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path: root/drivers/rtc/rtc-m41t80.c
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Diffstat (limited to 'drivers/rtc/rtc-m41t80.c')
-rw-r--r--drivers/rtc/rtc-m41t80.c251
1 files changed, 175 insertions, 76 deletions
diff --git a/drivers/rtc/rtc-m41t80.c b/drivers/rtc/rtc-m41t80.c
index 5ec4653022ff..8940e9e43ea0 100644
--- a/drivers/rtc/rtc-m41t80.c
+++ b/drivers/rtc/rtc-m41t80.c
@@ -16,6 +16,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/bcd.h>
+#include <linux/clk-provider.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/kernel.h>
@@ -53,6 +54,8 @@
#define M41T80_ALARM_REG_SIZE \
(M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
+#define M41T80_SQW_MAX_FREQ 32768
+
#define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */
#define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */
#define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */
@@ -147,7 +150,11 @@ MODULE_DEVICE_TABLE(of, m41t80_of_match);
struct m41t80_data {
unsigned long features;
+ struct i2c_client *client;
struct rtc_device *rtc;
+#ifdef CONFIG_COMMON_CLK
+ struct clk_hw sqw;
+#endif
};
static irqreturn_t m41t80_handle_irq(int irq, void *dev_id)
@@ -227,6 +234,7 @@ static int m41t80_get_datetime(struct i2c_client *client,
/* Sets the given date and time to the real time clock. */
static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
+ struct m41t80_data *clientdata = i2c_get_clientdata(client);
unsigned char buf[8];
int err, flags;
@@ -242,6 +250,17 @@ static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100);
buf[M41T80_REG_WDAY] = tm->tm_wday;
+ /* If the square wave output is controlled in the weekday register */
+ if (clientdata->features & M41T80_FEATURE_SQ_ALT) {
+ int val;
+
+ val = i2c_smbus_read_byte_data(client, M41T80_REG_WDAY);
+ if (val < 0)
+ return val;
+
+ buf[M41T80_REG_WDAY] |= (val & 0xf0);
+ }
+
err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC,
sizeof(buf), buf);
if (err < 0) {
@@ -332,6 +351,9 @@ static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
return err;
}
+ /* Keep SQWE bit value */
+ alarmvals[0] |= (ret & M41T80_ALMON_SQWE);
+
ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
if (ret < 0)
return ret;
@@ -431,103 +453,175 @@ static ssize_t flags_show(struct device *dev,
}
static DEVICE_ATTR_RO(flags);
-static ssize_t sqwfreq_show(struct device *dev,
- struct device_attribute *attr, char *buf)
+static struct attribute *attrs[] = {
+ &dev_attr_flags.attr,
+ NULL,
+};
+
+static struct attribute_group attr_group = {
+ .attrs = attrs,
+};
+
+#ifdef CONFIG_COMMON_CLK
+#define sqw_to_m41t80_data(_hw) container_of(_hw, struct m41t80_data, sqw)
+
+static unsigned long m41t80_sqw_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
{
- struct i2c_client *client = to_i2c_client(dev);
- struct m41t80_data *clientdata = i2c_get_clientdata(client);
- int val, reg_sqw;
+ struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
+ struct i2c_client *client = m41t80->client;
+ int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ?
+ M41T80_REG_WDAY : M41T80_REG_SQW;
+ int ret = i2c_smbus_read_byte_data(client, reg_sqw);
+ unsigned long val = M41T80_SQW_MAX_FREQ;
- if (!(clientdata->features & M41T80_FEATURE_SQ))
- return -EINVAL;
+ if (ret < 0)
+ return 0;
- reg_sqw = M41T80_REG_SQW;
- if (clientdata->features & M41T80_FEATURE_SQ_ALT)
- reg_sqw = M41T80_REG_WDAY;
- val = i2c_smbus_read_byte_data(client, reg_sqw);
- if (val < 0)
- return val;
- val = (val >> 4) & 0xf;
- switch (val) {
- case 0:
- break;
- case 1:
- val = 32768;
- break;
- default:
- val = 32768 >> val;
- }
- return sprintf(buf, "%d\n", val);
+ ret >>= 4;
+ if (ret == 0)
+ val = 0;
+ else if (ret > 1)
+ val = val / (1 << ret);
+
+ return val;
}
-static ssize_t sqwfreq_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count)
+static long m41t80_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
{
- struct i2c_client *client = to_i2c_client(dev);
- struct m41t80_data *clientdata = i2c_get_clientdata(client);
- int almon, sqw, reg_sqw, rc;
- unsigned long val;
+ int i, freq = M41T80_SQW_MAX_FREQ;
- rc = kstrtoul(buf, 0, &val);
- if (rc < 0)
- return rc;
+ if (freq <= rate)
+ return freq;
- if (!(clientdata->features & M41T80_FEATURE_SQ))
- return -EINVAL;
+ for (i = 2; i <= ilog2(M41T80_SQW_MAX_FREQ); i++) {
+ freq /= 1 << i;
+ if (freq <= rate)
+ return freq;
+ }
- if (val) {
- if (!is_power_of_2(val))
+ return 0;
+}
+
+static int m41t80_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
+ struct i2c_client *client = m41t80->client;
+ int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ?
