[PATCH v3 19/21] clk: at91: clk-generic: add driver compatible with ccf

[Claudiu Beznea]

Add clk-generic driver compatible with common clock framework.

Signed-off-by: Claudiu Beznea <claudiu.beznea at microchip.com>
---
 drivers/clk/at91/Makefile      |   1 +
 drivers/clk/at91/clk-generic.c | 202 +++++++++++++++++++++++++++++++++++++++++
 drivers/clk/at91/pmc.h         |   6 ++
 3 files changed, 209 insertions(+)
 create mode 100644 drivers/clk/at91/clk-generic.c

diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index b5529065b5c4..2cd840af3859 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -6,6 +6,7 @@ ifdef CONFIG_CLK_CCF
 obj-y += pmc.o sckc.o clk-main.o clk-master.o clk-programmable.o clk-system.o
 obj-y += clk-peripheral.o
 
+obj-$(CONFIG_AT91_GENERIC_CLK)	+= clk-generic.o
 obj-$(CONFIG_AT91_UTMI)		+= clk-utmi.o
 obj-$(CONFIG_AT91_SAM9X60_PLL)	+= clk-sam9x60-pll.o
 else
diff --git a/drivers/clk/at91/clk-generic.c b/drivers/clk/at91/clk-generic.c
new file mode 100644
index 000000000000..87738b7b5bff
--- /dev/null
+++ b/drivers/clk/at91/clk-generic.c
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Generic clock support for AT91 architectures.
+ *
+ * Copyright (C) 2020 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Claudiu Beznea <claudiu.beznea at microchip.com>
+ *
+ * Based on drivers/clk/at91/clk-generated.c from Linux.
+ */
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm.h>
+#include <linux/io.h>
+#include <linux/clk-provider.h>
+#include <linux/clk/at91_pmc.h>
+
+#include "pmc.h"
+
+#define UBOOT_DM_CLK_AT91_GCK		"at91-gck-clk"
+
+#define GENERATED_MAX_DIV	255
+
+struct clk_gck {
+	void __iomem *base;
+	const u32 *clk_mux_table;
+	const u32 *mux_table;
+	const struct clk_pcr_layout *layout;
+	struct clk_range range;
+	struct clk clk;
+	u32 num_parents;
+	u32 id;
+};
+
+#define to_clk_gck(_c) container_of(_c, struct clk_gck, clk)
+
+static int clk_gck_enable(struct clk *clk)
+{
+	struct clk_gck *gck = to_clk_gck(clk);
+
+	pmc_write(gck->base, gck->layout->offset,
+		  (gck->id & gck->layout->pid_mask));
+	pmc_update_bits(gck->base, gck->layout->offset,
+			gck->layout->cmd | AT91_PMC_PCR_GCKEN,
+			gck->layout->cmd | AT91_PMC_PCR_GCKEN);
+
+	return 0;
+}
+
+static int clk_gck_disable(struct clk *clk)
+{
+	struct clk_gck *gck = to_clk_gck(clk);
+
+	pmc_write(gck->base, gck->layout->offset,
+		  (gck->id & gck->layout->pid_mask));
+	pmc_update_bits(gck->base, gck->layout->offset,
+			gck->layout->cmd | AT91_PMC_PCR_GCKEN,
+			gck->layout->cmd);
+
+	return 0;
+}
+
+static int clk_gck_set_parent(struct clk *clk, struct clk *parent)
+{
+	struct clk_gck *gck = to_clk_gck(clk);
+	int index;
+
+	index = at91_clk_mux_val_to_index(gck->clk_mux_table, gck->num_parents,
+					  parent->id);
+	if (index < 0)
+		return index;
+
+	index = at91_clk_mux_index_to_val(gck->mux_table, gck->num_parents,
+					  index);
+	if (index < 0)
+		return index;
+
+	pmc_write(gck->base, gck->layout->offset,
+		  (gck->id & gck->layout->pid_mask));
+	pmc_update_bits(gck->base, gck->layout->offset,
+			gck->layout->gckcss_mask | gck->layout->cmd,
+			(index << (ffs(gck->layout->gckcss_mask) - 1)) |
+			gck->layout->cmd);
+
+	return 0;
+}
+
+static ulong clk_gck_set_rate(struct clk *clk, ulong rate)
+{
+	struct clk_gck *gck = to_clk_gck(clk);
+	ulong parent_rate = clk_get_parent_rate(clk);
+	u32 div;
+
+	if (!rate || !parent_rate)
+		return 0;
+
