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https://github.com/brain-hackers/u-boot-brain
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![Simon Glass](/assets/img/avatar_default.png)
This header file should not be included in other header files. Remove it and use a forward declaration and un-inlining of dev_get_clk_ptr() instead. Fix up the kendryte header files to avoid build errors. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Sean Anderson <seanga2@gmail.com>
274 lines
6.0 KiB
C
274 lines
6.0 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
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*/
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#define LOG_CATEGORY UCLASS_CLK
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#include <common.h>
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#include <clk.h>
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#include <clk-uclass.h>
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#include <dm.h>
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#include <log.h>
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#include <kendryte/bypass.h>
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#include <linux/clk-provider.h>
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#include <linux/err.h>
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#define CLK_K210_BYPASS "k210_clk_bypass"
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/*
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* This is a small driver to do a software bypass of a clock if hardware bypass
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* is not working. I have tried to write this in a generic fashion, so that it
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* could be potentially broken out of the kendryte code at some future date.
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*
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* Say you have the following clock configuration
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*
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* +---+ +---+
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* |osc| |pll|
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* +---+ +---+
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* ^
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* /|
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* / |
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* / |
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* / |
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* / |
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* +---+ +---+
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* |clk| |clk|
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* +---+ +---+
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*
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* But the pll does not have a bypass, so when you configure the pll, the
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* configuration needs to change to look like
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*
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* +---+ +---+
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* |osc| |pll|
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* +---+ +---+
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* ^
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* |\
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* | \
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* | \
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* | \
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* | \
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* +---+ +---+
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* |clk| |clk|
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* +---+ +---+
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*
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* To set this up, create a bypass clock with bypassee=pll and alt=osc. When
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* creating the child clocks, set their parent to the bypass clock. After
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* creating all the children, call k210_bypass_setchildren().
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*/
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static int k210_bypass_dobypass(struct k210_bypass *bypass)
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{
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int ret, i;
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/*
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* If we already have saved parents, then the children are already
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* bypassed
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*/
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if (bypass->child_count && bypass->saved_parents[0])
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return 0;
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for (i = 0; i < bypass->child_count; i++) {
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struct clk *child = bypass->children[i];
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struct clk *parent = clk_get_parent(child);
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if (IS_ERR(parent)) {
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for (; i; i--)
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bypass->saved_parents[i] = NULL;
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return PTR_ERR(parent);
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}
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bypass->saved_parents[i] = parent;
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}
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for (i = 0; i < bypass->child_count; i++) {
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struct clk *child = bypass->children[i];
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ret = clk_set_parent(child, bypass->alt);
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if (ret) {
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for (; i; i--)
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clk_set_parent(bypass->children[i],
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bypass->saved_parents[i]);
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for (i = 0; i < bypass->child_count; i++)
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bypass->saved_parents[i] = NULL;
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return ret;
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}
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}
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return 0;
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}
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static int k210_bypass_unbypass(struct k210_bypass *bypass)
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{
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int err, ret, i;
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if (!bypass->child_count && !bypass->saved_parents[0]) {
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log_warning("Cannot unbypass children; dobypass not called first\n");
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return 0;
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}
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ret = 0;
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for (i = 0; i < bypass->child_count; i++) {
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err = clk_set_parent(bypass->children[i],
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bypass->saved_parents[i]);
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if (err)
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ret = err;
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bypass->saved_parents[i] = NULL;
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}
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return ret;
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}
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static ulong k210_bypass_get_rate(struct clk *clk)
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{
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struct k210_bypass *bypass = to_k210_bypass(clk);
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const struct clk_ops *ops = bypass->bypassee_ops;
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if (ops->get_rate)
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return ops->get_rate(bypass->bypassee);
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else
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return clk_get_parent_rate(bypass->bypassee);
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}
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static ulong k210_bypass_set_rate(struct clk *clk, unsigned long rate)
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{
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int ret;
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struct k210_bypass *bypass = to_k210_bypass(clk);
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const struct clk_ops *ops = bypass->bypassee_ops;
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/* Don't bother bypassing if we aren't going to set the rate */
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if (!ops->set_rate)
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return k210_bypass_get_rate(clk);
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ret = k210_bypass_dobypass(bypass);
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if (ret)
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return ret;
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ret = ops->set_rate(bypass->bypassee, rate);
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if (ret < 0)
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return ret;
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return k210_bypass_unbypass(bypass);
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}
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static int k210_bypass_set_parent(struct clk *clk, struct clk *parent)
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{
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struct k210_bypass *bypass = to_k210_bypass(clk);
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const struct clk_ops *ops = bypass->bypassee_ops;
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if (ops->set_parent)
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return ops->set_parent(bypass->bypassee, parent);
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else
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return -ENOTSUPP;
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}
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/*
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* For these next two functions, do the bypassing even if there is no
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* en-/-disable function, since the bypassing itself can be observed in between
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* calls.
