From: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
To: <rtc-linux@googlegroups.com>
Cc: Sean Nyekjaer <sean.nyekjaer@prevas.dk>,
<alexandre.belloni@free-electrons.com>
Subject: [rtc-linux] [RFC] rtc: ds1307: add square wave output from ds1308
Date: Mon, 31 Jul 2017 15:30:13 +0200 [thread overview]
Message-ID: <20170731133013.22347-1-sean.nyekjaer@prevas.dk> (raw)
add square wave output to generic clock framework and
disable sqw output from ds1308 in order to reduce
the power consumption by ~50%.
Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
---
This contains some code duplication(of my opinion) I guess it could be done more
generic together with the ds3231.
drivers/rtc/rtc-ds1307.c | 172 ++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 170 insertions(+), 2 deletions(-)
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 1cedb21ba792..f92c99d7dd2e 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -79,6 +79,7 @@ enum ds_type {
# define DS1307_BIT_OUT 0x80
# define DS1338_BIT_OSF 0x20
# define DS1307_BIT_SQWE 0x10
+# define DS1308_BIT_BBCLK 0x04
# define DS1307_BIT_RS1 0x02
# define DS1307_BIT_RS0 0x01
#define DS1337_REG_CONTROL 0x0e
@@ -1056,6 +1057,13 @@ enum {
#define clk_32khz_to_ds1307(clk) \
container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
+static int ds1308_clk_sqw_rates[] = {
+ 1,
+ 4096,
+ 8192,
+ 32768,
+};
+
static int ds3231_clk_sqw_rates[] = {
1,
1024,
@@ -1063,6 +1071,19 @@ static int ds3231_clk_sqw_rates[] = {
8192,
};
+static int ds1308_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
+{
+ struct mutex *lock = &ds1307->rtc->ops_lock;
+ int ret;
+
+ mutex_lock(lock);
+ ret = regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL,
+ mask, value);
+ mutex_unlock(lock);
+
+ return ret;
+}
+
static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
{
struct mutex *lock = &ds1307->rtc->ops_lock;
@@ -1076,6 +1097,24 @@ static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
return ret;
}
+static unsigned long ds1308_clk_sqw_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
+ int control, ret;
+ int rate_sel = 0;
+
+ ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &control);
+ if (ret)
+ return ret;
+ if (control & DS1307_BIT_RS0)
+ rate_sel += 1;
+ if (control & DS1307_BIT_RS1)
+ rate_sel += 2;
+
+ return ds1308_clk_sqw_rates[rate_sel];
+}
+
static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
@@ -1094,6 +1133,19 @@ static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
return ds3231_clk_sqw_rates[rate_sel];
}
+static long ds1308_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ int i;
+
+ for (i = ARRAY_SIZE(ds1308_clk_sqw_rates) - 1; i >= 0; i--) {
+ if (ds1308_clk_sqw_rates[i] <= rate)
+ return ds1308_clk_sqw_rates[i];
+ }
+
+ return 0;
+}
+
static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
@@ -1107,6 +1159,31 @@ static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
return 0;
}
+static int ds1308_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
+ int control = 0;
+ int rate_sel;
+
+ for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds1308_clk_sqw_rates);
+ rate_sel++) {
+ if (ds1308_clk_sqw_rates[rate_sel] == rate)
+ break;
+ }
+
+ if (rate_sel == ARRAY_SIZE(ds1308_clk_sqw_rates))
+ return -EINVAL;
+
+ if (rate_sel & 1)
+ control |= DS1307_BIT_RS0;
+ if (rate_sel & 2)
+ control |= DS1307_BIT_RS1;
+
+ return ds1337_write_control(ds1307, DS1307_BIT_RS0 | DS1307_BIT_RS1,
+ control);
+}
+
static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
@@ -1132,6 +1209,13 @@ static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
control);
}
+static int ds1308_clk_sqw_prepare(struct clk_hw *hw)
+{
+ struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
+
+ return ds1308_write_control(ds1307, DS1307_BIT_SQWE, 1);
+}
+
static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
{
struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
@@ -1139,6 +1223,13 @@ static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
}
