u-boot/drivers/clk/at91/clk-system.c

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/*
* Copyright (C) 2016 Atmel Corporation
* Wenyou.Yang <wenyou.yang@atmel.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <clk-uclass.h>
#include <dm.h>
#include <linux/io.h>
#include <mach/at91_pmc.h>
#include "pmc.h"
#define SYSTEM_MAX_ID 31
/**
* at91_system_clk_bind() - for the system clock driver
* Recursively bind its children as clk devices.
*
* @return: 0 on success, or negative error code on failure
*/
static int at91_system_clk_bind(struct udevice *dev)
{
return at91_clk_sub_device_bind(dev, "system-clk");
}
static const struct udevice_id at91_system_clk_match[] = {
{ .compatible = "atmel,at91rm9200-clk-system" },
{}
};
U_BOOT_DRIVER(at91_system_clk) = {
.name = "at91-system-clk",
.id = UCLASS_MISC,
.of_match = at91_system_clk_match,
.bind = at91_system_clk_bind,
};
/*----------------------------------------------------------*/
static inline int is_pck(int id)
{
return (id >= 8) && (id <= 15);
}
static int system_clk_enable(struct clk *clk)
{
struct pmc_platdata *plat = dev_get_platdata(clk->dev);
struct at91_pmc *pmc = plat->reg_base;
u32 mask;
if (clk->id > SYSTEM_MAX_ID)
return -EINVAL;
mask = BIT(clk->id);
writel(mask, &pmc->scer);
/**
* For the programmable clocks the Ready status in the PMC
* status register should be checked after enabling.
* For other clocks this is unnecessary.
*/
if (!is_pck(clk->id))
return 0;
while (!(readl(&pmc->sr) & mask))
;
return 0;
}
static struct clk_ops system_clk_ops = {
.of_xlate = at91_clk_of_xlate,
.enable = system_clk_enable,
};
U_BOOT_DRIVER(system_clk) = {
.name = "system-clk",
.id = UCLASS_CLK,
.probe = at91_clk_probe,
.platdata_auto_alloc_size = sizeof(struct pmc_platdata),
.ops = &system_clk_ops,
};