diff options
Diffstat (limited to 'drivers/clk/ingenic/cgu.c')
| -rw-r--r-- | drivers/clk/ingenic/cgu.c | 711 |
1 files changed, 711 insertions, 0 deletions
diff --git a/drivers/clk/ingenic/cgu.c b/drivers/clk/ingenic/cgu.c new file mode 100644 index 0000000..b936cdd --- /dev/null +++ b/drivers/clk/ingenic/cgu.c @@ -0,0 +1,711 @@ +/* + * Ingenic SoC CGU driver + * + * Copyright (c) 2013-2015 Imagination Technologies + * Author: Paul Burton <paul.burton@imgtec.com> + * + * 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/bitops.h> +#include <linux/clk-provider.h> +#include <linux/clkdev.h> +#include <linux/delay.h> +#include <linux/math64.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include "cgu.h" + +#define MHZ (1000 * 1000) + +/** + * ingenic_cgu_gate_get() - get the value of clock gate register bit + * @cgu: reference to the CGU whose registers should be read + * @info: info struct describing the gate bit + * + * Retrieves the state of the clock gate bit described by info. The + * caller must hold cgu->lock. + * + * Return: true if the gate bit is set, else false. + */ +static inline bool +ingenic_cgu_gate_get(struct ingenic_cgu *cgu, + const struct ingenic_cgu_gate_info *info) +{ + return readl(cgu->base + info->reg) & BIT(info->bit); +} + +/** + * ingenic_cgu_gate_set() - set the value of clock gate register bit + * @cgu: reference to the CGU whose registers should be modified + * @info: info struct describing the gate bit + * @val: non-zero to gate a clock, otherwise zero + * + * Sets the given gate bit in order to gate or ungate a clock. + * + * The caller must hold cgu->lock. + */ +static inline void +ingenic_cgu_gate_set(struct ingenic_cgu *cgu, + const struct ingenic_cgu_gate_info *info, bool val) +{ + u32 clkgr = readl(cgu->base + info->reg); + + if (val) + clkgr |= BIT(info->bit); + else + clkgr &= ~BIT(info->bit); + + writel(clkgr, cgu->base + info->reg); +} + +/* + * PLL operations + */ + +static unsigned long +ingenic_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) +{ + struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); + struct ingenic_cgu *cgu = ingenic_clk->cgu; + const struct ingenic_cgu_clk_info *clk_info; + const struct ingenic_cgu_pll_info *pll_info; + unsigned m, n, od_enc, od; + bool bypass, enable; + unsigned long flags; + u32 ctl; + + clk_info = &cgu->clock_info[ingenic_clk->idx]; + BUG_ON(clk_info->type != CGU_CLK_PLL); + pll_info = &clk_info->pll; + + spin_lock_irqsave(&cgu->lock, flags); + ctl = readl(cgu->base + pll_info->reg); + spin_unlock_irqrestore(&cgu->lock, flags); + + m = (ctl >> pll_info->m_shift) & GENMASK(pll_info->m_bits - 1, 0); + m += pll_info->m_offset; + n = (ctl >> pll_info->n_shift) & GENMASK(pll_info->n_bits - 1, 0); + n += pll_info->n_offset; + od_enc = ctl >> pll_info->od_shift; + od_enc &= GENMASK(pll_info->od_bits - 1, 0); + bypass = !!(ctl & BIT(pll_info->bypass_bit)); + enable = !!(ctl & BIT(pll_info->enable_bit)); + + if (bypass) + return parent_rate; + + if (!enable) + return 0; + + for (od = 0; od < pll_info->od_max; od++) { + if (pll_info->od_encoding[od] == od_enc) + break; + } + BUG_ON(od == pll_info->od_max); + od++; + + return div_u64((u64)parent_rate * m, n * od); +} + +static unsigned long +ingenic_pll_calc(const struct ingenic_cgu_clk_info *clk_info, + unsigned long rate, unsigned long parent_rate, + unsigned *pm, unsigned *pn, unsigned *pod) +{ + const struct ingenic_cgu_pll_info *pll_info; + unsigned m, n, od; + + pll_info = &clk_info->pll; + od = 1; + + /* + * The frequency after the input divider must be