clk: Port Linux common clock framework [CCF] for imx6q to U-boot (tag: v5.1.12)
This patch brings the files from Linux kernel (linux-stable/linux-5.1.y
SHA1: 5752b50477da)to provide clocks support as it is used on the Linux
kernel with Common Clock Framework [CCF] setup.
The directory structure has been preserved. The ported code only supports
reading information from PLL, MUX, Divider, etc and enabling/disabling
the clocks USDHCx/ECSPIx depending on used bus. Moreover, it is agnostic
to the alias numbering as the information about the clock is read from the
device tree.
One needs to pay attention to the comments indicating necessary for U-Boot's
driver model changes.
If needed, the code can be extended to support the "set" part of the clock
management.
Signed-off-by: Lukasz Majewski <lukma@denx.de>
diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
new file mode 100644
index 0000000..3348d97
--- /dev/null
+++ b/drivers/clk/clk-divider.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 DENX Software Engineering
+ * Lukasz Majewski, DENX Software Engineering, lukma@denx.de
+ *
+ * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
+ * Copyright (C) 2011 Richard Zhao, Linaro <richard.zhao@linaro.org>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ *
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <malloc.h>
+#include <clk-uclass.h>
+#include <dm/device.h>
+#include <dm/uclass.h>
+#include <dm/lists.h>
+#include <dm/device-internal.h>
+#include <linux/clk-provider.h>
+#include <div64.h>
+#include <clk.h>
+#include "clk.h"
+
+#define UBOOT_DM_CLK_CCF_DIVIDER "ccf_clk_divider"
+
+static unsigned int _get_table_div(const struct clk_div_table *table,
+ unsigned int val)
+{
+ const struct clk_div_table *clkt;
+
+ for (clkt = table; clkt->div; clkt++)
+ if (clkt->val == val)
+ return clkt->div;
+ return 0;
+}
+
+static unsigned int _get_div(const struct clk_div_table *table,
+ unsigned int val, unsigned long flags, u8 width)
+{
+ if (flags & CLK_DIVIDER_ONE_BASED)
+ return val;
+ if (flags & CLK_DIVIDER_POWER_OF_TWO)
+ return 1 << val;
+ if (flags & CLK_DIVIDER_MAX_AT_ZERO)
+ return val ? val : clk_div_mask(width) + 1;
+ if (table)
+ return _get_table_div(table, val);
+ return val + 1;
+}
+
+unsigned long divider_recalc_rate(struct clk *hw, unsigned long parent_rate,
+ unsigned int val,
+ const struct clk_div_table *table,
+ unsigned long flags, unsigned long width)
+{
+ unsigned int div;
+
+ div = _get_div(table, val, flags, width);
+ if (!div) {
+ WARN(!(flags & CLK_DIVIDER_ALLOW_ZERO),
+ "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
+ clk_hw_get_name(hw));
+ return parent_rate;
+ }
+
+ return DIV_ROUND_UP_ULL((u64)parent_rate, div);
+}
+
+static ulong clk_divider_recalc_rate(struct clk *clk)
+{
+ struct clk_divider *divider =
+ to_clk_divider(dev_get_clk_ptr(clk->dev));
+ unsigned long parent_rate = clk_get_parent_rate(clk);
+ unsigned int val;
+
+ val = readl(divider->reg) >> divider->shift;
+ val &= clk_div_mask(divider->width);
+
+ return divider_recalc_rate(clk, parent_rate, val, divider->table,
+ divider->flags, divider->width);
+}
+
+const struct clk_ops clk_divider_ops = {
+ .get_rate = clk_divider_recalc_rate,
+};
+
+static struct clk *_register_divider(struct device *dev, const char *name,
+ const char *parent_name, unsigned long flags,
+ void __iomem *reg, u8 shift, u8 width,
+ u8 clk_divider_flags, const struct clk_div_table *table)
+{
+ struct clk_divider *div;
+ struct clk *clk;
+ int ret;
+
+ if (clk_divider_flags & CLK_DIVIDER_HIWORD_MASK) {
+ if (width + shift > 16) {
+ pr_warn("divider value exceeds LOWORD field\n");
+ return ERR_PTR(-EINVAL);
+ }
+ }
+
+ /* allocate the divider */
+ div = kzalloc(sizeof(*div), GFP_KERNEL);
+ if (!div)
+ return ERR_PTR(-ENOMEM);
+
+ /* struct clk_divider assignments */
+ div->reg = reg;
+ div->shift = shift;
+ div->width = width;
+ div->flags = clk_divider_flags;
+ div->table = table;
+
+ /* register the clock */
+ clk = &div->clk;
+
+ ret = clk_register(clk, UBOOT_DM_CLK_CCF_DIVIDER, name, parent_name);
+ if (ret) {
+ kfree(div);
+ return ERR_PTR(ret);
+ }
+
+ return clk;
+}
+
+struct clk *clk_register_divider(struct device *dev, const char *name,
+ const char *parent_name, unsigned long flags,
+ void __iomem *reg, u8 shift, u8 width,
+ u8 clk_divider_flags)
+{
+ struct clk *clk;
+
+ clk = _register_divider(dev, name, parent_name, flags, reg, shift,
+ width, clk_divider_flags, NULL);
+ if (IS_ERR(clk))
+ return ERR_CAST(clk);
+ return clk;
+}
+
+U_BOOT_DRIVER(ccf_clk_divider) = {
+ .name = UBOOT_DM_CLK_CCF_DIVIDER,
+ .id = UCLASS_CLK,
+ .ops = &clk_divider_ops,
+ .flags = DM_FLAG_PRE_RELOC,
+};