[PATCH 1/3] rtc: rtc-m48t86: add devicetree bindings
Alexander Clouter
alex at digriz.org.uk
Mon Apr 1 08:56:09 EST 2013
This patch allows rtc-m48t86 to be used via devicetree.
Signed-off-by: Alexander Clouter <alex at digriz.org.uk>
---
.../devicetree/bindings/rtc/rtc-m48t86.txt | 17 ++
drivers/rtc/rtc-m48t86.c | 254 +++++++++++++++-----
include/linux/m48t86.h | 16 --
3 files changed, 213 insertions(+), 74 deletions(-)
create mode 100644 Documentation/devicetree/bindings/rtc/rtc-m48t86.txt
delete mode 100644 include/linux/m48t86.h
diff --git a/Documentation/devicetree/bindings/rtc/rtc-m48t86.txt b/Documentation/devicetree/bindings/rtc/rtc-m48t86.txt
new file mode 100644
index 0000000..1336c98
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/rtc-m48t86.txt
@@ -0,0 +1,17 @@
+ST M48T86 / Dallas DS12887 RTC driver
+
+Required properties:
+- compatible: "rtc-m48t86"
+- reg: array of two address ranges of the RTC index and data registers
+- reg-names: must have "rtc_index" and "rtc_data" present
+
+Example:
+
+rtc at 808 {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ compatible = "rtc-m48t86";
+ reg = <0x808 0x04>,
+ <0x80c 0x04>;
+ reg-names = "rtc_index", "rtc_data";
+};
diff --git a/drivers/rtc/rtc-m48t86.c b/drivers/rtc/rtc-m48t86.c
index 2ffbcac..47e9fd1 100644
--- a/drivers/rtc/rtc-m48t86.c
+++ b/drivers/rtc/rtc-m48t86.c
@@ -16,8 +16,10 @@
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
-#include <linux/m48t86.h>
#include <linux/bcd.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/io.h>
#define M48T86_REG_SEC 0x00
#define M48T86_REG_SECALRM 0x01
@@ -41,40 +43,61 @@
#define DRV_VERSION "0.1"
+struct m48t86_rtc_private_data {
+ void __iomem *io_index;
+ void __iomem *io_data;
+
+ struct rtc_device *rtc;
+};
+
+static unsigned char m48t86_rtc_readbyte(
+ struct m48t86_rtc_private_data *priv,
+ unsigned long addr)
+{
+ writeb(addr, priv->io_index);
+ return readb(priv->io_data);
+}
+
+static void m48t86_rtc_writebyte(
+ struct m48t86_rtc_private_data *priv,
+ unsigned char value, unsigned long addr)
+{
+ writeb(addr, priv->io_index);
+ writeb(value, priv->io_data);
+}
static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
unsigned char reg;
- struct platform_device *pdev = to_platform_device(dev);
- struct m48t86_ops *ops = pdev->dev.platform_data;
+ struct m48t86_rtc_private_data *priv = dev_get_drvdata(dev);
- reg = ops->readbyte(M48T86_REG_B);
+ reg = m48t86_rtc_readbyte(priv, M48T86_REG_B);
if (reg & M48T86_REG_B_DM) {
/* data (binary) mode */
- tm->tm_sec = ops->readbyte(M48T86_REG_SEC);
- tm->tm_min = ops->readbyte(M48T86_REG_MIN);
- tm->tm_hour = ops->readbyte(M48T86_REG_HOUR) & 0x3F;
- tm->tm_mday = ops->readbyte(M48T86_REG_DOM);
+ tm->tm_sec = m48t86_rtc_readbyte(priv, M48T86_REG_SEC);
+ tm->tm_min = m48t86_rtc_readbyte(priv, M48T86_REG_MIN);
+ tm->tm_hour = m48t86_rtc_readbyte(priv, M48T86_REG_HOUR) & 0x3F;
+ tm->tm_mday = m48t86_rtc_readbyte(priv, M48T86_REG_DOM);
/* tm_mon is 0-11 */
- tm->tm_mon = ops->readbyte(M48T86_REG_MONTH) - 1;
- tm->tm_year = ops->readbyte(M48T86_REG_YEAR) + 100;
- tm->tm_wday = ops->readbyte(M48T86_REG_DOW);
+ tm->tm_mon = m48t86_rtc_readbyte(priv, M48T86_REG_MONTH) - 1;
+ tm->tm_year = m48t86_rtc_readbyte(priv, M48T86_REG_YEAR) + 100;
