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authorAlexandre Belloni <alexandre.belloni@free-electrons.com>2016-09-20 22:58:30 +0200
committerStephen Boyd <sboyd@codeaurora.org>2016-09-20 17:02:58 -0700
commit4b13b6451a9dce278881d236d33d4bb0cb28592b (patch)
tree65c8c7bfda88b2ff30ebf77628c2c4a1110e1b92 /drivers
parentec187ef0ce9880d9dc360261807c434e77783ac8 (diff)
downloadlinux-4b13b6451a9dce278881d236d33d4bb0cb28592b.tar.bz2
clk: at91: Add sama5d4 sckc support
Starting with sama5d4, the crystal oscillator is always enabled at startup and the SCKC doesn't have an OSC32EN bit anymore. Add support for that new controller. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/clk/at91/sckc.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/drivers/clk/at91/sckc.c b/drivers/clk/at91/sckc.c
index 311956abf4aa..199d1b3f5ad3 100644
--- a/drivers/clk/at91/sckc.c
+++ b/drivers/clk/at91/sckc.c
@@ -36,6 +36,15 @@ struct clk_slow_osc {
#define to_clk_slow_osc(hw) container_of(hw, struct clk_slow_osc, hw)
+struct clk_sama5d4_slow_osc {
+ struct clk_hw hw;
+ void __iomem *sckcr;
+ unsigned long startup_usec;
+ bool prepared;
+};
+
+#define to_clk_sama5d4_slow_osc(hw) container_of(hw, struct clk_sama5d4_slow_osc, hw)
+
struct clk_slow_rc_osc {
struct clk_hw hw;
void __iomem *sckcr;
@@ -417,3 +426,94 @@ static void __init of_at91sam9x5_sckc_setup(struct device_node *np)
}
CLK_OF_DECLARE(at91sam9x5_clk_sckc, "atmel,at91sam9x5-sckc",
of_at91sam9x5_sckc_setup);
+
+static int clk_sama5d4_slow_osc_prepare(struct clk_hw *hw)
+{
+ struct clk_sama5d4_slow_osc *osc = to_clk_sama5d4_slow_osc(hw);
+
+ if (osc->prepared)
+ return 0;
+
+ /*
+ * Assume that if it has already been selected (for example by the
+ * bootloader), enough time has aready passed.
+ */
+ if ((readl(osc->sckcr) & AT91_SCKC_OSCSEL)) {
+ osc->prepared = true;
+ return 0;
+ }
+
+ usleep_range(osc->startup_usec, osc->startup_usec + 1);
+ osc->prepared = true;
+
+ return 0;
+}
+
+static int clk_sama5d4_slow_osc_is_prepared(struct clk_hw *hw)
+{
+ struct clk_sama5d4_slow_osc *osc = to_clk_sama5d4_slow_osc(hw);
+
+ return osc->prepared;
+}
+
+static const struct clk_ops sama5d4_slow_osc_ops = {
+ .prepare = clk_sama5d4_slow_osc_prepare,
+ .is_prepared = clk_sama5d4_slow_osc_is_prepared,
+};
+
+static void __init of_sama5d4_sckc_setup(struct device_node *np)
+{
+ void __iomem *regbase = of_iomap(np, 0);
+ struct clk_hw *hw;
+ struct clk_sama5d4_slow_osc *osc;
+ struct clk_init_data init;
+ const char *xtal_name;
+ const char *parent_names[2] = { "slow_rc_osc", "slow_osc" };
+ bool bypass;
+ int ret;
+
+ if (!regbase)
+ return;
+
+ hw = clk_hw_register_fixed_rate_with_accuracy(NULL, parent_names[0],
+ NULL, 0, 32768,
+ 250000000);
+ if (IS_ERR(hw))
+ return;
+
+ xtal_name = of_clk_get_parent_name(np, 0);
+
+ bypass = of_property_read_bool(np, "atmel,osc-bypass");
+
+ osc = kzalloc(sizeof(*osc), GFP_KERNEL);
+ if (!osc)
+ return;
+
+ init.name = parent_names[1];
+ init.ops = &sama5d4_slow_osc_ops;
+ init.parent_names = &xtal_name;
+ init.num_parents = 1;
+ init.flags = CLK_IGNORE_UNUSED;
+
+ osc->hw.init = &init;
+ osc->sckcr = regbase;
+ osc->startup_usec = 1200000;
+
+ if (bypass)
+ writel((readl(regbase) | AT91_SCKC_OSC32BYP), regbase);
+
+ hw = &osc->hw;
+ ret = clk_hw_register(NULL, &osc->hw);
+ if (ret) {
+ kfree(osc);
+ return;
+ }
+
+ hw = at91_clk_register_sam9x5_slow(regbase, "slowck", parent_names, 2);
+ if (IS_ERR(hw))
+ return;
+
+ of_clk_add_hw_provider(np, of_clk_hw_simple_get, hw);
+}
+CLK_OF_DECLARE(sama5d4_clk_sckc, "atmel,sama5d4-sckc",
+ of_sama5d4_sckc_setup);