u-boot/drivers/clk/microchip/mpfs_clk_msspll.c
Conor Dooley 32cfdd5163 clk: microchip: mpfs: fix reference clock handling
The original devicetrees for PolarFire SoC messed up & defined the
msspll's output as a fixed-frequency, 600 MHz clock & used that as the
input for the clock controller node. The msspll is not a fixed
frequency clock and later devicetrees handled this properly. Check the
devicetree & if it is one of the fixed ones, register the msspll.
Otherwise, skip registering it & pass the reference clock directly to
the cfg clock registration function so that existing devicetrees are
not broken by this change.

As the MSS PLL is not a "cfg" or a "periph" clock, add a new driver for
it, based on the one in Linux.

Fixes: 2f27c9219e ("clk: Add Microchip PolarFire SoC clock driver")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Padmarao Begari <padmarao.begari@microchip.com>
Tested-by: Padmarao Begari <padmarao.begari@microchip.com>
2022-11-15 15:37:17 +08:00

119 lines
3.2 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2022 Microchip Technology Inc.
*/
#include <common.h>
#include <clk.h>
#include <clk-uclass.h>
#include <asm/io.h>
#include <dm/device.h>
#include <dm/devres.h>
#include <dm/uclass.h>
#include <dt-bindings/clock/microchip-mpfs-clock.h>
#include <linux/err.h>
#include "mpfs_clk.h"
#define MPFS_MSSPLL_CLOCK "mpfs_msspll_clock"
/* address offset of control registers */
#define REG_MSSPLL_REF_CR 0x08u
#define REG_MSSPLL_POSTDIV_CR 0x10u
#define REG_MSSPLL_SSCG_2_CR 0x2Cu
#define MSSPLL_FBDIV_SHIFT 0x00u
#define MSSPLL_FBDIV_WIDTH 0x0Cu
#define MSSPLL_REFDIV_SHIFT 0x08u
#define MSSPLL_REFDIV_WIDTH 0x06u
#define MSSPLL_POSTDIV_SHIFT 0x08u
#define MSSPLL_POSTDIV_WIDTH 0x07u
#define MSSPLL_FIXED_DIV 4u
/**
* struct mpfs_msspll_hw_clock
* @id: index of the msspll clock
* @name: the msspll clocks name
* @reg_offset: offset to the core complex's output of the msspll
* @shift: shift to the divider bit field of a msspll clock output
* @width: width of the divider bit field of the msspll clock output
* @flags: common clock framework flags
* @prate: the reference clock rate
* @hw: clock instance
*/
struct mpfs_msspll_hw_clock {
void __iomem *base;
unsigned int id;
const char *name;
u32 reg_offset;
u32 shift;
u32 width;
u32 flags;
u32 prate;
struct clk hw;
};
#define to_mpfs_msspll_clk(_hw) container_of(_hw, struct mpfs_msspll_hw_clock, hw)
static unsigned long mpfs_clk_msspll_recalc_rate(struct clk *hw)
{
struct mpfs_msspll_hw_clock *msspll_hw = to_mpfs_msspll_clk(hw);
void __iomem *mult_addr = msspll_hw->base + msspll_hw->reg_offset;
void __iomem *ref_div_addr = msspll_hw->base + REG_MSSPLL_REF_CR;
void __iomem *postdiv_addr = msspll_hw->base + REG_MSSPLL_POSTDIV_CR;
u32 mult, ref_div, postdiv;
unsigned long temp;
mult = readl(mult_addr) >> MSSPLL_FBDIV_SHIFT;
mult &= clk_div_mask(MSSPLL_FBDIV_WIDTH);
ref_div = readl(ref_div_addr) >> MSSPLL_REFDIV_SHIFT;
ref_div &= clk_div_mask(MSSPLL_REFDIV_WIDTH);
postdiv = readl(postdiv_addr) >> MSSPLL_POSTDIV_SHIFT;
postdiv &= clk_div_mask(MSSPLL_POSTDIV_WIDTH);
temp = msspll_hw->prate / (ref_div * MSSPLL_FIXED_DIV * postdiv);
return temp * mult;
}
#define CLK_PLL(_id, _name, _shift, _width, _reg_offset, _flags) { \
.id = _id, \
.name = _name, \
.shift = _shift, \
.width = _width, \
.reg_offset = _reg_offset, \
.flags = _flags, \
}
static struct mpfs_msspll_hw_clock mpfs_msspll_clks[] = {
CLK_PLL(CLK_MSSPLL, "clk_msspll", MSSPLL_FBDIV_SHIFT,
MSSPLL_FBDIV_WIDTH, REG_MSSPLL_SSCG_2_CR, 0),
};
int mpfs_clk_register_msspll(void __iomem *base, struct clk *parent)
{
int id, ret;
const char *name;
struct clk *hw;
hw = &mpfs_msspll_clks[0].hw;
mpfs_msspll_clks[0].base = base;
mpfs_msspll_clks[0].prate = clk_get_rate(parent);
name = mpfs_msspll_clks[0].name;
ret = clk_register(hw, MPFS_MSSPLL_CLOCK, name, parent->dev->name);
if (ret)
ERR_PTR(ret);
id = mpfs_msspll_clks[0].id;
clk_dm(id, hw);
return 0;
}
const struct clk_ops mpfs_msspll_clk_ops = {
.get_rate = mpfs_clk_msspll_recalc_rate,
};
U_BOOT_DRIVER(mpfs_msspll_clock) = {
.name = MPFS_MSSPLL_CLOCK,
.id = UCLASS_CLK,
.ops = &mpfs_msspll_clk_ops,
};