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;
 }