clk: ti: add gate clock driver
The patch adds support for TI gate clock binding. The code is based on
the drivers/clk/ti/gate.c driver of the Linux kernel version 5.9-rc7.
For DT binding details see:
- Documentation/devicetree/bindings/clock/ti/gate.txt
Signed-off-by: Dario Binacchi <dariobin@libero.it>
diff --git a/drivers/clk/ti/clk-gate.c b/drivers/clk/ti/clk-gate.c
new file mode 100644
index 0000000..236eaed
--- /dev/null
+++ b/drivers/clk/ti/clk-gate.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * TI gate clock support
+ *
+ * Copyright (C) 2020 Dario Binacchi <dariobin@libero.it>
+ *
+ * Loosely based on Linux kernel drivers/clk/ti/gate.c
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <clk-uclass.h>
+#include <asm/io.h>
+#include <linux/clk-provider.h>
+
+struct clk_ti_gate_priv {
+ fdt_addr_t reg;
+ u8 enable_bit;
+ u32 flags;
+ bool invert_enable;
+};
+
+static int clk_ti_gate_disable(struct clk *clk)
+{
+ struct clk_ti_gate_priv *priv = dev_get_priv(clk->dev);
+ u32 v;
+
+ v = readl(priv->reg);
+ if (priv->invert_enable)
+ v |= (1 << priv->enable_bit);
+ else
+ v &= ~(1 << priv->enable_bit);
+
+ writel(v, priv->reg);
+ /* No OCP barrier needed here since it is a disable operation */
+ return 0;
+}
+
+static int clk_ti_gate_enable(struct clk *clk)
+{
+ struct clk_ti_gate_priv *priv = dev_get_priv(clk->dev);
+ u32 v;
+
+ v = readl(priv->reg);
+ if (priv->invert_enable)
+ v &= ~(1 << priv->enable_bit);
+ else
+ v |= (1 << priv->enable_bit);
+
+ writel(v, priv->reg);
+ /* OCP barrier */
+ v = readl(priv->reg);
+ return 0;
+}
+
+static int clk_ti_gate_of_to_plat(struct udevice *dev)
+{
+ struct clk_ti_gate_priv *priv = dev_get_priv(dev);
+
+ priv->reg = dev_read_addr(dev);
+ if (priv->reg == FDT_ADDR_T_NONE) {
+ dev_err(dev, "failed to get control register\n");
+ return -EINVAL;
+ }
+
+ dev_dbg(dev, "reg=0x%08lx\n", priv->reg);
+ priv->enable_bit = dev_read_u32_default(dev, "ti,bit-shift", 0);
+ if (dev_read_bool(dev, "ti,set-rate-parent"))
+ priv->flags |= CLK_SET_RATE_PARENT;
+
+ priv->invert_enable = dev_read_bool(dev, "ti,set-bit-to-disable");
+ return 0;
+}
+
+static struct clk_ops clk_ti_gate_ops = {
+ .enable = clk_ti_gate_enable,
+ .disable = clk_ti_gate_disable,
+};
+
+static const struct udevice_id clk_ti_gate_of_match[] = {
+ { .compatible = "ti,gate-clock" },
+ { },
+};
+
+U_BOOT_DRIVER(clk_ti_gate) = {
+ .name = "ti_gate_clock",
+ .id = UCLASS_CLK,
+ .of_match = clk_ti_gate_of_match,
+ .ofdata_to_platdata = clk_ti_gate_of_to_plat,
+ .priv_auto = sizeof(struct clk_ti_gate_priv),
+ .ops = &clk_ti_gate_ops,
+};