clk: at91: clk-utmi: add driver compatible with ccf

Add clk-utmi driver compatible with common clock framework.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>

drivers/clk/at91/Makefile

@@ -4,6 +4,7 @@
 
 ifdef CONFIG_CLK_CCF
 obj-y += pmc.o sckc.o clk-main.o clk-master.o
+obj-$(CONFIG_AT91_UTMI)		+= clk-utmi.o
 obj-$(CONFIG_AT91_SAM9X60_PLL)	+= clk-sam9x60-pll.o
 else
 obj-y += compat.o

drivers/clk/at91/clk-utmi.c

@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * UTMI clock support for AT91 architectures.
+ *
+ * Copyright (C) 2020 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Claudiu Beznea <claudiu.beznea@microchip.com>
+ *
+ * Based on drivers/clk/at91/clk-utmi.c from Linux.
+ */
+#include <asm/processor.h>
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm.h>
+#include <linux/clk-provider.h>
+#include <linux/clk/at91_pmc.h>
+#include <mach/at91_sfr.h>
+#include <regmap.h>
+#include <syscon.h>
+
+#include "pmc.h"
+
+#define UBOOT_DM_CLK_AT91_UTMI		"at91-utmi-clk"
+
+/*
+ * The purpose of this clock is to generate a 480 MHz signal. A different
+ * rate can't be configured.
+ */
+#define UTMI_RATE	480000000
+
+struct clk_utmi {
+	void __iomem *base;
+	struct regmap *regmap_sfr;
+	struct clk clk;
+};
+
+#define to_clk_utmi(_clk) container_of(_clk, struct clk_utmi, clk)
+
+static inline bool clk_utmi_ready(struct regmap *regmap)
+{
+	unsigned int status;
+
+	pmc_read(regmap, AT91_PMC_SR, &status);
+
+	return !!(status & AT91_PMC_LOCKU);
+}
+
+static int clk_utmi_enable(struct clk *clk)
+{
+	struct clk_utmi *utmi = to_clk_utmi(clk);
+	unsigned int uckr = AT91_PMC_UPLLEN | AT91_PMC_UPLLCOUNT |
+			    AT91_PMC_BIASEN;
+	unsigned int utmi_ref_clk_freq;
+	ulong parent_rate = clk_get_parent_rate(clk);
+
+	/*
+	 * If mainck rate is different from 12 MHz, we have to configure the
+	 * FREQ field of the SFR_UTMICKTRIM register to generate properly
+	 * the utmi clock.
+	 */
+	switch (parent_rate) {
+	case 12000000:
+		utmi_ref_clk_freq = 0;
+		break;
+	case 16000000:
+		utmi_ref_clk_freq = 1;
+		break;
+	case 24000000:
+		utmi_ref_clk_freq = 2;
+		break;
+	/*
+	 * Not supported on SAMA5D2 but it's not an issue since MAINCK
+	 * maximum value is 24 MHz.
+	 */
+	case 48000000:
+		utmi_ref_clk_freq = 3;
+		break;
+	default:
+		debug("UTMICK: unsupported mainck rate\n");
+		return -EINVAL;
+	}
+
+	if (utmi->regmap_sfr) {
+		regmap_update_bits(utmi->regmap_sfr, AT91_SFR_UTMICKTRIM,
+				   AT91_UTMICKTRIM_FREQ, utmi_ref_clk_freq);
+	} else if (utmi_ref_clk_freq) {
+		debug("UTMICK: sfr node required\n");
+		return -EINVAL;
+	}
+
+	pmc_update_bits(utmi->base, AT91_CKGR_UCKR, uckr, uckr);
+
+	while (!clk_utmi_ready(utmi->base)) {
+		debug("waiting for utmi...\n");
+		cpu_relax();
+	}
+
+	return 0;
+}
+
+static int clk_utmi_disable(struct clk *clk)
+{
+	struct clk_utmi *utmi = to_clk_utmi(clk);
+
+	pmc_update_bits(utmi->base, AT91_CKGR_UCKR, AT91_PMC_UPLLEN, 0);
+
+	return 0;
+}
+
+static ulong clk_utmi_get_rate(struct clk *clk)
+{
+	/* UTMI clk rate is fixed. */
+	return UTMI_RATE;
+}
+
+static const struct clk_ops utmi_ops = {
+	.enable = clk_utmi_enable,
+	.disable = clk_utmi_disable,
+	.get_rate = clk_utmi_get_rate,
+};
+
+struct clk *at91_clk_register_utmi(void __iomem *base, struct udevice *dev,
+				   const char *name, const char *parent_name)
+{
+	struct udevice *syscon;
+	struct clk_utmi *utmi;
+	struct clk *clk;
+	int ret;
+
+	if (!base || !dev || !name || !parent_name)
+		return ERR_PTR(-EINVAL);
+
+	ret = uclass_get_device_by_phandle(UCLASS_SYSCON, dev,
+					   "regmap-sfr", &syscon);
+	if (ret)
+		return ERR_PTR(ret);
+
+	utmi = kzalloc(sizeof(*utmi), GFP_KERNEL);
+	if (!utmi)
+		return ERR_PTR(-ENOMEM);
+
+	utmi->base = base;
+	utmi->regmap_sfr = syscon_get_regmap(syscon);
+	if (!utmi->regmap_sfr) {
+		kfree(utmi);
+		return ERR_PTR(-ENODEV);
+	}
+
+	clk = &utmi->clk;
+	clk->flags = CLK_GET_RATE_NOCACHE;
+	ret = clk_register(clk, UBOOT_DM_CLK_AT91_UTMI, name, parent_name);
+	if (ret) {
+		kfree(utmi);
+		clk = ERR_PTR(ret);
+	}
+
+	return clk;
+}
+
+U_BOOT_DRIVER(at91_utmi_clk) = {
+	.name = UBOOT_DM_CLK_AT91_UTMI,
+	.id = UCLASS_CLK,
+	.ops = &utmi_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};

drivers/clk/at91/pmc.h

@@ -85,6 +85,9 @@ at91_clk_sama7g5_register_master(void __iomem *base, const char *name,
 			const char * const *parent_names, int num_parents,
 			const u32 *mux_table, const u32 *clk_mux_table,
 			bool critical, u8 id);
+struct clk *
+at91_clk_register_utmi(void __iomem *base, struct udevice *dev,
+			const char *name, const char *parent_name);
 
 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);