+ M41T80_REG_WDAY : M41T80_REG_SQW;
+ int reg, ret, val = 0;
+
+ if (rate) {
+ if (!is_power_of_2(rate))
return -EINVAL;
- val = ilog2(val);
- if (val == 15)
+ val = ilog2(rate);
+ if (val == ilog2(M41T80_SQW_MAX_FREQ))
val = 1;
- else if (val < 14)
- val = 15 - val;
+ else if (val < (ilog2(M41T80_SQW_MAX_FREQ) - 1))
+ val = ilog2(M41T80_SQW_MAX_FREQ) - val;
else
return -EINVAL;
}
- /* disable SQW, set SQW frequency & re-enable */
- almon = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
- if (almon < 0)
- return almon;
- reg_sqw = M41T80_REG_SQW;
- if (clientdata->features & M41T80_FEATURE_SQ_ALT)
- reg_sqw = M41T80_REG_WDAY;
- sqw = i2c_smbus_read_byte_data(client, reg_sqw);
- if (sqw < 0)
- return sqw;
- sqw = (sqw & 0x0f) | (val << 4);
-
- rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
- almon & ~M41T80_ALMON_SQWE);
- if (rc < 0)
- return rc;
- if (val) {
- rc = i2c_smbus_write_byte_data(client, reg_sqw, sqw);
- if (rc < 0)
- return rc;
+ reg = i2c_smbus_read_byte_data(client, reg_sqw);
+ if (reg < 0)
+ return reg;
- rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
- almon | M41T80_ALMON_SQWE);
- if (rc < 0)
- return rc;
- }
- return count;
+ reg = (reg & 0x0f) | (val << 4);
+
+ ret = i2c_smbus_write_byte_data(client, reg_sqw, reg);
+ if (ret < 0)
+ return ret;
+
+ return -EINVAL;
}
-static DEVICE_ATTR_RW(sqwfreq);
-static struct attribute *attrs[] = {
- &dev_attr_flags.attr,
- &dev_attr_sqwfreq.attr,
- NULL,
-};
+static int m41t80_sqw_control(struct clk_hw *hw, bool enable)
+{
+ struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
+ struct i2c_client *client = m41t80->client;
+ int ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
-static struct attribute_group attr_group = {
- .attrs = attrs,
+ if (ret < 0)
+ return ret;
+
+ if (enable)
+ ret |= M41T80_ALMON_SQWE;
+ else
+ ret &= ~M41T80_ALMON_SQWE;
+
+ return i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret);
+}
+
+static int m41t80_sqw_prepare(struct clk_hw *hw)
+{
+ return m41t80_sqw_control(hw, 1);
+}
+
+static void m41t80_sqw_unprepare(struct clk_hw *hw)
+{
+ m41t80_sqw_control(hw, 0);
+}
+
+static int m41t80_sqw_is_prepared(struct clk_hw *hw)
+{
+ struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
+ struct i2c_client *client = m41t80->client;
+ int ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
+
+ if (ret < 0)
+ return ret;
+
+ return !!(ret & M41T80_ALMON_SQWE);
+}
+
+static const struct clk_ops m41t80_sqw_ops = {
+ .prepare = m41t80_sqw_prepare,
+ .unprepare = m41t80_sqw_unprepare,
+ .is_prepared = m41t80_sqw_is_prepared,
+ .recalc_rate = m41t80_sqw_recalc_rate,
+ .round_rate = m41t80_sqw_round_rate,
+ .set_rate = m41t80_sqw_set_rate,
};
+static struct clk *m41t80_sqw_register_clk(struct m41t80_data *m41t80)
+{
+ struct i2c_client *client = m41t80->client;
+ struct device_node *node = client->dev.of_node;
+ struct clk *clk;
+ struct clk_init_data init;
+ int ret;
+
+ /* First disable the clock */
+ ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
+ ret & ~(M41T80_ALMON_SQWE));
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ init.name = "m41t80-sqw";
+ init.ops = &m41t80_sqw_ops;
+ init.flags = 0;
+ init.parent_names = NULL;
+ init.num_parents = 0;
+ m41t80->sqw.init = &init;
+
+ /* optional override of the clockname */
+ of_property_read_string(node, "clock-output-names", &init.name);
+
+ /* register the clock */
+ clk = clk_register(&client->dev, &m41t80->sqw);
+ if (!IS_ERR(clk))
+ of_clk_add_provider(node, of_clk_src_simple_get, clk);
+
+ return clk;
+}
+#endif
+
#ifdef CONFIG_RTC_DRV_M41T80_WDT
/*
*****************************************************************************
@@ -845,6 +939,7 @@ static int m41t80_probe(struct i2c_client *client,
if (!m41t80_data)
return -ENOMEM;
+ m41t80_data->client = client;
if (client->dev.of_node)
m41t80_data->features = (unsigned long)
of_device_get_match_data(&client->dev);
@@ -937,6 +1032,10 @@ static int m41t80_probe(struct i2c_client *client,
}
}
#endif
+#ifdef CONFIG_COMMON_CLK
+ if (m41t80_data->features & M41T80_FEATURE_SQ)
+ m41t80_sqw_register_clk(m41t80_data);
+#endif
return 0;
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-07 09:39:27 +0300