[PATCH 2/2] clk: rs9: Add Renesas 9-series PCIe clock generator driver

Marek Vasut
2022-02-13T17:33:41Z

Add driver for Renesas 9-series PCIe clock generators. This driver
is designed to support 9FGV/9DBV/9DMV/9FGL/9DML/9QXL/9SQ series I2C
PCIe clock generators, currently the only tested and supported chip
is 9FGV0241.

The driver is capable of configuring per-chip spread spectrum mode
and output amplitude, as well as per-output slew rate.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: devicetree@vger.kernel.org
To: linux-clk@vger.kernel.org
---
drivers/clk/Kconfig | 9 +
drivers/clk/Makefile | 1 +
drivers/clk/clk-renesas-pcie.c | 336 +++++++++++++++++++++++++++++++++
3 files changed, 346 insertions(+)
create mode 100644 drivers/clk/clk-renesas-pcie.c

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 3cdf33470a750..05fc6fb2fddd5 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -340,6 +340,15 @@ config COMMON_CLK_OXNAS
help
Support for the OXNAS SoC Family clocks.

+config COMMON_CLK_RS9_PCIE
+ tristate "Clock driver for Renesas 9-series PCIe clock generators"
+ depends on I2C
+ depends on OF
+ select REGMAP_I2C
+ help
+ This driver supports the Renesas 9-series PCIe clock generator
+ models 9FGV/9DBV/9DMV/9FGL/9DML/9QXL/9SQ.
+
config COMMON_CLK_VC5
tristate "Clock driver for IDT VersaClock 5,6 devices"
depends on I2C
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 6a98291350b64..3ec27842ec779 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_COMMON_CLK_STM32MP157) += clk-stm32mp1.o
obj-$(CONFIG_COMMON_CLK_TPS68470) += clk-tps68470.o
obj-$(CONFIG_CLK_TWL6040) += clk-twl6040.o
obj-$(CONFIG_ARCH_VT8500) += clk-vt8500.o
+obj-$(CONFIG_COMMON_CLK_RS9_PCIE) += clk-renesas-pcie.o
obj-$(CONFIG_COMMON_CLK_VC5) += clk-versaclock5.o
obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o
obj-$(CONFIG_COMMON_CLK_XGENE) += clk-xgene.o
diff --git a/drivers/clk/clk-renesas-pcie.c b/drivers/clk/clk-renesas-pcie.c
new file mode 100644
index 0000000000000..0ad132cbe41b8
--- /dev/null
+++ b/drivers/clk/clk-renesas-pcie.c
@@ -0,0 +1,336 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Renesas 9-series PCIe clock generator driver
+ *
+ * The following series can be supported:
+ * - 9FGV/9DBV/9DMV/9FGL/9DML/9QXL/9SQ
+ * Currently supported:
+ * - 9FGV0241
+ *
+ * Copyright (C) 2022 Marek Vasut <marex@denx.de>
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/rational.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define RS9_REG_OE 0x0
+#define RS9_REG_OE_DIF_OE(n) BIT((n) + 1)
+#define RS9_REG_SS 0x1
+#define RS9_REG_SS_AMP_0V6 0x0
+#define RS9_REG_SS_AMP_0V7 0x1
+#define RS9_REG_SS_AMP_0V8 0x2
+#define RS9_REG_SS_AMP_0V9 0x3
+#define RS9_REG_SS_AMP_MASK 0x3
+#define RS9_REG_SS_SSC_100 0
+#define RS9_REG_SS_SSC_M025 (1 << 3)
+#define RS9_REG_SS_SSC_M050 (3 << 3)
+#define RS9_REG_SS_SSC_MASK (3 << 3)
+#define RS9_REG_SS_SSC_LOCK BIT(5)
+#define RS9_REG_SR 0x2
+#define RS9_REG_SR_2V0_DIF(n) 0
+#define RS9_REG_SR_3V0_DIF(n) BIT((n) + 1)
+#define RS9_REG_SR_DIF_MASK(n) BIT((n) + 1)
+#define RS9_REG_REF 0x3
+#define RS9_REG_REF_OE BIT(4)
+#define RS9_REG_REF_OD BIT(5)
+#define RS9_REG_REF_SR_SLOWEST 0
+#define RS9_REG_REF_SR_SLOW (1 << 6)
+#define RS9_REG_REF_SR_FAST (2 << 6)
+#define RS9_REG_REF_SR_FASTER (3 << 6)
+#define RS9_REG_VID 0x5
+#define RS9_REG_DID 0x6
+#define RS9_REG_BCP 0x7
+
+/* Supported Renesas 9-series models. */
+enum rs9_model {
+ RENESAS_9FGV0241,
+};
+
+/* Structure to describe features of a particular 9-series model */
+struct rs9_chip_info {
+ const enum rs9_model model;
+ unsigned int num_clks;
+};
+
+struct rs9_driver_data {
