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Subject[PATCH] rtc: rv3028: add clkout support
Date
rv3028 provides clkout (enabled by default). Add clkout
to clock framework source and control from device tree for
variable frequency with enable and disable functionality.

Signed-off-by: Parthiban Nallathambi <pn@denx.de>
---
drivers/rtc/rtc-rv3028.c | 156 +++++++++++++++++++++++++++++++++++++++
1 file changed, 156 insertions(+)

diff --git a/drivers/rtc/rtc-rv3028.c b/drivers/rtc/rtc-rv3028.c
index 2b316661a578..61a2ed32639f 100644
--- a/drivers/rtc/rtc-rv3028.c
+++ b/drivers/rtc/rtc-rv3028.c
@@ -8,6 +8,7 @@
*
*/

+#include <linux/clk-provider.h>
#include <linux/bcd.h>
#include <linux/bitops.h>
#include <linux/i2c.h>
@@ -52,6 +53,11 @@
#define RV3028_STATUS_CLKF BIT(6)
#define RV3028_STATUS_EEBUSY BIT(7)

+#define RV3028_CLKOUT_FD_MASK GENMASK(2, 0)
+#define RV3028_CLKOUT_PORIE BIT(3)
+#define RV3028_CLKOUT_CLKSY BIT(6)
+#define RV3028_CLKOUT_CLKOE BIT(7)
+
#define RV3028_CTRL1_EERD BIT(3)
#define RV3028_CTRL1_WADA BIT(5)

@@ -84,6 +90,9 @@ struct rv3028_data {
struct regmap *regmap;
struct rtc_device *rtc;
enum rv3028_type type;
+#ifdef CONFIG_COMMON_CLK
+ struct clk_hw clkout_hw;
+#endif
};

static u16 rv3028_trickle_resistors[] = {1000, 3000, 6000, 11000};
@@ -581,6 +590,150 @@ static int rv3028_eeprom_read(void *priv, unsigned int offset, void *val,
return ret;
}

+#ifdef CONFIG_COMMON_CLK
+#define clkout_hw_to_rv3028(hw) container_of(hw, struct rv3028_data, clkout_hw)
+
+static int clkout_rates[] = {
+ 32768,
+ 8192,
+ 1024,
+ 64,
+ 32,
+ 1,
+};
+
+static unsigned long rv3028_clkout_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ int clkout, ret;
+ struct rv3028_data *rv3028 = clkout_hw_to_rv3028(hw);
+
+ ret = regmap_read(rv3028->regmap, RV3028_CLKOUT, &clkout);
+ if (ret < 0)
+ return 0;
+
+ clkout &= RV3028_CLKOUT_FD_MASK;
+ return clkout_rates[clkout];
+}
+
+static long rv3028_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
+ if (clkout_rates[i] <= rate)
+ return clkout_rates[i];
+
+ return 0;
+}
+
+static int rv3028_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ int i, ret;
+ struct rv3028_data *rv3028 = clkout_hw_to_rv3028(hw);
+
+ ret = regmap_write(rv3028->regmap, RV3028_CLKOUT, 0x0);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_update_bits(rv3028->regmap, RV3028_STATUS,
+ RV3028_STATUS_CLKF, 0);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < ARRAY_SIZE(clkout_rates); i++) {
+ if (clkout_rates[i] == rate) {
+ ret = regmap_update_bits(rv3028->regmap,
+ RV3028_CLKOUT,
+ RV3028_CLKOUT_FD_MASK, i);
+ if (ret < 0)
+ return ret;
+
+ return regmap_write(rv3028->regmap, RV3028_CLKOUT,
+ RV3028_CLKOUT_CLKSY | RV3028_CLKOUT_CLKOE);
+ }
+ }
+
+ return -EINVAL;
+}
+
+static int rv3028_clkout_prepare(struct clk_hw *hw)
+{
+ struct rv3028_data *rv3028 = clkout_hw_to_rv3028(hw);
+
+ return regmap_write(rv3028->regmap, RV3028_CLKOUT,
+ RV3028_CLKOUT_CLKSY | RV3028_CLKOUT_CLKOE);
+}
+
+static void rv3028_clkout_unprepare(struct clk_hw *hw)
+{
+ struct rv3028_data *rv3028 = clkout_hw_to_rv3028(hw);
+
+ regmap_write(rv3028->regmap, RV3028_CLKOUT, 0x0);
+ regmap_update_bits(rv3028->regmap, RV3028_STATUS,
+ RV3028_STATUS_CLKF, 0);
+}
+
+static int rv3028_clkout_is_prepared(struct clk_hw *hw)
+{
+ int clkout, ret;
+ struct rv3028_data *rv3028 = clkout_hw_to_rv3028(hw);
+
+ ret = regmap_read(rv3028->regmap, RV3028_CLKOUT, &clkout);
+ if (ret < 0)
+ return ret;
+
+ return !!(clkout & RV3028_CLKOUT_CLKOE);
+}
+
+static const struct clk_ops rv3028_clkout_ops = {
+ .prepare = rv3028_clkout_prepare,
+ .unprepare = rv3028_clkout_unprepare,
+ .is_prepared = rv3028_clkout_is_prepared,
+ .recalc_rate = rv3028_clkout_recalc_rate,
+ .round_rate = rv3028_clkout_round_rate,
+ .set_rate = rv3028_clkout_set_rate,
+};
+
+static int rv3028_clkout_register_clk(struct rv3028_data *rv3028,
+ struct i2c_client *client)
+{
+ int ret;
+ struct clk *clk;
+ struct clk_init_data init;
+ struct device_node *node = client->dev.of_node;
+
+ /* disable the clkout output */
+ ret = regmap_write(rv3028->regmap, RV3028_CLKOUT, 0x0);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_update_bits(rv3028->regmap, RV3028_STATUS,
+ RV3028_STATUS_CLKF, 0);
+ if (ret < 0)
+ return ret;
+
+ init.name = "rv3028-clkout";
+ init.ops = &rv3028_clkout_ops;
+ init.flags = 0;
+ init.parent_names = NULL;
+ init.num_parents = 0;
+ rv3028->clkout_hw.init = &init;
+
+ /* optional override of the clockname */
+ of_property_read_string(node, "clock-output-names", &init.name);
+
+ /* register the clock */
+ clk = devm_clk_register(&client->dev, &rv3028->clkout_hw);
+ if (!IS_ERR(clk))
+ of_clk_add_provider(node, of_clk_src_simple_get, clk);
+
+ return 0;
+}
+#endif
+
static struct rtc_class_ops rv3028_rtc_ops = {
.read_time = rv3028_get_time,
.set_time = rv3028_set_time,
@@ -708,6 +861,9 @@ static int rv3028_probe(struct i2c_client *client)

rv3028->rtc->max_user_freq = 1;

+#ifdef CONFIG_COMMON_CLK
+ rv3028_clkout_register_clk(rv3028, client);
+#endif
return 0;
}

--
2.21.0
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