u-boot-brain/drivers/clk/ti/clk-am3-dpll.c
Dario Binacchi 756d64e43e clk: ti: am33xx: add DPLL clock drivers
The digital phase-locked loop (DPLL) provides all interface clocks and
functional clocks to the processor of the AM33xx device. The AM33xx
device integrates five different DPLLs:
 * Core DPLL
 * Per DPLL
 * LCD DPLL
 * DDR DPLL
 * MPU DPLL

The patch adds support for the compatible strings:
 * "ti,am3-dpll-core-clock"
 * "ti,am3-dpll-no-gate-clock"
 * "ti,am3-dpll-no-gate-j-type-clock"
 * "ti,am3-dpll-x2-clock"

The code is loosely based on the drivers/clk/ti/dpll.c drivers of the
Linux kernel version 5.9-rc7.
For DT binding details see:
- Documentation/devicetree/bindings/clock/ti/dpll.txt

Signed-off-by: Dario Binacchi <dariobin@libero.it>
2021-01-12 10:58:04 +05:30

269 lines
6.3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* TI DPLL clock support
*
* Copyright (C) 2020 Dario Binacchi <dariobin@libero.it>
*
* Loosely based on Linux kernel drivers/clk/ti/dpll.c
*/
#include <common.h>
#include <clk.h>
#include <clk-uclass.h>
#include <div64.h>
#include <dm.h>
#include <dm/device_compat.h>
#include <hang.h>
#include <asm/arch/clock.h>
#include <asm/arch/sys_proto.h>
#include <asm/io.h>
struct clk_ti_am3_dpll_drv_data {
ulong max_rate;
};
struct clk_ti_am3_dpll_priv {
fdt_addr_t clkmode_reg;
fdt_addr_t idlest_reg;
fdt_addr_t clksel_reg;
struct clk clk_bypass;
struct clk clk_ref;
u16 last_rounded_mult;
u8 last_rounded_div;
ulong max_rate;
};
static ulong clk_ti_am3_dpll_round_rate(struct clk *clk, ulong rate)
{
struct clk_ti_am3_dpll_priv *priv = dev_get_priv(clk->dev);
ulong ret, ref_rate, r;
int m, d, err_min, err;
int mult = INT_MAX, div = INT_MAX;
if (priv->max_rate && rate > priv->max_rate) {
dev_warn(clk->dev, "%ld is to high a rate, lowered to %ld\n",
rate, priv->max_rate);
rate = priv->max_rate;
}
ret = -EFAULT;
err = rate;
err_min = rate;
ref_rate = clk_get_rate(&priv->clk_ref);
for (d = 1; err_min && d <= 128; d++) {
for (m = 2; m <= 2047; m++) {
r = (ref_rate * m) / d;
err = abs(r - rate);
if (err < err_min) {
err_min = err;
ret = r;
mult = m;
div = d;
if (err == 0)
break;
} else if (r > rate) {
break;
}
}
}
priv->last_rounded_mult = mult;
priv->last_rounded_div = div;
dev_dbg(clk->dev, "rate=%ld, best_rate=%ld, mult=%d, div=%d\n", rate,
ret, mult, div);
return ret;
}
static ulong clk_ti_am3_dpll_set_rate(struct clk *clk, ulong rate)
{
struct clk_ti_am3_dpll_priv *priv = dev_get_priv(clk->dev);
u32 v;
ulong round_rate;
round_rate = clk_ti_am3_dpll_round_rate(clk, rate);
if (IS_ERR_VALUE(round_rate))
return round_rate;
v = readl(priv->clksel_reg);
/* enter bypass mode */
clrsetbits_le32(priv->clkmode_reg, CM_CLKMODE_DPLL_DPLL_EN_MASK,
DPLL_EN_MN_BYPASS << CM_CLKMODE_DPLL_EN_SHIFT);
/* wait for bypass mode */
if (!wait_on_value(ST_DPLL_CLK_MASK, 0,
(void *)priv->idlest_reg, LDELAY))
dev_err(clk->dev, "failed bypassing dpll\n");
/* set M & N */
v &= ~CM_CLKSEL_DPLL_M_MASK;
v |= (priv->last_rounded_mult << CM_CLKSEL_DPLL_M_SHIFT) &
CM_CLKSEL_DPLL_M_MASK;
v &= ~CM_CLKSEL_DPLL_N_MASK;
v |= ((priv->last_rounded_div - 1) << CM_CLKSEL_DPLL_N_SHIFT) &
CM_CLKSEL_DPLL_N_MASK;
writel(v, priv->clksel_reg);
/* lock dpll */
clrsetbits_le32(priv->clkmode_reg, CM_CLKMODE_DPLL_DPLL_EN_MASK,
DPLL_EN_LOCK << CM_CLKMODE_DPLL_EN_SHIFT);
/* wait till the dpll locks */
if (!wait_on_value(ST_DPLL_CLK_MASK, ST_DPLL_CLK_MASK,
(void *)priv->idlest_reg, LDELAY)) {
dev_err(clk->dev, "failed locking dpll\n");
hang();
}
return round_rate;