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*/
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static int k210_bypass_enable(struct clk *clk)
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{
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int ret;
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struct k210_bypass *bypass = to_k210_bypass(clk);
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const struct clk_ops *ops = bypass->bypassee_ops;
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ret = k210_bypass_dobypass(bypass);
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if (ret)
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return ret;
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if (ops->enable)
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ret = ops->enable(bypass->bypassee);
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else
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ret = 0;
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if (ret)
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return ret;
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return k210_bypass_unbypass(bypass);
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}
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static int k210_bypass_disable(struct clk *clk)
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{
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int ret;
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struct k210_bypass *bypass = to_k210_bypass(clk);
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const struct clk_ops *ops = bypass->bypassee_ops;
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ret = k210_bypass_dobypass(bypass);
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if (ret)
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return ret;
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if (ops->disable)
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return ops->disable(bypass->bypassee);
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else
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return 0;
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}
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static const struct clk_ops k210_bypass_ops = {
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.get_rate = k210_bypass_get_rate,
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.set_rate = k210_bypass_set_rate,
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.set_parent = k210_bypass_set_parent,
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.enable = k210_bypass_enable,
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.disable = k210_bypass_disable,
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};
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int k210_bypass_set_children(struct clk *clk, struct clk **children,
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size_t child_count)
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{
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struct k210_bypass *bypass = to_k210_bypass(clk);
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kfree(bypass->saved_parents);
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if (child_count) {
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bypass->saved_parents =
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kcalloc(child_count, sizeof(struct clk *), GFP_KERNEL);
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if (!bypass->saved_parents)
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return -ENOMEM;
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}
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bypass->child_count = child_count;
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bypass->children = children;
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return 0;
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}
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struct clk *k210_register_bypass_struct(const char *name,
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const char *parent_name,
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struct k210_bypass *bypass)
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{
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int ret;
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struct clk *clk;
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clk = &bypass->clk;
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ret = clk_register(clk, CLK_K210_BYPASS, name, parent_name);
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if (ret)
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return ERR_PTR(ret);
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bypass->bypassee->dev = clk->dev;
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return clk;
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}
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struct clk *k210_register_bypass(const char *name, const char *parent_name,
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struct clk *bypassee,
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const struct clk_ops *bypassee_ops,
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struct clk *alt)
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{
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struct clk *clk;
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struct k210_bypass *bypass;
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bypass = kzalloc(sizeof(*bypass), GFP_KERNEL);
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if (!bypass)
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return ERR_PTR(-ENOMEM);
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bypass->bypassee = bypassee;
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bypass->bypassee_ops = bypassee_ops;
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bypass->alt = alt;
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clk = k210_register_bypass_struct(name, parent_name, bypass);
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if (IS_ERR(clk))
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kfree(bypass);
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return clk;
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}
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U_BOOT_DRIVER(k210_bypass) = {
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.name = CLK_K210_BYPASS,
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.id = UCLASS_CLK,
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.ops = &k210_bypass_ops,
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};
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