+ tm->tm_wday = m48t86_rtc_readbyte(priv, M48T86_REG_DOW);
} else {
/* bcd mode */
- tm->tm_sec = bcd2bin(ops->readbyte(M48T86_REG_SEC));
- tm->tm_min = bcd2bin(ops->readbyte(M48T86_REG_MIN));
- tm->tm_hour = bcd2bin(ops->readbyte(M48T86_REG_HOUR) & 0x3F);
- tm->tm_mday = bcd2bin(ops->readbyte(M48T86_REG_DOM));
+ tm->tm_sec = bcd2bin(m48t86_rtc_readbyte(priv, M48T86_REG_SEC));
+ tm->tm_min = bcd2bin(m48t86_rtc_readbyte(priv, M48T86_REG_MIN));
+ tm->tm_hour = bcd2bin(m48t86_rtc_readbyte(priv, M48T86_REG_HOUR) & 0x3F);
+ tm->tm_mday = bcd2bin(m48t86_rtc_readbyte(priv, M48T86_REG_DOM));
/* tm_mon is 0-11 */
- tm->tm_mon = bcd2bin(ops->readbyte(M48T86_REG_MONTH)) - 1;
- tm->tm_year = bcd2bin(ops->readbyte(M48T86_REG_YEAR)) + 100;
- tm->tm_wday = bcd2bin(ops->readbyte(M48T86_REG_DOW));
+ tm->tm_mon = bcd2bin(m48t86_rtc_readbyte(priv, M48T86_REG_MONTH)) - 1;
+ tm->tm_year = bcd2bin(m48t86_rtc_readbyte(priv, M48T86_REG_YEAR)) + 100;
+ tm->tm_wday = bcd2bin(m48t86_rtc_readbyte(priv, M48T86_REG_DOW));
}
/* correct the hour if the clock is in 12h mode */
if (!(reg & M48T86_REG_B_H24))
- if (ops->readbyte(M48T86_REG_HOUR) & 0x80)
+ if (m48t86_rtc_readbyte(priv, M48T86_REG_HOUR) & 0x80)
tm->tm_hour += 12;
return rtc_valid_tm(tm);
@@ -83,38 +106,37 @@ static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
unsigned char reg;
- struct platform_device *pdev = to_platform_device(dev);
- struct m48t86_ops *ops = pdev->dev.platform_data;
+ struct m48t86_rtc_private_data *priv = dev_get_drvdata(dev);
- reg = ops->readbyte(M48T86_REG_B);
+ reg = m48t86_rtc_readbyte(priv, M48T86_REG_B);
/* update flag and 24h mode */
reg |= M48T86_REG_B_SET | M48T86_REG_B_H24;
- ops->writebyte(reg, M48T86_REG_B);
+ m48t86_rtc_writebyte(priv, reg, M48T86_REG_B);
if (reg & M48T86_REG_B_DM) {
/* data (binary) mode */
- ops->writebyte(tm->tm_sec, M48T86_REG_SEC);
- ops->writebyte(tm->tm_min, M48T86_REG_MIN);
- ops->writebyte(tm->tm_hour, M48T86_REG_HOUR);
- ops->writebyte(tm->tm_mday, M48T86_REG_DOM);
- ops->writebyte(tm->tm_mon + 1, M48T86_REG_MONTH);
- ops->writebyte(tm->tm_year % 100, M48T86_REG_YEAR);
- ops->writebyte(tm->tm_wday, M48T86_REG_DOW);
+ m48t86_rtc_writebyte(priv, tm->tm_sec, M48T86_REG_SEC);
+ m48t86_rtc_writebyte(priv, tm->tm_min, M48T86_REG_MIN);
+ m48t86_rtc_writebyte(priv, tm->tm_hour, M48T86_REG_HOUR);
+ m48t86_rtc_writebyte(priv, tm->tm_mday, M48T86_REG_DOM);
+ m48t86_rtc_writebyte(priv, tm->tm_mon + 1, M48T86_REG_MONTH);
+ m48t86_rtc_writebyte(priv, tm->tm_year % 100, M48T86_REG_YEAR);
+ m48t86_rtc_writebyte(priv, tm->tm_wday, M48T86_REG_DOW);
} else {
/* bcd mode */
- ops->writebyte(bin2bcd(tm->tm_sec), M48T86_REG_SEC);
- ops->writebyte(bin2bcd(tm->tm_min), M48T86_REG_MIN);
- ops->writebyte(bin2bcd(tm->tm_hour), M48T86_REG_HOUR);
- ops->writebyte(bin2bcd(tm->tm_mday), M48T86_REG_DOM);
- ops->writebyte(bin2bcd(tm->tm_mon + 1), M48T86_REG_MONTH);
- ops->writebyte(bin2bcd(tm->tm_year % 100), M48T86_REG_YEAR);
- ops->writebyte(bin2bcd(tm->tm_wday), M48T86_REG_DOW);
+ m48t86_rtc_writebyte(priv, bin2bcd(tm->tm_sec), M48T86_REG_SEC);
+ m48t86_rtc_writebyte(priv, bin2bcd(tm->tm_min), M48T86_REG_MIN);
+ m48t86_rtc_writebyte(priv, bin2bcd(tm->tm_hour), M48T86_REG_HOUR);
+ m48t86_rtc_writebyte(priv, bin2bcd(tm->tm_mday), M48T86_REG_DOM);
