[PATCH 2/2] rtc: driver for Conexant Digicolor CX92755 on-chip RTC
Baruch Siach
baruch at tkos.co.il
Mon Mar 23 06:28:54 PDT 2015
Add driver for the RTC hardware block on the Conexant CX92755 SoC, from the
Digicolor series of SoCs. Tested on the Equinox evaluation board for the
CX92755 chip.
Cc: Alessandro Zummo <a.zummo at towertech.it>
Signed-off-by: Baruch Siach <baruch at tkos.co.il>
---
drivers/rtc/Kconfig | 10 ++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-digicolor.c | 227 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 238 insertions(+)
create mode 100644 drivers/rtc/rtc-digicolor.c
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index b5b5c3d485d6..faeee2d2550b 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1111,6 +1111,16 @@ config RTC_DRV_DAVINCI
This driver can also be built as a module. If so, the module
will be called rtc-davinci.
+config RTC_DRV_DIGICOLOR
+ tristate "Conexant Digicolor RTC"
+ depends on ARCH_DIGICOLOR
+ help
+ If you say yes here you get support for the RTC on Conexant
+ Digicolor platforms. This currently includes the CX92755 SoC.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-digicolor.
+
config RTC_DRV_IMXDI
tristate "Freescale IMX DryIce Real Time Clock"
depends on ARCH_MXC
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 69c87062b098..c31731c29762 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_RTC_DRV_DA9052) += rtc-da9052.o
obj-$(CONFIG_RTC_DRV_DA9055) += rtc-da9055.o
obj-$(CONFIG_RTC_DRV_DA9063) += rtc-da9063.o
obj-$(CONFIG_RTC_DRV_DAVINCI) += rtc-davinci.o
+obj-$(CONFIG_RTC_DRV_DIGICOLOR) += rtc-digicolor.o
obj-$(CONFIG_RTC_DRV_DM355EVM) += rtc-dm355evm.o
obj-$(CONFIG_RTC_DRV_VRTC) += rtc-mrst.o
obj-$(CONFIG_RTC_DRV_DS1216) += rtc-ds1216.o
diff --git a/drivers/rtc/rtc-digicolor.c b/drivers/rtc/rtc-digicolor.c
new file mode 100644
index 000000000000..658aeab0c161
--- /dev/null
+++ b/drivers/rtc/rtc-digicolor.c
@@ -0,0 +1,227 @@
+/*
+ * Real Time Clock driver for Conexant Digicolor
+ *
+ * Copyright (C) 2015 Paradox Innovation Ltd.
+ *
+ * Author: Baruch Siach <baruch at tkos.co.il>
+ *
+ * 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/io.h>
+#include <linux/iopoll.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/of.h>
+
+#define DC_RTC_CONTROL 0x0
+#define DC_RTC_TIME 0x8
+#define DC_RTC_REFERENCE 0xc
+#define DC_RTC_ALARM 0x10
+#define DC_RTC_INTFLAG_CLEAR 0x14
+#define DC_RTC_INTENABLE 0x16
+
+#define DC_RTC_CMD_MASK 0xf
+#define DC_RTC_GO_BUSY BIT(7)
+
+#define CMD_NOP 0
+#define CMD_RESET 1
+#define CMD_WRITE 3
+#define CMD_READ 4
+
+#define CMD_DELAY_US (10*1000)
+#define CMD_TIMEOUT_US (500*CMD_DELAY_US)
+
+struct dc_rtc {
+ struct rtc_device *rtc_dev;
+ void __iomem *regs;
+};
+
+static int dc_rtc_cmds(struct dc_rtc *rtc, u8 *cmds, int len)
+{
+ u8 val;
+ int i, ret;
+
+ for (i = 0; i < len; i++) {
+ writeb_relaxed((cmds[i] & DC_RTC_CMD_MASK) | DC_RTC_GO_BUSY,
+ rtc->regs + DC_RTC_CONTROL);
+ ret = readb_relaxed_poll_timeout(
+ rtc->regs + DC_RTC_CONTROL, val,
+ !(val & DC_RTC_GO_BUSY), CMD_DELAY_US, CMD_TIMEOUT_US);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int dc_rtc_read(struct dc_rtc *rtc, unsigned long *val)
+{
+ u8 read_cmds[] = {CMD_READ, CMD_NOP};
+ u32 reference, time1, time2;
+ int ret;
+
+ ret = dc_rtc_cmds(rtc, read_cmds, ARRAY_SIZE(read_cmds));
+ if (ret < 0)
+ return ret;
+
+ reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE);
+ time1 = readl_relaxed(rtc->regs + DC_RTC_TIME);
+ /* Read twice to ensure consistency */
+ while (1) {
+ time2 = readl_relaxed(rtc->regs + DC_RTC_TIME);
+ if (time1 == time2)
+ break;