between 10 and 50 MHz. + * The highest divider yields the best resolution. + */ + n = parent_rate / (10 * MHZ); + n = min_t(unsigned, n, 1 << clk_info->pll.n_bits); + n = max_t(unsigned, n, pll_info->n_offset); + + m = (rate / MHZ) * od * n / (parent_rate / MHZ); + m = min_t(unsigned, m, 1 << clk_info->pll.m_bits); + m = max_t(unsigned, m, pll_info->m_offset); + + if (pm) + *pm = m; + if (pn) + *pn = n; + if (pod) + *pod = od; + + return div_u64((u64)parent_rate * m, n * od); +} + +static long +ingenic_pll_round_rate(struct clk_hw *hw, unsigned long req_rate, + unsigned long *prate) +{ + struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); + struct ingenic_cgu *cgu = ingenic_clk->cgu; + const struct ingenic_cgu_clk_info *clk_info; + + clk_info = &cgu->clock_info[ingenic_clk->idx]; + BUG_ON(clk_info->type != CGU_CLK_PLL); + + return ingenic_pll_calc(clk_info, req_rate, *prate, NULL, NULL, NULL); +} + +static int +ingenic_pll_set_rate(struct clk_hw *hw, unsigned long req_rate, + unsigned long parent_rate) +{ + const unsigned timeout = 100; + struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); + struct ingenic_cgu *cgu = ingenic_clk->cgu; + const struct ingenic_cgu_clk_info *clk_info; + const struct ingenic_cgu_pll_info *pll_info; + unsigned long rate, flags; + unsigned m, n, od, i; + u32 ctl; + + clk_info = &cgu->clock_info[ingenic_clk->idx]; + BUG_ON(clk_info->type != CGU_CLK_PLL); + pll_info = &clk_info->pll; + + rate = ingenic_pll_calc(clk_info, req_rate, parent_rate, + &m, &n, &od); + if (rate != req_rate) + pr_info("ingenic-cgu: request '%s' rate %luHz, actual %luHz\n", + clk_info->name, req_rate, rate); + + spin_lock_irqsave(&cgu->lock, flags); + ctl = readl(cgu->base + pll_info->reg); + + ctl &= ~(GENMASK(pll_info->m_bits - 1, 0) << pll_info->m_shift); + ctl |= (m - pll_info->m_offset) << pll_info->m_shift; + + ctl &= ~(GENMASK(pll_info->n_bits - 1, 0) << pll_info->n_shift); + ctl |= (n - pll_info->n_offset) << pll_info->n_shift; + + ctl &= ~(GENMASK(pll_info->od_bits - 1, 0) << pll_info->od_shift); + ctl |= pll_info->od_encoding[od - 1] << pll_info->od_shift; + + ctl &= ~BIT(pll_info->bypass_bit); + ctl |= BIT(pll_info->enable_bit); + + writel(ctl, cgu->base + pll_info->reg); + + /* wait for the PLL to stabilise */ + for (i = 0; i < timeout; i++) { + ctl = readl(cgu->base + pll_info->reg); + if (ctl & BIT(pll_info->stable_bit)) + break; + mdelay(1); + } + + spin_unlock_irqrestore(&cgu->lock, flags); + + if (i == timeout) + return -EBUSY; + + return 0; +} + +static const struct clk_ops ingenic_pll_ops = { + .recalc_rate = ingenic_pll_recalc_rate, + .round_rate = ingenic_pll_round_rate, + .set_rate = ingenic_pll_set_rate, +}; + +/* + * Operations for all non-PLL clocks + */ + +static u8 ingenic_clk_get_parent(struct clk_hw *hw) +{ + struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); + struct ingenic_cgu *cgu = ingenic_clk->cgu; + const struct ingenic_cgu_clk_info *clk_info; + u32 reg; + u8 i, hw_idx, idx = 0; + + clk_info = &cgu->clock_info[ingenic_clk->idx]; + + if (clk_info->type & CGU_CLK_MUX) { + reg = readl(cgu->base + clk_info->mux.reg); + hw_idx = (reg >> clk_info->mux.shift) & + GENMASK(clk_info->mux.bits - 1, 0); + + /* + * Convert the hardware index to the parent index by skipping + * over any -1's in the parents array. + */ + for (i = 0; i < hw_idx; i++) { + if (clk_info->parents[i] != -1) + idx++; + } + } + + return idx; +} + +static int ingenic_clk_set_parent(struct clk_hw *hw, u8 idx) +{ + struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); + struct ingenic_cgu *cgu = ingenic_clk->cgu; + const struct ingenic_cgu_clk_info *clk_info; + unsigned long flags; + u8 curr_idx, hw_idx, num_poss; + u32 reg, mask; + + clk_info = &cgu->clock_info[ingenic_clk->idx]; + + if (clk_info->type & CGU_CLK_MUX) { + /* + * Convert the parent index to the hardware index by adding + * 1 for any -1 in the parents array preceding the given + * index. That is, we want the index of idx'th entry in + * clk_info->parents which does not equal -1. + */ + hw_idx = curr_idx = 0; + num_poss = 1 << clk_info->mux.bits; + for (; hw_idx < num_poss; hw_idx++) { + if (clk_info->parents[hw_idx] == -1) + continue; + if (curr_idx == idx) + break; + curr_idx++; + } + + /* idx should always be a valid parent */ + BUG_ON(curr_idx != idx); + + mask = GENMASK(clk_info->mux.bits - 1, 0); + mask <<= clk_info->mux.shift; + + spin_lock_irqsave(&cgu->lock, flags); + + /* write the register */ + reg = readl(cgu->base + clk_info->mux.reg); + reg &= ~mask; + reg |= hw_idx << clk_info->mux.shift; + writel(reg, cgu->base + clk_info->mux.reg); + + spin_unlock_irqrestore(&cgu->lock, flags); + return 0; + } + + return idx ? -EINVAL : 0; +} + +static unsigned long +ingenic_clk_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) +{ + struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); + struct ingenic_cgu *cgu = ingenic_clk->cgu; + const struct ingenic_cgu_clk_info *clk_info; + unsigned long rate = parent_rate; + u32 div_reg, div; + + clk_info = &cgu->clock_info[ingenic_clk->idx]; + + if (clk_info->type & CGU_CLK_DIV) { + div_reg = readl(cgu->base + clk_info->div.reg); + div = (div_reg >> clk_info->div.shift) & + GENMASK(clk_info->div.bits - 1, 0); + div += 1; + + rate /= div; + } + + return rate; +} + +static unsigned +ingenic_clk_calc_div(const struct ingenic_cgu_clk_info *clk_info, + unsigned long parent_rate, unsigned long req_rate) +{ + unsigned div; + + /* calculate the divide */ + div = DIV_ROUND_UP(parent_rate, req_rate); + + /* and impose hardware constraints */ + div = min_t(unsigned, div, 1 << clk_info->div.bits); + div = max_t(unsigned, div, 1); + + return div; +} + +static long +ingenic_clk_round_rate(struct clk_hw *hw, unsigned long req_rate, + unsigned long *parent_rate) +{ + struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); + struct ingenic_cgu *cgu = ingenic_clk->cgu; + const struct ingenic_cgu_clk_info *clk_info; + long rate = *parent_rate; + + clk_info = &cgu->clock_info[ingenic_clk->idx]; + + if (clk_info->type & CGU_CLK_DIV) + rate /= ingenic_clk_calc_div(clk_info, *parent_rate, req_rate); + else if (clk_info->type & CGU_CLK_FIXDIV) + rate /= clk_info->fixdiv.div; + + return rate; +} + +static int +ingenic_clk_set_rate(struct clk_hw *hw, unsigned long req_rate, + unsigned long parent_rate) +{ + struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); + struct ingenic_cgu *cgu = ingenic_clk->cgu; + const struct ingenic_cgu_clk_info *clk_info; + const unsigned timeout = 100; + unsigned long rate, flags; + unsigned div, i; + u32 reg, mask; + int ret = 0; + + clk_info = &cgu->clock_info[ingenic_clk->idx]; + + if (clk_info->type & CGU_CLK_DIV) { + div = ingenic_clk_calc_div(clk_info, parent_rate, req_rate); + rate = parent_rate / div; + + if (rate != req_rate) + return -EINVAL; + + spin_lock_irqsave(&cgu->lock, flags); + reg = readl(cgu->base + clk_info->div.reg); + + /* update the divide */ + mask = GENMASK(clk_info->div.bits - 1, 0); + reg &= ~(mask << clk_info->div.shift); + reg |= (div - 1) << clk_info->div.shift; + + /* clear the stop bit */ + if (clk_info->div.stop_bit != -1) + reg &= ~BIT(clk_info->div.stop_bit); + + /* set the change enable bit */ + if (clk_info->div.ce_bit != -1) + reg |= BIT(clk_info->div.ce_bit); + + /* update the hardware */ + writel(reg, cgu->base + clk_info->div.reg); + + /* wait for the change to take effect */ + if (clk_info->div.busy_bit != -1) { + for (i = 0; i < timeout; i++) { + reg = readl(cgu->base + clk_info->div.reg); + if (!