+ m48t86_rtc_writebyte(priv, bin2bcd(tm->tm_mon + 1), M48T86_REG_MONTH);
+ m48t86_rtc_writebyte(priv, bin2bcd(tm->tm_year % 100), M48T86_REG_YEAR);
+ m48t86_rtc_writebyte(priv, bin2bcd(tm->tm_wday), M48T86_REG_DOW);
}
/* update ended */
reg &= ~M48T86_REG_B_SET;
- ops->writebyte(reg, M48T86_REG_B);
+ m48t86_rtc_writebyte(priv, reg, M48T86_REG_B);
return 0;
}
@@ -122,15 +144,14 @@ static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm)
static int m48t86_rtc_proc(struct device *dev, struct seq_file *seq)
{
unsigned char reg;
- struct platform_device *pdev = to_platform_device(dev);
- struct m48t86_ops *ops = pdev->dev.platform_data;
+ struct m48t86_rtc_private_data *priv = dev_get_drvdata(dev);
- reg = ops->readbyte(M48T86_REG_B);
+ reg = m48t86_rtc_readbyte(priv, M48T86_REG_B);
seq_printf(seq, "mode\t\t: %s\n",
(reg & M48T86_REG_B_DM) ? "binary" : "bcd");
- reg = ops->readbyte(M48T86_REG_D);
+ reg = m48t86_rtc_readbyte(priv, M48T86_REG_D);
seq_printf(seq, "battery\t\t: %s\n",
(reg & M48T86_REG_D_VRT) ? "ok" : "exhausted");
@@ -144,42 +165,159 @@ static const struct rtc_class_ops m48t86_rtc_ops = {
.proc = m48t86_rtc_proc,
};
-static int m48t86_rtc_probe(struct platform_device *dev)
+/*
+ * The RTC chip has 114 bytes upper bytes that can be used as user storage
+ * space which we can use to test if the chip is present; for example it is
+ * an optional feature and not all boards will have it present.
+ *
+ * I've used the method Technologic Systems use in their rtc7800.c example
+ * for the detection.
+ *
+ * TODO: track down a guinea pig without an RTC to see if we can work out a
+ * better RTC detection routine
+ */
+static int m48t86_rtc_detect(struct device *dev)
+{
+ struct m48t86_rtc_private_data *priv = dev_get_drvdata(dev);
+
+ unsigned char tmp_rtc0, tmp_rtc1;
+
+ tmp_rtc0 = m48t86_rtc_readbyte(priv, 126);
+ tmp_rtc1 = m48t86_rtc_readbyte(priv, 127);
+
+ m48t86_rtc_writebyte(priv, 0x00, 126);
+ m48t86_rtc_writebyte(priv, 0x55, 127);
+ if (m48t86_rtc_readbyte(priv, 127) == 0x55) {
+ m48t86_rtc_writebyte(priv, 0xaa, 127);
+ if (m48t86_rtc_readbyte(priv, 127) == 0xaa
+ && m48t86_rtc_readbyte(priv, 126) == 0x00) {
+ m48t86_rtc_writebyte(priv, tmp_rtc0, 126);
+ m48t86_rtc_writebyte(priv, tmp_rtc1, 127);
+
+ return 0;
+ }
+ }
+
+ dev_info(dev, "RTC not found\n");
+ return -ENODEV;
+}
+
+static int m48t86_rtc_probe(struct platform_device *pdev)
{
+ struct m48t86_rtc_private_data *priv;
+ struct resource *res_index, *res_data;
unsigned char reg;
- struct m48t86_ops *ops = dev->dev.platform_data;
- struct rtc_device *rtc = rtc_device_register("m48t86",
- &dev->dev, &m48t86_rtc_ops, THIS_MODULE);
+ int err;
+
+ res_index = platform_get_resource_byname(
+ pdev, IORESOURCE_MEM, "rtc_index");
+ if (!res_index)
+ return -ENXIO;
+ res_data = platform_get_resource_byname(
+ pdev, IORESOURCE_MEM, "rtc_data");
+ if (!res_data)
+ return -ENXIO;
+
+ /* Allocate memory for the device structure (and zero it) */
+ priv = kzalloc(sizeof(struct m48t86_rtc_private_data), GFP_KERNEL);
+ if (!priv) {
+ dev_err(&pdev->dev, "failed to allocate device structure.\n");
+ return -ENOMEM;
+ }
+
+ if (!request_mem_region(res_index->start, resource_size(res_index),
+ dev_name(&pdev->dev))) {
+ dev_err(&pdev->dev, "request_mem_region failed\n");
