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// SPDX-License-Identifier: GPL-2.0
/*
* System Control and Power Interface (SCMI) Protocol based clock driver
*
* Copyright (C) 2018 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>
struct scmi_clk {
u32 id;
struct clk_hw hw;
const struct scmi_clock_info *info;
const struct scmi_handle *handle;
};
#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 = clk->handle->clk_ops->rate_get(clk->handle, 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)
{
int step;
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 */
step = do_div(ftmp, clk->info->range.step_size);
return step * 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 clk->handle->clk_ops->rate_set(clk->handle, clk->id, 0, rate);
}
static int scmi_clk_enable(struct clk_hw *hw)
{
struct scmi_clk *clk = to_scmi_clk(hw);
return clk->handle->clk_ops->enable(clk->handle, clk->id);
}
static void scmi_clk_disable(struct clk_hw *hw)
{
struct scmi_clk *clk = to_scmi_clk(hw);
clk->handle->clk_ops->disable(clk->handle, clk->id);
}
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,
/*
* We can't provide enable/disable callback as we can't perform the same
* in atomic context. Since the clock framework provides standard API
* clk_prepare_enable that helps cases using clk_enable in non-atomic
* context, it should be fine providing prepare/unprepare.
*/
.prepare = scmi_clk_enable,
.unprepare = scmi_clk_disable,
};
static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk)
{
int ret;
struct clk_init_data init = {
.flags = CLK_GET_RATE_NOCACHE,
.num_parents = 0,
.ops = &scmi_clk_ops,
.name = sclk->info->name,
};
sclk->hw.init = &init;
ret = devm_clk_hw_register(dev, &sclk->hw);
if (!ret)
clk_hw_set_rate_range(&sclk->hw, sclk->info->range.min_rate,
sclk->info->range.max_rate);
return ret;
}
static int scmi_clocks_probe(struct scmi_device *sdev)
{
int idx, count, err;
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;
if (!handle || !handle->clk_ops)
return -ENODEV;
count = handle->clk_ops->count_get(handle);
if (count < 0) {
dev_err(dev, "%s: invalid clock output count\n", np->name);
return -EINVAL;
}
clk_data = devm_kzalloc(dev, sizeof(*clk_data) +
sizeof(*clk_data->hws) * count, GFP_KERNEL);
if (!clk_data)
return -ENOMEM;
clk_data->num = count;
hws = clk_data->hws;
for (idx = 0; idx < count; idx++) {
struct scmi_clk *sclk;
sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL);
if (!sclk)
return -ENOMEM;
sclk->info = handle->clk_ops->info_get(handle, idx);
if (!sclk->info) {
dev_dbg(dev, "invalid clock info for idx %d\n", idx);
continue;
}
sclk->id = idx;
sclk->handle = handle;
err = scmi_clk_ops_init(dev, sclk);
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\n", sclk->info->name);
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 },
{ },
};
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 <sudeep.holla@arm.com>");
MODULE_DESCRIPTION("ARM SCMI clock driver");
MODULE_LICENSE("GPL v2");
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