This adds Generic Clock Controller driver for lan966x SoC.
Lan966x clock controller contains 3 PLLs - cpu_clk, ddr_clk
and sys_clk. It generates and supplies clock to various
peripherals within SoC.
Register settings required to provide GCK clocking to a
peripheral is as below:
GCK_SRC_SEL = Select clock source.
GCK_PRESCALER = Set divider value.
GCK_ENA = 1 - Enable GCK clock.
Signed-off-by: Kavyasree Kotagiri <kavyasree.kotagiri@xxxxxxxxxxxxx>
Co-developed-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
---
v4 -> v5:
- Returning proper error - PTR_ERR.
- Removed unused variable "ret" in probe function.
v3 -> v4:
- Used clk_parent_data instead of of_clk_get_parent_name().
v2 -> v3:
- No changes.
v1 -> v2:
- No changes.
drivers/clk/clk-lan966x.c | 236 ++++++++++++++++++++++++++++++++++++++
1 file changed, 236 insertions(+)
create mode 100644 drivers/clk/clk-lan966x.c
diff --git a/drivers/clk/clk-lan966x.c b/drivers/clk/clk-lan966x.c
new file mode 100644
index 000000000000..0f24b95fd78f
--- /dev/null
+++ b/drivers/clk/clk-lan966x.c
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Microchip LAN966x SoC Clock driver.
+ *
+ * Copyright (C) 2021 Microchip Technology, Inc. and its subsidiaries
+ *
+ * Author: Kavyasree Kotagiri <kavyasree.kotagiri@xxxxxxxxxxxxx>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <dt-bindings/clock/microchip,lan966x.h>
+
+#define GCK_ENA BIT(0)
+#define GCK_SRC_SEL GENMASK(9, 8)
+#define GCK_PRESCALER GENMASK(23, 16)
+
+static const char *clk_names[N_CLOCKS] = {
+ "qspi0", "qspi1", "qspi2", "sdmmc0",
+ "pi", "mcan0", "mcan1", "flexcom0",
+ "flexcom1", "flexcom2", "flexcom3",
+ "flexcom4", "timer", "usb_refclk",
+};
+
+struct lan966x_gck {
+ struct clk_hw hw;
+ void __iomem *reg;
+};
+#define to_lan966x_gck(hw) container_of(hw, struct lan966x_gck, hw)
+
+static const struct clk_parent_data lan966x_gck_pdata[] = {
+ { .fw_name = "cpu_clk", .name = "cpu_clk" },
+ { .fw_name = "ddr_clk", .name = "ddr_clk" },
+ { .fw_name = "sys_clk", .name = "sys_clk" },
+};
+
+static struct clk_init_data init = {
+ .parent_data = lan966x_gck_pdata,
+ .num_parents = ARRAY_SIZE(lan966x_gck_pdata),
+};
+
+static void __iomem *base;
+
+static int lan966x_gck_enable(struct clk_hw *hw)
+{
+ struct lan966x_gck *gck = to_lan966x_gck(hw);
+ u32 val = readl(gck->reg);
+
+ val |= GCK_ENA;
+ writel(val, gck->reg);
+
+ return 0;
+}
+
+static void lan966x_gck_disable(struct clk_hw *hw)
+{
+ struct lan966x_gck *gck = to_lan966x_gck(hw);
+ u32 val = readl(gck->reg);
+
+ val &= ~GCK_ENA;
+ writel(val, gck->reg);
+}
+
+static int lan966x_gck_set_rate(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct lan966x_gck *gck = to_lan966x_gck(hw);
+ u32 div, val = readl(gck->reg);
+
+ if (rate == 0 || parent_rate == 0)
+ return -EINVAL;
+
+ /* Set Prescalar */
+ div = parent_rate / rate;
+ val &= ~GCK_PRESCALER;
+ val |= FIELD_PREP(GCK_PRESCALER, (div - 1));
+ writel(val, gck->reg);
+
+ return 0;
+}
+
+static long lan966x_gck_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ unsigned int div;
+
+ if (rate == 0 || *parent_rate == 0)
+ return -EINVAL;
+
+ if (rate >= *parent_rate)
+ return *parent_rate;
+
