--- /dev/null
+/*
+ * drivers/rtc/rtc-pcf8583.c
+ *
+ * Copyright (C) 2000 Russell King
+ * Copyright (C) 2008 Wolfram Sang & Juergen Beisert, Pengutronix
+ *
+ * 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.
+ *
+ * Driver for PCF8583 RTC & RAM chip
+ *
+ * Converted to the generic RTC susbsystem by G. Liakhovetski (2006)
+ */
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/rtc.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/bcd.h>
+
+struct rtc_mem {
+ unsigned int loc;
+ unsigned int nr;
+ unsigned char *data;
+};
+
+struct pcf8583 {
+ struct rtc_device *rtc;
+ unsigned char ctrl;
+};
+
+#define CTRL_STOP 0x80
+#define CTRL_HOLD 0x40
+#define CTRL_32KHZ 0x00
+#define CTRL_MASK 0x08
+#define CTRL_ALARMEN 0x04
+#define CTRL_ALARM 0x02
+#define CTRL_TIMER 0x01
+
+
+static struct i2c_driver pcf8583_driver;
+
+#define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl
+#define set_ctrl(x, v) get_ctrl(x) = v
+
+#define CMOS_YEAR (64 + 128)
+#define CMOS_CHECKSUM (63)
+
+static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt)
+{
+ unsigned char buf[8], addr[1] = { 1 };
+ struct i2c_msg msgs[2] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = addr,
+ }, {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = 6,
+ .buf = buf,
+ }
+ };
+ int ret;
+
+ memset(buf, 0, sizeof(buf));
+
+ ret = i2c_transfer(client->adapter, msgs, 2);
+ if (ret == 2) {
+ dt->tm_year = buf[4] >> 6;
+ dt->tm_wday = buf[5] >> 5;
+
+ buf[4] &= 0x3f;
+ buf[5] &= 0x1f;
+
+ dt->tm_sec = bcd2bin(buf[1]);
+ dt->tm_min = bcd2bin(buf[2]);
+ dt->tm_hour = bcd2bin(buf[3]);
+ dt->tm_mday = bcd2bin(buf[4]);
+ dt->tm_mon = bcd2bin(buf[5]) - 1;
+ }
+
+ return ret == 2 ? 0 : -EIO;
+}
+
+static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo)
+{
+ unsigned char buf[8];
+ int ret, len = 6;
+
+ buf[0] = 0;
+ buf[1] = get_ctrl(client) | 0x80;
+ buf[2] = 0;
+ buf[3] = bin2bcd(dt->tm_sec);
+ buf[4] = bin2bcd(dt->tm_min);
+ buf[5] = bin2bcd(dt->tm_hour);
+
+ if (datetoo) {
+ len = 8;
+ buf[6] = bin2bcd(dt->tm_mday) | (dt->tm_year << 6);
+ buf[7] = bin2bcd(dt->tm_mon + 1) | (dt->tm_wday << 5);
+ }
+
+ ret = i2c_master_send(client, (char *)buf, len);
+ if (ret != len)
+ return -EIO;
+
+ buf[1] = get_ctrl(client);
+ ret = i2c_master_send(client, (char *)buf, 2);
+
+ return ret == 2 ? 0 : -EIO;
+}
+
+static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)
+{
+ *ctrl = get_ctrl(client);
+ return 0;
+}
+
+static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl)
+{
+ unsigned char buf[2];
+
+ buf[0] = 0;
+ buf[1] = *ctrl;
+ set_ctrl(client, *ctrl);
+
+ return i2c_master_send(client, (char *)buf, 2);
+}
+
+static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem)
+{
+ unsigned char addr[1];
+ struct i2c_msg msgs[2] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = addr,
+ }, {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = mem->nr,
+ .buf = mem->data,
+ }
+ };
+
+ if (mem->loc < 8)
+ return -EINVAL;
+
+ addr[0] = mem->loc;
+
+ return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
+}
+
+static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem)
+{
+ unsigned char buf[9];
+ int ret;
+
+ if (mem->loc < 8 || mem->nr > 8)
+ return -EINVAL;
+
+ buf[0] = mem->loc;
+ memcpy(buf + 1, mem->data, mem->nr);
+
+ ret = i2c_master_send(client, buf, mem->nr + 1);
+ return ret == mem->nr + 1 ? 0 : -EIO;
+}
+
+static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned char ctrl, year[2];
+ struct rtc_mem mem = {
+ .loc = CMOS_YEAR,
+ .nr = sizeof(year),
+ .data = year
+ };
+ int real_year, year_offset, err;
+
+ /*
+ * Ensure that the RTC is running.