+ struct i2c_client *client;
+ struct regmap *regmap;
+ const struct rs9_chip_info *chip_info;
+ struct clk *pin_xin;
+ struct clk_hw *clk_dif[2];
+ u8 pll_amplitude;
+ u8 pll_ssc;
+ u8 clk_dif_sr;
+};
+
+/*
+ * Renesas 9-series i2c regmap
+ */
+static const struct regmap_range rs9_readable_ranges[] = {
+ regmap_reg_range(RS9_REG_OE, RS9_REG_REF),
+ regmap_reg_range(RS9_REG_VID, RS9_REG_BCP),
+};
+
+static const struct regmap_access_table rs9_readable_table = {
+ .yes_ranges = rs9_readable_ranges,
+ .n_yes_ranges = ARRAY_SIZE(rs9_readable_ranges),
+};
+
+static const struct regmap_range rs9_writeable_ranges[] = {
+ regmap_reg_range(RS9_REG_OE, RS9_REG_REF),
+ regmap_reg_range(RS9_REG_BCP, RS9_REG_BCP),
+};
+
+static const struct regmap_access_table rs9_writeable_table = {
+ .yes_ranges = rs9_writeable_ranges,
+ .n_yes_ranges = ARRAY_SIZE(rs9_writeable_ranges),
+};
+
+static const struct regmap_config rs9_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .cache_type = REGCACHE_RBTREE,
+ .max_register = 0x8,
+ .rd_table = &rs9_readable_table,
+ .wr_table = &rs9_writeable_table,
+};
+
+static int rs9_get_output_config(struct rs9_driver_data *rs9, int idx)
+{
+ struct i2c_client *client = rs9->client;
+ unsigned char *name = "DIF0";
+ struct device_node *np;
+ int ret;
+ u32 sr;
+
+ /* Set defaults */
+ rs9->clk_dif_sr &= ~RS9_REG_SR_DIF_MASK(idx);
+ rs9->clk_dif_sr |= RS9_REG_SR_3V0_DIF(idx);
+
+ name[3] += idx;
+ np = of_get_child_by_name(client->dev.of_node, name);
+ if (!np)
+ return 0;
+
+ /* Output clock slew rate */
+ ret = of_property_read_u32(np, "renesas,slew-rate", &sr);
+ if (!ret) {
+ if (sr == 2000000) { /* 2V/ns */
+ rs9->clk_dif_sr &= ~RS9_REG_SR_DIF_MASK(idx);
+ rs9->clk_dif_sr |= RS9_REG_SR_2V0_DIF(idx);
+ } else if (sr == 3000000) { /* 3V/ns (default) */
+ rs9->clk_dif_sr &= ~RS9_REG_SR_DIF_MASK(idx);
+ rs9->clk_dif_sr |= RS9_REG_SR_3V0_DIF(idx);
+ } else
+ ret = dev_err_probe(&client->dev, -EINVAL,
+ "Invalid renesas,slew-rate value\n");
+ }
+
+ of_node_put(np);
+
+ return ret;
+}
+
+static int rs9_get_common_config(struct rs9_driver_data *rs9)
+{
+ struct i2c_client *client = rs9->client;
+ struct device_node *np = client->dev.of_node;
+ unsigned int amp, ssc;
+ int ret;
+
+ /* Set defaults */
+ rs9->pll_amplitude = RS9_REG_SS_AMP_0V7;
+ rs9->pll_ssc = RS9_REG_SS_SSC_100;
+
+ /* Output clock amplitude */
+ ret = of_property_read_u32(np, "renesas,out-amplitude", &amp);
+ if (!ret) {
+ if (amp == 600000) /* 0.6V */
+ rs9->pll_amplitude = RS9_REG_SS_AMP_0V6;
+ else if (amp == 700000) /* 0.7V (default) */
+ rs9->pll_amplitude = RS9_REG_SS_AMP_0V7;
+ else if (amp == 800000) /* 0.8V */
+ rs9->pll_amplitude = RS9_REG_SS_AMP_0V8;
+ else if (amp == 900000) /* 0.9V */
+ rs9->pll_amplitude = RS9_REG_SS_AMP_0V9;
+ else
+ return dev_err_probe(&client->dev, -EINVAL,
+ "Invalid renesas,out-amplitude value\n");
+ }
+
+ /* Output clock spread spectrum */
+ ret = of_property_read_u32(np, "renesas,out-spread-spectrum", &ssc);
+ if (!ret) {
+ if (ssc == 100000) /* 100% ... no spread (default) */
+ rs9->pll_ssc = RS9_REG_SS_SSC_100;
+ else if (ssc == 99750) /* -0.25% ... down spread */
+ rs9->pll_ssc = RS9_REG_SS_SSC_M025;
+ else if (ssc == 99500) /* -0.50% ... down spread */
+ rs9->pll_ssc = RS9_REG_SS_SSC_M050;
+ else
+ return dev_err_probe(&client->dev, -EINVAL,
+ "Invalid renesas,out-spread-spectrum value\n");
+ }
+
+ return 0;
+}
+
+static void rs9_update_config(struct rs9_driver_data *rs9)
+{
+ int i;
+
+ /* If amplitude is non-default, update it. */
+ if (rs9->pll_amplitude != RS9_REG_SS_AMP_0V7) {
+ regmap_update_bits(rs9->regmap, RS9_REG_SS, RS9_REG_SS_AMP_MASK,
