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-rw-r--r--drivers/rtc/rtc-rs5c372.c935
1 files changed, 935 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
new file mode 100644
index 000000000..9562c477e
--- /dev/null
+++ b/drivers/rtc/rtc-rs5c372.c
@@ -0,0 +1,935 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * An I2C driver for Ricoh RS5C372, R2025S/D and RV5C38[67] RTCs
+ *
+ * Copyright (C) 2005 Pavel Mironchik <pmironchik@optifacio.net>
+ * Copyright (C) 2006 Tower Technologies
+ * Copyright (C) 2008 Paul Mundt
+ */
+
+#include <linux/i2c.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+/*
+ * Ricoh has a family of I2C based RTCs, which differ only slightly from
+ * each other. Differences center on pinout (e.g. how many interrupts,
+ * output clock, etc) and how the control registers are used. The '372
+ * is significant only because that's the one this driver first supported.
+ */
+#define RS5C372_REG_SECS 0
+#define RS5C372_REG_MINS 1
+#define RS5C372_REG_HOURS 2
+#define RS5C372_REG_WDAY 3
+#define RS5C372_REG_DAY 4
+#define RS5C372_REG_MONTH 5
+#define RS5C372_REG_YEAR 6
+#define RS5C372_REG_TRIM 7
+# define RS5C372_TRIM_XSL 0x80 /* only if RS5C372[a|b] */
+# define RS5C372_TRIM_MASK 0x7F
+# define R2221TL_TRIM_DEV (1 << 7) /* only if R2221TL */
+# define RS5C372_TRIM_DECR (1 << 6)
+
+#define RS5C_REG_ALARM_A_MIN 8 /* or ALARM_W */
+#define RS5C_REG_ALARM_A_HOURS 9
+#define RS5C_REG_ALARM_A_WDAY 10
+
+#define RS5C_REG_ALARM_B_MIN 11 /* or ALARM_D */
+#define RS5C_REG_ALARM_B_HOURS 12
+#define RS5C_REG_ALARM_B_WDAY 13 /* (ALARM_B only) */
+
+#define RS5C_REG_CTRL1 14
+# define RS5C_CTRL1_AALE (1 << 7) /* or WALE */
+# define RS5C_CTRL1_BALE (1 << 6) /* or DALE */
+# define RV5C387_CTRL1_24 (1 << 5)
+# define RS5C372A_CTRL1_SL1 (1 << 5)
+# define RS5C_CTRL1_CT_MASK (7 << 0)
+# define RS5C_CTRL1_CT0 (0 << 0) /* no periodic irq */
+# define RS5C_CTRL1_CT4 (4 << 0) /* 1 Hz level irq */
+#define RS5C_REG_CTRL2 15
+# define RS5C372_CTRL2_24 (1 << 5)
+# define RS5C_CTRL2_XSTP (1 << 4) /* only if !R2x2x */
+# define R2x2x_CTRL2_VDET (1 << 6) /* only if R2x2x */
+# define R2x2x_CTRL2_XSTP (1 << 5) /* only if R2x2x */
+# define R2x2x_CTRL2_PON (1 << 4) /* only if R2x2x */
+# define RS5C_CTRL2_CTFG (1 << 2)
+# define RS5C_CTRL2_AAFG (1 << 1) /* or WAFG */
+# define RS5C_CTRL2_BAFG (1 << 0) /* or DAFG */
+
+
+/* to read (style 1) or write registers starting at R */
+#define RS5C_ADDR(R) (((R) << 4) | 0)
+
+
+enum rtc_type {
+ rtc_undef = 0,
+ rtc_r2025sd,
+ rtc_r2221tl,
+ rtc_rs5c372a,
+ rtc_rs5c372b,
+ rtc_rv5c386,
+ rtc_rv5c387a,
+};
+
+static const struct i2c_device_id rs5c372_id[] = {
+ { "r2025sd", rtc_r2025sd },
+ { "r2221tl", rtc_r2221tl },
+ { "rs5c372a", rtc_rs5c372a },
+ { "rs5c372b", rtc_rs5c372b },
+ { "rv5c386", rtc_rv5c386 },
+ { "rv5c387a", rtc_rv5c387a },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, rs5c372_id);
+
+static const __maybe_unused struct of_device_id rs5c372_of_match[] = {
+ {
+ .compatible = "ricoh,r2025sd",
+ .data = (void *)rtc_r2025sd
+ },
+ {
+ .compatible = "ricoh,r2221tl",
+ .data = (void *)rtc_r2221tl
+ },
+ {
+ .compatible = "ricoh,rs5c372a",
+ .data = (void *)rtc_rs5c372a
+ },
+ {
+ .compatible = "ricoh,rs5c372b",
+ .data = (void *)rtc_rs5c372b
+ },
+ {
+ .compatible = "ricoh,rv5c386",
+ .data = (void *)rtc_rv5c386
+ },
+ {
+ .compatible = "ricoh,rv5c387a",
+ .data = (void *)rtc_rv5c387a
+ },
+ { }
+};