+	if (gck->range.max && rate > gck->range.max)
+		return 0;
+
+	div = DIV_ROUND_CLOSEST(parent_rate, rate);
+	if (div > GENERATED_MAX_DIV + 1 || !div)
+		return 0;
+
+	pmc_write(gck->base, gck->layout->offset,
+		  (gck->id & gck->layout->pid_mask));
+	pmc_update_bits(gck->base, gck->layout->offset,
+			AT91_PMC_PCR_GCKDIV_MASK | gck->layout->cmd,
+			((div - 1) << (ffs(AT91_PMC_PCR_GCKDIV_MASK) - 1)) |
+			gck->layout->cmd);
+
+	return parent_rate / div;
+}
+
+static ulong clk_gck_get_rate(struct clk *clk)
+{
+	struct clk_gck *gck = to_clk_gck(clk);
+	ulong parent_rate = clk_get_parent_rate(clk);
+	u32 val, div;
+
+	if (!parent_rate)
+		return 0;
+
+	pmc_write(gck->base, gck->layout->offset,
+		  (gck->id & gck->layout->pid_mask));
+	pmc_read(gck->base, gck->layout->offset, &val);
+
+	div = (val & AT91_PMC_PCR_GCKDIV_MASK) >>
+		(ffs(AT91_PMC_PCR_GCKDIV_MASK) - 1);
+
+	return parent_rate / (div + 1);
+}
+
+static const struct clk_ops gck_ops = {
+	.enable = clk_gck_enable,
+	.disable = clk_gck_disable,
+	.set_parent = clk_gck_set_parent,
+	.set_rate = clk_gck_set_rate,
+	.get_rate = clk_gck_get_rate,
+};
+
+struct clk *
+at91_clk_register_generic(void __iomem *base,
+			  const struct clk_pcr_layout *layout,
+			  const char *name, const char * const *parent_names,
+			  const u32 *clk_mux_table, const u32 *mux_table,
+			  u8 num_parents, u8 id,
+			  const struct clk_range *range)
+{
+	struct clk_gck *gck;
+	struct clk *clk;
+	int ret, index;
+	u32 val;
+
+	if (!base || !layout || !name || !parent_names || !num_parents ||
+	    !clk_mux_table || !mux_table || !range)
+		return ERR_PTR(-EINVAL);
+
+	gck = kzalloc(sizeof(*gck), GFP_KERNEL);
+	if (!gck)
+		return ERR_PTR(-ENOMEM);
+
+	gck->id = id;
+	gck->base = base;
+	gck->range = *range;
+	gck->layout = layout;
+	gck->clk_mux_table = clk_mux_table;
+	gck->mux_table = mux_table;
+	gck->num_parents = num_parents;
+
+	clk = &gck->clk;
+	clk->flags = CLK_GET_RATE_NOCACHE;
+
+	pmc_write(gck->base, gck->layout->offset,
+		  (gck->id & gck->layout->pid_mask));
+	pmc_read(gck->base, gck->layout->offset, &val);
+
+	val = (val & gck->layout->gckcss_mask) >>
+		(ffs(gck->layout->gckcss_mask) - 1);
+
+	index = at91_clk_mux_val_to_index(gck->mux_table, gck->num_parents,
+					  val);
+	if (index < 0) {
+		kfree(gck);
+		return ERR_PTR(index);
+	}
+
+	ret = clk_register(clk, UBOOT_DM_CLK_AT91_GCK, name,
+			   parent_names[index]);
+	if (ret) {
+		kfree(gck);
+		clk = ERR_PTR(ret);
+	}
+
+	return clk;
+}
+
+U_BOOT_DRIVER(at91_gck_clk) = {
+	.name = UBOOT_DM_CLK_AT91_GCK,
+	.id = UCLASS_CLK,
+	.ops = &gck_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};
diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
index 5e80f353e6c2..176855e7a0ed 100644
--- a/drivers/clk/at91/pmc.h
+++ b/drivers/clk/at91/pmc.h
@@ -127,6 +127,12 @@ at91_clk_register_sam9x5_peripheral(void __iomem *base,
 			const struct clk_pcr_layout *layout,
 			const char *name, const char *parent_name,
 			u32 id, const struct clk_range *range);
+struct clk *
+at91_clk_register_generic(void __iomem *base,
+			const struct clk_pcr_layout *layout, const char *name,
+			const char * const *parent_names,
+			const u32 *clk_mux_table, const u32 *mux_table,
+			u8 num_parents, u8 id, const struct clk_range *range);
 
 int at91_clk_mux_val_to_index(const u32 *table, u32 num_parents, u32 val);
 int at91_clk_mux_index_to_val(const u32 *table, u32 num_parents, u32 index);
-- 
2.7.4