[PATCH 08/13] clk: add AD24xx clock driver

Alvin Šipraga
2024-05-17T13:14:40Z

From: Alvin Šipraga <alsi@bang-olufsen.dk>

Analog Devices Inc. AD24xx series A2B transceivers support muxing IO
pins to a CLKOUT function. The clock supports division of the internal
PLL of the transceiver.

Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
---
drivers/a2b/Kconfig | 1 +
drivers/clk/Kconfig | 7 +
drivers/clk/Makefile | 1 +
drivers/clk/clk-ad24xx.c | 341 +++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 350 insertions(+)

diff --git a/drivers/a2b/Kconfig b/drivers/a2b/Kconfig
index 6ba5dc11c51d..08acf5728023 100644
--- a/drivers/a2b/Kconfig
+++ b/drivers/a2b/Kconfig
@@ -35,6 +35,7 @@ config A2B_AD24XX_NODE
select REGMAP_A2B
imply GPIO_AD24XX
imply SND_SOC_AD24XX
+ imply COMMON_CLK_AD24XX
help
Say Y here to enable support for AD24xx A2B transceiver nodes. This
applies to both main nodes and subordinate nodes. Supported models
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 3e9099504fad..a3d54b077e68 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -257,6 +257,13 @@ config COMMON_CLK_LAN966X
LAN966X SoC. GCK generates and supplies clock to various peripherals
within the SoC.