+MODULE_DEVICE_TABLE(of, rs5c372_of_match);
+
+/* REVISIT: this assumes that:
+ * - we're in the 21st century, so it's safe to ignore the century
+ * bit for rv5c38[67] (REG_MONTH bit 7);
+ * - we should use ALARM_A not ALARM_B (may be wrong on some boards)
+ */
+struct rs5c372 {
+ struct i2c_client *client;
+ struct rtc_device *rtc;
+ enum rtc_type type;
+ unsigned time24:1;
+ unsigned has_irq:1;
+ unsigned smbus:1;
+ char buf[17];
+ char *regs;
+};
+
+static int rs5c_get_regs(struct rs5c372 *rs5c)
+{
+ struct i2c_client *client = rs5c->client;
+ struct i2c_msg msgs[] = {
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = sizeof(rs5c->buf),
+ .buf = rs5c->buf
+ },
+ };
+
+ /* This implements the third reading method from the datasheet, using
+ * an internal address that's reset after each transaction (by STOP)
+ * to 0x0f ... so we read extra registers, and skip the first one.
+ *
+ * The first method doesn't work with the iop3xx adapter driver, on at
+ * least 80219 chips; this works around that bug.
+ *
+ * The third method on the other hand doesn't work for the SMBus-only
+ * configurations, so we use the the first method there, stripping off
+ * the extra register in the process.
+ */
+ if (rs5c->smbus) {
+ int addr = RS5C_ADDR(RS5C372_REG_SECS);
+ int size = sizeof(rs5c->buf) - 1;
+
+ if (i2c_smbus_read_i2c_block_data(client, addr, size,
+ rs5c->buf + 1) != size) {
+ dev_warn(&client->dev, "can't read registers\n");
+ return -EIO;
+ }
+ } else {
+ if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
+ dev_warn(&client->dev, "can't read registers\n");
+ return -EIO;
+ }
+ }
+
+ dev_dbg(&client->dev,
+ "%3ph (%02x) %3ph (%02x), %3ph, %3ph; %02x %02x\n",
+ rs5c->regs + 0, rs5c->regs[3],
+ rs5c->regs + 4, rs5c->regs[7],
+ rs5c->regs + 8, rs5c->regs + 11,
+ rs5c->regs[14], rs5c->regs[15]);
+
+ return 0;
+}
+
+static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
+{
+ unsigned hour;
+
+ if (rs5c->time24)
+ return bcd2bin(reg & 0x3f);
+
+ hour = bcd2bin(reg & 0x1f);
+ if (hour == 12)
+ hour = 0;
+ if (reg & 0x20)
+ hour += 12;
+ return hour;
+}
+
+static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
+{
+ if (rs5c->time24)
+ return bin2bcd(hour);
+
+ if (hour > 12)
+ return 0x20 | bin2bcd(hour - 12);
+ if (hour == 12)
+ return 0x20 | bin2bcd(12);
+ if (hour == 0)
+ return bin2bcd(12);
+ return bin2bcd(hour);
+}
+
+static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct rs5c372 *rs5c = i2c_get_clientdata(client);
+ int status = rs5c_get_regs(rs5c);
+ unsigned char ctrl2 = rs5c->regs[RS5C_REG_CTRL2];
+
+ if (status < 0)
+ return status;
+
+ switch (rs5c->type) {
+ case rtc_r2025sd:
+ case rtc_r2221tl:
+ if ((rs5c->type == rtc_r2025sd && !(ctrl2 & R2x2x_CTRL2_XSTP)) ||
+ (rs5c->type == rtc_r2221tl && (ctrl2 & R2x2x_CTRL2_XSTP))) {
+ dev_warn(&client->dev, "rtc oscillator interruption detected. Please reset the rtc clock.\n");
+ return -EINVAL;
+ }
+ break;
+ default:
+ if (ctrl2 & RS5C_CTRL2_XSTP) {
+ dev_warn(&client->dev, "rtc oscillator interruption detected. Please reset the rtc clock.\n");
+ return -EINVAL;
+ }
+ }
+
+ tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
+ tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
+ tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
+
+ tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
+ tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
+
+ /* tm->tm_mon is zero-based */
+ tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