+ err = -EBUSY;
+ goto out_free;
+ }
+ if (!request_mem_region(res_data->start, resource_size(res_data),
+ dev_name(&pdev->dev))) {
+ dev_err(&pdev->dev, "request_mem_region failed\n");
+ err = -EBUSY;
+ goto out_release_io_index;
+ }
+
+ priv->io_index = ioremap(res_index->start, resource_size(res_index));
+ if (priv->io_index == NULL) {
+ dev_err(&pdev->dev, "ioremap failed\n");
+ err = -EIO;
+ goto out_release_io_data;
+ }
+ priv->io_data = ioremap(res_data->start, resource_size(res_data));
+ if (priv->io_data == NULL) {
+ dev_err(&pdev->dev, "ioremap failed\n");
+ err = -EIO;
+ goto out_ctrl;
+ }
+
+ platform_set_drvdata(pdev, priv);
- if (IS_ERR(rtc))
- return PTR_ERR(rtc);
+ err = m48t86_rtc_detect(&pdev->dev);
+ if (err)
+ goto out;
- platform_set_drvdata(dev, rtc);
+ priv->rtc = rtc_device_register("m48t86",
+ &pdev->dev, &m48t86_rtc_ops, THIS_MODULE);
+ if (IS_ERR(priv->rtc)) {
+ err = PTR_ERR(priv->rtc);
+ goto out;
+ }
/* read battery status */
- reg = ops->readbyte(M48T86_REG_D);
- dev_info(&dev->dev, "battery %s\n",
+ reg = m48t86_rtc_readbyte(priv, M48T86_REG_D);
+ dev_info(&pdev->dev, "battery %s\n",
(reg & M48T86_REG_D_VRT) ? "ok" : "exhausted");
return 0;
+
+out:
+ platform_set_drvdata(pdev, NULL);
+ iounmap(priv->io_data);
+out_ctrl:
+ iounmap(priv->io_index);
+out_release_io_data:
+ release_mem_region(res_data->start, resource_size(res_data));
+out_release_io_index:
+ release_mem_region(res_index->start, resource_size(res_index));
+out_free:
+ kfree(priv);
+ return err;
}
-static int m48t86_rtc_remove(struct platform_device *dev)
+static int m48t86_rtc_remove(struct platform_device *pdev)
{
- struct rtc_device *rtc = platform_get_drvdata(dev);
+ struct m48t86_rtc_private_data *priv = platform_get_drvdata(pdev);
+ struct resource *res;
+
+ rtc_device_unregister(priv->rtc);
- if (rtc)
- rtc_device_unregister(rtc);
+ platform_set_drvdata(pdev, NULL);
- platform_set_drvdata(dev, NULL);
+ iounmap(priv->io_data);
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc_data");
+ release_mem_region(res->start, resource_size(res));
+
+ iounmap(priv->io_index);
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc_index");
+ release_mem_region(res->start, resource_size(res));
+
+ kfree(priv);
return 0;
}
+static const struct of_device_id m48t86_rtc_match[] = {
+ { .compatible = "rtc-m48t86" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, m48t86_rtc_match);
+
static struct platform_driver m48t86_rtc_platform_driver = {
.driver = {
- .name = "rtc-m48t86",
- .owner = THIS_MODULE,
+ .name = "rtc-m48t86",
+ .owner = THIS_MODULE,
+ .of_match_table = m48t86_rtc_match,
},
.probe = m48t86_rtc_probe,
.remove = m48t86_rtc_remove,
diff --git a/include/linux/m48t86.h b/include/linux/m48t86.h
deleted file mode 100644
index 915d6b4..0000000
--- a/include/linux/m48t86.h
+++ /dev/null
@@ -1,16 +0,0 @@
-/*
- * ST M48T86 / Dallas DS12887 RTC driver
- * Copyright (c) 2006 Tower Technologies
- *
- * Author: Alessandro Zummo <a.zummo at towertech.it>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
-*/
-
-struct m48t86_ops
-{
- void (*writebyte)(unsigned char value, unsigned long addr);
- unsigned char (*readbyte)(unsigned long addr);
-};
--
1.7.10.4
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