drivers: timer: Add in driver support for ADI SC5XX-family GP timer peripheral

Co-developed-by: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
Signed-off-by: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
Co-developed-by: Angelo Dureghello <angelo.dureghello@timesys.com>
Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
Co-developed-by: Ian Roberts <ian.roberts@timesys.com>
Signed-off-by: Ian Roberts <ian.roberts@timesys.com>
Signed-off-by: Greg Malysa <greg.malysa@timesys.com>

drivers/timer/Kconfig

@@ -50,6 +50,14 @@ config TIMER_EARLY
 	  use an early timer. These functions must be supported by your timer
 	  driver: timer_early_get_count() and timer_early_get_rate().
 
+config ADI_SC5XX_TIMER
+	bool "ADI ADSP-SC5xx Timer Support"
+	depends on TIMER && (SC57X || SC58X || SC59X || SC59X_64)
+	help
+	  gptimer based timer support on ADI's ADSP-SC5xx platforms. Available
+	  but not required on sc59x-64-based platforms (598 and similar).
+	  Required on 32-bit platforms (sc57x, sc58x, sc594 and earlier).
+
 config ALTERA_TIMER
 	bool "Altera timer support"
 	depends on TIMER

drivers/timer/Makefile

@@ -3,6 +3,7 @@
 # Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
 
 obj-y += timer-uclass.o
+obj-$(CONFIG_ADI_SC5XX_TIMER) += adi_sc5xx_timer.o
 obj-$(CONFIG_ALTERA_TIMER)	+= altera_timer.o
 obj-$(CONFIG_$(SPL_)ANDES_PLMT_TIMER) += andes_plmt_timer.o
 obj-$(CONFIG_ARC_TIMER)	+= arc_timer.o

drivers/timer/adi_sc5xx_timer.c

@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * (C) Copyright 2022 - Analog Devices, Inc.
+ *
+ * Written and/or maintained by Timesys Corporation
+ *
+ * Converted to driver model by Nathan Barrett-Morrison
+ *
+ * Author: Greg Malysa <greg.malysa@timesys.com>
+ * Additional Contact: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
+ *
+ * dm timer implementation for ADI ADSP-SC5xx SoCs
+ *
+ */
+
+#include <clk.h>
+#include <dm.h>
+#include <timer.h>
+#include <asm/io.h>
+#include <dm/device_compat.h>
+#include <linux/compiler_types.h>
+
+/*
+ * Timer Configuration Register Bits
+ */
+#define TIMER_OUT_DIS       0x0800
+#define TIMER_PULSE_HI      0x0080
+#define TIMER_MODE_PWM_CONT 0x000c
+
+#define __BFP(m) u16 m; u16 __pad_##m
+
+struct gptimer3 {
+	__BFP(config);
+	u32 counter;
+	u32 period;
+	u32 width;
+	u32 delay;
+};
+
+struct gptimer3_group_regs {
+	__BFP(run);
+	__BFP(enable);
+	__BFP(disable);
+	__BFP(stop_cfg);
+	__BFP(stop_cfg_set);
+	__BFP(stop_cfg_clr);
+	__BFP(data_imsk);
+	__BFP(stat_imsk);
+	__BFP(tr_msk);
+	__BFP(tr_ie);
+	__BFP(data_ilat);
+	__BFP(stat_ilat);
+	__BFP(err_status);
+	__BFP(bcast_per);
+	__BFP(bcast_wid);
+	__BFP(bcast_dly);
+};
+
+#define MAX_TIM_LOAD	0xFFFFFFFF
+
+struct adi_gptimer_priv {
+	struct gptimer3_group_regs __iomem *timer_group;
+	struct gptimer3 __iomem *timer_base;
+	u32 prev;
+	u64 upper;
+};
+
+static u64 adi_gptimer_get_count(struct udevice *udev)
+{
+	struct adi_gptimer_priv *priv = dev_get_priv(udev);
+
+	u32 now = readl(&priv->timer_base->counter);
+
+	if (now < priv->prev)
+		priv->upper += (1ull << 32);
+
+	priv->prev = now;
+
+	return (priv->upper + (u64)now);
+}
+
+static const struct timer_ops adi_gptimer_ops = {
+	.get_count = adi_gptimer_get_count,
+};
+
+static int adi_gptimer_probe(struct udevice *udev)
+{
+	struct timer_dev_priv *uc_priv = dev_get_uclass_priv(udev);
+	struct adi_gptimer_priv *priv = dev_get_priv(udev);
+	struct clk clk;
+	u16 imask;
+	int ret;
+
+	priv->timer_group = dev_remap_addr_index(udev, 0);
+	priv->timer_base = dev_remap_addr_index(udev, 1);
+	priv->upper = 0;
+	priv->prev = 0;
+
+	if (!priv->timer_group || !priv->timer_base) {
+		dev_err(udev, "Missing timer_group or timer_base reg entries\n");
+		return -ENODEV;
+	}
+
+	ret = clk_get_by_index(udev, 0, &clk);
+	if (ret < 0) {
+		dev_err(udev, "Missing clock reference for timer\n");
+		return ret;
+	}
+
+	ret = clk_enable(&clk);
+	if (ret) {
+		dev_err(udev, "Failed to enable clock\n");
+		return ret;
+	}
+
+	uc_priv->clock_rate = clk_get_rate(&clk);
+
+	/* Enable timer */
+	writew(TIMER_OUT_DIS | TIMER_MODE_PWM_CONT | TIMER_PULSE_HI,
+	       &priv->timer_base->config);
+	writel(MAX_TIM_LOAD, &priv->timer_base->period);
+	writel(MAX_TIM_LOAD - 1, &priv->timer_base->width);
+
+	/* We only use timer 0 in uboot */
+	imask = readw(&priv->timer_group->data_imsk);
+	imask &= ~(1 << 0);
+	writew(imask, &priv->timer_group->data_imsk);
+	writew((1 << 0), &priv->timer_group->enable);
+
+	return 0;
+}
+
+static const struct udevice_id adi_gptimer_ids[] = {
+	{ .compatible = "adi,sc5xx-gptimer" },
+	{ },
+};
+
+U_BOOT_DRIVER(adi_gptimer) = {
+	.name = "adi_gptimer",
+	.id = UCLASS_TIMER,
+	.of_match = adi_gptimer_ids,
+	.priv_auto = sizeof(struct adi_gptimer_priv),
+	.probe = adi_gptimer_probe,
+	.ops = &adi_gptimer_ops,
+};