+
+ /* year is 1900 + tm->tm_year */
+ tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
+
+ dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
+ "mday=%d, mon=%d, year=%d, wday=%d\n",
+ __func__,
+ tm->tm_sec, tm->tm_min, tm->tm_hour,
+ tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+ return 0;
+}
+
+static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct rs5c372 *rs5c = i2c_get_clientdata(client);
+ unsigned char buf[7];
+ unsigned char ctrl2;
+ int addr;
+
+ dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
+ "mday=%d, mon=%d, year=%d, wday=%d\n",
+ __func__,
+ tm->tm_sec, tm->tm_min, tm->tm_hour,
+ tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
+
+ addr = RS5C_ADDR(RS5C372_REG_SECS);
+ buf[0] = bin2bcd(tm->tm_sec);
+ buf[1] = bin2bcd(tm->tm_min);
+ buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
+ buf[3] = bin2bcd(tm->tm_wday);
+ buf[4] = bin2bcd(tm->tm_mday);
+ buf[5] = bin2bcd(tm->tm_mon + 1);
+ buf[6] = bin2bcd(tm->tm_year - 100);
+
+ if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
+ dev_dbg(&client->dev, "%s: write error in line %i\n",
+ __func__, __LINE__);
+ return -EIO;
+ }
+
+ addr = RS5C_ADDR(RS5C_REG_CTRL2);
+ ctrl2 = i2c_smbus_read_byte_data(client, addr);
+
+ /* clear rtc warning bits */
+ switch (rs5c->type) {
+ case rtc_r2025sd:
+ case rtc_r2221tl:
+ ctrl2 &= ~(R2x2x_CTRL2_VDET | R2x2x_CTRL2_PON);
+ if (rs5c->type == rtc_r2025sd)
+ ctrl2 |= R2x2x_CTRL2_XSTP;
+ else
+ ctrl2 &= ~R2x2x_CTRL2_XSTP;
+ break;
+ default:
+ ctrl2 &= ~RS5C_CTRL2_XSTP;
+ break;
+ }
+
+ if (i2c_smbus_write_byte_data(client, addr, ctrl2) < 0) {
+ dev_dbg(&client->dev, "%s: write error in line %i\n",
+ __func__, __LINE__);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+#if IS_ENABLED(CONFIG_RTC_INTF_PROC)
+#define NEED_TRIM
+#endif
+
+#if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
+#define NEED_TRIM
+#endif
+
+#ifdef NEED_TRIM
+static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
+{
+ struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
+ u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
+
+ if (osc) {
+ if (rs5c372->type == rtc_rs5c372a || rs5c372->type == rtc_rs5c372b)
+ *osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
+ else
+ *osc = 32768;
+ }
+
+ if (trim) {
+ dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
+ tmp &= RS5C372_TRIM_MASK;
+ if (tmp & 0x3e) {
+ int t = tmp & 0x3f;
+
+ if (tmp & 0x40)
+ t = (~t | (s8)0xc0) + 1;
+ else
+ t = t - 1;
+
+ tmp = t * 2;
+ } else
+ tmp = 0;
+ *trim = tmp;
+ }
+
+ return 0;
+}
+#endif
+
+static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct rs5c372 *rs5c = i2c_get_clientdata(client);
+ unsigned char buf;
+ int status, addr;
+
+ buf = rs5c->regs[RS5C_REG_CTRL1];
+
+ if (!rs5c->has_irq)
+ return -EINVAL;
+
+ status = rs5c_get_regs(rs5c);
+ if (status < 0)
+ return status;
+
+ addr = RS5C_ADDR(RS5C_REG_CTRL1);
+ if (enabled)
+ buf |= RS5C_CTRL1_AALE;
+ else
+ buf &= ~RS5C_CTRL1_AALE;
+
+ if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
+ dev_warn(dev, "can't update alarm\n");
+ status = -EIO;
+ } else
+ rs5c->regs[RS5C_REG_CTRL1] = buf;
+
+ return status;
+}
+
+
+/* NOTE: Since RTC_WKALM_{RD,SET} were originally defined for EFI,
+ * which only exposes a polled programming interface; and since
+ * these calls map directly to those EFI requests; we don't demand
+ * we have an IRQ for this chip when we go through this API.