(reg & BIT(clk_info->div.busy_bit))) + break; + mdelay(1); + } + if (i == timeout) + ret = -EBUSY; + } + + spin_unlock_irqrestore(&cgu->lock, flags); + return ret; + } + + return -EINVAL; +} + +static int ingenic_clk_enable(struct clk_hw *hw) +{ + struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); + struct ingenic_cgu *cgu = ingenic_clk->cgu; + const struct ingenic_cgu_clk_info *clk_info; + unsigned long flags; + + clk_info = &cgu->clock_info[ingenic_clk->idx]; + + if (clk_info->type & CGU_CLK_GATE) { + /* ungate the clock */ + spin_lock_irqsave(&cgu->lock, flags); + ingenic_cgu_gate_set(cgu, &clk_info->gate, false); + spin_unlock_irqrestore(&cgu->lock, flags); + } + + return 0; +} + +static void ingenic_clk_disable(struct clk_hw *hw) +{ + struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); + struct ingenic_cgu *cgu = ingenic_clk->cgu; + const struct ingenic_cgu_clk_info *clk_info; + unsigned long flags; + + clk_info = &cgu->clock_info[ingenic_clk->idx]; + + if (clk_info->type & CGU_CLK_GATE) { + /* gate the clock */ + spin_lock_irqsave(&cgu->lock, flags); + ingenic_cgu_gate_set(cgu, &clk_info->gate, true); + spin_unlock_irqrestore(&cgu->lock, flags); + } +} + +static int ingenic_clk_is_enabled(struct clk_hw *hw) +{ + struct ingenic_clk *ingenic_clk = to_ingenic_clk(hw); + struct ingenic_cgu *cgu = ingenic_clk->cgu; + const struct ingenic_cgu_clk_info *clk_info; + unsigned long flags; + int enabled = 1; + + clk_info = &cgu->clock_info[ingenic_clk->idx]; + + if (clk_info->type & CGU_CLK_GATE) { + spin_lock_irqsave(&cgu->lock, flags); + enabled = !ingenic_cgu_gate_get(cgu, &clk_info->gate); + spin_unlock_irqrestore(&cgu->lock, flags); + } + + return enabled; +} + +static const struct clk_ops ingenic_clk_ops = { + .get_parent = ingenic_clk_get_parent, + .set_parent = ingenic_clk_set_parent, + + .recalc_rate = ingenic_clk_recalc_rate, + .round_rate = ingenic_clk_round_rate, + .set_rate = ingenic_clk_set_rate, + + .enable = ingenic_clk_enable, + .disable = ingenic_clk_disable, + .is_enabled = ingenic_clk_is_enabled, +}; + +/* + * Setup functions. + */ + +static int ingenic_register_clock(struct ingenic_cgu *cgu, unsigned idx) +{ + const struct ingenic_cgu_clk_info *clk_info = &cgu->clock_info[idx]; + struct clk_init_data clk_init; + struct ingenic_clk *ingenic_clk = NULL; + struct clk *clk, *parent; + const char *parent_names[4]; + unsigned caps, i, num_possible; + int err = -EINVAL; + + BUILD_BUG_ON(ARRAY_SIZE(clk_info->parents) > ARRAY_SIZE(parent_names)); + + if (clk_info->type == CGU_CLK_EXT) { + clk = of_clk_get_by_name(cgu->np, clk_info->name); + if (IS_ERR(clk)) { + pr_err("%s: no external clock '%s' provided\n", + __func__, clk_info->name); + err = -ENODEV; + goto out; + } + err = clk_register_clkdev(clk, clk_info->name, NULL); + if (err) { + clk_put(clk); + goto out; + } + cgu->clocks.clks[idx] = clk; + return 0; + } + + if (!clk_info->type) { + pr_err("%s: no clock type specified for '%s'\n", __func__, + clk_info->name); + goto out; + } + + ingenic_clk = kzalloc(sizeof(*ingenic_clk), GFP_KERNEL); + if (!ingenic_clk) { + err = -ENOMEM; + goto out; + } + + ingenic_clk->hw.init = &clk_init; + ingenic_clk->cgu = cgu; + ingenic_clk->idx = idx; + + clk_init.name = clk_info->name; + clk_init.flags = 0; + clk_init.parent_names = parent_names; + + caps = clk_info->type; + + if (caps & (CGU_CLK_MUX | CGU_CLK_CUSTOM)) { + clk_init.num_parents = 0; + + if (caps & CGU_CLK_MUX) + num_possible = 1 << clk_info->mux.bits; + else + num_possible = ARRAY_SIZE(clk_info->parents); + + for (i = 0; i < num_possible; i++) { + if (clk_info->parents[i] == -1) + continue; + + parent = cgu->clocks.clks[clk_info->parents[i]]; + parent_names[clk_init.num_parents] = + __clk_get_name(parent); + clk_init.num_parents++; + } + + BUG_ON(!clk_init.num_parents); + BUG_ON(clk_init.num_parents > ARRAY_SIZE(parent_names)); + } else { + BUG_ON(clk_info->parents[0] == -1); + clk_init.num_parents = 1; + parent = cgu->clocks.clks[clk_info->parents[0]]; + parent_names[0] = __clk_get_name(parent); + } + + if (caps & CGU_CLK_CUSTOM) { + clk_init.ops = clk_info->custom.clk_ops; + + caps &= ~CGU_CLK_CUSTOM; + + if (caps) { + pr_err("%s: custom clock may not be combined with type 0x%x\n", + __func__, caps); + goto out; + } + } else if (caps & CGU_CLK_PLL) { + clk_init.ops = &ingenic_pll_ops; + + caps &= ~CGU_CLK_PLL; + + if (caps) { + pr_err("%s: PLL may not be combined with type 0x%x\n", + __func__, caps); + goto out; + } + } else { + clk_init.ops = &ingenic_clk_ops; + } + + /* nothing to do for gates or fixed dividers */ + caps &= ~(CGU_CLK_GATE | CGU_CLK_FIXDIV); + + if (caps & CGU_CLK_MUX) { + if (!(caps & CGU_CLK_MUX_GLITCHFREE)) + clk_init.flags |= CLK_SET_PARENT_GATE; + + caps &= ~(CGU_CLK_MUX | CGU_CLK_MUX_GLITCHFREE); + } + + if (caps & CGU_CLK_DIV) { + caps &= ~CGU_CLK_DIV; + } else { + /* pass rate changes to the parent clock */ + clk_init.flags |= CLK_SET_RATE_PARENT; + } + + if (caps) { + pr_err("%s: unknown clock type 0x%x\n", __func__, caps); + goto out; + } + + clk = clk_register(NULL, &ingenic_clk->hw); + if (IS_ERR(clk)) { + pr_err("%s: failed to register clock '%s'\n", __func__, + clk_info->name); + err = PTR_ERR(clk); + goto out; + } + + err = clk_register_clkdev(clk, clk_info->name, NULL); + if (err) + goto out; + + cgu->clocks.clks[idx] = clk; +out: + if (err) + kfree(ingenic_clk); + return err; +} + +struct ingenic_cgu * +ingenic_cgu_new(const struct ingenic_cgu_clk_info *clock_info, + unsigned num_clocks, struct device_node *np) +{ + struct ingenic_cgu *cgu; + + cgu = kzalloc(sizeof(*cgu), GFP_KERNEL); + if (!cgu) + goto err_out; + + cgu->base = of_iomap(np, 0); + if (!cgu->base) { + pr_err("%s: failed to map CGU registers\n", __func__); + goto err_out_free; + } + + cgu->np = np; + cgu->clock_info = clock_info; + cgu->clocks.clk_num = num_clocks; + + spin_lock_init(&cgu->lock); + + return cgu; + +err_out_free: + kfree(cgu); +err_out: + return NULL; +} + +int ingenic_cgu_register_clocks(struct ingenic_cgu *cgu) +{ + unsigned i; + int err; + + cgu->clocks.clks = kcalloc(cgu->clocks.clk_num, sizeof(struct clk *), + GFP_KERNEL); + if (!cgu->clocks.clks) { + err = -ENOMEM; + goto err_out; + } + + for (i = 0; i < cgu->clocks.clk_num; i++) { + err = ingenic_register_clock(cgu, i); + if (err) + goto err_out_unregister; + } + + err = of_clk_add_provider(cgu->np, of_clk_src_onecell_get, + &cgu->clocks); + if (err) + goto err_out_unregister; + + return 0; + +err_out_unregister: + for (i = 0; i < cgu->clocks.clk_num; i++) { + if (!cgu->clocks.clks[i]) + continue; + if (cgu->clock_info[i].type & CGU_CLK_EXT) + clk_put(cgu->clocks.clks[i]); + else + clk_unregister(cgu->clocks.clks[i]); + } + kfree(cgu->clocks.clks); +err_out: + return err; +} |