+config COMMON_CLK_AD24XX
+ bool "Clock driver for Analog Devices Inc. AD24xx"
+ depends on A2B_AD24XX_NODE
+ help
+ This driver supports the clock output functionality of AD24xx series
+ A2B transceiver chips.
+
config COMMON_CLK_ASPEED
bool "Clock driver for Aspeed BMC SoCs"
depends on ARCH_ASPEED || COMPILE_TEST
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 4abe16c8ccdf..cf5c867bf71a 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_COMMON_CLK_FIXED_MMIO) += clk-fixed-mmio.o
obj-$(CONFIG_COMMON_CLK_FSL_FLEXSPI) += clk-fsl-flexspi.o
obj-$(CONFIG_COMMON_CLK_FSL_SAI) += clk-fsl-sai.o
obj-$(CONFIG_COMMON_CLK_GEMINI) += clk-gemini.o
+obj-$(CONFIG_COMMON_CLK_AD24XX) += clk-ad24xx.o
obj-$(CONFIG_COMMON_CLK_ASPEED) += clk-aspeed.o
obj-$(CONFIG_MACH_ASPEED_G6) += clk-ast2600.o
obj-$(CONFIG_ARCH_HIGHBANK) += clk-highbank.o
diff --git a/drivers/clk/clk-ad24xx.c b/drivers/clk/clk-ad24xx.c
new file mode 100644
index 000000000000..ed227c317faa
--- /dev/null
+++ b/drivers/clk/clk-ad24xx.c
@@ -0,0 +1,341 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AD24xx clock driver
+ *
+ * Copyright (c) 2023 Alvin Šipraga <alsi@bang-olufsen.dk>
+ */
+
+#include <linux/a2b/a2b.h>
+#include <linux/a2b/ad24xx.h>
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#define AD24XX_NUM_CLKS 2
+
+/* Define some safe macros to make the code more readable */
+#define A2B_CLKCFG(_idx) (!(_idx) ? A2B_CLK1CFG : A2B_CLK2CFG)
+
+#define A2B_CLKCFG_DIV_SHIFT A2B_CLK1CFG_CLK1DIV_SHIFT
+#define A2B_CLKCFG_PDIV_SHIFT A2B_CLK1CFG_CLK1PDIV_SHIFT
+
+#define A2B_CLKCFG_DIV_MASK A2B_CLK1CFG_CLK1DIV_MASK
+#define A2B_CLKCFG_PDIV_MASK A2B_CLK1CFG_CLK1PDIV_MASK
+#define A2B_CLKCFG_INV_MASK A2B_CLK1CFG_CLK1INV_MASK
+#define A2B_CLKCFG_EN_MASK A2B_CLK1CFG_CLK1EN_MASK
+
+static_assert(A2B_CLK1CFG_CLK1DIV_MASK == A2B_CLK2CFG_CLK2DIV_MASK);
+static_assert(A2B_CLK1CFG_CLK1PDIV_MASK == A2B_CLK2CFG_CLK2PDIV_MASK);
+static_assert(A2B_CLK1CFG_CLK1INV_MASK == A2B_CLK2CFG_CLK2INV_MASK);
+static_assert(A2B_CLK1CFG_CLK1EN_MASK == A2B_CLK2CFG_CLK2EN_MASK);
+
+struct ad24xx_clkout {
+ struct clk_hw hw;
+ unsigned int idx;
+ bool registered;
+};
+
+struct ad24xx_clk {
+ struct device *dev;
+ struct a2b_func *func;
+ struct a2b_node *node;
+ struct regmap *regmap;
+ struct clk_hw *pll_hw;
+ struct ad24xx_clkout clkouts[AD24XX_NUM_CLKS];
+};
+
+static struct ad24xx_clkout *to_ad24xx_clkout(struct clk_hw *hw)
+{
+ return container_of(hw, struct ad24xx_clkout, hw);
+}
+
+static struct ad24xx_clk *to_ad24xx_clk(struct ad24xx_clkout *clkout)
+{
+ return container_of(clkout, struct ad24xx_clk, clkouts[clkout->idx]);
+}
+
+/*
+ * A CLKOUT signal is derived from the PLL frequency (2048 * SFF), going through
+ * a pre-divide step and a divide step.
+ *
+ * The pre-divide is either 2 or 32. The divisor is between 1 and 16.
+ *
+ * The pre-divide register PDIV is 1 bit and selects between 2 (0) or 32 (1).
+ * The divide register DIV is 4 bit and the resultant divisor is 2 * (DIV + 1).
+ */
+
+#define VAL(_pdiv, _div) \
+ (((_pdiv) << A2B_CLKCFG_PDIV_SHIFT) | ((_div) << A2B_CLKCFG_DIV_SHIFT))
+#define DIV(_div) (2 * ((_div) + 1))
+
+/* In total there are 6 bits to the value, with the 4th bit going unused */
+#define AD24XX_CLK_DIV_WIDTH 6
+static const struct clk_div_table ad24xx_clk_div_table[] = {
+ { VAL(0, 0), 2 * DIV(0) }, { VAL(0, 1), 2 * DIV(1) },
+ { VAL(0, 2), 2 * DIV(2) }, { VAL(0, 3), 2 * DIV(3) },
+ { VAL(0, 4), 2 * DIV(4) }, { VAL(0, 5), 2 * DIV(5) },
+ { VAL(0, 6), 2 * DIV(6) }, { VAL(0, 7), 2 * DIV(7) },
+ { VAL(0, 8), 2 * DIV(8) }, { VAL(0, 9), 2 * DIV(9) },
+ { VAL(0, 10), 2 * DIV(10) }, { VAL(0, 11), 2 * DIV(11) },
+ { VAL(0, 12), 2 * DIV(12) }, { VAL(0, 13), 2 * DIV(13) },
