Commit c29efc15 authored by Sean Anderson's avatar Sean Anderson Committed by Leo Yu-Chi Liang
Browse files

clk: k210: Remove bypass driver



This driver no longer serves a purpose now that we have moved away from
CCF. Drop it.
Signed-off-by: default avatarSean Anderson <seanga2@gmail.com>
Reviewed-by: default avatarLeo Yu-Chi Liang <ycliang@andestech.com>
parent df79e2b4
obj-y += bypass.o clk.o
obj-y += clk.o
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
*/
#define LOG_CATEGORY UCLASS_CLK
#include <common.h>
#include <clk.h>
#include <clk-uclass.h>
#include <dm.h>
#include <log.h>
#include <kendryte/bypass.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#define CLK_K210_BYPASS "k210_clk_bypass"
/*
* This is a small driver to do a software bypass of a clock if hardware bypass
* is not working. I have tried to write this in a generic fashion, so that it
* could be potentially broken out of the kendryte code at some future date.
*
* Say you have the following clock configuration
*
* +---+ +---+
* |osc| |pll|
* +---+ +---+
* ^
* /|
* / |
* / |
* / |
* / |
* +---+ +---+
* |clk| |clk|
* +---+ +---+
*
* But the pll does not have a bypass, so when you configure the pll, the
* configuration needs to change to look like
*
* +---+ +---+
* |osc| |pll|
* +---+ +---+
* ^
* |\
* | \
* | \
* | \
* | \
* +---+ +---+
* |clk| |clk|
* +---+ +---+
*
* To set this up, create a bypass clock with bypassee=pll and alt=osc. When
* creating the child clocks, set their parent to the bypass clock. After
* creating all the children, call k210_bypass_setchildren().
*/
static int k210_bypass_dobypass(struct k210_bypass *bypass)
{
int ret, i;
/*
* If we already have saved parents, then the children are already
* bypassed
*/
if (bypass->child_count && bypass->saved_parents[0])
return 0;
for (i = 0; i < bypass->child_count; i++) {
struct clk *child = bypass->children[i];
struct clk *parent = clk_get_parent(child);
if (IS_ERR(parent)) {
for (; i; i--)
bypass->saved_parents[i] = NULL;
return PTR_ERR(parent);
}
bypass->saved_parents[i] = parent;
}
for (i = 0; i < bypass->child_count; i++) {
struct clk *child = bypass->children[i];
ret = clk_set_parent(child, bypass->alt);
if (ret) {
for (; i; i--)
clk_set_parent(bypass->children[i],
bypass->saved_parents[i]);
for (i = 0; i < bypass->child_count; i++)
bypass->saved_parents[i] = NULL;
return ret;
}
}
return 0;
}
static int k210_bypass_unbypass(struct k210_bypass *bypass)
{
int err, ret, i;
if (!bypass->child_count && !bypass->saved_parents[0]) {
log_warning("Cannot unbypass children; dobypass not called first\n");
return 0;
}
ret = 0;
for (i = 0; i < bypass->child_count; i++) {
err = clk_set_parent(bypass->children[i],
bypass->saved_parents[i]);
if (err)
ret = err;
bypass->saved_parents[i] = NULL;
}
return ret;
}
static ulong k210_bypass_get_rate(struct clk *clk)
{
struct k210_bypass *bypass = to_k210_bypass(clk);
const struct clk_ops *ops = bypass->bypassee_ops;
if (ops->get_rate)
return ops->get_rate(bypass->bypassee);
else
return clk_get_parent_rate(bypass->bypassee);
}
static ulong k210_bypass_set_rate(struct clk *clk, unsigned long rate)
{
int ret;
struct k210_bypass *bypass = to_k210_bypass(clk);
const struct clk_ops *ops = bypass->bypassee_ops;
/* Don't bother bypassing if we aren't going to set the rate */
if (!ops->set_rate)
return k210_bypass_get_rate(clk);
ret = k210_bypass_dobypass(bypass);
if (ret)
return ret;
ret = ops->set_rate(bypass->bypassee, rate);
if (ret < 0)
return ret;
return k210_bypass_unbypass(bypass);
}
static int k210_bypass_set_parent(struct clk *clk, struct clk *parent)
{
struct k210_bypass *bypass = to_k210_bypass(clk);
const struct clk_ops *ops = bypass->bypassee_ops;
if (ops->set_parent)
return ops->set_parent(bypass->bypassee, parent);
else
return -EINVAL;
}
/*
* For these next two functions, do the bypassing even if there is no
* en-/-disable function, since the bypassing itself can be observed in between
* calls.
