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path: root/drivers/clk/rockchip/clk-mmc-phase.c
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-rw-r--r--drivers/clk/rockchip/clk-mmc-phase.c154
1 files changed, 154 insertions, 0 deletions
diff --git a/drivers/clk/rockchip/clk-mmc-phase.c b/drivers/clk/rockchip/clk-mmc-phase.c
new file mode 100644
index 0000000..c842e3b
--- /dev/null
+++ b/drivers/clk/rockchip/clk-mmc-phase.c
@@ -0,0 +1,154 @@
+/*
+ * Copyright 2014 Google, Inc
+ * Author: Alexandru M Stan <amstan@chromium.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/slab.h>
+#include <linux/clk-provider.h>
+#include "clk.h"
+
+struct rockchip_mmc_clock {
+ struct clk_hw hw;
+ void __iomem *reg;
+ int id;
+ int shift;
+};
+
+#define to_mmc_clock(_hw) container_of(_hw, struct rockchip_mmc_clock, hw)
+
+#define RK3288_MMC_CLKGEN_DIV 2
+
+static unsigned long rockchip_mmc_recalc(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ return parent_rate / RK3288_MMC_CLKGEN_DIV;
+}
+
+#define ROCKCHIP_MMC_DELAY_SEL BIT(10)
+#define ROCKCHIP_MMC_DEGREE_MASK 0x3
+#define ROCKCHIP_MMC_DELAYNUM_OFFSET 2
+#define ROCKCHIP_MMC_DELAYNUM_MASK (0xff << ROCKCHIP_MMC_DELAYNUM_OFFSET)
+
+#define PSECS_PER_SEC 1000000000000LL
+
+/*
+ * Each fine delay is between 40ps-80ps. Assume each fine delay is 60ps to
+ * simplify calculations. So 45degs could be anywhere between 33deg and 66deg.
+ */
+#define ROCKCHIP_MMC_DELAY_ELEMENT_PSEC 60
+
+static int rockchip_mmc_get_phase(struct clk_hw *hw)
+{
+ struct rockchip_mmc_clock *mmc_clock = to_mmc_clock(hw);
+ unsigned long rate = clk_get_rate(hw->clk);
+ u32 raw_value;
+ u16 degrees;
+ u32 delay_num = 0;
+
+ raw_value = readl(mmc_clock->reg) >> (mmc_clock->shift);
+
+ degrees = (raw_value & ROCKCHIP_MMC_DEGREE_MASK) * 90;
+
+ if (raw_value & ROCKCHIP_MMC_DELAY_SEL) {
+ /* degrees/delaynum * 10000 */
+ unsigned long factor = (ROCKCHIP_MMC_DELAY_ELEMENT_PSEC / 10) *
+ 36 * (rate / 1000000);
+
+ delay_num = (raw_value & ROCKCHIP_MMC_DELAYNUM_MASK);
+ delay_num >>= ROCKCHIP_MMC_DELAYNUM_OFFSET;
+ degrees += delay_num * factor / 10000;
+ }
+
+ return degrees % 360;
+}
+
+static int rockchip_mmc_set_phase(struct clk_hw *hw, int degrees)
+{
+ struct rockchip_mmc_clock *mmc_clock = to_mmc_clock(hw);
+ unsigned long rate = clk_get_rate(hw->clk);
+ u8 nineties, remainder;
+ u8 delay_num;
+ u32 raw_value;
+ u64 delay;
+
+ /* allow 22 to be 22.5 */
+ degrees++;
+ /* floor to 22.5 increment */
+ degrees -= ((degrees) * 10 % 225) / 10;
+
+ nineties = degrees / 90;
+ /* 22.5 multiples */
+ remainder = (degrees % 90) / 22;
+
+ delay = PSECS_PER_SEC;
+ do_div(delay, rate);
+ /* / 360 / 22.5 */
+ do_div(delay, 16);
+ do_div(delay, ROCKCHIP_MMC_DELAY_ELEMENT_PSEC);
+
+ delay *= remainder;
+ delay_num = (u8) min(delay, 255ULL);
+
+ raw_value = delay_num ? ROCKCHIP_MMC_DELAY_SEL : 0;
+ raw_value |= delay_num << ROCKCHIP_MMC_DELAYNUM_OFFSET;
+ raw_value |= nineties;
+ writel(HIWORD_UPDATE(raw_value, 0x07ff, mmc_clock->shift), mmc_clock->reg);
+
+ pr_debug("%s->set_phase(%d) delay_nums=%u reg[0x%p]=0x%03x actual_degrees=%d\n",
+ __clk_get_name(hw->clk), degrees, delay_num,
+ mmc_clock->reg, raw_value>>(mmc_clock->shift),
+ rockchip_mmc_get_phase(hw)
+ );
+
+ return 0;
+}
+
+static const struct clk_ops rockchip_mmc_clk_ops = {
+ .recalc_rate = rockchip_mmc_recalc,
+ .get_phase = rockchip_mmc_get_phase,
+ .set_phase = rockchip_mmc_set_phase,
+};
+
+struct clk *rockchip_clk_register_mmc(const char *name,
+ const char **parent_names, u8 num_parents,
+ void __iomem *reg, int shift)
+{
+ struct clk_init_data init;
+ struct rockchip_mmc_clock *mmc_clock;
+ struct clk *clk;
+
+ mmc_clock = kmalloc(sizeof(*mmc_clock), GFP_KERNEL);
+ if (!mmc_clock)
+ return NULL;
+
+ init.num_parents = num_parents;
+ init.parent_names = parent_names;
+ init.ops = &rockchip_mmc_clk_ops;
+
+ mmc_clock->hw.init = &init;
+ mmc_clock->reg = reg;
+ mmc_clock->shift = shift;
+
+ if (name)
+ init.name = name;
+
+ clk = clk_register(NULL, &mmc_clock->hw);
+ if (IS_ERR(clk))
+ goto err_free;
+
+ return clk;
+
+err_free:
+ kfree(mmc_clock);
+ return NULL;
+}
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