u-boot/drivers/clk/clk_vexpress_osc.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2018 Arm Ltd
* Author: Liviu Dudau <liviu.dudau@foss.arm.com>
*
*/
#define DEBUG
#include <common.h>
#include <clk-uclass.h>
#include <dm.h>
#include <log.h>
#include <dm/device_compat.h>
#include <dm/lists.h>
#include <errno.h>
#include <misc.h>
#include <linux/bitops.h>
#define CLK_FUNCTION BIT(20)
struct vexpress_osc_clk_priv {
u8 osc;
ulong rate_min;
ulong rate_max;
};
static ulong vexpress_osc_clk_get_rate(struct clk *clk)
{
int err;
u32 data;
struct udevice *vexpress_cfg = dev_get_parent(clk->dev);
struct vexpress_osc_clk_priv *priv = dev_get_priv(clk->dev);
data = CLK_FUNCTION | priv->osc;
err = misc_read(vexpress_cfg, 0, &data, sizeof(data));
if (err < 0)
return err;
return data;
}
#ifndef CONFIG_SPL_BUILD
static ulong vexpress_osc_clk_set_rate(struct clk *clk, ulong rate)
{
int err;
u32 buffer[2];
struct udevice *vexpress_cfg = dev_get_parent(clk->dev);
struct vexpress_osc_clk_priv *priv = dev_get_priv(clk->dev);
if (rate < priv->rate_min || rate > priv->rate_max)
return -EINVAL;
/*
* we are sending the parent the info about the oscillator
* and the value we want to set
*/
buffer[0] = CLK_FUNCTION | priv->osc;
buffer[1] = rate;
err = misc_write(vexpress_cfg, 0, buffer, 2 * sizeof(u32));
if (err < 0)
return err;
return rate;
}
#endif
static struct clk_ops vexpress_osc_clk_ops = {
.get_rate = vexpress_osc_clk_get_rate,
#ifndef CONFIG_SPL_BUILD
.set_rate = vexpress_osc_clk_set_rate,
#endif
};
static int vexpress_osc_clk_probe(struct udevice *dev)
{
struct vexpress_osc_clk_priv *priv = dev_get_priv(dev);
u32 values[2];
int err;
err = dev_read_u32_array(dev, "freq-range", values, 2);
if (err)
return err;
priv->rate_min = values[0];
priv->rate_max = values[1];
err = dev_read_u32_array(dev, "arm,vexpress-sysreg,func", values, 2);
if (err)
return err;
if (values[0] != 1) {
dev_err(dev, "Invalid VExpress function for clock, must be '1'");
return -EINVAL;
}
priv->osc = values[1];
debug("clk \"%s%d\", min freq %luHz, max freq %luHz\n", dev->name,
priv->osc, priv->rate_min, priv->rate_max);
return 0;
}
static const struct udevice_id vexpress_osc_clk_ids[] = {
{ .compatible = "arm,vexpress-osc", },
{}
};
U_BOOT_DRIVER(vexpress_osc_clk) = {
.name = "vexpress_osc_clk",
.id = UCLASS_CLK,
.of_match = vexpress_osc_clk_ids,
.ops = &vexpress_osc_clk_ops,
.priv_auto = sizeof(struct vexpress_osc_clk_priv),
.probe = vexpress_osc_clk_probe,
};