*/
static int k210_bypass_enable(struct clk *clk)
{
int ret;
struct k210_bypass *bypass = to_k210_bypass(clk);
const struct clk_ops *ops = bypass->bypassee_ops;
ret = k210_bypass_dobypass(bypass);
if (ret)
return ret;
if (ops->enable)
ret = ops->enable(bypass->bypassee);
else
ret = 0;
if (ret)
return ret;
return k210_bypass_unbypass(bypass);
}
static int k210_bypass_disable(struct clk *clk)
{
int ret;
struct k210_bypass *bypass = to_k210_bypass(clk);
const struct clk_ops *ops = bypass->bypassee_ops;
ret = k210_bypass_dobypass(bypass);
if (ret)
return ret;
if (ops->disable)
return ops->disable(bypass->bypassee);
else
return 0;
}
static const struct clk_ops k210_bypass_ops = {
.get_rate = k210_bypass_get_rate,
.set_rate = k210_bypass_set_rate,
.set_parent = k210_bypass_set_parent,
.enable = k210_bypass_enable,
.disable = k210_bypass_disable,
};
int k210_bypass_set_children(struct clk *clk, struct clk **children,
size_t child_count)
{
struct k210_bypass *bypass = to_k210_bypass(clk);
kfree(bypass->saved_parents);
if (child_count) {
bypass->saved_parents =
kcalloc(child_count, sizeof(struct clk *), GFP_KERNEL);
if (!bypass->saved_parents)
return -ENOMEM;
}
bypass->child_count = child_count;
bypass->children = children;
return 0;
}
struct clk *k210_register_bypass_struct(const char *name,
const char *parent_name,
struct k210_bypass *bypass)
{
int ret;
struct clk *clk;
clk = &bypass->clk;
ret = clk_register(clk, CLK_K210_BYPASS, name, parent_name);
if (ret)
return ERR_PTR(ret);
bypass->bypassee->dev = clk->dev;
return clk;
}
struct clk *k210_register_bypass(const char *name, const char *parent_name,
struct clk *bypassee,
const struct clk_ops *bypassee_ops,
struct clk *alt)
{
struct clk *clk;
struct k210_bypass *bypass;
bypass = kzalloc(sizeof(*bypass), GFP_KERNEL);
if (!bypass)
return ERR_PTR(-ENOMEM);
bypass->bypassee = bypassee;
bypass->bypassee_ops = bypassee_ops;
bypass->alt = alt;
clk = k210_register_bypass_struct(name, parent_name, bypass);
if (IS_ERR(clk))
kfree(bypass);
return clk;
}
U_BOOT_DRIVER(k210_bypass) = {
.name = CLK_K210_BYPASS,
.id = UCLASS_CLK,
.ops = &k210_bypass_ops,
};
/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
*/
#ifndef K210_BYPASS_H
#define K210_BYPASS_H
struct clk;
struct k210_bypass {
struct clk clk;
struct clk **children; /* Clocks to reparent */
struct clk **saved_parents; /* Parents saved over en-/dis-able */
struct clk *bypassee; /* Clock to bypass */
const struct clk_ops *bypassee_ops; /* Ops of the bypass clock */
struct clk *alt; /* Clock to set children to when bypassing */
size_t child_count;
};
#define to_k210_bypass(_clk) container_of(_clk, struct k210_bypass, clk)
int k210_bypass_set_children(struct clk *clk, struct clk **children,
size_t child_count);
struct clk *k210_register_bypass_struct(const char *name,
const char *parent_name,
struct k210_bypass *bypass);
struct clk *k210_register_bypass(const char *name, const char *parent_name,
struct clk *bypassee,
const struct clk_ops *bypassee_ops,
struct clk *alt);
#endif /* K210_BYPASS_H */
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