+ { VAL(0, 14), 2 * DIV(14) }, { VAL(0, 15), 2 * DIV(15) },
+ { VAL(1, 0), 32 * DIV(0) }, { VAL(1, 1), 32 * DIV(1) },
+ { VAL(1, 2), 32 * DIV(2) }, { VAL(1, 3), 32 * DIV(3) },
+ { VAL(1, 4), 32 * DIV(4) }, { VAL(1, 5), 32 * DIV(5) },
+ { VAL(1, 6), 32 * DIV(6) }, { VAL(1, 7), 32 * DIV(7) },
+ { VAL(1, 8), 32 * DIV(8) }, { VAL(1, 9), 32 * DIV(9) },
+ { VAL(1, 10), 32 * DIV(10) }, { VAL(1, 11), 32 * DIV(11) },
+ { VAL(1, 12), 32 * DIV(12) }, { VAL(1, 13), 32 * DIV(13) },
+ { VAL(1, 14), 32 * DIV(14) }, { VAL(1, 15), 32 * DIV(15) },
+ { /* sentinel */ }
+};
+
+static int ad24xx_clk_prepare(struct clk_hw *hw)
+{
+ struct ad24xx_clkout *clkout = to_ad24xx_clkout(hw);
+ struct ad24xx_clk *adclk = to_ad24xx_clk(clkout);
+ unsigned int idx = clkout->idx;
+
+ return regmap_update_bits(adclk->regmap, A2B_CLKCFG(idx),
+ A2B_CLKCFG_EN_MASK,
+ FIELD_PREP(A2B_CLKCFG_EN_MASK, 1));
+}
+
+static void ad24xx_clk_unprepare(struct clk_hw *hw)
+{
+ struct ad24xx_clkout *clkout = to_ad24xx_clkout(hw);
+ struct ad24xx_clk *adclk = to_ad24xx_clk(clkout);
+ unsigned int idx = clkout->idx;
+
+ regmap_update_bits(adclk->regmap, A2B_CLKCFG(idx), A2B_CLKCFG_EN_MASK,
+ FIELD_PREP(A2B_CLKCFG_EN_MASK, 0));
+}
+
+static unsigned long ad24xx_clk_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct ad24xx_clkout *clkout = to_ad24xx_clkout(hw);
+ struct ad24xx_clk *adclk = to_ad24xx_clk(clkout);
+ unsigned int idx = clkout->idx;
+ unsigned int val;
+ int ret;
+
+ ret = regmap_read(adclk->regmap, A2B_CLKCFG(idx), &val);
+ if (ret)
+ return 0;
+
+ val &= A2B_CLKCFG_PDIV_MASK | A2B_CLKCFG_DIV_MASK;
+
+ return divider_recalc_rate(hw, parent_rate, val, ad24xx_clk_div_table,
+ 0, AD24XX_CLK_DIV_WIDTH);
+}
+
+static long ad24xx_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ return divider_round_rate(hw, rate, parent_rate, ad24xx_clk_div_table,
+ AD24XX_CLK_DIV_WIDTH, 0);
+}
+
+static int ad24xx_clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
+{
+ return divider_determine_rate(hw, req, ad24xx_clk_div_table,
+ AD24XX_CLK_DIV_WIDTH, 0);
+}
+
+static int ad24xx_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct ad24xx_clkout *clkout = to_ad24xx_clkout(hw);
+ struct ad24xx_clk *adclk = to_ad24xx_clk(clkout);
+ unsigned int idx = clkout->idx;
+ int val;
+
+ val = divider_get_val(rate, parent_rate, ad24xx_clk_div_table,
+ AD24XX_CLK_DIV_WIDTH, 0);
+ if (val < 0)
+ return val;
+
+ return regmap_update_bits(adclk->regmap, A2B_CLKCFG(idx),
+ A2B_CLKCFG_PDIV_MASK | A2B_CLKCFG_DIV_MASK,
+ val);
+}
+
+static int ad24xx_clk_get_phase(struct clk_hw *hw)
+{
+ struct ad24xx_clkout *clkout = to_ad24xx_clkout(hw);
+ struct ad24xx_clk *adclk = to_ad24xx_clk(clkout);
+ unsigned int idx = clkout->idx;
+ unsigned int val;
+ bool invert;
+ int ret;
+
+ ret = regmap_read(adclk->regmap, A2B_CLKCFG(idx), &val);
+ if (ret)
+ return ret;
+
+ invert = FIELD_GET(A2B_CLKCFG_INV_MASK, val);
+
+ return invert ? 180 : 0;
+}
+
+static int ad24xx_clk_set_phase(struct clk_hw *hw, int degrees)
+{
+ struct ad24xx_clkout *clkout = to_ad24xx_clkout(hw);
+ struct ad24xx_clk *adclk = to_ad24xx_clk(clkout);
+ unsigned int idx = clkout->idx;
+ bool invert = !!degrees;
+
+ if (degrees != 0 && degrees != 180)
+ return -EINVAL;
+
+ return regmap_update_bits(adclk->regmap, A2B_CLKCFG(idx),
+ A2B_CLKCFG_INV_MASK,
+ FIELD_PREP(A2B_CLKCFG_INV_MASK, invert));
+}
+
+static const struct clk_ops ad24xx_clk_ops = {
+ .prepare = ad24xx_clk_prepare,
+ .unprepare = ad24xx_clk_unprepare,
+ .recalc_rate = ad24xx_clk_recalc_rate,
+ .round_rate = ad24xx_clk_round_rate,
+ .determine_rate = ad24xx_clk_determine_rate,
+ .set_rate = ad24xx_clk_set_rate,
+ .get_phase = ad24xx_clk_get_phase,
+ .set_phase = ad24xx_clk_set_phase,
+};
+
