--- /dev/null
+/*
+ * Copyright (C) 2012 Sven Schnelle <svens@stackframe.org>
+ *
+ * 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.
+ *
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rtc.h>
+#include <linux/types.h>
+#include <linux/bcd.h>
+#include <linux/rtc-ds2404.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/slab.h>
+
+#include <linux/io.h>
+
+#define DS2404_STATUS_REG 0x200
+#define DS2404_CONTROL_REG 0x201
+#define DS2404_RTC_REG 0x202
+
+#define DS2404_WRITE_SCRATCHPAD_CMD 0x0f
+#define DS2404_READ_SCRATCHPAD_CMD 0xaa
+#define DS2404_COPY_SCRATCHPAD_CMD 0x55
+#define DS2404_READ_MEMORY_CMD 0xf0
+
+struct ds2404;
+
+struct ds2404_chip_ops {
+ int (*map_io)(struct ds2404 *chip, struct platform_device *pdev,
+ struct ds2404_platform_data *pdata);
+ void (*unmap_io)(struct ds2404 *chip);
+};
+
+#define DS2404_RST 0
+#define DS2404_CLK 1
+#define DS2404_DQ 2
+
+struct ds2404_gpio {
+ const char *name;
+ unsigned int gpio;
+};
+
+struct ds2404 {
+ struct ds2404_gpio *gpio;
+ struct ds2404_chip_ops *ops;
+ struct rtc_device *rtc;
+};
+
+static struct ds2404_gpio ds2404_gpio[] = {
+ { "RTC RST", 0 },
+ { "RTC CLK", 0 },
+ { "RTC DQ", 0 },
+};
+
+static int ds2404_gpio_map(struct ds2404 *chip, struct platform_device *pdev,
+ struct ds2404_platform_data *pdata)
+{
+ int i, err;
+
+ ds2404_gpio[DS2404_RST].gpio = pdata->gpio_rst;
+ ds2404_gpio[DS2404_CLK].gpio = pdata->gpio_clk;
+ ds2404_gpio[DS2404_DQ].gpio = pdata->gpio_dq;
+
+ for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++) {
+ err = gpio_request(ds2404_gpio[i].gpio, ds2404_gpio[i].name);
+ if (err) {
+ dev_err(&pdev->dev, "error mapping gpio %s: %d\n",
+ ds2404_gpio[i].name, err);
+ goto err_request;
+ }
+ if (i != DS2404_DQ)
+ gpio_direction_output(ds2404_gpio[i].gpio, 1);
+ }
+
+ chip->gpio = ds2404_gpio;
+ return 0;
+
+err_request:
+ while (--i >= 0)
+ gpio_free(ds2404_gpio[i].gpio);
+ return err;
+}
+
+static void ds2404_gpio_unmap(struct ds2404 *chip)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++)
+ gpio_free(ds2404_gpio[i].gpio);
+}
+
+static struct ds2404_chip_ops ds2404_gpio_ops = {
+ .map_io = ds2404_gpio_map,
+ .unmap_io = ds2404_gpio_unmap,
+};
+
+static void ds2404_reset(struct device *dev)
+{
+ gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 0);
+ udelay(1000);
+ gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 1);
+ gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
+ gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 0);
+ udelay(10);
+}
+
+static void ds2404_write_byte(struct device *dev, u8 byte)
+{
+ int i;
+
+ gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 1);
+ for (i = 0; i < 8; i++) {
+ gpio_set_value(ds2404_gpio[DS2404_DQ].gpio, byte & (1 << i));
+ udelay(10);
+ gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1);
+ udelay(10);
+ gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
+ udelay(10);
+ }
+}
+
+static u8 ds2404_read_byte(struct device *dev)
+{
+ int i;
+ u8 ret = 0;
+
+ gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio);
+
+ for (i = 0; i < 8; i++) {
+ gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
+ udelay(10);
+ if (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio))
+ ret |= 1 << i;
+ gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1);
+ udelay(10);
+ }
+ return ret;
+}
+
