rtc: sun6i: Add support for the external oscillator gate

The RTC can output its 32kHz clock outside of the SoC, for example to clock
a WiFi chip.

Create a new clock that other devices will be able to retrieve, while
maintaining the DT stability by providing a default name for that clock if
clock-output-names doesn't list one.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

diff --git a/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt b/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
index 945934918b71fc127da6729f38b6498884ad5fca..d5e26d313f62624abb929c1334d2a9b1b77a73b2 100644 (file)
--- a/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
+++ b/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
@@ -10,7 +10,7 @@ Required properties:
 
 Required properties for new device trees
 - clocks       : phandle to the 32kHz external oscillator
-- clock-output-names : name of the LOSC clock created
+- clock-output-names : names of the LOSC and its external output clocks created
 - #clock-cells  : must be equals to 1. The RTC provides two clocks: the
                  LOSC and its external output, with index 0 and 1
                  respectively.
@@ -21,7 +21,7 @@ rtc: rtc@01f00000 {
        compatible = "allwinner,sun6i-a31-rtc";
        reg = <0x01f00000 0x54>;
        interrupts = <0 40 4>, <0 41 4>;
-       clock-output-names = "osc32k";
+       clock-output-names = "osc32k", "osc32k-out";
        clocks = <&ext_osc32k>;
        #clock-cells = <1>;
 };

diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
index 305c4d043f61da20390d9f15f09a097da930fab1..3d2216ccd860c6fef173882e3e24a92e2309eca2 100644 (file)
--- a/drivers/rtc/rtc-sun6i.c
+++ b/drivers/rtc/rtc-sun6i.c
@@ -73,6 +73,9 @@
 #define SUN6I_ALARM_CONFIG                     0x0050
 #define SUN6I_ALARM_CONFIG_WAKEUP              BIT(0)
 
+#define SUN6I_LOSC_OUT_GATING                  0x0060
+#define SUN6I_LOSC_OUT_GATING_EN               BIT(0)
+
 /*
  * Get date values
  */
@@ -125,6 +128,7 @@ struct sun6i_rtc_dev {
        struct clk_hw hw;
        struct clk_hw *int_osc;
        struct clk *losc;
+       struct clk *ext_losc;
 
        spinlock_t lock;
 };
@@ -188,13 +192,14 @@ static void __init sun6i_rtc_clk_init(struct device_node *node)
        struct clk_init_data init = {
                .ops            = &sun6i_rtc_osc_ops,
        };
+       const char *clkout_name = "osc32k-out";
        const char *parents[2];
 
        rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
        if (!rtc)
                return;
 
-       clk_data = kzalloc(sizeof(*clk_data) + sizeof(*clk_data->hws),
+       clk_data = kzalloc(sizeof(*clk_data) + (sizeof(*clk_data->hws) * 2),
                           GFP_KERNEL);
        if (!clk_data)
                return;
@@ -235,7 +240,8 @@ static void __init sun6i_rtc_clk_init(struct device_node *node)
 
        init.parent_names = parents;
        init.num_parents = of_clk_get_parent_count(node) + 1;
-       of_property_read_string(node, "clock-output-names", &init.name);
+       of_property_read_string_index(node, "clock-output-names", 0,
+                                     &init.name);
 
        rtc->losc = clk_register(NULL, &rtc->hw);
        if (IS_ERR(rtc->losc)) {
@@ -243,8 +249,20 @@ static void __init sun6i_rtc_clk_init(struct device_node *node)
                return;
        }
 
-       clk_data->num = 1;
+       of_property_read_string_index(node, "clock-output-names", 1,
+                                     &clkout_name);
+       rtc->ext_losc = clk_register_gate(NULL, clkout_name, rtc->hw.init->name,
+                                         0, rtc->base + SUN6I_LOSC_OUT_GATING,
+                                         SUN6I_LOSC_OUT_GATING_EN, 0,
+                                         &rtc->lock);
+       if (IS_ERR(rtc->ext_losc)) {
+               pr_crit("Couldn't register the LOSC external gate\n");
+               return;
+       }
+
+       clk_data->num = 2;
        clk_data->hws[0] = &rtc->hw;
+       clk_data->hws[1] = __clk_get_hw(rtc->ext_losc);
        of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
        return;