+ *
+ * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
+ * though, managed through RTC_AIE_{ON,OFF} requests.
+ */
+
+static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct rs5c372 *rs5c = i2c_get_clientdata(client);
+ int status;
+
+ status = rs5c_get_regs(rs5c);
+ if (status < 0)
+ return status;
+
+ /* report alarm time */
+ t->time.tm_sec = 0;
+ t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
+ t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
+
+ /* ... and status */
+ t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
+ t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
+
+ return 0;
+}
+
+static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct rs5c372 *rs5c = i2c_get_clientdata(client);
+ int status, addr, i;
+ unsigned char buf[3];
+
+ /* only handle up to 24 hours in the future, like RTC_ALM_SET */
+ if (t->time.tm_mday != -1
+ || t->time.tm_mon != -1
+ || t->time.tm_year != -1)
+ return -EINVAL;
+
+ /* REVISIT: round up tm_sec */
+
+ /* if needed, disable irq (clears pending status) */
+ status = rs5c_get_regs(rs5c);
+ if (status < 0)
+ return status;
+ if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
+ addr = RS5C_ADDR(RS5C_REG_CTRL1);
+ buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
+ if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
+ dev_dbg(dev, "can't disable alarm\n");
+ return -EIO;
+ }
+ rs5c->regs[RS5C_REG_CTRL1] = buf[0];
+ }
+
+ /* set alarm */
+ buf[0] = bin2bcd(t->time.tm_min);
+ buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
+ buf[2] = 0x7f; /* any/all days */
+
+ for (i = 0; i < sizeof(buf); i++) {
+ addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
+ if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
+ dev_dbg(dev, "can't set alarm time\n");
+ return -EIO;
+ }
+ }
+
+ /* ... and maybe enable its irq */
+ if (t->enabled) {
+ addr = RS5C_ADDR(RS5C_REG_CTRL1);
+ buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
+ if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
+ dev_warn(dev, "can't enable alarm\n");
+ rs5c->regs[RS5C_REG_CTRL1] = buf[0];
+ }
+
+ return 0;
+}
+
+#if IS_ENABLED(CONFIG_RTC_INTF_PROC)
+
+static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+ int err, osc, trim;
+
+ err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
+ if (err == 0) {
+ seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
+ osc / 1000, osc % 1000);
+ seq_printf(seq, "trim\t\t: %d\n", trim);
+ }
+
+ return 0;
+}
+
+#else
+#define rs5c372_rtc_proc NULL
+#endif
+
+#ifdef CONFIG_RTC_INTF_DEV
+static int rs5c372_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+ struct rs5c372 *rs5c = i2c_get_clientdata(to_i2c_client(dev));
+ unsigned char ctrl2;
+ int addr;
+ unsigned int flags;
+
+ dev_dbg(dev, "%s: cmd=%x\n", __func__, cmd);
+
+ addr = RS5C_ADDR(RS5C_REG_CTRL2);
+ ctrl2 = i2c_smbus_read_byte_data(rs5c->client, addr);
+
+ switch (cmd) {
+ case RTC_VL_READ:
+ flags = 0;
+
+ switch (rs5c->type) {
+ case rtc_r2025sd:
+ case rtc_r2221tl:
+ if ((rs5c->type == rtc_r2025sd && !(ctrl2 & R2x2x_CTRL2_XSTP)) ||
