clk: tegra: Model oscillator as clock

Currently the Tegra clock driver simplifies the clock tree somewhat by
taking advantage of the fact that clk_m runs at the same frequency as
the oscillator. While that's true on all currently supported SoCs, it
does not apply to Tegra210 anymore. On Tegra210 clk_m is typically
divided down from the oscillator frequency. To support that setup, add
a separate clock for the oscillator that both clk_m and pll_ref derive
from.

Modify the tegra_osc_clk_init() function to take an additional divider
parameter for clk_m. Existing SoCs always pass in 1, whereas Tegra210
will read the divider from a register in the clock & reset controller.

Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 13 insertions, 11 deletions

diff --git a/drivers/clk/tegra/clk-tegra-fixed.c b/drivers/clk/tegra/clk-tegra-fixed.c
index f3b7738..605676d 100644
--- a/drivers/clk/tegra/clk-tegra-fixed.c
+++ b/drivers/clk/tegra/clk-tegra-fixed.c
@@ -30,13 +30,12 @@
 #define OSC_CTRL_OSC_FREQ_SHIFT		28
 #define OSC_CTRL_PLL_REF_DIV_SHIFT	26
 
-int __init tegra_osc_clk_init(void __iomem *clk_base,
-				struct tegra_clk *tegra_clks,
-				unsigned long *input_freqs, int num,
-				unsigned long *osc_freq,
-				unsigned long *pll_ref_freq)
+int __init tegra_osc_clk_init(void __iomem *clk_base, struct tegra_clk *clks,
+			      unsigned long *input_freqs, unsigned int num,
+			      unsigned int clk_m_div, unsigned long *osc_freq,
+			      unsigned long *pll_ref_freq)
 {
-	struct clk *clk;
+	struct clk *clk, *osc;
 	struct clk **dt_clk;
 	u32 val, pll_ref_div;
 	unsigned osc_idx;
@@ -54,22 +53,25 @@ int __init tegra_osc_clk_init(void __iomem *clk_base,
 		return -EINVAL;
 	}
 
-	dt_clk = tegra_lookup_dt_id(tegra_clk_clk_m, tegra_clks);
+	osc = clk_register_fixed_rate(NULL, "osc", NULL, CLK_IS_ROOT,
+				      *osc_freq);
+
+	dt_clk = tegra_lookup_dt_id(tegra_clk_clk_m, clks);
 	if (!dt_clk)
 		return 0;
 
-	clk = clk_register_fixed_rate(NULL, "clk_m", NULL, CLK_IS_ROOT,
-				      *osc_freq);
+	clk = clk_register_fixed_factor(NULL, "clk_m", "osc",
+					0, 1, clk_m_div);
 	*dt_clk = clk;
 
 	/* pll_ref */
 	val = (val >> OSC_CTRL_PLL_REF_DIV_SHIFT) & 3;
 	pll_ref_div = 1 << val;
-	dt_clk = tegra_lookup_dt_id(tegra_clk_pll_ref, tegra_clks);
+	dt_clk = tegra_lookup_dt_id(tegra_clk_pll_ref, clks);
 	if (!dt_clk)
 		return 0;
 
-	clk = clk_register_fixed_factor(NULL, "pll_ref", "clk_m",
+	clk = clk_register_fixed_factor(NULL, "pll_ref", "osc",
 					0, 1, pll_ref_div);
 	*dt_clk = clk;