diff options
Diffstat (limited to 'drivers/clk/zynqmp/divider.c')
| -rw-r--r-- | drivers/clk/zynqmp/divider.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/drivers/clk/zynqmp/divider.c b/drivers/clk/zynqmp/divider.c new file mode 100644 index 000000000000..a371c66e72ef --- /dev/null +++ b/drivers/clk/zynqmp/divider.c @@ -0,0 +1,217 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Zynq UltraScale+ MPSoC Divider support + * + * Copyright (C) 2016-2018 Xilinx + * + * Adjustable divider clock implementation + */ + +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/slab.h> +#include "clk-zynqmp.h" + +/* + * DOC: basic adjustable divider clock that cannot gate + * + * Traits of this clock: + * prepare - clk_prepare only ensures that parents are prepared + * enable - clk_enable only ensures that parents are enabled + * rate - rate is adjustable. clk->rate = ceiling(parent->rate / divisor) + * parent - fixed parent. No clk_set_parent support + */ + +#define to_zynqmp_clk_divider(_hw) \ + container_of(_hw, struct zynqmp_clk_divider, hw) + +#define CLK_FRAC BIT(13) /* has a fractional parent */ + +/** + * struct zynqmp_clk_divider - adjustable divider clock + * @hw: handle between common and hardware-specific interfaces + * @flags: Hardware specific flags + * @clk_id: Id of clock + * @div_type: divisor type (TYPE_DIV1 or TYPE_DIV2) + */ +struct zynqmp_clk_divider { + struct clk_hw hw; + u8 flags; + u32 clk_id; + u32 div_type; +}; + +static inline int zynqmp_divider_get_val(unsigned long parent_rate, + unsigned long rate) +{ + return DIV_ROUND_CLOSEST(parent_rate, rate); +} + +/** + * zynqmp_clk_divider_recalc_rate() - Recalc rate of divider clock + * @hw: handle between common and hardware-specific interfaces + * @parent_rate: rate of parent clock + * + * Return: 0 on success else error+reason + */ +static unsigned long zynqmp_clk_divider_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw); + const char *clk_name = clk_hw_get_name(hw); + u32 clk_id = divider->clk_id; + u32 div_type = divider->div_type; + u32 div, value; + int ret; + const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops(); + + ret = eemi_ops->clock_getdivider(clk_id, &div); + + if (ret) + pr_warn_once("%s() get divider failed for %s, ret = %d\n", + __func__, clk_name, ret); + + if (div_type == TYPE_DIV1) + value = div & 0xFFFF; + else + value = div >> 16; + + return DIV_ROUND_UP_ULL(parent_rate, value); +} + +/** + * zynqmp_clk_divider_round_rate() - Round rate of divider clock + * @hw: handle between common and hardware-specific interfaces + * @rate: rate of clock to be set + * @prate: rate of parent clock + * + * Return: 0 on success else error+reason + */ +static long zynqmp_clk_divider_round_rate(struct clk_hw *hw, + unsigned long rate, + unsigned long *prate) +{ + struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw); + const char *clk_name = clk_hw_get_name(hw); + u32 clk_id = divider->clk_id; + u32 div_type = divider->div_type; + u32 bestdiv; + int ret; + const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops(); + + /* if read only, just return current value */ + if (divider->flags & CLK_DIVIDER_READ_ONLY) { + ret = eemi_ops->clock_getdivider(clk_id, &bestdiv); + + if (ret) + pr_warn_once("%s() get divider failed for %s, ret = %d\n", + __func__, clk_name, ret); + if (div_type == TYPE_DIV1) + bestdiv = bestdiv & 0xFFFF; + else + bestdiv = bestdiv >> 16; + + return DIV_ROUND_UP_ULL((u64)*prate, bestdiv); + } + + bestdiv = zynqmp_divider_get_val(*prate, rate); + + if ((clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) && + (divider->flags & CLK_FRAC)) + bestdiv = rate % *prate ? 1 : bestdiv; + *prate = rate * bestdiv; + + return rate; +} + +/** + * zynqmp_clk_divider_set_rate() - Set rate of divider clock + * @hw: handle between common and hardware-specific interfaces + * @rate: rate of clock to be set + * @parent_rate: rate of parent clock + * + * Return: 0 on success else error+reason + */ +static int zynqmp_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct zynqmp_clk_divider *divider = to_zynqmp_clk_divider(hw); + const char *clk_name = clk_hw_get_name(hw); + u32 clk_id = divider->clk_id; + u32 div_type = divider->div_type; + u32 value, div; + int ret; + const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops(); + + value = zynqmp_divider_get_val(parent_rate, rate); + if (div_type == TYPE_DIV1) { + div = value & 0xFFFF; + div |= 0xffff << 16; + } else { + div = 0xffff; + div |= value << 16; + } + + ret = eemi_ops->clock_setdivider(clk_id, div); + + if (ret) + pr_warn_once("%s() set divider failed for %s, ret = %d\n", + __func__, clk_name, ret); + + return ret; +} + +static const struct clk_ops zynqmp_clk_divider_ops = { + .recalc_rate = zynqmp_clk_divider_recalc_rate, + .round_rate = zynqmp_clk_divider_round_rate, + .set_rate = zynqmp_clk_divider_set_rate, +}; + +/** + * zynqmp_clk_register_divider() - Register a divider clock + * @name: Name of this clock + * @clk_id: Id of clock + * @parents: Name of this clock's parents + * @num_parents: Number of parents + * @nodes: Clock topology node + * + * Return: clock hardware to registered clock divider + */ +struct clk_hw *zynqmp_clk_register_divider(const char *name, + u32 clk_id, + const char * const *parents, + u8 num_parents, + const struct clock_topology *nodes) +{ + struct zynqmp_clk_divider *div; + struct clk_hw *hw; + struct clk_init_data init; + int ret; + + /* allocate the divider */ + div = kzalloc(sizeof(*div), GFP_KERNEL); + if (!div) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &zynqmp_clk_divider_ops; + init.flags = nodes->flag; + init.parent_names = parents; + init.num_parents = 1; + + /* struct clk_divider assignments */ + div->flags = nodes->type_flag; + div->hw.init = &init; + div->clk_id = clk_id; + div->div_type = nodes->type; + + hw = &div->hw; + ret = clk_hw_register(NULL, hw); + if (ret) { + kfree(div); + hw = ERR_PTR(ret); + } + + return hw; +} +EXPORT_SYMBOL_GPL(zynqmp_clk_register_divider); |