+ (rs5c->type == rtc_r2221tl && (ctrl2 & R2x2x_CTRL2_XSTP))) {
+ flags |= RTC_VL_DATA_INVALID;
+ }
+ if (ctrl2 & R2x2x_CTRL2_VDET)
+ flags |= RTC_VL_BACKUP_LOW;
+ break;
+ default:
+ if (ctrl2 & RS5C_CTRL2_XSTP)
+ flags |= RTC_VL_DATA_INVALID;
+ break;
+ }
+
+ return put_user(flags, (unsigned int __user *)arg);
+ case RTC_VL_CLR:
+ /* clear VDET bit */
+ if (rs5c->type == rtc_r2025sd || rs5c->type == rtc_r2221tl) {
+ ctrl2 &= ~R2x2x_CTRL2_VDET;
+ if (i2c_smbus_write_byte_data(rs5c->client, addr, ctrl2) < 0) {
+ dev_dbg(&rs5c->client->dev, "%s: write error in line %i\n",
+ __func__, __LINE__);
+ return -EIO;
+ }
+ }
+ return 0;
+ default:
+ return -ENOIOCTLCMD;
+ }
+ return 0;
+}
+#else
+#define rs5c372_ioctl NULL
+#endif
+
+static int rs5c372_read_offset(struct device *dev, long *offset)
+{
+ struct rs5c372 *rs5c = i2c_get_clientdata(to_i2c_client(dev));
+ u8 val = rs5c->regs[RS5C372_REG_TRIM];
+ long ppb_per_step = 0;
+ bool decr = val & RS5C372_TRIM_DECR;
+
+ switch (rs5c->type) {
+ case rtc_r2221tl:
+ ppb_per_step = val & R2221TL_TRIM_DEV ? 1017 : 3051;
+ break;
+ case rtc_rs5c372a:
+ case rtc_rs5c372b:
+ ppb_per_step = val & RS5C372_TRIM_XSL ? 3125 : 3051;
+ break;
+ default:
+ ppb_per_step = 3051;
+ break;
+ }
+
+ /* Only bits[0:5] repsents the time counts */
+ val &= 0x3F;
+
+ /* If bits[1:5] are all 0, it means no increment or decrement */
+ if (!(val & 0x3E)) {
+ *offset = 0;
+ } else {
+ if (decr)
+ *offset = -(((~val) & 0x3F) + 1) * ppb_per_step;
+ else
+ *offset = (val - 1) * ppb_per_step;
+ }
+
+ return 0;
+}
+
+static int rs5c372_set_offset(struct device *dev, long offset)
+{
+ struct rs5c372 *rs5c = i2c_get_clientdata(to_i2c_client(dev));
+ int addr = RS5C_ADDR(RS5C372_REG_TRIM);
+ u8 val = 0;
+ u8 tmp = 0;
+ long ppb_per_step = 3051;
+ long steps = LONG_MIN;
+
+ switch (rs5c->type) {
+ case rtc_rs5c372a:
+ case rtc_rs5c372b:
+ tmp = rs5c->regs[RS5C372_REG_TRIM];
+ if (tmp & RS5C372_TRIM_XSL) {
+ ppb_per_step = 3125;
+ val |= RS5C372_TRIM_XSL;
+ }
+ break;
+ case rtc_r2221tl:
+ /*
+ * Check if it is possible to use high resolution mode (DEV=1).
+ * In this mode, the minimum resolution is 2 / (32768 * 20 * 3),
+ * which is about 1017 ppb.
+ */
+ steps = DIV_ROUND_CLOSEST(offset, 1017);
+ if (steps >= -0x3E && steps <= 0x3E) {
+ ppb_per_step = 1017;
+ val |= R2221TL_TRIM_DEV;
+ } else {
+ /*
+ * offset is out of the range of high resolution mode.
+ * Try to use low resolution mode (DEV=0). In this mode,
+ * the minimum resolution is 2 / (32768 * 20), which is
+ * about 3051 ppb.
+ */
+ steps = LONG_MIN;
+ }
+ break;
+ default:
+ break;
+ }
+
+ if (steps == LONG_MIN) {
+ steps = DIV_ROUND_CLOSEST(offset, ppb_per_step);
+ if (steps > 0x3E || steps < -0x3E)
+ return -ERANGE;
+ }
+
+ if (steps > 0) {
+ val |= steps + 1;
+ } else {
+ val |= RS5C372_TRIM_DECR;
+ val |= (~(-steps - 1)) & 0x3F;
+ }
+
+ if (!steps || !(val & 0x3E)) {
+ /*
+ * if offset is too small, set oscillation adjustment register
+ * or time trimming register with its default value whic means
+ * no increment or decrement. But for rs5c372[a|b], the XSL bit
+ * should be kept unchanged.
