u-boot/drivers/clk/clk_fixed_factor.c
Anup Patel b630d57d0a clk: Add fixed-factor clock driver
This patch adds fixed-factor clock driver which derives clock
rate by dividing (div) and multiplying (mult) fixed factors
to a parent clock.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2019-02-27 09:12:33 +08:00

74 lines
1.6 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2019 Western Digital Corporation or its affiliates.
*
* Author: Anup Patel <anup.patel@wdc.com>
*/
#include <common.h>
#include <clk-uclass.h>
#include <div64.h>
#include <dm.h>
struct clk_fixed_factor {
struct clk parent;
unsigned int div;
unsigned int mult;
};
#define to_clk_fixed_factor(dev) \
((struct clk_fixed_factor *)dev_get_platdata(dev))
static ulong clk_fixed_factor_get_rate(struct clk *clk)
{
uint64_t rate;
struct clk_fixed_factor *ff = to_clk_fixed_factor(clk->dev);
if (clk->id != 0)
return -EINVAL;
rate = clk_get_rate(&ff->parent);
if (IS_ERR_VALUE(rate))
return rate;
do_div(rate, ff->div);
return rate * ff->mult;
}
const struct clk_ops clk_fixed_factor_ops = {
.get_rate = clk_fixed_factor_get_rate,
};
static int clk_fixed_factor_ofdata_to_platdata(struct udevice *dev)
{
#if !CONFIG_IS_ENABLED(OF_PLATDATA)
int err;
struct clk_fixed_factor *ff = to_clk_fixed_factor(dev);
err = clk_get_by_index(dev, 0, &ff->parent);
if (err)
return err;
ff->div = dev_read_u32_default(dev, "clock-div", 1);
ff->mult = dev_read_u32_default(dev, "clock-mult", 1);
#endif
return 0;
}
static const struct udevice_id clk_fixed_factor_match[] = {
{
.compatible = "fixed-factor-clock",
},
{ /* sentinel */ }
};
U_BOOT_DRIVER(clk_fixed_factor) = {
.name = "fixed_factor_clock",
.id = UCLASS_CLK,
.of_match = clk_fixed_factor_match,
.ofdata_to_platdata = clk_fixed_factor_ofdata_to_platdata,
.platdata_auto_alloc_size = sizeof(struct clk_fixed_factor),
.ops = &clk_fixed_factor_ops,
};