+ time1 = time2;
+ }
+
+ *val = reference + time1;
+ return 0;
+}
+
+static int dc_rtc_write(struct dc_rtc *rtc, u32 val)
+{
+ u8 write_cmds[] = {CMD_WRITE, CMD_NOP, CMD_RESET, CMD_NOP};
+
+ writel_relaxed(val, rtc->regs + DC_RTC_REFERENCE);
+ return dc_rtc_cmds(rtc, write_cmds, ARRAY_SIZE(write_cmds));
+}
+
+static int dc_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct dc_rtc *rtc = dev_get_drvdata(dev);
+ unsigned long now;
+ int ret;
+
+ ret = dc_rtc_read(rtc, &now);
+ if (ret < 0)
+ return ret;
+ rtc_time64_to_tm(now, tm);
+
+ return 0;
+}
+
+static int dc_rtc_set_mmss(struct device *dev, unsigned long secs)
+{
+ struct dc_rtc *rtc = dev_get_drvdata(dev);
+
+ return dc_rtc_write(rtc, secs);
+}
+
+static int dc_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+ struct dc_rtc *rtc = dev_get_drvdata(dev);
+ u32 alarm_reg, reference;
+ unsigned long now;
+ int ret;
+
+ alarm_reg = readl_relaxed(rtc->regs + DC_RTC_ALARM);
+ reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE);
+ rtc_time64_to_tm(reference + alarm_reg, &alarm->time);
+
+ ret = dc_rtc_read(rtc, &now);
+ if (ret < 0)
+ return ret;
+
+ alarm->pending = alarm_reg + reference > now;
+ alarm->enabled = readl_relaxed(rtc->regs + DC_RTC_INTENABLE);
+
+ return 0;
+}
+
+static int dc_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+ struct dc_rtc *rtc = dev_get_drvdata(dev);
+ time64_t alarm_time;
+ u32 reference;
+
+ alarm_time = rtc_tm_to_time64(&alarm->time);
+
+ reference = readl_relaxed(rtc->regs + DC_RTC_REFERENCE);
+ writel_relaxed(alarm_time - reference, rtc->regs + DC_RTC_ALARM);
+
+ writeb_relaxed(!!alarm->enabled, rtc->regs + DC_RTC_INTENABLE);
+
+ return 0;
+}
+
+static int dc_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct dc_rtc *rtc = dev_get_drvdata(dev);
+
+ writeb_relaxed(!!enabled, rtc->regs + DC_RTC_INTENABLE);
+
+ return 0;
+}
+
+static struct rtc_class_ops dc_rtc_ops = {
+ .read_time = dc_rtc_read_time,
+ .set_mmss = dc_rtc_set_mmss,
+ .read_alarm = dc_rtc_read_alarm,
+ .set_alarm = dc_rtc_set_alarm,
+ .alarm_irq_enable = dc_rtc_alarm_irq_enable,
+};
+
+static irqreturn_t dc_rtc_irq(int irq, void *dev_id)
+{
+ struct dc_rtc *rtc = dev_id;
+
+ writeb_relaxed(1, rtc->regs + DC_RTC_INTFLAG_CLEAR);
+ rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF);
+
+ return IRQ_HANDLED;
+}
+
+static int __init dc_rtc_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct dc_rtc *rtc;
+ int irq, ret;
+
+ rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+ if (!rtc)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ rtc->regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(rtc->regs))
+ return PTR_ERR(rtc->regs);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+ ret = devm_request_irq(&pdev->dev, irq, dc_rtc_irq, 0, pdev->name, rtc);
+ if (ret < 0)
+ return ret;
+
+ platform_set_drvdata(pdev, rtc);
+ rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
+ &dc_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc->rtc_dev))
+ return PTR_ERR(rtc->rtc_dev);
+
+ return 0;
+}
+
+static const struct of_device_id dc_dt_ids[] = {
+ { .compatible = "cnxt,cx92755-rtc" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, dc_dt_ids);
+
+static struct platform_driver dc_rtc_driver = {
+ .driver = {
+ .name = "digicolor_rtc",
+ .of_match_table = of_match_ptr(dc_dt_ids),
+ },
+};
+module_platform_driver_probe(dc_rtc_driver, dc_rtc_probe);
+
+MODULE_AUTHOR("Baruch Siach <baruch at tkos.co.il>");
+MODULE_DESCRIPTION("Conexant Digicolor Realtime Clock Driver (RTC)");
+MODULE_LICENSE("GPL");
--
2.1.4
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