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The Meson8/Meson8b/Meson8m2 SoCs embed a DDR clock controller in the
MMCBUS registers. There is no public documentation, but the u-boot GPL
sources from the Amlogic BSP show that the DDR clock controller is
identical on all three SoCs:
#define CFG_DDR_CLK 792
#define CFG_PLL_M (((CFG_DDR_CLK/12)*12)/24)
#define CFG_PLL_N 1
#define CFG_PLL_OD 1
// from set_ddr_clock:
t_ddr_pll_cntl= (CFG_PLL_OD << 16)|(CFG_PLL_N<<9)|(CFG_PLL_M<<0)
writel(timing_reg->t_ddr_pll_cntl|(1<<29),AM_DDR_PLL_CNTL);
writel(readl(AM_DDR_PLL_CNTL) & (~(1<<29)),AM_DDR_PLL_CNTL);
// from hx_ddr_power_down_enter: shut down DDR PLL
writel(readl(AM_DDR_PLL_CNTL)|(1<<30),AM_DDR_PLL_CNTL);
do { ... } while((readl(AM_DDR_PLL_CNTL)&(1<<31))==0)
This translates to:
- AM_DDR_PLL_CNTL[29] is the reset bit
- AM_DDR_PLL_CNTL[30] is the enable bit
- AM_DDR_PLL_CNTL[31] is the lock bit
- AM_DDR_PLL_CNTL[8:0] is the m value (assuming the width is 9 bits
based on the start of the n value)
- AM_DDR_PLL_CNTL[13:9] is the n value (assuming the width is 5 bits
based on the start of the od)
- AM_DDR_PLL_CNTL[17:16] is the od (assuming the width is 2 bits based
on other PLLs on this SoC)
Add a driver for this PLL setup because it's used as one of the inputs
of the audio clocks. There may be more clocks inside that clock
controller - those can be added in subsequent patches.
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
150 lines
3.3 KiB
C
150 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Amlogic Meson8 DDR clock controller
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*
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* Copyright (C) 2019 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
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*/
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#include <dt-bindings/clock/meson8-ddr-clkc.h>
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#include <linux/clk-provider.h>
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#include <linux/platform_device.h>
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#include "clk-regmap.h"
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#include "clk-pll.h"
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#define AM_DDR_PLL_CNTL 0x00
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#define AM_DDR_PLL_CNTL1 0x04
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#define AM_DDR_PLL_CNTL2 0x08
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#define AM_DDR_PLL_CNTL3 0x0c
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#define AM_DDR_PLL_CNTL4 0x10
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#define AM_DDR_PLL_STS 0x14
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#define DDR_CLK_CNTL 0x18
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#define DDR_CLK_STS 0x1c
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static struct clk_regmap meson8_ddr_pll_dco = {
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.data = &(struct meson_clk_pll_data){
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.en = {
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.reg_off = AM_DDR_PLL_CNTL,
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.shift = 30,
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.width = 1,
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},
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.m = {
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.reg_off = AM_DDR_PLL_CNTL,
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.shift = 0,
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.width = 9,
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},
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.n = {
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.reg_off = AM_DDR_PLL_CNTL,
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.shift = 9,
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.width = 5,
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},
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.l = {
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.reg_off = AM_DDR_PLL_CNTL,
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.shift = 31,
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.width = 1,
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},
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.rst = {
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.reg_off = AM_DDR_PLL_CNTL,
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.shift = 29,
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.width = 1,
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},
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},
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.hw.init = &(struct clk_init_data){
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.name = "ddr_pll_dco",
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.ops = &meson_clk_pll_ro_ops,
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.parent_data = &(const struct clk_parent_data) {
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.fw_name = "xtal",
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},
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.num_parents = 1,
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},
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};
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static struct clk_regmap meson8_ddr_pll = {
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.data = &(struct clk_regmap_div_data){
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.offset = AM_DDR_PLL_CNTL,
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.shift = 16,
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.width = 2,
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.flags = CLK_DIVIDER_POWER_OF_TWO,
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},
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.hw.init = &(struct clk_init_data){
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.name = "ddr_pll",
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.ops = &clk_regmap_divider_ro_ops,
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.parent_hws = (const struct clk_hw *[]) {
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&meson8_ddr_pll_dco.hw
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},
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.num_parents = 1,
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},
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};
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static struct clk_hw_onecell_data meson8_ddr_clk_hw_onecell_data = {
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.hws = {
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[DDR_CLKID_DDR_PLL_DCO] = &meson8_ddr_pll_dco.hw,
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[DDR_CLKID_DDR_PLL] = &meson8_ddr_pll.hw,
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},
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.num = 2,
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};
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static struct clk_regmap *const meson8_ddr_clk_regmaps[] = {
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&meson8_ddr_pll_dco,
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&meson8_ddr_pll,
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};
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static const struct regmap_config meson8_ddr_clkc_regmap_config = {
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.reg_bits = 8,
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.val_bits = 32,
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.reg_stride = 4,
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.max_register = DDR_CLK_STS,
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};
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static int meson8_ddr_clkc_probe(struct platform_device *pdev)
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{
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struct regmap *regmap;
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void __iomem *base;
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struct clk_hw *hw;
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int ret, i;
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base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(base))
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return PTR_ERR(base);
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regmap = devm_regmap_init_mmio(&pdev->dev, base,
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&meson8_ddr_clkc_regmap_config);
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if (IS_ERR(regmap))
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return PTR_ERR(regmap);
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/* Populate regmap */
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for (i = 0; i < ARRAY_SIZE(meson8_ddr_clk_regmaps); i++)
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meson8_ddr_clk_regmaps[i]->map = regmap;
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/* Register all clks */
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for (i = 0; i < meson8_ddr_clk_hw_onecell_data.num; i++) {
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hw = meson8_ddr_clk_hw_onecell_data.hws[i];
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ret = devm_clk_hw_register(&pdev->dev, hw);
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if (ret) {
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dev_err(&pdev->dev, "Clock registration failed\n");
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return ret;
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}
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}
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return devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_onecell_get,
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&meson8_ddr_clk_hw_onecell_data);
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}
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static const struct of_device_id meson8_ddr_clkc_match_table[] = {
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{ .compatible = "amlogic,meson8-ddr-clkc" },
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{ .compatible = "amlogic,meson8b-ddr-clkc" },
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{ /* sentinel */ }
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};
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static struct platform_driver meson8_ddr_clkc_driver = {
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.probe = meson8_ddr_clkc_probe,
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.driver = {
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.name = "meson8-ddr-clkc",
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.of_match_table = meson8_ddr_clkc_match_table,
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},
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};
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builtin_platform_driver(meson8_ddr_clkc_driver);
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