[PATCH 2/6] clk: meson: add a driver for the Meson8/8b/8m2 DDR clock controller
From: Martin Blumenstingl
Date: Sat Sep 21 2019 - 11:18:55 EST
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@xxxxxxxxxxxxxx>
---
drivers/clk/meson/Makefile | 2 +-
drivers/clk/meson/meson8-ddr.c | 153 +++++++++++++++++++++++++++++++++
2 files changed, 154 insertions(+), 1 deletion(-)
create mode 100644 drivers/clk/meson/meson8-ddr.c
diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
index 3939f218587a..6eca2a406ee3 100644
--- a/drivers/clk/meson/Makefile
+++ b/drivers/clk/meson/Makefile
@@ -18,4 +18,4 @@ obj-$(CONFIG_COMMON_CLK_AXG) += axg.o axg-aoclk.o
obj-$(CONFIG_COMMON_CLK_AXG_AUDIO) += axg-audio.o
obj-$(CONFIG_COMMON_CLK_GXBB) += gxbb.o gxbb-aoclk.o
obj-$(CONFIG_COMMON_CLK_G12A) += g12a.o g12a-aoclk.o
-obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o
+obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o meson8-ddr.o
diff --git a/drivers/clk/meson/meson8-ddr.c b/drivers/clk/meson/meson8-ddr.c
new file mode 100644
index 000000000000..64ab4c27cce0
--- /dev/null
+++ b/drivers/clk/meson/meson8-ddr.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Amlogic Meson8 DDR clock controller
+ *
+ * Copyright (C) 2019 Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
+ */
+
+#include <dt-bindings/clock/meson8-ddr-clkc.h>
+
+#include <linux/platform_device.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+
+#include "clk-regmap.h"
+#include "clk-pll.h"
+
+#define AM_DDR_PLL_CNTL 0x00
+#define AM_DDR_PLL_CNTL1 0x04
+#define AM_DDR_PLL_CNTL2 0x08
+#define AM_DDR_PLL_CNTL3 0x0c
+#define AM_DDR_PLL_CNTL4 0x10
+#define AM_DDR_PLL_STS 0x14
+#define DDR_CLK_CNTL 0x18
+#define DDR_CLK_STS 0x1c
+
+static struct clk_regmap meson8_ddr_pll_dco = {
+ .data = &(struct meson_clk_pll_data){
+ .en = {
+ .reg_off = AM_DDR_PLL_CNTL,
+ .shift = 30,
+ .width = 1,
+ },
+ .m = {
+ .reg_off = AM_DDR_PLL_CNTL,
+ .shift = 0,
+ .width = 9,
+ },
+ .n = {
+ .reg_off = AM_DDR_PLL_CNTL,
+ .shift = 9,
+ .width = 5,
+ },
+ .l = {
+ .reg_off = AM_DDR_PLL_CNTL,
+ .shift = 31,
+ .width = 1,
+ },
+ .rst = {
+ .reg_off = AM_DDR_PLL_CNTL,
+ .shift = 29,
+ .width = 1,
+ },
+ },
+ .hw.init = &(struct clk_init_data){
+ .name = "ddr_pll_dco",
+ .ops = &meson_clk_pll_ro_ops,
+ .parent_data = &(const struct clk_parent_data) {
+ .fw_name = "xtal",
+ },
+ .num_parents = 1,
+ },
+};
+
+static struct clk_regmap meson8_ddr_pll = {
+ .data = &(struct clk_regmap_div_data){
+ .offset = AM_DDR_PLL_CNTL,
+ .shift = 16,
+ .width = 2,
+ .flags = CLK_DIVIDER_POWER_OF_TWO,
+ },
+ .hw.init = &(struct clk_init_data){
+ .name = "ddr_pll",
+ .ops = &clk_regmap_divider_ro_ops,
+ .parent_hws = (const struct clk_hw *[]) {
+ &meson8_ddr_pll_dco.hw
+ },
+ .num_parents = 1,
+ },
+};
+
+static struct clk_hw_onecell_data meson8_ddr_clk_hw_onecell_data = {
+ .hws = {
+ [DDR_CLKID_DDR_PLL_DCO] = &meson8_ddr_pll_dco.hw,
+ [DDR_CLKID_DDR_PLL] = &meson8_ddr_pll.hw,
+ },
+ .num = 2,
+};
+
+static struct clk_regmap *const meson8_ddr_clk_regmaps[] = {
+ &meson8_ddr_pll_dco,
+ &meson8_ddr_pll,
+};
+
+static const struct regmap_config meson8_ddr_clkc_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 32,
+ .reg_stride = 4,
+ .fast_io = true,
+};
+
+static int meson8_ddr_clkc_probe(struct platform_device *pdev)
+{
+ struct regmap *regmap;
+ struct resource *res;
+ void __iomem *base;
+ struct clk_hw *hw;
+ int ret, i;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ regmap = devm_regmap_init_mmio(&pdev->dev, base,
+ &meson8_ddr_clkc_regmap_config);
+ if (IS_ERR(regmap))
+ return PTR_ERR(regmap);
+
+ /* Populate regmap */
+ for (i = 0; i < ARRAY_SIZE(meson8_ddr_clk_regmaps); i++)
+ meson8_ddr_clk_regmaps[i]->map = regmap;
+
+ /* Register all clks */
+ for (i = 0; i < meson8_ddr_clk_hw_onecell_data.num; i++) {
+ hw = meson8_ddr_clk_hw_onecell_data.hws[i];
+
+ ret = devm_clk_hw_register(&pdev->dev, hw);
+ if (ret) {
+ dev_err(&pdev->dev, "Clock registration failed\n");
+ return ret;
+ }
+ }
+
+ return devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_onecell_get,
+ &meson8_ddr_clk_hw_onecell_data);
+}
+
+static const struct of_device_id meson8_ddr_clkc_match_table[] = {
+ { .compatible = "amlogic,meson8-ddr-clkc" },
+ { .compatible = "amlogic,meson8b-ddr-clkc" },
+ { /* sentinel */ },
+};
+
+static struct platform_driver meson8_ddr_clkc_driver = {
+ .probe = meson8_ddr_clkc_probe,
+ .driver = {
+ .name = "meson8-ddr-clkc",
+ .of_match_table = meson8_ddr_clkc_match_table,
+ },
+};
+
+builtin_platform_driver(meson8_ddr_clkc_driver);
--
2.23.0