diff options
Diffstat (limited to 'drivers/clk/at91/clk-generated.c')
| -rw-r--r-- | drivers/clk/at91/clk-generated.c | 386 |
1 files changed, 386 insertions, 0 deletions
diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c new file mode 100644 index 000000000..b397556c3 --- /dev/null +++ b/drivers/clk/at91/clk-generated.c @@ -0,0 +1,386 @@ +/* + * Copyright (C) 2015 Atmel Corporation, + * Nicolas Ferre <nicolas.ferre@atmel.com> + * + * Based on clk-programmable & clk-peripheral drivers by Boris BREZILLON. + * + * 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. + * + */ + +#include <linux/clk-provider.h> +#include <linux/clkdev.h> +#include <linux/clk/at91_pmc.h> +#include <linux/of.h> +#include <linux/mfd/syscon.h> +#include <linux/regmap.h> + +#include "pmc.h" + +#define PERIPHERAL_MAX 64 +#define PERIPHERAL_ID_MIN 2 + +#define GENERATED_SOURCE_MAX 6 +#define GENERATED_MAX_DIV 255 + +#define GCK_ID_SSC0 43 +#define GCK_ID_SSC1 44 +#define GCK_ID_I2S0 54 +#define GCK_ID_I2S1 55 +#define GCK_ID_CLASSD 59 +#define GCK_INDEX_DT_AUDIO_PLL 5 + +struct clk_generated { + struct clk_hw hw; + struct regmap *regmap; + struct clk_range range; + spinlock_t *lock; + u32 id; + u32 gckdiv; + u8 parent_id; + bool audio_pll_allowed; +}; + +#define to_clk_generated(hw) \ + container_of(hw, struct clk_generated, hw) + +static int clk_generated_enable(struct clk_hw *hw) +{ + struct clk_generated *gck = to_clk_generated(hw); + unsigned long flags; + + pr_debug("GCLK: %s, gckdiv = %d, parent id = %d\n", + __func__, gck->gckdiv, gck->parent_id); + + spin_lock_irqsave(gck->lock, flags); + regmap_write(gck->regmap, AT91_PMC_PCR, + (gck->id & AT91_PMC_PCR_PID_MASK)); + regmap_update_bits(gck->regmap, AT91_PMC_PCR, + AT91_PMC_PCR_GCKDIV_MASK | AT91_PMC_PCR_GCKCSS_MASK | + AT91_PMC_PCR_CMD | AT91_PMC_PCR_GCKEN, + AT91_PMC_PCR_GCKCSS(gck->parent_id) | + AT91_PMC_PCR_CMD | + AT91_PMC_PCR_GCKDIV(gck->gckdiv) | + AT91_PMC_PCR_GCKEN); + spin_unlock_irqrestore(gck->lock, flags); + return 0; +} + +static void clk_generated_disable(struct clk_hw *hw) +{ + struct clk_generated *gck = to_clk_generated(hw); + unsigned long flags; + + spin_lock_irqsave(gck->lock, flags); + regmap_write(gck->regmap, AT91_PMC_PCR, + (gck->id & AT91_PMC_PCR_PID_MASK)); + regmap_update_bits(gck->regmap, AT91_PMC_PCR, + AT91_PMC_PCR_CMD | AT91_PMC_PCR_GCKEN, + AT91_PMC_PCR_CMD); + spin_unlock_irqrestore(gck->lock, flags); +} + +static int clk_generated_is_enabled(struct clk_hw *hw) +{ + struct clk_generated *gck = to_clk_generated(hw); + unsigned long flags; + unsigned int status; + + spin_lock_irqsave(gck->lock, flags); + regmap_write(gck->regmap, AT91_PMC_PCR, + (gck->id & AT91_PMC_PCR_PID_MASK)); + regmap_read(gck->regmap, AT91_PMC_PCR, &status); + spin_unlock_irqrestore(gck->lock, flags); + + return status & AT91_PMC_PCR_GCKEN ? 1 : 0; +} + +static unsigned long +clk_generated_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_generated *gck = to_clk_generated(hw); + + return DIV_ROUND_CLOSEST(parent_rate, gck->gckdiv + 1); +} + +static void clk_generated_best_diff(struct clk_rate_request *req, + struct clk_hw *parent, + unsigned long parent_rate, u32 div, + int *best_diff, long *best_rate) +{ + unsigned long tmp_rate; + int tmp_diff; + + if (!div) + tmp_rate = parent_rate; + else + tmp_rate = parent_rate / div; + + if (tmp_rate < req->min_rate || tmp_rate > req->max_rate) + return; + + tmp_diff = abs(req->rate - tmp_rate); + + if (*best_diff < 0 || *best_diff > tmp_diff) { + *best_rate = tmp_rate; + *best_diff = tmp_diff; + req->best_parent_rate = parent_rate; + req->best_parent_hw = parent; + } +} + +static int clk_generated_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + struct clk_generated *gck = to_clk_generated(hw); + struct clk_hw *parent = NULL; + struct clk_rate_request req_parent = *req; + long best_rate = -EINVAL; + unsigned long min_rate, parent_rate; + int best_diff = -1; + int i; + u32 div; + + for (i = 0; i < clk_hw_get_num_parents(hw) - 1; i++) { + parent = clk_hw_get_parent_by_index(hw, i); + if (!parent) + continue; + + parent_rate = clk_hw_get_rate(parent); + min_rate = DIV_ROUND_CLOSEST(parent_rate, GENERATED_MAX_DIV + 1); + if (!parent_rate || + (gck->range.max && min_rate > gck->range.max)) + continue; + + div = DIV_ROUND_CLOSEST(parent_rate, req->rate); + if (div > GENERATED_MAX_DIV + 1) + div = GENERATED_MAX_DIV + 1; + + clk_generated_best_diff(req, parent, parent_rate, div, + &best_diff, &best_rate); + + if (!best_diff) + break; + } + + /* + * The audio_pll rate can be modified, unlike the five others clocks + * that should never be altered. + * The audio_pll can technically be used by multiple consumers. However, + * with the rate locking, the first consumer to enable to clock will be + * the one definitely setting the rate of the clock. + * Since audio IPs are most likely to request the same rate, we enforce + * that the only clks able to modify gck rate are those of audio IPs. + */ + + if (!gck->audio_pll_allowed) + goto end; + + parent = clk_hw_get_parent_by_index(hw, GCK_INDEX_DT_AUDIO_PLL); + if (!parent) + goto end; + + for (div = 1; div < GENERATED_MAX_DIV + 2; div++) { + req_parent.rate = req->rate * div; + __clk_determine_rate(parent, &req_parent); + clk_generated_best_diff(req, parent, req_parent.rate, div, + &best_diff, &best_rate); + + if (!best_diff) + break; + } + +end: + pr_debug("GCLK: %s, best_rate = %ld, parent clk: %s @ %ld\n", + __func__, best_rate, + __clk_get_name((req->best_parent_hw)->clk), + req->best_parent_rate); + + if (best_rate < 0) + return best_rate; + + req->rate = best_rate; + return 0; +} + +/* No modification of hardware as we have the flag CLK_SET_PARENT_GATE set */ +static int clk_generated_set_parent(struct clk_hw *hw, u8 index) +{ + struct clk_generated *gck = to_clk_generated(hw); + + if (index >= clk_hw_get_num_parents(hw)) + return -EINVAL; + + gck->parent_id = index; + return 0; +} + +static u8 clk_generated_get_parent(struct clk_hw *hw) +{ + struct clk_generated *gck = to_clk_generated(hw); + + return gck->parent_id; +} + +/* No modification of hardware as we have the flag CLK_SET_RATE_GATE set */ +static int clk_generated_set_rate(struct clk_hw *hw, + unsigned long rate, + unsigned long parent_rate) +{ + struct clk_generated *gck = to_clk_generated(hw); + u32 div; + + if (!rate) + return -EINVAL; + + if (gck->range.max && rate > gck->range.max) + return -EINVAL; + + div = DIV_ROUND_CLOSEST(parent_rate, rate); + if (div > GENERATED_MAX_DIV + 1 || !div) + return -EINVAL; + + gck->gckdiv = div - 1; + return 0; +} + +static const struct clk_ops generated_ops = { + .enable = clk_generated_enable, + .disable = clk_generated_disable, + .is_enabled = clk_generated_is_enabled, + .recalc_rate = clk_generated_recalc_rate, + .determine_rate = clk_generated_determine_rate, + .get_parent = clk_generated_get_parent, + .set_parent = clk_generated_set_parent, + .set_rate = clk_generated_set_rate, +}; + +/** + * clk_generated_startup - Initialize a given clock to its default parent and + * divisor parameter. + * + * @gck: Generated clock to set the startup parameters for. + * + * Take parameters from the hardware and update local clock configuration + * accordingly. + */ +static void clk_generated_startup(struct clk_generated *gck) +{ + u32 tmp; + unsigned long flags; + + spin_lock_irqsave(gck->lock, flags); + regmap_write(gck->regmap, AT91_PMC_PCR, + (gck->id & AT91_PMC_PCR_PID_MASK)); + regmap_read(gck->regmap, AT91_PMC_PCR, &tmp); + spin_unlock_irqrestore(gck->lock, flags); + + gck->parent_id = (tmp & AT91_PMC_PCR_GCKCSS_MASK) + >> AT91_PMC_PCR_GCKCSS_OFFSET; + gck->gckdiv = (tmp & AT91_PMC_PCR_GCKDIV_MASK) + >> AT91_PMC_PCR_GCKDIV_OFFSET; +} + +static struct clk_hw * __init +at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock, + const char *name, const char **parent_names, + u8 num_parents, u8 id, bool pll_audio, + const struct clk_range *range) +{ + struct clk_generated *gck; + struct clk_init_data init; + struct clk_hw *hw; + int ret; + + gck = kzalloc(sizeof(*gck), GFP_KERNEL); + if (!gck) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &generated_ops; + init.parent_names = parent_names; + init.num_parents = num_parents; + init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE | + CLK_SET_RATE_PARENT; + + gck->id = id; + gck->hw.init = &init; + gck->regmap = regmap; + gck->lock = lock; + gck->range = *range; + gck->audio_pll_allowed = pll_audio; + + clk_generated_startup(gck); + hw = &gck->hw; + ret = clk_hw_register(NULL, &gck->hw); + if (ret) { + kfree(gck); + hw = ERR_PTR(ret); + } else { + pmc_register_id(id); + } + + return hw; +} + +static void __init of_sama5d2_clk_generated_setup(struct device_node *np) +{ + int num; + u32 id; + const char *name; + struct clk_hw *hw; + unsigned int num_parents; + const char *parent_names[GENERATED_SOURCE_MAX]; + struct device_node *gcknp; + struct clk_range range = CLK_RANGE(0, 0); + struct regmap *regmap; + + num_parents = of_clk_get_parent_count(np); + if (num_parents == 0 || num_parents > GENERATED_SOURCE_MAX) + return; + + of_clk_parent_fill(np, parent_names, num_parents); + + num = of_get_child_count(np); + if (!num || num > PERIPHERAL_MAX) + return; + + regmap = syscon_node_to_regmap(of_get_parent(np)); + if (IS_ERR(regmap)) + return; + + for_each_child_of_node(np, gcknp) { + bool pll_audio = false; + + if (of_property_read_u32(gcknp, "reg", &id)) + continue; + + if (id < PERIPHERAL_ID_MIN || id >= PERIPHERAL_MAX) + continue; + + if (of_property_read_string(np, "clock-output-names", &name)) + name = gcknp->name; + + of_at91_get_clk_range(gcknp, "atmel,clk-output-range", + &range); + + if (of_device_is_compatible(np, "atmel,sama5d2-clk-generated") && + (id == GCK_ID_I2S0 || id == GCK_ID_I2S1 || + id == GCK_ID_CLASSD)) + pll_audio = true; + + hw = at91_clk_register_generated(regmap, &pmc_pcr_lock, name, + parent_names, num_parents, + id, pll_audio, &range); + if (IS_ERR(hw)) + continue; + + of_clk_add_hw_provider(gcknp, of_clk_hw_simple_get, hw); + } +} +CLK_OF_DECLARE(of_sama5d2_clk_generated_setup, "atmel,sama5d2-clk-generated", + of_sama5d2_clk_generated_setup); |