diff options
Diffstat (limited to 'drivers/clk/rockchip/clk-mmc-phase.c')
| -rw-r--r-- | drivers/clk/rockchip/clk-mmc-phase.c | 154 |
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 000000000000..c842e3b60f21 --- /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; +} |