[PATCH v3 09/21] clk: at91: sckc: add driver compatible with ccf

[Claudiu Beznea]

Add sckc driver compatible with common clock framework. Driver
implements slow clock support for SAM9X60 compatible IPs (in this
list it is also present SAMA7G5's slow clock IP).

Signed-off-by: Claudiu Beznea <claudiu.beznea at microchip.com>
---
 drivers/clk/at91/Makefile |   2 +-
 drivers/clk/at91/sckc.c   | 172 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 173 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/at91/sckc.c

diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index e2413af40360..7083ce2890d6 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -3,7 +3,7 @@
 #
 
 ifdef CONFIG_CLK_CCF
-obj-y += pmc.o
+obj-y += pmc.o sckc.o
 else
 obj-y += compat.o
 endif
diff --git a/drivers/clk/at91/sckc.c b/drivers/clk/at91/sckc.c
new file mode 100644
index 000000000000..dd62dc5510e4
--- /dev/null
+++ b/drivers/clk/at91/sckc.c
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Slow clock support for AT91 architectures.
+ *
+ * Copyright (C) 2020 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Claudiu Beznea <claudiu.beznea at microchip.com>
+ */
+
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm.h>
+#include <dt-bindings/clk/at91.h>
+#include <linux/clk-provider.h>
+
+#include "pmc.h"
+
+#define UBOOT_DM_CLK_AT91_SAM9X60_TD_SLCK	"at91-sam9x60-td-slck"
+#define UBOOT_DM_CLK_AT91_SCKC			"at91-sckc"
+
+#define AT91_OSC_SEL		BIT(24)
+#define AT91_OSC_SEL_SHIFT	(24)
+
+struct sam9x60_sckc {
+	void __iomem *reg;
+	const char **parent_names;
+	unsigned int num_parents;
+	struct clk clk;
+};
+
+#define to_sam9x60_sckc(c)	container_of(c, struct sam9x60_sckc, clk)
+
+static int sam9x60_sckc_of_xlate(struct clk *clk,
+				 struct ofnode_phandle_args *args)
+{
+	if (args->args_count != 1) {
+		debug("AT91: SCKC: Invalid args_count: %d\n", args->args_count);
+		return -EINVAL;
+	}
+
+	clk->id = AT91_TO_CLK_ID(PMC_TYPE_SLOW, args->args[0]);
+
+	return 0;
+}
+
+static const struct clk_ops sam9x60_sckc_ops = {
+	.of_xlate = sam9x60_sckc_of_xlate,
+	.get_rate = clk_generic_get_rate,
+};
+
+static int sam9x60_td_slck_set_parent(struct clk *clk, struct clk *parent)
+{
+	struct sam9x60_sckc *sckc = to_sam9x60_sckc(clk);
+	u32 i;
+
+	for (i = 0; i < sckc->num_parents; i++) {
+		if (!strcmp(parent->dev->name, sckc->parent_names[i]))
+			break;
+	}
+	if (i == sckc->num_parents)
+		return -EINVAL;
+
+	pmc_update_bits(sckc->reg, 0, AT91_OSC_SEL, (i << AT91_OSC_SEL_SHIFT));
+
+	return 0;
+}
+
+static const struct clk_ops sam9x60_td_slck_ops = {
+	.get_rate = clk_generic_get_rate,
+	.set_parent = sam9x60_td_slck_set_parent,
+};
+
+static struct clk *at91_sam9x60_clk_register_td_slck(struct sam9x60_sckc *sckc,
+		const char *name, const char * const *parent_names,
+		int num_parents)
+{
+	struct clk *clk;
+	int ret = -ENOMEM;
+	u32 val, i;
+
+	if (!sckc || !name || !parent_names || num_parents != 2)
+		return ERR_PTR(-EINVAL);
+
+	sckc->parent_names = kzalloc(sizeof(*sckc->parent_names) * num_parents,
+				     GFP_KERNEL);
+	if (!sckc->parent_names)
+		return ERR_PTR(ret);
+
+	for (i = 0; i < num_parents; i++) {
+		sckc->parent_names[i] = kmemdup(parent_names[i],
+				strlen(parent_names[i]) + 1, GFP_KERNEL);
+		if (!sckc->parent_names[i])
+			goto free;
+	}
+	sckc->num_parents = num_parents;
+
+	pmc_read(sckc->reg, 0, &val);
+	val = (val & AT91_OSC_SEL) >> AT91_OSC_SEL_SHIFT;
+
+	clk = &sckc->clk;
+	ret = clk_register(clk, UBOOT_DM_CLK_AT91_SAM9X60_TD_SLCK, name,
+			   parent_names[val]);
+	if (ret)
+		goto free;
+
+	return clk;
+
+free:
+	for (; i >= 0; i--)
+		kfree(sckc->parent_names[i]);
+	kfree(sckc->parent_names);
+
+	return ERR_PTR(ret);
+}
+
+U_BOOT_DRIVER(at91_sam9x60_td_slck) = {
+	.name = UBOOT_DM_CLK_AT91_SAM9X60_TD_SLCK,
+	.id = UCLASS_CLK,
+	.ops = &sam9x60_td_slck_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};
+
+static int at91_sam9x60_sckc_probe(struct udevice *dev)
+{
+	struct sam9x60_sckc *sckc = dev_get_priv(dev);
+	void __iomem *base = (void *)devfdt_get_addr(dev);
+	const char *slow_rc_osc, *slow_osc;
+	const char *parents[2];
+	struct clk *clk, c;
+	int ret;
+
+	ret = clk_get_by_index(dev, 0, &c);
+	if (ret)
+		return ret;
+	slow_rc_osc = clk_hw_get_name(&c);
+
+	ret = clk_get_by_index(dev, 1, &c);
+	if (ret)
+		return ret;
+	slow_osc = clk_hw_get_name(&c);
+
+	clk = clk_register_fixed_factor(NULL, "md_slck", slow_rc_osc, 0, 1, 1);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+	clk_dm(AT91_TO_CLK_ID(PMC_TYPE_SLOW, 0), clk);
+
+	parents[0] = slow_rc_osc;
+	parents[1] = slow_osc;
+	sckc[1].reg = base;
+	clk = at91_sam9x60_clk_register_td_slck(&sckc[1], "td_slck",
+						parents, 2);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+	clk_dm(AT91_TO_CLK_ID(PMC_TYPE_SLOW, 1), clk);
+
+	return 0;
+}
+
+static const struct udevice_id sam9x60_sckc_ids[] = {
+	{ .compatible = "microchip,sam9x60-sckc" },
+	{ /* Sentinel. */ },
+};
+
+U_BOOT_DRIVER(at91_sckc) = {
+	.name = UBOOT_DM_CLK_AT91_SCKC,
+	.id = UCLASS_CLK,
+	.of_match = sam9x60_sckc_ids,
+	.priv_auto_alloc_size = sizeof(struct sam9x60_sckc) * 2,
+	.ops = &sam9x60_sckc_ops,
+	.probe = at91_sam9x60_sckc_probe,
+	.flags = DM_FLAG_PRE_RELOC,
+};
-- 
2.7.4