diff options
Diffstat (limited to 'drivers/clk/renesas/clk-mstp.c')
| -rw-r--r-- | drivers/clk/renesas/clk-mstp.c | 351 |
1 files changed, 351 insertions, 0 deletions
diff --git a/drivers/clk/renesas/clk-mstp.c b/drivers/clk/renesas/clk-mstp.c new file mode 100644 index 000000000..45d94fb97 --- /dev/null +++ b/drivers/clk/renesas/clk-mstp.c @@ -0,0 +1,351 @@ +/* + * R-Car MSTP clocks + * + * Copyright (C) 2013 Ideas On Board SPRL + * Copyright (C) 2015 Glider bvba + * + * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.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; version 2 of the License. + */ + +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/clkdev.h> +#include <linux/clk/renesas.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/pm_clock.h> +#include <linux/pm_domain.h> +#include <linux/spinlock.h> + +/* + * MSTP clocks. We can't use standard gate clocks as we need to poll on the + * status register when enabling the clock. + */ + +#define MSTP_MAX_CLOCKS 32 + +/** + * struct mstp_clock_group - MSTP gating clocks group + * + * @data: clocks in this group + * @smstpcr: module stop control register + * @mstpsr: module stop status register (optional) + * @lock: protects writes to SMSTPCR + * @width_8bit: registers are 8-bit, not 32-bit + */ +struct mstp_clock_group { + struct clk_onecell_data data; + void __iomem *smstpcr; + void __iomem *mstpsr; + spinlock_t lock; + bool width_8bit; +}; + +/** + * struct mstp_clock - MSTP gating clock + * @hw: handle between common and hardware-specific interfaces + * @bit_index: control bit index + * @group: MSTP clocks group + */ +struct mstp_clock { + struct clk_hw hw; + u32 bit_index; + struct mstp_clock_group *group; +}; + +#define to_mstp_clock(_hw) container_of(_hw, struct mstp_clock, hw) + +static inline u32 cpg_mstp_read(struct mstp_clock_group *group, + u32 __iomem *reg) +{ + return group->width_8bit ? readb(reg) : readl(reg); +} + +static inline void cpg_mstp_write(struct mstp_clock_group *group, u32 val, + u32 __iomem *reg) +{ + group->width_8bit ? writeb(val, reg) : writel(val, reg); +} + +static int cpg_mstp_clock_endisable(struct clk_hw *hw, bool enable) +{ + struct mstp_clock *clock = to_mstp_clock(hw); + struct mstp_clock_group *group = clock->group; + u32 bitmask = BIT(clock->bit_index); + unsigned long flags; + unsigned int i; + u32 value; + + spin_lock_irqsave(&group->lock, flags); + + value = cpg_mstp_read(group, group->smstpcr); + if (enable) + value &= ~bitmask; + else + value |= bitmask; + cpg_mstp_write(group, value, group->smstpcr); + + if (!group->mstpsr) { + /* dummy read to ensure write has completed */ + cpg_mstp_read(group, group->smstpcr); + barrier_data(group->smstpcr); + } + + spin_unlock_irqrestore(&group->lock, flags); + + if (!enable || !group->mstpsr) + return 0; + + for (i = 1000; i > 0; --i) { + if (!(cpg_mstp_read(group, group->mstpsr) & bitmask)) + break; + cpu_relax(); + } + + if (!i) { + pr_err("%s: failed to enable %p[%d]\n", __func__, + group->smstpcr, clock->bit_index); + return -ETIMEDOUT; + } + + return 0; +} + +static int cpg_mstp_clock_enable(struct clk_hw *hw) +{ + return cpg_mstp_clock_endisable(hw, true); +} + +static void cpg_mstp_clock_disable(struct clk_hw *hw) +{ + cpg_mstp_clock_endisable(hw, false); +} + +static int cpg_mstp_clock_is_enabled(struct clk_hw *hw) +{ + struct mstp_clock *clock = to_mstp_clock(hw); + struct mstp_clock_group *group = clock->group; + u32 value; + + if (group->mstpsr) + value = cpg_mstp_read(group, group->mstpsr); + else + value = cpg_mstp_read(group, group->smstpcr); + + return !(value & BIT(clock->bit_index)); +} + +static const struct clk_ops cpg_mstp_clock_ops = { + .enable = cpg_mstp_clock_enable, + .disable = cpg_mstp_clock_disable, + .is_enabled = cpg_mstp_clock_is_enabled, +}; + +static struct clk * __init cpg_mstp_clock_register(const char *name, + const char *parent_name, unsigned int index, + struct mstp_clock_group *group) +{ + struct clk_init_data init; + struct mstp_clock *clock; + struct clk *clk; + + clock = kzalloc(sizeof(*clock), GFP_KERNEL); + if (!clock) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &cpg_mstp_clock_ops; + init.flags = CLK_IS_BASIC | CLK_SET_RATE_PARENT; + /* INTC-SYS is the module clock of the GIC, and must not be disabled */ + if (!strcmp(name, "intc-sys")) { + pr_debug("MSTP %s setting CLK_IS_CRITICAL\n", name); + init.flags |= CLK_IS_CRITICAL; + } + init.parent_names = &parent_name; + init.num_parents = 1; + + clock->bit_index = index; + clock->group = group; + clock->hw.init = &init; + + clk = clk_register(NULL, &clock->hw); + + if (IS_ERR(clk)) + kfree(clock); + + return clk; +} + +static void __init cpg_mstp_clocks_init(struct device_node *np) +{ + struct mstp_clock_group *group; + const char *idxname; + struct clk **clks; + unsigned int i; + + group = kzalloc(sizeof(*group), GFP_KERNEL); + clks = kmalloc_array(MSTP_MAX_CLOCKS, sizeof(*clks), GFP_KERNEL); + if (group == NULL || clks == NULL) { + kfree(group); + kfree(clks); + return; + } + + spin_lock_init(&group->lock); + group->data.clks = clks; + + group->smstpcr = of_iomap(np, 0); + group->mstpsr = of_iomap(np, 1); + + if (group->smstpcr == NULL) { + pr_err("%s: failed to remap SMSTPCR\n", __func__); + kfree(group); + kfree(clks); + return; + } + + if (of_device_is_compatible(np, "renesas,r7s72100-mstp-clocks")) + group->width_8bit = true; + + for (i = 0; i < MSTP_MAX_CLOCKS; ++i) + clks[i] = ERR_PTR(-ENOENT); + + if (of_find_property(np, "clock-indices", &i)) + idxname = "clock-indices"; + else + idxname = "renesas,clock-indices"; + + for (i = 0; i < MSTP_MAX_CLOCKS; ++i) { + const char *parent_name; + const char *name; + u32 clkidx; + int ret; + + /* Skip clocks with no name. */ + ret = of_property_read_string_index(np, "clock-output-names", + i, &name); + if (ret < 0 || strlen(name) == 0) + continue; + + parent_name = of_clk_get_parent_name(np, i); + ret = of_property_read_u32_index(np, idxname, i, &clkidx); + if (parent_name == NULL || ret < 0) + break; + + if (clkidx >= MSTP_MAX_CLOCKS) { + pr_err("%s: invalid clock %s %s index %u\n", + __func__, np->name, name, clkidx); + continue; + } + + clks[clkidx] = cpg_mstp_clock_register(name, parent_name, + clkidx, group); + if (!IS_ERR(clks[clkidx])) { + group->data.clk_num = max(group->data.clk_num, + clkidx + 1); + /* + * Register a clkdev to let board code retrieve the + * clock by name and register aliases for non-DT + * devices. + * + * FIXME: Remove this when all devices that require a + * clock will be instantiated from DT. + */ + clk_register_clkdev(clks[clkidx], name, NULL); + } else { + pr_err("%s: failed to register %s %s clock (%ld)\n", + __func__, np->name, name, PTR_ERR(clks[clkidx])); + } + } + + of_clk_add_provider(np, of_clk_src_onecell_get, &group->data); +} +CLK_OF_DECLARE(cpg_mstp_clks, "renesas,cpg-mstp-clocks", cpg_mstp_clocks_init); + +int cpg_mstp_attach_dev(struct generic_pm_domain *unused, struct device *dev) +{ + struct device_node *np = dev->of_node; + struct of_phandle_args clkspec; + struct clk *clk; + int i = 0; + int error; + + while (!of_parse_phandle_with_args(np, "clocks", "#clock-cells", i, + &clkspec)) { + if (of_device_is_compatible(clkspec.np, + "renesas,cpg-mstp-clocks")) + goto found; + + /* BSC on r8a73a4/sh73a0 uses zb_clk instead of an mstp clock */ + if (!strcmp(clkspec.np->name, "zb_clk")) + goto found; + + of_node_put(clkspec.np); + i++; + } + + return 0; + +found: + clk = of_clk_get_from_provider(&clkspec); + of_node_put(clkspec.np); + + if (IS_ERR(clk)) + return PTR_ERR(clk); + + error = pm_clk_create(dev); + if (error) { + dev_err(dev, "pm_clk_create failed %d\n", error); + goto fail_put; + } + + error = pm_clk_add_clk(dev, clk); + if (error) { + dev_err(dev, "pm_clk_add_clk %pC failed %d\n", clk, error); + goto fail_destroy; + } + + return 0; + +fail_destroy: + pm_clk_destroy(dev); +fail_put: + clk_put(clk); + return error; +} + +void cpg_mstp_detach_dev(struct generic_pm_domain *unused, struct device *dev) +{ + if (!pm_clk_no_clocks(dev)) + pm_clk_destroy(dev); +} + +void __init cpg_mstp_add_clk_domain(struct device_node *np) +{ + struct generic_pm_domain *pd; + u32 ncells; + + if (of_property_read_u32(np, "#power-domain-cells", &ncells)) { + pr_warn("%pOF lacks #power-domain-cells\n", np); + return; + } + + pd = kzalloc(sizeof(*pd), GFP_KERNEL); + if (!pd) + return; + + pd->name = np->name; + pd->flags = GENPD_FLAG_PM_CLK | GENPD_FLAG_ALWAYS_ON | + GENPD_FLAG_ACTIVE_WAKEUP; + pd->attach_dev = cpg_mstp_attach_dev; + pd->detach_dev = cpg_mstp_detach_dev; + pm_genpd_init(pd, &pm_domain_always_on_gov, false); + + of_genpd_add_provider_simple(np, pd); +} |