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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>
zero-colors
Maxime Ripard 2017-08-25 09:42:02 +02:00 committed by Alexandre Belloni
parent f22d9cdcb5
commit 17ecd24641
2 changed files with 23 additions and 5 deletions
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4
Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
View File

@ -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>;
};

24
drivers/rtc/rtc-sun6i.c
View File

@ -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;