+ */
+ if (rs5c->type == rtc_rs5c372a || rs5c->type == rtc_rs5c372b)
+ val &= RS5C372_TRIM_XSL;
+ else
+ val = 0;
+ }
+
+ dev_dbg(&rs5c->client->dev, "write 0x%x for offset %ld\n", val, offset);
+
+ if (i2c_smbus_write_byte_data(rs5c->client, addr, val) < 0) {
+ dev_err(&rs5c->client->dev, "failed to write 0x%x to reg %d\n", val, addr);
+ return -EIO;
+ }
+
+ rs5c->regs[RS5C372_REG_TRIM] = val;
+
+ return 0;
+}
+
+static const struct rtc_class_ops rs5c372_rtc_ops = {
+ .proc = rs5c372_rtc_proc,
+ .read_time = rs5c372_rtc_read_time,
+ .set_time = rs5c372_rtc_set_time,
+ .read_alarm = rs5c_read_alarm,
+ .set_alarm = rs5c_set_alarm,
+ .alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
+ .ioctl = rs5c372_ioctl,
+ .read_offset = rs5c372_read_offset,
+ .set_offset = rs5c372_set_offset,
+};
+
+#if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
+
+static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int err, trim;
+
+ err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
+ if (err)
+ return err;
+
+ return sprintf(buf, "%d\n", trim);
+}
+static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
+
+static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int err, osc;
+
+ err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
+ if (err)
+ return err;
+
+ return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
+}
+static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
+
+static int rs5c_sysfs_register(struct device *dev)
+{
+ int err;
+
+ err = device_create_file(dev, &dev_attr_trim);
+ if (err)
+ return err;
+ err = device_create_file(dev, &dev_attr_osc);
+ if (err)
+ device_remove_file(dev, &dev_attr_trim);
+
+ return err;
+}
+
+static void rs5c_sysfs_unregister(struct device *dev)
+{
+ device_remove_file(dev, &dev_attr_trim);
+ device_remove_file(dev, &dev_attr_osc);
+}
+
+#else
+static int rs5c_sysfs_register(struct device *dev)
+{
+ return 0;
+}
+
+static void rs5c_sysfs_unregister(struct device *dev)
+{
+ /* nothing */
+}
+#endif /* SYSFS */
+
+static struct i2c_driver rs5c372_driver;
+
+static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
+{
+ unsigned char buf[2];
+ int addr, i, ret = 0;
+
+ addr = RS5C_ADDR(RS5C_REG_CTRL1);
+ buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
+ buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
+
+ switch (rs5c372->type) {
+ case rtc_r2025sd:
+ if (buf[1] & R2x2x_CTRL2_XSTP)
+ return ret;
+ break;
+ case rtc_r2221tl:
+ if (!(buf[1] & R2x2x_CTRL2_XSTP))
+ return ret;
+ break;
+ default:
+ if (!(buf[1] & RS5C_CTRL2_XSTP))
+ return ret;
+ break;
+ }
+
+ /* use 24hr mode */
+ switch (rs5c372->type) {
+ case rtc_rs5c372a:
+ case rtc_rs5c372b:
+ buf[1] |= RS5C372_CTRL2_24;
+ rs5c372->time24 = 1;
+ break;
+ case rtc_r2025sd:
+ case rtc_r2221tl:
+ case rtc_rv5c386:
+ case rtc_rv5c387a:
+ buf[0] |= RV5C387_CTRL1_24;
+ rs5c372->time24 = 1;
+ break;
+ default:
+ /* impossible */
+ break;
+ }
+
+ for (i = 0; i < sizeof(buf); i++) {
+ addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
+ ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
+ if (unlikely(ret < 0))
+ return ret;
+ }
+
+ rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
+ rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
+
+ return 0;
+}
+
+static int rs5c372_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int err = 0;
+ int smbus_mode = 0;
+ struct rs5c372 *rs5c372;
+
+ dev_dbg(&client->dev, "%s\n", __func__);
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
+ I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
+ /*
+ * If we don't have any master mode adapter, try breaking
+ * it down in to the barest of capabilities.
