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path: root/drivers/clk/tegra/clk-utils.c
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Diffstat (limited to 'drivers/clk/tegra/clk-utils.c')
-rw-r--r--drivers/clk/tegra/clk-utils.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/drivers/clk/tegra/clk-utils.c b/drivers/clk/tegra/clk-utils.c
new file mode 100644
index 000000000000..1a5daae4e501
--- /dev/null
+++ b/drivers/clk/tegra/clk-utils.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018, NVIDIA CORPORATION. All rights reserved.
+ */
+
+#include <asm/div64.h>
+
+#include "clk.h"
+
+#define div_mask(w) ((1 << (w)) - 1)
+
+int div_frac_get(unsigned long rate, unsigned parent_rate, u8 width,
+ u8 frac_width, u8 flags)
+{
+ u64 divider_ux1 = parent_rate;
+ int mul;
+
+ if (!rate)
+ return 0;
+
+ mul = 1 << frac_width;
+
+ if (!(flags & TEGRA_DIVIDER_INT))
+ divider_ux1 *= mul;
+
+ if (flags & TEGRA_DIVIDER_ROUND_UP)
+ divider_ux1 += rate - 1;
+
+ do_div(divider_ux1, rate);
+
+ if (flags & TEGRA_DIVIDER_INT)
+ divider_ux1 *= mul;
+
+ if (divider_ux1 < mul)
+ return 0;
+
+ divider_ux1 -= mul;
+
+ if (divider_ux1 > div_mask(width))
+ return div_mask(width);
+
+ return divider_ux1;
+}