+ rs9->pll_amplitude);
+ }
+
+ /* If SSC is non-default, update it. */
+ if (rs9->pll_ssc != RS9_REG_SS_SSC_100) {
+ regmap_update_bits(rs9->regmap, RS9_REG_SS, RS9_REG_SS_SSC_MASK,
+ rs9->pll_ssc);
+ }
+
+ for (i = 0; i < rs9->chip_info->num_clks; i++) {
+ if (rs9->clk_dif_sr & RS9_REG_SR_3V0_DIF(i))
+ continue;
+
+ regmap_update_bits(rs9->regmap, RS9_REG_SR, RS9_REG_SR_3V0_DIF(i),
+ rs9->clk_dif_sr & RS9_REG_SR_3V0_DIF(i));
+ }
+}
+
+static struct clk_hw *
+rs9_of_clk_get(struct of_phandle_args *clkspec, void *data)
+{
+ struct rs9_driver_data *rs9 = data;
+ unsigned int idx = clkspec->args[0];
+
+ return rs9->clk_dif[idx];
+}
+
+static const struct of_device_id clk_rs9_of_match[];
+
+static int rs9_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+ struct device_node *np = client->dev.of_node;
+ unsigned char *name = "DIF0";
+ struct rs9_driver_data *rs9;
+ const char *parent_clk;
+ struct clk_hw *hw;
+ int i, ret;
+
+ rs9 = devm_kzalloc(&client->dev, sizeof(*rs9), GFP_KERNEL);
+ if (!rs9)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, rs9);
+ rs9->client = client;
+ rs9->chip_info = of_device_get_match_data(&client->dev);
+
+ /* Fetch common configuration from DT (if specified) */
+ ret = rs9_get_common_config(rs9);
+ if (ret)
+ return ret;
+
+ /* Fetch DIFx output configuration from DT (if specified) */
+ for (i = 0; i < rs9->chip_info->num_clks; i++) {
+ ret = rs9_get_output_config(rs9, i);
+ if (ret)
+ return ret;
+ }
+
+ /* Mandatory XTal */
+ parent_clk = of_clk_get_parent_name(np, 0);
+ if (!parent_clk)
+ return dev_err_probe(&client->dev, -EINVAL,
+ "Missing XTal input clock\n");
+
+ rs9->regmap = devm_regmap_init_i2c(client, &rs9_regmap_config);
+ if (IS_ERR(rs9->regmap))
+ return dev_err_probe(&client->dev, PTR_ERR(rs9->regmap),
+ "Failed to allocate register map\n");
+
+ /* Register clock */
+ for (i = 0; i < rs9->chip_info->num_clks; i++) {
+ name[3]++;
+ hw = clk_hw_register_fixed_factor(&client->dev, name,
+ parent_clk, 0, 4, 1);
+ if (IS_ERR(hw))
+ return PTR_ERR(hw);
+
+ rs9->clk_dif[i] = hw;
+ }
+
+ ret = devm_of_clk_add_hw_provider(&client->dev, rs9_of_clk_get, rs9);
+ if (!ret)
+ rs9_update_config(rs9);
+
+ return ret;
+}
+
+static int __maybe_unused rs9_suspend(struct device *dev)
+{
+ struct rs9_driver_data *rs9 = dev_get_drvdata(dev);
+
+ regcache_cache_only(rs9->regmap, true);
+ regcache_mark_dirty(rs9->regmap);
+
+ return 0;
+}
+
+static int __maybe_unused rs9_resume(struct device *dev)
+{
+ struct rs9_driver_data *rs9 = dev_get_drvdata(dev);
+ int ret;
+
+ regcache_cache_only(rs9->regmap, false);
+ ret = regcache_sync(rs9->regmap);
+ if (ret)
+ dev_err(dev, "Failed to restore register map: %d\n", ret);
+ return ret;
+}
+
+static const struct rs9_chip_info renesas_9fgv0241_info = {
+ .model = RENESAS_9FGV0241,
+ .num_clks = 2,
+};
+
+static const struct i2c_device_id rs9_id[] = {
+ { "9fgv0241", .driver_data = RENESAS_9FGV0241 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, rs9_id);
+
+static const struct of_device_id clk_rs9_of_match[] = {
+ { .compatible = "renesas,9fgv0241", .data = &renesas_9fgv0241_info },
+ { },
+};
+MODULE_DEVICE_TABLE(of, clk_rs9_of_match);
+
+static SIMPLE_DEV_PM_OPS(rs9_pm_ops, rs9_suspend, rs9_resume);
+
+static struct i2c_driver rs9_driver = {
+ .driver = {
+ .name = "clk-renesas-pcie-9series",
+ .pm = &rs9_pm_ops,
+ .of_match_table = clk_rs9_of_match,
+ },
+ .probe = rs9_probe,
+ .id_table = rs9_id,
+};
+module_i2c_driver(rs9_driver);
+
+MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
+MODULE_DESCRIPTION("Renesas 9-series PCIe clock generator driver");
+MODULE_LICENSE("GPL");
--
2.34.1