From: Laurent Pinchart Date: Thu, 17 Oct 2013 21:54:07 +0000 (+0200) Subject: clk: shmobile: Add MSTP clock support X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=f94859c215b6d977;p=linux-beck.git clk: shmobile: Add MSTP clock support MSTP clocks are gate clocks controlled through a register that handles up to 32 clocks. The register is often sparsely populated. Those clocks are found on Renesas ARM SoCs. Signed-off-by: Laurent Pinchart Signed-off-by: Mike Turquette --- diff --git a/Documentation/devicetree/bindings/clock/renesas,cpg-mstp-clocks.txt b/Documentation/devicetree/bindings/clock/renesas,cpg-mstp-clocks.txt new file mode 100644 index 000000000000..a6a352c2771e --- /dev/null +++ b/Documentation/devicetree/bindings/clock/renesas,cpg-mstp-clocks.txt @@ -0,0 +1,51 @@ +* Renesas CPG Module Stop (MSTP) Clocks + +The CPG can gate SoC device clocks. The gates are organized in groups of up to +32 gates. + +This device tree binding describes a single 32 gate clocks group per node. +Clocks are referenced by user nodes by the MSTP node phandle and the clock +index in the group, from 0 to 31. + +Required Properties: + + - compatible: Must be one of the following + - "renesas,r8a7790-mstp-clocks" for R8A7790 (R-Car H2) MSTP gate clocks + - "renesas,r8a7791-mstp-clocks" for R8A7791 (R-Car M2) MSTP gate clocks + - "renesas,cpg-mstp-clock" for generic MSTP gate clocks + - reg: Base address and length of the I/O mapped registers used by the MSTP + clocks. The first register is the clock control register and is mandatory. + The second register is the clock status register and is optional when not + implemented in hardware. + - clocks: Reference to the parent clocks, one per output clock. The parents + must appear in the same order as the output clocks. + - #clock-cells: Must be 1 + - clock-output-names: The name of the clocks as free-form strings + - renesas,indices: Indices of the gate clocks into the group (0 to 31) + +The clocks, clock-output-names and renesas,indices properties contain one +entry per gate clock. The MSTP groups are sparsely populated. Unimplemented +gate clocks must not be declared. + + +Example +------- + + #include + + mstp3_clks: mstp3_clks@e615013c { + compatible = "renesas,r8a7790-mstp-clocks", "renesas,cpg-mstp-clocks"; + reg = <0 0xe615013c 0 4>, <0 0xe6150048 0 4>; + clocks = <&cp_clk>, <&mmc1_clk>, <&sd3_clk>, <&sd2_clk>, + <&cpg_clocks R8A7790_CLK_SD1>, <&cpg_clocks R8A7790_CLK_SD0>, + <&mmc0_clk>; + #clock-cells = <1>; + clock-output-names = + "tpu0", "mmcif1", "sdhi3", "sdhi2", + "sdhi1", "sdhi0", "mmcif0"; + renesas,clock-indices = < + R8A7790_CLK_TPU0 R8A7790_CLK_MMCIF1 R8A7790_CLK_SDHI3 + R8A7790_CLK_SDHI2 R8A7790_CLK_SDHI1 R8A7790_CLK_SDHI0 + R8A7790_CLK_MMCIF0 + >; + }; diff --git a/drivers/clk/shmobile/Makefile b/drivers/clk/shmobile/Makefile index 2e4a1197aa0a..706adc6ae70c 100644 --- a/drivers/clk/shmobile/Makefile +++ b/drivers/clk/shmobile/Makefile @@ -1,6 +1,7 @@ obj-$(CONFIG_ARCH_R8A7790) += clk-rcar-gen2.o obj-$(CONFIG_ARCH_R8A7791) += clk-rcar-gen2.o obj-$(CONFIG_ARCH_SHMOBILE_MULTI) += clk-div6.o +obj-$(CONFIG_ARCH_SHMOBILE_MULTI) += clk-mstp.o # for emply built-in.o obj-n := dummy diff --git a/drivers/clk/shmobile/clk-mstp.c b/drivers/clk/shmobile/clk-mstp.c new file mode 100644 index 000000000000..e576b60de20e --- /dev/null +++ b/drivers/clk/shmobile/clk-mstp.c @@ -0,0 +1,229 @@ +/* + * R-Car MSTP clocks + * + * Copyright (C) 2013 Ideas On Board SPRL + * + * Contact: Laurent Pinchart + * + * 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 +#include +#include +#include +#include +#include + +/* + * 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 + */ +struct mstp_clock_group { + struct clk_onecell_data data; + void __iomem *smstpcr; + void __iomem *mstpsr; + spinlock_t lock; +}; + +/** + * 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 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 = clk_readl(group->smstpcr); + if (enable) + value &= ~bitmask; + else + value |= bitmask; + clk_writel(value, group->smstpcr); + + spin_unlock_irqrestore(&group->lock, flags); + + if (!enable || !group->mstpsr) + return 0; + + for (i = 1000; i > 0; --i) { + if (!(clk_readl(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 = clk_readl(group->mstpsr); + else + value = clk_readl(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) { + pr_err("%s: failed to allocate MSTP clock.\n", __func__); + return ERR_PTR(-ENOMEM); + } + + init.name = name; + init.ops = &cpg_mstp_clock_ops; + init.flags = CLK_IS_BASIC; + 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; + struct clk **clks; + unsigned int i; + + group = kzalloc(sizeof(*group), GFP_KERNEL); + clks = kzalloc(MSTP_MAX_CLOCKS * sizeof(*clks), GFP_KERNEL); + if (group == NULL || clks == NULL) { + kfree(group); + kfree(clks); + pr_err("%s: failed to allocate group\n", __func__); + 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; + } + + 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, "renesas,clock-indices", 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, i, + group); + if (!IS_ERR(clks[clkidx])) { + group->data.clk_num = max(group->data.clk_num, clkidx); + /* + * 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);