+static const struct regmap_config ad24xx_clk_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .cache_type = REGCACHE_RBTREE,
+};
+
+static struct clk_hw *ad24xx_clk_of_get(struct of_phandle_args *clkspec, void *data)
+{
+ struct ad24xx_clk *adclk = data;
+ unsigned int idx = clkspec->args[0];
+
+ if (idx >= AD24XX_NUM_CLKS)
+ return ERR_PTR(-EINVAL);
+
+ if (!adclk->clkouts[idx].registered)
+ return ERR_PTR(-ENOENT);
+
+ return &adclk->clkouts[idx].hw;
+}
+
+static int ad24xx_clk_probe(struct device *dev)
+{
+ struct a2b_func *func = to_a2b_func(dev);
+ struct a2b_node *node = func->node;
+ struct device_node *np = dev->of_node;
+ char *pll_name;
+ const char *sync_clk_name;
+ struct ad24xx_clk *adclk;
+ int num_clks;
+ int ret;
+ int i;
+
+ /*
+ * Older series AD240x and AD241x chips have a single discrete
+ * A2B_CLKCFG register that behaves differently to the A2B_CLKnCFG
+ * registers of the later AD242x series. This driver only supports the
+ * latter right now.
+ */
+ if (!(node->chip_info->caps & A2B_CHIP_CAP_CLKOUT))
+ return -ENODEV;
+
+ adclk = devm_kzalloc(dev, sizeof(*adclk), GFP_KERNEL);
+ if (!adclk)
+ return -ENOMEM;
+
+ adclk->regmap =
+ devm_regmap_init_a2b_func(func, &ad24xx_clk_regmap_config);
+ if (IS_ERR(adclk->regmap))
+ return PTR_ERR(adclk->regmap);
+
+ adclk->dev = dev;
+ adclk->func = func;
+ adclk->node = node;
+ dev_set_drvdata(dev, adclk);
+
+ num_clks = of_property_count_strings(np, "clock-output-names");
+ if (num_clks < 0 || num_clks > AD24XX_NUM_CLKS)
+ return -EINVAL;
+
+ /*
+ * Register the PLL internally to use it as the parent of the CLKOUTs.
+ * The PLL runs at 2048 times the SYNC clock rate.
+ */
+ pll_name =
+ devm_kasprintf(dev, GFP_KERNEL, "%s_pll", dev_name(&node->dev));
+ if (!pll_name)
+ return -ENOMEM;
+ sync_clk_name = __clk_get_name(a2b_node_get_sync_clk(func->node));
+ adclk->pll_hw = devm_clk_hw_register_fixed_factor(
+ dev, pll_name, sync_clk_name, 0, 2048, 1);
+ if (IS_ERR(adclk->pll_hw))
+ return PTR_ERR(adclk->pll_hw);
+
+ for (i = 0; i < num_clks; i++) {
+ struct clk_init_data init = { };
+ const char *parent_names = clk_hw_get_name(adclk->pll_hw);
+ unsigned int idx = i;
+
+ /* Clock outputs can be skipped with the clock-indices property */
+ of_property_read_u32_index(np, "clock-indices", i, &idx);
+ if (idx > AD24XX_NUM_CLKS)
+ return -EINVAL;
+
+ ret = of_property_read_string_index(np, "clock-output-names", i,
+ &init.name);
+ if (ret)
+ return ret;
+
+ init.ops = &ad24xx_clk_ops;
+ init.parent_names = &parent_names;
+ init.num_parents = 1;
+
+ adclk->clkouts[idx].hw.init = &init;
+ adclk->clkouts[idx].idx = idx;
+ adclk->clkouts[idx].registered = true;
+
+ ret = devm_clk_hw_register(dev, &adclk->clkouts[idx].hw);
+ if (ret)
+ return ret;
+ }
+
+ ret = devm_of_clk_add_hw_provider(dev, ad24xx_clk_of_get, adclk);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static const struct of_device_id ad24xx_clk_of_match_table[] = {
+ { .compatible = "adi,ad2420-clk" },
+ { .compatible = "adi,ad2421-clk" },
+ { .compatible = "adi,ad2422-clk" },
+ { .compatible = "adi,ad2425-clk" },
+ { .compatible = "adi,ad2426-clk" },
+ { .compatible = "adi,ad2427-clk" },
+ { .compatible = "adi,ad2428-clk" },
+ { .compatible = "adi,ad2429-clk" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ad24xx_clk_of_match_table);
+
+static struct a2b_driver ad24xx_clk_driver = {
+ .driver = {
+ .name = "ad24xx-clk",
+ .of_match_table = ad24xx_clk_of_match_table,
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ },
+ .probe = ad24xx_clk_probe,
+};
+module_a2b_driver(ad24xx_clk_driver);
+
+MODULE_AUTHOR("Alvin Šipraga <alsi@bang-olufsen.dk>");
+MODULE_DESCRIPTION("AD24xx CLK driver");
+MODULE_LICENSE("GPL");

--
2.44.0