From: Dongsheng Wang <dongsheng.wang@freescale.com>
To: <shawn.guo@linaro.org>
CC: <linus.walleij@linaro.org>, <sandeep_n@ti.com>, <hdegoede@redhat.com>,
        <alison.wang@freescale.com>, <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>,
        Wang Dongsheng <dongsheng.wang@freescale.com>
Subject: [PATCH 2/2] soc/fsl: add ftm alarm driver for ls1021a platform
Date: Wed, 12 Aug 2015 13:53:27 +0800
Message-ID: <1439358807-9024-2-git-send-email-dongsheng.wang@freescale.com>
In-Reply-To: <1439358807-9024-1-git-send-email-dongsheng.wang@freescale.com>
References: <1439358807-9024-1-git-send-email-dongsheng.wang@freescale.com>
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From: Wang Dongsheng <dongsheng.wang@freescale.com>

Only Ftm0 can be used when system going to deep sleep. So this driver
to support ftm0 as a wakeup source.

Signed-off-by: Wang Dongsheng <dongsheng.wang@freescale.com>
---
*V2*
Change Copyright 2014 to 2015.

diff --git a/drivers/soc/fsl/ls1/Kconfig b/drivers/soc/fsl/ls1/Kconfig
index 7556f44..e6282dc 100644
--- a/drivers/soc/fsl/ls1/Kconfig
+++ b/drivers/soc/fsl/ls1/Kconfig
@@ -1,3 +1,11 @@
 #
 # LS-1 Soc drivers
 #
+config	FTM_ALARM
+	bool "FTM alarm driver"
+	depends on SOC_LS1021A
+	default n
+	help
+	  Say y here to enable FTM alarm support.  The FTM alarm provides
+	  alarm functions for wakeup system from deep sleep.  There is only
+	  one FTM can be used in ALARM(FTM 0).
diff --git a/drivers/soc/fsl/ls1/Makefile b/drivers/soc/fsl/ls1/Makefile
new file mode 100644
index 0000000..6299aa1
--- /dev/null
+++ b/drivers/soc/fsl/ls1/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_FTM_ALARM) += ftm_alarm.o
diff --git a/drivers/soc/fsl/ls1/ftm_alarm.c b/drivers/soc/fsl/ls1/ftm_alarm.c
new file mode 100644
index 0000000..f7629cd
--- /dev/null
+++ b/drivers/soc/fsl/ls1/ftm_alarm.c
@@ -0,0 +1,272 @@
+/*
+ * Freescale FlexTimer Module (FTM) Alarm driver.
+ *
+ * Copyright 2015 Freescale Semiconductor, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+
+#define FTM_SC			0x00
+#define FTM_SC_CLK_SHIFT	3
+#define FTM_SC_CLK_MASK		(0x3 << FTM_SC_CLK_SHIFT)
+#define FTM_SC_CLK(c)		((c) << FTM_SC_CLK_SHIFT)
+#define FTM_SC_PS_MASK		0x7
+#define FTM_SC_TOIE		BIT(6)
+#define FTM_SC_TOF		BIT(7)
+
+#define FTM_SC_CLKS_FIXED_FREQ	0x02
+
+#define FTM_CNT			0x04
+#define FTM_MOD			0x08
+#define FTM_CNTIN		0x4C
+
+#define FIXED_FREQ_CLK		32000
+#define MAX_FREQ_DIV		(1 << FTM_SC_PS_MASK)
+#define MAX_COUNT_VAL		0xffff
+
+static void __iomem *ftm1_base;
+static u32 alarm_freq;
+static bool big_endian;
+
+static inline u32 ftm_readl(void __iomem *addr)
+{
+	if (big_endian)
+		return ioread32be(addr);
+
+	return ioread32(addr);
+}
+
+static inline void ftm_writel(u32 val, void __iomem *addr)
+{
+	if (big_endian)
+		iowrite32be(val, addr);
+	else
+		iowrite32(val, addr);
+}
+
+static inline void ftm_counter_enable(void __iomem *base)
+{
+	u32 val;
+
+	/* select and enable counter clock source */
+	val = ftm_readl(base + FTM_SC);
+	val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK);
+	val |= (FTM_SC_PS_MASK | FTM_SC_CLK(FTM_SC_CLKS_FIXED_FREQ));
+	ftm_writel(val, base + FTM_SC);
+}
+
+static inline void ftm_counter_disable(void __iomem *base)
+{
+	u32 val;
+
+	/* disable counter clock source */
+	val = ftm_readl(base + FTM_SC);
+	val &= ~(FTM_SC_PS_MASK | FTM_SC_CLK_MASK);
+	ftm_writel(val, base + FTM_SC);
+}
+
+static inline void ftm_irq_acknowledge(void __iomem *base)
+{
+	u32 val;
+
+	val = ftm_readl(base + FTM_SC);
+	val &= ~FTM_SC_TOF;
+	ftm_writel(val, base + FTM_SC);
+}
+
+static inline void ftm_irq_enable(void __iomem *base)
+{
+	u32 val;
+
+	val = ftm_readl(base + FTM_SC);
+	val |= FTM_SC_TOIE;
+	ftm_writel(val, base + FTM_SC);
+}
+
+static inline void ftm_irq_disable(void __iomem *base)
