diff options
Diffstat (limited to 'drivers/clk/imx/clk-pfdv2.c')
| -rw-r--r-- | drivers/clk/imx/clk-pfdv2.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/drivers/clk/imx/clk-pfdv2.c b/drivers/clk/imx/clk-pfdv2.c new file mode 100644 index 000000000..6b744c842 --- /dev/null +++ b/drivers/clk/imx/clk-pfdv2.c @@ -0,0 +1,229 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2016 Freescale Semiconductor, Inc. + * Copyright 2017~2018 NXP + * + * Author: Dong Aisheng <aisheng.dong@nxp.com> + * + */ + +#include <linux/clk-provider.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/slab.h> + +#include "clk.h" + +/** + * struct clk_pfdv2 - IMX PFD clock + * @hw: clock source + * @reg: PFD register address + * @gate_bit: Gate bit offset + * @vld_bit: Valid bit offset + * @frac_off: PLL Fractional Divider offset + */ + +struct clk_pfdv2 { + struct clk_hw hw; + void __iomem *reg; + u8 gate_bit; + u8 vld_bit; + u8 frac_off; +}; + +#define to_clk_pfdv2(_hw) container_of(_hw, struct clk_pfdv2, hw) + +#define CLK_PFDV2_FRAC_MASK 0x3f + +#define LOCK_TIMEOUT_US USEC_PER_MSEC + +static DEFINE_SPINLOCK(pfd_lock); + +static int clk_pfdv2_wait(struct clk_pfdv2 *pfd) +{ + u32 val; + + return readl_poll_timeout(pfd->reg, val, val & (1 << pfd->vld_bit), + 0, LOCK_TIMEOUT_US); +} + +static int clk_pfdv2_enable(struct clk_hw *hw) +{ + struct clk_pfdv2 *pfd = to_clk_pfdv2(hw); + unsigned long flags; + u32 val; + + spin_lock_irqsave(&pfd_lock, flags); + val = readl_relaxed(pfd->reg); + val &= ~(1 << pfd->gate_bit); + writel_relaxed(val, pfd->reg); + spin_unlock_irqrestore(&pfd_lock, flags); + + return clk_pfdv2_wait(pfd); +} + +static void clk_pfdv2_disable(struct clk_hw *hw) +{ + struct clk_pfdv2 *pfd = to_clk_pfdv2(hw); + unsigned long flags; + u32 val; + + spin_lock_irqsave(&pfd_lock, flags); + val = readl_relaxed(pfd->reg); + val |= (1 << pfd->gate_bit); + writel_relaxed(val, pfd->reg); + spin_unlock_irqrestore(&pfd_lock, flags); +} + +static unsigned long clk_pfdv2_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_pfdv2 *pfd = to_clk_pfdv2(hw); + u64 tmp = parent_rate; + u8 frac; + + frac = (readl_relaxed(pfd->reg) >> pfd->frac_off) + & CLK_PFDV2_FRAC_MASK; + + if (!frac) { + pr_debug("clk_pfdv2: %s invalid pfd frac value 0\n", + clk_hw_get_name(hw)); + return 0; + } + + tmp *= 18; + do_div(tmp, frac); + + return tmp; +} + +static int clk_pfdv2_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + unsigned long parent_rates[] = { + 480000000, + 528000000, + req->best_parent_rate + }; + unsigned long best_rate = -1UL, rate = req->rate; + unsigned long best_parent_rate = req->best_parent_rate; + u64 tmp; + u8 frac; + int i; + + for (i = 0; i < ARRAY_SIZE(parent_rates); i++) { + tmp = parent_rates[i]; + tmp = tmp * 18 + rate / 2; + do_div(tmp, rate); + frac = tmp; + + if (frac < 12) + frac = 12; + else if (frac > 35) + frac = 35; + + tmp = parent_rates[i]; + tmp *= 18; + do_div(tmp, frac); + + if (abs(tmp - req->rate) < abs(best_rate - req->rate)) { + best_rate = tmp; + best_parent_rate = parent_rates[i]; + } + } + + req->best_parent_rate = best_parent_rate; + req->rate = best_rate; + + return 0; +} + +static int clk_pfdv2_is_enabled(struct clk_hw *hw) +{ + struct clk_pfdv2 *pfd = to_clk_pfdv2(hw); + + if (readl_relaxed(pfd->reg) & (1 << pfd->gate_bit)) + return 0; + + return 1; +} + +static int clk_pfdv2_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_pfdv2 *pfd = to_clk_pfdv2(hw); + unsigned long flags; + u64 tmp = parent_rate; + u32 val; + u8 frac; + + if (!rate) + return -EINVAL; + + /* PFD can NOT change rate without gating */ + WARN_ON(clk_pfdv2_is_enabled(hw)); + + tmp = tmp * 18 + rate / 2; + do_div(tmp, rate); + frac = tmp; + if (frac < 12) + frac = 12; + else if (frac > 35) + frac = 35; + + spin_lock_irqsave(&pfd_lock, flags); + val = readl_relaxed(pfd->reg); + val &= ~(CLK_PFDV2_FRAC_MASK << pfd->frac_off); + val |= frac << pfd->frac_off; + writel_relaxed(val, pfd->reg); + spin_unlock_irqrestore(&pfd_lock, flags); + + return 0; +} + +static const struct clk_ops clk_pfdv2_ops = { + .enable = clk_pfdv2_enable, + .disable = clk_pfdv2_disable, + .recalc_rate = clk_pfdv2_recalc_rate, + .determine_rate = clk_pfdv2_determine_rate, + .set_rate = clk_pfdv2_set_rate, + .is_enabled = clk_pfdv2_is_enabled, +}; + +struct clk_hw *imx_clk_hw_pfdv2(const char *name, const char *parent_name, + void __iomem *reg, u8 idx) +{ + struct clk_init_data init; + struct clk_pfdv2 *pfd; + struct clk_hw *hw; + int ret; + + WARN_ON(idx > 3); + + pfd = kzalloc(sizeof(*pfd), GFP_KERNEL); + if (!pfd) + return ERR_PTR(-ENOMEM); + + pfd->reg = reg; + pfd->gate_bit = (idx + 1) * 8 - 1; + pfd->vld_bit = pfd->gate_bit - 1; + pfd->frac_off = idx * 8; + + init.name = name; + init.ops = &clk_pfdv2_ops; + init.parent_names = &parent_name; + init.num_parents = 1; + init.flags = CLK_SET_RATE_GATE | CLK_SET_RATE_PARENT; + + pfd->hw.init = &init; + + hw = &pfd->hw; + ret = clk_hw_register(NULL, hw); + if (ret) { + kfree(pfd); + hw = ERR_PTR(ret); + } + + return hw; +} |