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// SPDX-License-Identifier: GPL-2.0
/*
* System Control and Power Interface (SCMI) Protocol based clock driver
*
* Copyright (C) 2018-2021 ARM Ltd.
*/
#include <common.h>
#include <linux/clk.h>
#include <driver.h>
#include <linux/err.h>
#include <of.h>
#include <linux/scmi_protocol.h>
#include <linux/overflow.h>
#include <linux/math64.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 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,
/*
* Unlike Linux, we can provide enable/disable callback as everything
* runs in atomic context.
*/
.enable = scmi_clk_enable,
.disable = scmi_clk_disable,
};
static int scmi_clk_ops_init(struct device_d *dev, struct scmi_clk *sclk)
{
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;
return clk_hw_register(dev, &sclk->hw);
}
static int scmi_clocks_probe(struct scmi_device *sdev)
{
int idx, count, err;
struct clk **clks;
struct clk_onecell_data *clk_data;
struct device_d *dev = &sdev->dev;
struct device_node *np = dev->device_node;
const struct scmi_handle *handle = sdev->handle;
struct scmi_protocol_handle *ph;
if (!handle)
return -ENODEV;
scmi_proto_clk_ops =
handle->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 = kzalloc(sizeof (*clk_data), GFP_KERNEL);
if (!clk_data)
return -ENOMEM;
clk_data->clk_num = count;
clks = clk_data->clks = calloc(clk_data->clk_num, sizeof(struct clk *));
for (idx = 0; idx < count; idx++) {
struct scmi_clk *sclk;
sclk = kzalloc(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);
continue;
}
sclk->id = idx;
sclk->ph = ph;
err = scmi_clk_ops_init(dev, sclk);
if (err) {
dev_err(dev, "failed to register clock %d\n", idx);
kfree(sclk);
clks[idx] = NULL;
} else {
dev_dbg(dev, "Registered clock:%s\n", sclk->info->name);
clks[idx] = &sclk->hw.clk;
}
}
return of_clk_add_provider(dev->device_node, of_clk_src_onecell_get, clk_data);
}
static const struct scmi_device_id scmi_id_table[] = {
{ SCMI_PROTOCOL_CLOCK, "clocks" },
{ },
};
static struct scmi_driver scmi_clocks_driver = {
.name = "scmi-clocks",
.probe = scmi_clocks_probe,
.id_table = scmi_id_table,
};
core_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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