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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2017 BayLibre, SAS.
* Author: Neil Armstrong <narmstrong@baylibre.com>
*/
#include <linux/clk-provider.h>
#include <linux/bitfield.h>
#include <linux/regmap.h>
#include "gxbb-aoclk.h"
/*
* The AO Domain embeds a dual/divider to generate a more precise
* 32,768KHz clock for low-power suspend mode and CEC.
* ______ ______
* | | | |
* ______ | Div1 |-| Cnt1 | ______
* | | /|______| |______|\ | |
* Xtal-->| Gate |---| ______ ______ X-X--| Gate |-->
* |______| | \| | | |/ | |______|
* | | Div2 |-| Cnt2 | |
* | |______| |______| |
* |_______________________|
*
* The dividing can be switched to single or dual, with a counter
* for each divider to set when the switching is done.
* The entire dividing mechanism can be also bypassed.
*/
#define CLK_CNTL0_N1_MASK GENMASK(11, 0)
#define CLK_CNTL0_N2_MASK GENMASK(23, 12)
#define CLK_CNTL0_DUALDIV_EN BIT(28)
#define CLK_CNTL0_OUT_GATE_EN BIT(30)
#define CLK_CNTL0_IN_GATE_EN BIT(31)
#define CLK_CNTL1_M1_MASK GENMASK(11, 0)
#define CLK_CNTL1_M2_MASK GENMASK(23, 12)
#define CLK_CNTL1_BYPASS_EN BIT(24)
#define CLK_CNTL1_SELECT_OSC BIT(27)
#define PWR_CNTL_ALT_32K_SEL GENMASK(13, 10)
struct cec_32k_freq_table {
unsigned long parent_rate;
unsigned long target_rate;
bool dualdiv;
unsigned int n1;
unsigned int n2;
unsigned int m1;
unsigned int m2;
};
static const struct cec_32k_freq_table aoclk_cec_32k_table[] = {
[0] = {
.parent_rate = 24000000,
.target_rate = 32768,
.dualdiv = true,
.n1 = 733,
.n2 = 732,
.m1 = 8,
.m2 = 11,
},
};
/*
* If CLK_CNTL0_DUALDIV_EN == 0
* - will use N1 divider only
* If CLK_CNTL0_DUALDIV_EN == 1
* - hold M1 cycles of N1 divider then changes to N2
* - hold M2 cycles of N2 divider then changes to N1
* Then we can get more accurate division.
*/
static unsigned long aoclk_cec_32k_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct aoclk_cec_32k *cec_32k = to_aoclk_cec_32k(hw);
unsigned long n1;
u32 reg0, reg1;
regmap_read(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0, ®0);
regmap_read(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL1, ®1);
if (reg1 & CLK_CNTL1_BYPASS_EN)
return parent_rate;
if (reg0 & CLK_CNTL0_DUALDIV_EN) {
unsigned long n2, m1, m2, f1, f2, p1, p2;
n1 = FIELD_GET(CLK_CNTL0_N1_MASK, reg0) + 1;
n2 = FIELD_GET(CLK_CNTL0_N2_MASK, reg0) + 1;
m1 = FIELD_GET(CLK_CNTL1_M1_MASK, reg1) + 1;
m2 = FIELD_GET(CLK_CNTL1_M2_MASK, reg1) + 1;
f1 = DIV_ROUND_CLOSEST(parent_rate, n1);
f2 = DIV_ROUND_CLOSEST(parent_rate, n2);
p1 = DIV_ROUND_CLOSEST(100000000 * m1, f1 * (m1 + m2));
p2 = DIV_ROUND_CLOSEST(100000000 * m2, f2 * (m1 + m2));
return DIV_ROUND_UP(100000000, p1 + p2);
}
n1 = FIELD_GET(CLK_CNTL0_N1_MASK, reg0) + 1;
return DIV_ROUND_CLOSEST(parent_rate, n1);
}
static const struct cec_32k_freq_table *find_cec_32k_freq(unsigned long rate,
unsigned long prate)
{
int i;
for (i = 0 ; i < ARRAY_SIZE(aoclk_cec_32k_table) ; ++i)
if (aoclk_cec_32k_table[i].parent_rate == prate &&
aoclk_cec_32k_table[i].target_rate == rate)
return &aoclk_cec_32k_table[i];
return NULL;
}
static long aoclk_cec_32k_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
const struct cec_32k_freq_table *freq = find_cec_32k_freq(rate,
*prate);
/* If invalid return first one */
if (!freq)
return aoclk_cec_32k_table[0].target_rate;
return freq->target_rate;
}
/*
* From the Amlogic init procedure, the IN and OUT gates needs to be handled
* in the init procedure to avoid any glitches.
*/
static int aoclk_cec_32k_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
const struct cec_32k_freq_table *freq = find_cec_32k_freq(rate,
parent_rate);
struct aoclk_cec_32k *cec_32k = to_aoclk_cec_32k(hw);
u32 reg = 0;
if (!freq)
return -EINVAL;
/* Disable clock */
regmap_update_bits(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0,
CLK_CNTL0_IN_GATE_EN | CLK_CNTL0_OUT_GATE_EN, 0);
reg = FIELD_PREP(CLK_CNTL0_N1_MASK, freq->n1 - 1);
if (freq->dualdiv)
reg |= CLK_CNTL0_DUALDIV_EN |
FIELD_PREP(CLK_CNTL0_N2_MASK, freq->n2 - 1);
regmap_write(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0, reg);
reg = FIELD_PREP(CLK_CNTL1_M1_MASK, freq->m1 - 1);
if (freq->dualdiv)
reg |= FIELD_PREP(CLK_CNTL1_M2_MASK, freq->m2 - 1);
regmap_write(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL1, reg);
/* Enable clock */
regmap_update_bits(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0,
CLK_CNTL0_IN_GATE_EN, CLK_CNTL0_IN_GATE_EN);
udelay(200);
regmap_update_bits(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0,
CLK_CNTL0_OUT_GATE_EN, CLK_CNTL0_OUT_GATE_EN);
regmap_update_bits(cec_32k->regmap, AO_CRT_CLK_CNTL1,
CLK_CNTL1_SELECT_OSC, CLK_CNTL1_SELECT_OSC);
/* Select 32k from XTAL */
regmap_update_bits(cec_32k->regmap,
AO_RTI_PWR_CNTL_REG0,
PWR_CNTL_ALT_32K_SEL,
FIELD_PREP(PWR_CNTL_ALT_32K_SEL, 4));
return 0;
}
const struct clk_ops meson_aoclk_cec_32k_ops = {
.recalc_rate = aoclk_cec_32k_recalc_rate,
.round_rate = aoclk_cec_32k_round_rate,
.set_rate = aoclk_cec_32k_set_rate,
};
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