+{
+	u32 val;
+
+	val = ftm_readl(base + FTM_SC);
+	val &= ~FTM_SC_TOIE;
+	ftm_writel(val, base + FTM_SC);
+}
+
+static inline void ftm_reset_counter(void __iomem *base)
+{
+	/*
+	 * The CNT register contains the FTM counter value.
+	 * Reset clears the CNT register. Writing any value to COUNT
+	 * updates the counter with its initial value, CNTIN.
+	 */
+	ftm_writel(0x00, base + FTM_CNT);
+}
+
+static u32 time_to_cycle(unsigned long time)
+{
+	u32 cycle;
+
+	cycle = time * alarm_freq;
+	if (cycle > MAX_COUNT_VAL) {
+		pr_err("Out of alarm range.\n");
+		cycle = 0;
+	}
+
+	return cycle;
+}
+
+static u32 cycle_to_time(u32 cycle)
+{
+	return cycle / alarm_freq + 1;
+}
+
+static void ftm_clean_alarm(void)
+{
+	ftm_counter_disable(ftm1_base);
+
+	ftm_writel(0x00, ftm1_base + FTM_CNTIN);
+	ftm_writel(~0UL, ftm1_base + FTM_MOD);
+
+	ftm_reset_counter(ftm1_base);
+}
+
+static int ftm_set_alarm(u64 cycle)
+{
+	ftm_irq_disable(ftm1_base);
+
+	/*
+	 * The counter increments until the value of MOD is reached,
+	 * at which point the counter is reloaded with the value of CNTIN.
+	 * The TOF (the overflow flag) bit is set when the FTM counter
+	 * changes from MOD to CNTIN. So we should using the cycle - 1.
+	 */
+	ftm_writel(cycle - 1, ftm1_base + FTM_MOD);
+
+	ftm_counter_enable(ftm1_base);
+
+	ftm_irq_enable(ftm1_base);
+
+	return 0;
+}
+
+static irqreturn_t ftm_alarm_interrupt(int irq, void *dev_id)
+{
+	ftm_irq_acknowledge(ftm1_base);
+	ftm_irq_disable(ftm1_base);
+	ftm_clean_alarm();
+
+	return IRQ_HANDLED;
+}
+
+static ssize_t ftm_alarm_show(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	u32 count, val;
+
+	count = ftm_readl(ftm1_base + FTM_MOD);
+	val = ftm_readl(ftm1_base + FTM_CNT);
+	val = (count & MAX_COUNT_VAL) - val;
+	val = cycle_to_time(val);
+
+	return sprintf(buf, "%u\n", val);
+}
+
+static ssize_t ftm_alarm_store(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	u32 cycle;
+	unsigned long time;
+
+	if (kstrtoul(buf, 0, &time))
+		return -EINVAL;
+
+	ftm_clean_alarm();
+
+	cycle = time_to_cycle(time);
+	if (!cycle)
+		return -EINVAL;
+
+	ftm_set_alarm(cycle);
+
+	return count;
+}
+
+static struct device_attribute ftm_alarm_attributes = __ATTR(ftm_alarm, 0644,
+			ftm_alarm_show, ftm_alarm_store);
+
+static int ftm_alarm_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct resource *r;
+	int irq;
+	int ret;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r)
+		return -ENODEV;
+
+	ftm1_base = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(ftm1_base))
+		return PTR_ERR(ftm1_base);
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (irq <= 0) {
+		pr_err("ftm: unable to get IRQ from DT, %d\n", irq);
+		return -EINVAL;
+	}
+
+	big_endian = of_property_read_bool(np, "big-endian");
+
+	ret = devm_request_irq(&pdev->dev, irq, ftm_alarm_interrupt,
+			       IRQF_NO_SUSPEND, dev_name(&pdev->dev), NULL);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to request irq\n");
+		return ret;
+	}
+
+	ret = device_create_file(&pdev->dev, &ftm_alarm_attributes);
+	if (ret) {
+		dev_err(&pdev->dev, "create sysfs fail.\n");
+		return ret;
+	}
+
+	alarm_freq = (u32)FIXED_FREQ_CLK / (u32)MAX_FREQ_DIV;
+
+	ftm_clean_alarm();
+
+	return ret;
+}
+
+static const struct of_device_id ftm_alarm_match[] = {
+	{ .compatible = "fsl,ftm-alarm", },
+	{ .compatible = "fsl,ftm-timer", },
+	{ },
+};
+
+static struct platform_driver ftm_alarm_driver = {
+	.probe		= ftm_alarm_probe,
+	.driver		= {
+		.name	= "ftm-alarm",
+		.owner	= THIS_MODULE,
+		.of_match_table = ftm_alarm_match,
+	},
+};
+
+static int __init ftm_alarm_init(void)
+{
+	return platform_driver_register(&ftm_alarm_driver);
+}
+device_initcall(ftm_alarm_init);
-- 
2.1.0.27.g96db324

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