+static void ds1308_clk_sqw_unprepare(struct clk_hw *hw)
+{
+ struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
+
+ ds1308_write_control(ds1307, DS1307_BIT_SQWE, 0);
+}
+
static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
{
struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
@@ -1146,6 +1237,18 @@ static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
}
+static int ds1308_clk_sqw_is_prepared(struct clk_hw *hw)
+{
+ struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
+ int control, ret;
+
+ ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &control);
+ if (ret)
+ return ret;
+
+ return control & DS1307_BIT_SQWE;
+}
+
static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
{
struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
@@ -1158,6 +1261,15 @@ static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
return !(control & DS1337_BIT_INTCN);
}
+static const struct clk_ops ds1308_clk_sqw_ops = {
+ .prepare = ds1308_clk_sqw_prepare,
+ .unprepare = ds1308_clk_sqw_unprepare,
+ .is_prepared = ds1308_clk_sqw_is_prepared,
+ .recalc_rate = ds1308_clk_sqw_recalc_rate,
+ .round_rate = ds1308_clk_sqw_round_rate,
+ .set_rate = ds1308_clk_sqw_set_rate,
+};
+
static const struct clk_ops ds3231_clk_sqw_ops = {
.prepare = ds3231_clk_sqw_prepare,
.unprepare = ds3231_clk_sqw_unprepare,
@@ -1220,6 +1332,13 @@ static const struct clk_ops ds3231_clk_32khz_ops = {
.recalc_rate = ds3231_clk_32khz_recalc_rate,
};
+static struct clk_init_data ds1308_clks_init[] = {
+ {
+ .name = "ds1308_clk_sqw",
+ .ops = &ds1308_clk_sqw_ops,
+ },
+};
+
static struct clk_init_data ds3231_clks_init[] = {
[DS3231_CLK_SQW] = {
.name = "ds3231_clk_sqw",
@@ -1231,6 +1350,44 @@ static struct clk_init_data ds3231_clks_init[] = {
},
};
+static int ds1308_clks_register(struct ds1307 *ds1307)
+{
+ struct device_node *node = ds1307->dev->of_node;
+ struct clk_onecell_data *onecell;
+ int i;
+
+ onecell = devm_kzalloc(ds1307->dev, sizeof(*onecell), GFP_KERNEL);
+ if (!onecell)
+ return -ENOMEM;
+
+ onecell->clk_num = ARRAY_SIZE(ds1308_clks_init);
+ onecell->clks = devm_kcalloc(ds1307->dev, onecell->clk_num,
+ sizeof(onecell->clks[0]), GFP_KERNEL);
+ if (!onecell->clks)
+ return -ENOMEM;
+
+ for (i = 0; i < ARRAY_SIZE(ds1308_clks_init); i++) {
+ struct clk_init_data init = ds1308_clks_init[i];
+
+ /* optional override of the clockname */
+ of_property_read_string_index(node, "clock-output-names", i,
+ &init.name);
+ ds1307->clks[i].init = &init;
+
+ onecell->clks[i] = devm_clk_register(ds1307->dev,
+ &ds1307->clks[i]);
+ if (IS_ERR(onecell->clks[i]))
+ return PTR_ERR(onecell->clks[i]);
+ }
+
+ if (!node)
+ return 0;
+
+ of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
+
+ return 0;
+}
+
static int ds3231_clks_register(struct ds1307 *ds1307)
{
struct device_node *node = ds1307->dev->of_node;
@@ -1280,10 +1437,16 @@ static void ds1307_clks_register(struct ds1307 *ds1307)
{
int ret;
- if (ds1307->type != ds_3231)
+ switch (ds1307->type) {
+ case ds_1308:
+ ret = ds1308_clks_register(ds1307);
+ case ds_3231:
+ ret = ds3231_clks_register(ds1307);
+ break;
+ default:
return;
+ }
- ret = ds3231_clks_register(ds1307);
if (ret) {
dev_warn(ds1307->dev, "unable to register clock device %d\n",
ret);
@@ -1545,6 +1708,11 @@ static int ds1307_probe(struct i2c_client *client,
}
break;
case ds_1308:
+ /* disable sqw when driven from battery backup */
+ if (ds1307->regs[DS1307_REG_CONTROL] & DS1308_BIT_BBCLK)
+ i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
+ ds1307->regs[DS1307_REG_CONTROL]
+ & ~DS1308_BIT_BBCLK);
case ds_1338:
/* clock halted? turn it on, so clock can tick. */
if (tmp & DS1307_BIT_CH)
--
2.13.3
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next reply other threads:[~2017-07-31 13:30 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-31 13:30 Sean Nyekjaer [this message]
2017-07-31 14:02 ` [rtc-linux] Re: [RFC] rtc: ds1307: add square wave output from ds1308 Alexandre Belloni
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