+ div = DIV_ROUND_CLOSEST(*parent_rate, rate);
+
+ return *parent_rate / div;
+}
+
+static unsigned long lan966x_gck_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct lan966x_gck *gck = to_lan966x_gck(hw);
+ u32 div, val = readl(gck->reg);
+
+ div = FIELD_GET(GCK_PRESCALER, val);
+
+ return parent_rate / (div + 1);
+}
+
+static int lan966x_gck_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ struct clk_hw *parent;
+ int i;
+
+ for (i = 0; i < clk_hw_get_num_parents(hw); ++i) {
+ parent = clk_hw_get_parent_by_index(hw, i);
+ if (!parent)
+ continue;
+
+ if (clk_hw_get_rate(parent) / req->rate < 254) {
+ req->best_parent_hw = parent;
+ req->best_parent_rate = clk_hw_get_rate(parent);
+
+ return 0;
+ }
+ }
+
+ return -EINVAL;
+}
+
+static u8 lan966x_gck_get_parent(struct clk_hw *hw)
+{
+ struct lan966x_gck *gck = to_lan966x_gck(hw);
+ u32 val = readl(gck->reg);
+
+ return FIELD_GET(GCK_SRC_SEL, val);
+}
+
+static int lan966x_gck_set_parent(struct clk_hw *hw, u8 index)
+{
+ struct lan966x_gck *gck = to_lan966x_gck(hw);
+ u32 val = readl(gck->reg);
+
+ val &= ~GCK_SRC_SEL;
+ val |= FIELD_PREP(GCK_SRC_SEL, index);
+ writel(val, gck->reg);
+
+ return 0;
+}
+
+static const struct clk_ops lan966x_gck_ops = {
+ .enable = lan966x_gck_enable,
+ .disable = lan966x_gck_disable,
+ .set_rate = lan966x_gck_set_rate,
+ .round_rate = lan966x_gck_round_rate,
+ .recalc_rate = lan966x_gck_recalc_rate,
+ .determine_rate = lan966x_gck_determine_rate,
+ .set_parent = lan966x_gck_set_parent,
+ .get_parent = lan966x_gck_get_parent,
+};
+
+static struct clk_hw *lan966x_gck_clk_register(struct device *dev, int i)
+{
+ struct lan966x_gck *priv;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return ERR_PTR(-ENOMEM);
+
+ priv->reg = base + (i * 4);
+ priv->hw.init = &init;
+ ret = devm_clk_hw_register(dev, &priv->hw);
+ if (ret)
+ return ERR_PTR(ret);
+
+ return &priv->hw;
+};
+
+static int lan966x_clk_probe(struct platform_device *pdev)
+{
+ struct clk_hw_onecell_data *hw_data;
+ struct device *dev = &pdev->dev;
+ int i;
+
+ hw_data = devm_kzalloc(dev, sizeof(*hw_data), GFP_KERNEL);
+ if (!hw_data)
+ return -ENOMEM;
+
+ base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ init.ops = &lan966x_gck_ops;
+
+ hw_data->num = N_CLOCKS;
+
+ for (i = 0; i < N_CLOCKS; i++) {
+ init.name = clk_names[i];
+ hw_data->hws[i] = lan966x_gck_clk_register(dev, i);
+ if (IS_ERR(hw_data->hws[i])) {
+ dev_err(dev, "failed to register %s clock\n",
+ init.name);
+ return PTR_ERR(hw_data->hws[i]);
+ }
+ }
+
+ return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, hw_data);
+}
+
+static const struct of_device_id lan966x_clk_dt_ids[] = {
+ { .compatible = "microchip,lan966x-gck", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, lan966x_clk_dt_ids);
+
+static struct platform_driver lan966x_clk_driver = {
+ .probe = lan966x_clk_probe,
+ .driver = {
+ .name = "lan966x-clk",
+ .of_match_table = lan966x_clk_dt_ids,
+ },
+};
+builtin_platform_driver(lan966x_clk_driver);
+
+MODULE_AUTHOR("Kavyasree Kotagiri <kavyasree.kotagiri@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("LAN966X clock driver");
+MODULE_LICENSE("GPL v2");
--
2.17.1