+static void ds2404_read_memory(struct device *dev, u16 offset,
+ int length, u8 *out)
+{
+ ds2404_reset(dev);
+ ds2404_write_byte(dev, DS2404_READ_MEMORY_CMD);
+ ds2404_write_byte(dev, offset & 0xff);
+ ds2404_write_byte(dev, (offset >> 8) & 0xff);
+ while (length--)
+ *out++ = ds2404_read_byte(dev);
+}
+
+static void ds2404_write_memory(struct device *dev, u16 offset,
+ int length, u8 *out)
+{
+ int i;
+ u8 ta01, ta02, es;
+
+ ds2404_reset(dev);
+ ds2404_write_byte(dev, DS2404_WRITE_SCRATCHPAD_CMD);
+ ds2404_write_byte(dev, offset & 0xff);
+ ds2404_write_byte(dev, (offset >> 8) & 0xff);
+
+ for (i = 0; i < length; i++)
+ ds2404_write_byte(dev, out[i]);
+
+ ds2404_reset(dev);
+ ds2404_write_byte(dev, DS2404_READ_SCRATCHPAD_CMD);
+
+ ta01 = ds2404_read_byte(dev);
+ ta02 = ds2404_read_byte(dev);
+ es = ds2404_read_byte(dev);
+
+ for (i = 0; i < length; i++) {
+ if (out[i] != ds2404_read_byte(dev)) {
+ dev_err(dev, "read invalid data\n");
+ return;
+ }
+ }
+
+ ds2404_reset(dev);
+ ds2404_write_byte(dev, DS2404_COPY_SCRATCHPAD_CMD);
+ ds2404_write_byte(dev, ta01);
+ ds2404_write_byte(dev, ta02);
+ ds2404_write_byte(dev, es);
+
+ gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio);
+ while (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio))
+ ;
+}
+
+static void ds2404_enable_osc(struct device *dev)
+{
+ u8 in[1] = { 0x10 }; /* enable oscillator */
+ ds2404_write_memory(dev, 0x201, 1, in);
+}
+
+static int ds2404_read_time(struct device *dev, struct rtc_time *dt)
+{
+ unsigned long time = 0;
+
+ ds2404_read_memory(dev, 0x203, 4, (u8 *)&time);
+ time = le32_to_cpu(time);
+
+ rtc_time_to_tm(time, dt);
+ return rtc_valid_tm(dt);
+}
+
+static int ds2404_set_mmss(struct device *dev, unsigned long secs)
+{
+ u32 time = cpu_to_le32(secs);
+ ds2404_write_memory(dev, 0x203, 4, (u8 *)&time);
+ return 0;
+}
+
+static const struct rtc_class_ops ds2404_rtc_ops = {
+ .read_time = ds2404_read_time,
+ .set_mmss = ds2404_set_mmss,
+};
+
+static int rtc_probe(struct platform_device *pdev)
+{
+ struct ds2404_platform_data *pdata = dev_get_platdata(&pdev->dev);
+ struct ds2404 *chip;
+ int retval = -EBUSY;
+
+ chip = devm_kzalloc(&pdev->dev, sizeof(struct ds2404), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ chip->ops = &ds2404_gpio_ops;
+
+ retval = chip->ops->map_io(chip, pdev, pdata);
+ if (retval)
+ goto err_chip;
+
+ dev_info(&pdev->dev, "using GPIOs RST:%d, CLK:%d, DQ:%d\n",
+ chip->gpio[DS2404_RST].gpio, chip->gpio[DS2404_CLK].gpio,
+ chip->gpio[DS2404_DQ].gpio);
+
+ platform_set_drvdata(pdev, chip);
+
+ chip->rtc = devm_rtc_device_register(&pdev->dev, "ds2404",
+ &ds2404_rtc_ops, THIS_MODULE);
+ if (IS_ERR(chip->rtc)) {
+ retval = PTR_ERR(chip->rtc);
+ goto err_io;
+ }
+
+ ds2404_enable_osc(&pdev->dev);
+ return 0;
+
+err_io:
+ chip->ops->unmap_io(chip);
+err_chip:
+ return retval;
+}
+
+static int rtc_remove(struct platform_device *dev)
+{
+ struct ds2404 *chip = platform_get_drvdata(dev);
+
+ chip->ops->unmap_io(chip);
+
+ return 0;
+}
+
+static struct platform_driver rtc_device_driver = {
+ .probe = rtc_probe,
+ .remove = rtc_remove,
+ .driver = {
+ .name = "ds2404",
+ },
+};
+module_platform_driver(rtc_device_driver);
+
+MODULE_DESCRIPTION("DS2404 RTC");
+MODULE_AUTHOR("Sven Schnelle");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ds2404");
Code Review / kvmfornfv.git / blobdiff