+ */
+ if (i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_BYTE_DATA |
+ I2C_FUNC_SMBUS_I2C_BLOCK))
+ smbus_mode = 1;
+ else {
+ /* Still no good, give up */
+ err = -ENODEV;
+ goto exit;
+ }
+ }
+
+ rs5c372 = devm_kzalloc(&client->dev, sizeof(struct rs5c372),
+ GFP_KERNEL);
+ if (!rs5c372) {
+ err = -ENOMEM;
+ goto exit;
+ }
+
+ rs5c372->client = client;
+ i2c_set_clientdata(client, rs5c372);
+ if (client->dev.of_node)
+ rs5c372->type = (enum rtc_type)
+ of_device_get_match_data(&client->dev);
+ else
+ rs5c372->type = id->driver_data;
+
+ /* we read registers 0x0f then 0x00-0x0f; skip the first one */
+ rs5c372->regs = &rs5c372->buf[1];
+ rs5c372->smbus = smbus_mode;
+
+ err = rs5c_get_regs(rs5c372);
+ if (err < 0)
+ goto exit;
+
+ /* clock may be set for am/pm or 24 hr time */
+ switch (rs5c372->type) {
+ case rtc_rs5c372a:
+ case rtc_rs5c372b:
+ /* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
+ * so does periodic irq, except some 327a modes.
+ */
+ if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
+ rs5c372->time24 = 1;
+ break;
+ case rtc_r2025sd:
+ case rtc_r2221tl:
+ case rtc_rv5c386:
+ case rtc_rv5c387a:
+ if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
+ rs5c372->time24 = 1;
+ /* alarm uses ALARM_W; and nINTRB for alarm and periodic
+ * irq, on both 386 and 387
+ */
+ break;
+ default:
+ dev_err(&client->dev, "unknown RTC type\n");
+ goto exit;
+ }
+
+ /* if the oscillator lost power and no other software (like
+ * the bootloader) set it up, do it here.
+ *
+ * The R2025S/D does this a little differently than the other
+ * parts, so we special case that..
+ */
+ err = rs5c_oscillator_setup(rs5c372);
+ if (unlikely(err < 0)) {
+ dev_err(&client->dev, "setup error\n");
+ goto exit;
+ }
+
+ dev_info(&client->dev, "%s found, %s\n",
+ ({ char *s; switch (rs5c372->type) {
+ case rtc_r2025sd: s = "r2025sd"; break;
+ case rtc_r2221tl: s = "r2221tl"; break;
+ case rtc_rs5c372a: s = "rs5c372a"; break;
+ case rtc_rs5c372b: s = "rs5c372b"; break;
+ case rtc_rv5c386: s = "rv5c386"; break;
+ case rtc_rv5c387a: s = "rv5c387a"; break;
+ default: s = "chip"; break;
+ }; s;}),
+ rs5c372->time24 ? "24hr" : "am/pm"
+ );
+
+ /* REVISIT use client->irq to register alarm irq ... */
+ rs5c372->rtc = devm_rtc_device_register(&client->dev,
+ rs5c372_driver.driver.name,
+ &rs5c372_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(rs5c372->rtc)) {
+ err = PTR_ERR(rs5c372->rtc);
+ goto exit;
+ }
+
+ err = rs5c_sysfs_register(&client->dev);
+ if (err)
+ goto exit;
+
+ return 0;
+
+exit:
+ return err;
+}
+
+static void rs5c372_remove(struct i2c_client *client)
+{
+ rs5c_sysfs_unregister(&client->dev);
+}
+
+static struct i2c_driver rs5c372_driver = {
+ .driver = {
+ .name = "rtc-rs5c372",
+ .of_match_table = of_match_ptr(rs5c372_of_match),
+ },
+ .probe = rs5c372_probe,
+ .remove = rs5c372_remove,
+ .id_table = rs5c372_id,
+};
+
+module_i2c_driver(rs5c372_driver);
+
+MODULE_AUTHOR(
+ "Pavel Mironchik <pmironchik@optifacio.net>, "
+ "Alessandro Zummo <a.zummo@towertech.it>, "
+ "Paul Mundt <lethal@linux-sh.org>");
+MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
+MODULE_LICENSE("GPL");