+ */
+ pcf8583_get_ctrl(client, &ctrl);
+ if (ctrl & (CTRL_STOP | CTRL_HOLD)) {
+ unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD);
+
+ dev_warn(dev, "resetting control %02x -> %02x\n",
+ ctrl, new_ctrl);
+
+ err = pcf8583_set_ctrl(client, &new_ctrl);
+ if (err < 0)
+ return err;
+ }
+
+ if (pcf8583_get_datetime(client, tm) ||
+ pcf8583_read_mem(client, &mem))
+ return -EIO;
+
+ real_year = year[0];
+
+ /*
+ * The RTC year holds the LSB two bits of the current
+ * year, which should reflect the LSB two bits of the
+ * CMOS copy of the year. Any difference indicates
+ * that we have to correct the CMOS version.
+ */
+ year_offset = tm->tm_year - (real_year & 3);
+ if (year_offset < 0)
+ /*
+ * RTC year wrapped. Adjust it appropriately.
+ */
+ year_offset += 4;
+
+ tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900;
+
+ return 0;
+}
+
+static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned char year[2], chk;
+ struct rtc_mem cmos_year = {
+ .loc = CMOS_YEAR,
+ .nr = sizeof(year),
+ .data = year
+ };
+ struct rtc_mem cmos_check = {
+ .loc = CMOS_CHECKSUM,
+ .nr = 1,
+ .data = &chk
+ };
+ unsigned int proper_year = tm->tm_year + 1900;
+ int ret;
+
+ /*
+ * The RTC's own 2-bit year must reflect the least
+ * significant two bits of the CMOS year.
+ */
+
+ ret = pcf8583_set_datetime(client, tm, 1);
+ if (ret)
+ return ret;
+
+ ret = pcf8583_read_mem(client, &cmos_check);
+ if (ret)
+ return ret;
+
+ ret = pcf8583_read_mem(client, &cmos_year);
+ if (ret)
+ return ret;
+
+ chk -= year[1] + year[0];
+
+ year[1] = proper_year / 100;
+ year[0] = proper_year % 100;
+
+ chk += year[1] + year[0];
+
+ ret = pcf8583_write_mem(client, &cmos_year);
+
+ if (ret)
+ return ret;
+
+ ret = pcf8583_write_mem(client, &cmos_check);
+
+ return ret;
+}
+
+static const struct rtc_class_ops pcf8583_rtc_ops = {
+ .read_time = pcf8583_rtc_read_time,
+ .set_time = pcf8583_rtc_set_time,
+};
+
+static int pcf8583_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct pcf8583 *pcf8583;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ pcf8583 = devm_kzalloc(&client->dev, sizeof(struct pcf8583),
+ GFP_KERNEL);
+ if (!pcf8583)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, pcf8583);
+
+ pcf8583->rtc = devm_rtc_device_register(&client->dev,
+ pcf8583_driver.driver.name,
+ &pcf8583_rtc_ops, THIS_MODULE);
+
+ return PTR_ERR_OR_ZERO(pcf8583->rtc);
+}
+
+static const struct i2c_device_id pcf8583_id[] = {
+ { "pcf8583", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, pcf8583_id);
+
+static struct i2c_driver pcf8583_driver = {
+ .driver = {
+ .name = "pcf8583",
+ .owner = THIS_MODULE,
+ },
+ .probe = pcf8583_probe,
+ .id_table = pcf8583_id,
+};
+
+module_i2c_driver(pcf8583_driver);
+
+MODULE_AUTHOR("Russell King");
+MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff