL_CLOCK, &ph);
- if (IS_ERR(scmi_proto_clk_ops))
- return PTR_ERR(scmi_proto_clk_ops);
- count = scmi_proto_clk_ops->count_get(ph);
- if (count < 0) {
- dev_err(dev, "%pOFn: invalid clock output count\n", np);
- return -EINVAL;
- }
- clk_data = devm_kzalloc(dev, struct_size(clk_data, hws, count),
- GFP_KERNEL);
- if (!clk_data)
- return -ENOMEM;
- clk_data->num = count;
- hws = clk_data->hws;
- is_atomic = handle->is_transport_atomic(handle, &atomic_threshold);
- for (idx = 0; idx < count; idx++) {
- struct scmi_clk *sclk;
- const struct clk_ops *scmi_ops;
- sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL);
- if (!sclk)
- return -ENOMEM;
- sclk->info = scmi_proto_clk_ops->info_get(ph, idx);
- if (!sclk->info) {
- dev_dbg(dev, "invalid clock info for idx %d\n", idx);
- devm_kfree(dev, sclk);
- continue;
- }
- sclk->id = idx;
- sclk->ph = ph;
- /*
- * Note that when transport is atomic but SCMI protocol did not
- * specify (or support) an enable_latency associated with a
- * clock, we default to use atomic operations mode.
- */
- if (is_atomic &&
- sclk->info->enable_latency <= atomic_threshold)
- scmi_ops = &scmi_atomic_clk_ops;
- else
- scmi_ops = &scmi_clk_ops;
- err = scmi_clk_ops_init(dev, sclk, scmi_ops);
- if (err) {
- dev_err(dev, "failed to register clock %d\n", idx);
- devm_kfree(dev, sclk);
- hws[idx] = NULL;
- } else {
- dev_dbg(dev, "Registered clock:%s%s\n",
- sclk->info->name,
- scmi_ops == &scmi_atomic_clk_ops ?
- " (atomic ops)" : "");
- hws[idx] = &sclk->hw;
- }
- }
- return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
- clk_data);
- }
- static const struct scmi_device_id scmi_id_table[] = {
- { SCMI_PROTOCOL_CLOCK, "clocks" },
- { },
- };
- MODULE_DEVICE_TABLE(scmi, scmi_id_table);
- static struct scmi_driver scmi_clocks_driver = {
- .name = "scmi-clocks",
- .probe = scmi_clocks_probe,
- .id_table = scmi_id_table,
- };
- module_scmi_driver(scmi_clocks_driver);
- MODULE_AUTHOR("Sudeep Holla <[email protected]>");
- MODULE_DESCRIPTION("ARM SCMI clock driver");
- MODULE_LICENSE("GPL v2");
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