}
static ulong clk_ti_am3_dpll_get_rate(struct clk *clk)
{
struct clk_ti_am3_dpll_priv *priv = dev_get_priv(clk->dev);
u64 rate;
u32 m, n, v;
/* Return bypass rate if DPLL is bypassed */
v = readl(priv->clkmode_reg);
v &= CM_CLKMODE_DPLL_EN_MASK;
v >>= CM_CLKMODE_DPLL_EN_SHIFT;
switch (v) {
case DPLL_EN_MN_BYPASS:
case DPLL_EN_LOW_POWER_BYPASS:
case DPLL_EN_FAST_RELOCK_BYPASS:
rate = clk_get_rate(&priv->clk_bypass);
dev_dbg(clk->dev, "rate=%lld\n", rate);
return rate;
}
v = readl(priv->clksel_reg);
m = v & CM_CLKSEL_DPLL_M_MASK;
m >>= CM_CLKSEL_DPLL_M_SHIFT;
n = v & CM_CLKSEL_DPLL_N_MASK;
n >>= CM_CLKSEL_DPLL_N_SHIFT;
rate = clk_get_rate(&priv->clk_ref) * m;
do_div(rate, n + 1);
dev_dbg(clk->dev, "rate=%lld\n", rate);
return rate;
}
const struct clk_ops clk_ti_am3_dpll_ops = {
.round_rate = clk_ti_am3_dpll_round_rate,
.get_rate = clk_ti_am3_dpll_get_rate,
.set_rate = clk_ti_am3_dpll_set_rate,
};
static int clk_ti_am3_dpll_remove(struct udevice *dev)
{
struct clk_ti_am3_dpll_priv *priv = dev_get_priv(dev);
int err;
err = clk_release_all(&priv->clk_bypass, 1);
if (err) {
dev_err(dev, "failed to release bypass clock\n");
return err;
}
err = clk_release_all(&priv->clk_ref, 1);
if (err) {
dev_err(dev, "failed to release reference clock\n");
return err;
}
return 0;
}
static int clk_ti_am3_dpll_probe(struct udevice *dev)
{
struct clk_ti_am3_dpll_priv *priv = dev_get_priv(dev);
int err;
err = clk_get_by_index(dev, 0, &priv->clk_ref);
if (err) {
dev_err(dev, "failed to get reference clock\n");
return err;
}
err = clk_get_by_index(dev, 1, &priv->clk_bypass);
if (err) {
dev_err(dev, "failed to get bypass clock\n");
return err;
}
return 0;
}
static int clk_ti_am3_dpll_of_to_plat(struct udevice *dev)
{
struct clk_ti_am3_dpll_priv *priv = dev_get_priv(dev);
struct clk_ti_am3_dpll_drv_data *data =
(struct clk_ti_am3_dpll_drv_data *)dev_get_driver_data(dev);
priv->max_rate = data->max_rate;
priv->clkmode_reg = dev_read_addr_index(dev, 0);
if (priv->clkmode_reg == FDT_ADDR_T_NONE) {
dev_err(dev, "failed to get clkmode register\n");
return -EINVAL;
}
dev_dbg(dev, "clkmode_reg=0x%08lx\n", priv->clkmode_reg);
priv->idlest_reg = dev_read_addr_index(dev, 1);
if (priv->idlest_reg == FDT_ADDR_T_NONE) {
dev_err(dev, "failed to get idlest register\n");
return -EINVAL;
}
dev_dbg(dev, "idlest_reg=0x%08lx\n", priv->idlest_reg);
priv->clksel_reg = dev_read_addr_index(dev, 2);
if (priv->clksel_reg == FDT_ADDR_T_NONE) {
dev_err(dev, "failed to get clksel register\n");
return -EINVAL;
}
dev_dbg(dev, "clksel_reg=0x%08lx\n", priv->clksel_reg);
return 0;
}
static const struct clk_ti_am3_dpll_drv_data dpll_no_gate_data = {
.max_rate = 1000000000
};
static const struct clk_ti_am3_dpll_drv_data dpll_no_gate_j_type_data = {
.max_rate = 2000000000
};
static const struct clk_ti_am3_dpll_drv_data dpll_core_data = {
.max_rate = 1000000000
};
static const struct udevice_id clk_ti_am3_dpll_of_match[] = {
{.compatible = "ti,am3-dpll-core-clock",
.data = (ulong)&dpll_core_data},
{.compatible = "ti,am3-dpll-no-gate-clock",
.data = (ulong)&dpll_no_gate_data},
{.compatible = "ti,am3-dpll-no-gate-j-type-clock",
.data = (ulong)&dpll_no_gate_j_type_data},
{}
};
U_BOOT_DRIVER(clk_ti_am3_dpll) = {
.name = "ti_am3_dpll_clock",
.id = UCLASS_CLK,
.of_match = clk_ti_am3_dpll_of_match,
.ofdata_to_platdata = clk_ti_am3_dpll_of_to_plat,
.probe = clk_ti_am3_dpll_probe,
.remove = clk_ti_am3_dpll_remove,
.priv_auto = sizeof(struct clk_ti_am3_dpll_priv),
.ops = &clk_ti_am3_dpll_ops,
};