From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- drivers/rtc/rtc-pcf8583.c | 317 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 317 insertions(+) create mode 100644 drivers/rtc/rtc-pcf8583.c (limited to 'drivers/rtc/rtc-pcf8583.c') diff --git a/drivers/rtc/rtc-pcf8583.c b/drivers/rtc/rtc-pcf8583.c new file mode 100644 index 000000000..87074d178 --- /dev/null +++ b/drivers/rtc/rtc-pcf8583.c @@ -0,0 +1,317 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * drivers/rtc/rtc-pcf8583.c + * + * Copyright (C) 2000 Russell King + * Copyright (C) 2008 Wolfram Sang & Juergen Beisert, Pengutronix + * + * Driver for PCF8583 RTC & RAM chip + * + * Converted to the generic RTC susbsystem by G. Liakhovetski (2006) + */ +#include +#include +#include +#include +#include +#include +#include +#include + +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) +{ + 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", + }, + .probe_new = pcf8583_probe, + .id_table = pcf8583_id, +}; + +module_i2c_driver(pcf8583_driver); + +MODULE_AUTHOR("Russell King"); +MODULE_DESCRIPTION("PCF8583 I2C RTC driver"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3