drivers: timer: omap_timer: add timer driver for omap devices based on dm

Adding a timer driver for omap devices based on driver model
and device tree.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>

drivers/timer/Kconfig

@@ -30,4 +30,10 @@ config X86_TSC_TIMER
 	help
 	  Select this to enable Time-Stamp Counter (TSC) timer for x86.
 
+config OMAP_TIMER
+	bool "Omap timer support"
+	depends on TIMER
+	help
+	  Select this to enable an timer for Omap devices.
+
 endmenu

drivers/timer/Makefile

@@ -8,3 +8,4 @@ obj-$(CONFIG_TIMER)		+= timer-uclass.o
 obj-$(CONFIG_ALTERA_TIMER)	+= altera_timer.o
 obj-$(CONFIG_SANDBOX_TIMER)	+= sandbox_timer.o
 obj-$(CONFIG_X86_TSC_TIMER)	+= tsc_timer.o
+obj-$(CONFIG_OMAP_TIMER)	+= omap-timer.o

drivers/timer/omap-timer.c

@@ -0,0 +1,108 @@
+/*
+ * TI OMAP timer driver
+ *
+ * Copyright (C) 2015, Texas Instruments, Incorporated
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <timer.h>
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* Timer register bits */
+#define TCLR_START			BIT(0)	/* Start=1 */
+#define TCLR_AUTO_RELOAD		BIT(1)	/* Auto reload */
+#define TCLR_PRE_EN			BIT(5)	/* Pre-scaler enable */
+#define TCLR_PTV_SHIFT			(2)	/* Pre-scaler shift value */
+
+#define TIMER_CLOCK             (V_SCLK / (2 << CONFIG_SYS_PTV))
+
+struct omap_gptimer_regs {
+	unsigned int tidr;		/* offset 0x00 */
+	unsigned char res1[12];
+	unsigned int tiocp_cfg;		/* offset 0x10 */
+	unsigned char res2[12];
+	unsigned int tier;		/* offset 0x20 */
+	unsigned int tistatr;		/* offset 0x24 */
+	unsigned int tistat;		/* offset 0x28 */
+	unsigned int tisr;		/* offset 0x2c */
+	unsigned int tcicr;		/* offset 0x30 */
+	unsigned int twer;		/* offset 0x34 */
+	unsigned int tclr;		/* offset 0x38 */
+	unsigned int tcrr;		/* offset 0x3c */
+	unsigned int tldr;		/* offset 0x40 */
+	unsigned int ttgr;		/* offset 0x44 */
+	unsigned int twpc;		/* offset 0x48 */
+	unsigned int tmar;		/* offset 0x4c */
+	unsigned int tcar1;		/* offset 0x50 */
+	unsigned int tscir;		/* offset 0x54 */
+	unsigned int tcar2;		/* offset 0x58 */
+};
+
+/* Omap Timer Priv */
+struct omap_timer_priv {
+	struct omap_gptimer_regs *regs;
+};
+
+static int omap_timer_get_count(struct udevice *dev, u64 *count)
+{
+	struct omap_timer_priv *priv = dev_get_priv(dev);
+
+	*count = readl(&priv->regs->tcrr);
+
+	return 0;
+}
+
+static int omap_timer_probe(struct udevice *dev)
+{
+	struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+	struct omap_timer_priv *priv = dev_get_priv(dev);
+
+	uc_priv->clock_rate = TIMER_CLOCK;
+
+	/* start the counter ticking up, reload value on overflow */
+	writel(0, &priv->regs->tldr);
+	/* enable timer */
+	writel((CONFIG_SYS_PTV << 2) | TCLR_PRE_EN | TCLR_AUTO_RELOAD |
+	       TCLR_START, &priv->regs->tclr);
+
+	return 0;
+}
+
+static int omap_timer_ofdata_to_platdata(struct udevice *dev)
+{
+	struct omap_timer_priv *priv = dev_get_priv(dev);
+
+	priv->regs = (struct omap_gptimer_regs *)dev_get_addr(dev);
+
+	return 0;
+}
+
+
+static const struct timer_ops omap_timer_ops = {
+	.get_count = omap_timer_get_count,
+};
+
+static const struct udevice_id omap_timer_ids[] = {
+	{ .compatible = "ti,am335x-timer" },
+	{ .compatible = "ti,am4372-timer" },
+	{ .compatible = "ti,omap5430-timer" },
+	{}
+};
+
+U_BOOT_DRIVER(omap_timer) = {
+	.name	= "omap_timer",
+	.id	= UCLASS_TIMER,
+	.of_match = omap_timer_ids,
+	.ofdata_to_platdata = omap_timer_ofdata_to_platdata,
+	.priv_auto_alloc_size = sizeof(struct omap_timer_priv),
+	.probe = omap_timer_probe,
+	.ops	= &omap_timer_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};