From cd52c2a4b5c43631e429d06dce12e08b0cab477f Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Mon, 30 Mar 2015 10:59:52 +0100 Subject: clk: add support for clocks provided by SCP(System Control Processor) On some ARM based systems, a separate Cortex-M based System Control Processor(SCP) provides the overall power, clock, reset and system control. System Control and Power Interface(SCPI) Message Protocol is defined for the communication between the Application Cores(AP) and the SCP. This patch adds support for the clocks provided by SCP using SCPI protocol. Signed-off-by: Sudeep Holla Reviewed-by: Stephen Boyd Cc: Mike Turquette Cc: Liviu Dudau Cc: Lorenzo Pieralisi Cc: Jon Medhurst (Tixy) Cc: linux-clk@vger.kernel.org --- drivers/clk/clk-scpi.c | 312 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 312 insertions(+) create mode 100644 drivers/clk/clk-scpi.c (limited to 'drivers/clk/clk-scpi.c') diff --git a/drivers/clk/clk-scpi.c b/drivers/clk/clk-scpi.c new file mode 100644 index 000000000000..72f0486b5de6 --- /dev/null +++ b/drivers/clk/clk-scpi.c @@ -0,0 +1,312 @@ +/* + * System Control and Power Interface (SCPI) Protocol based clock driver + * + * Copyright (C) 2015 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope 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. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see . + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +struct scpi_clk { + u32 id; + struct clk_hw hw; + struct scpi_dvfs_info *info; + struct scpi_ops *scpi_ops; +}; + +#define to_scpi_clk(clk) container_of(clk, struct scpi_clk, hw) + +static unsigned long scpi_clk_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct scpi_clk *clk = to_scpi_clk(hw); + + return clk->scpi_ops->clk_get_val(clk->id); +} + +static long scpi_clk_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + /* + * We can't figure out what rate it will be, so just return the + * rate back to the caller. scpi_clk_recalc_rate() will be called + * after the rate is set and we'll know what rate the clock is + * running at then. + */ + return rate; +} + +static int scpi_clk_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct scpi_clk *clk = to_scpi_clk(hw); + + return clk->scpi_ops->clk_set_val(clk->id, rate); +} + +static const struct clk_ops scpi_clk_ops = { + .recalc_rate = scpi_clk_recalc_rate, + .round_rate = scpi_clk_round_rate, + .set_rate = scpi_clk_set_rate, +}; + +/* find closest match to given frequency in OPP table */ +static int __scpi_dvfs_round_rate(struct scpi_clk *clk, unsigned long rate) +{ + int idx; + u32 fmin = 0, fmax = ~0, ftmp; + const struct scpi_opp *opp = clk->info->opps; + + for (idx = 0; idx < clk->info->count; idx++, opp++) { + ftmp = opp->freq; + if (ftmp >= (u32)rate) { + if (ftmp <= fmax) + fmax = ftmp; + break; + } else if (ftmp >= fmin) { + fmin = ftmp; + } + } + return fmax != ~0 ? fmax : fmin; +} + +static unsigned long scpi_dvfs_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct scpi_clk *clk = to_scpi_clk(hw); + int idx = clk->scpi_ops->dvfs_get_idx(clk->id); + const struct scpi_opp *opp; + + if (idx < 0) + return 0; + + opp = clk->info->opps + idx; + return opp->freq; +} + +static long scpi_dvfs_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + struct scpi_clk *clk = to_scpi_clk(hw); + + return __scpi_dvfs_round_rate(clk, rate); +} + +static int __scpi_find_dvfs_index(struct scpi_clk *clk, unsigned long rate) +{ + int idx, max_opp = clk->info->count; + const struct scpi_opp *opp = clk->info->opps; + + for (idx = 0; idx < max_opp; idx++, opp++) + if (opp->freq == rate) + return idx; + return -EINVAL; +} + +static int scpi_dvfs_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct scpi_clk *clk = to_scpi_clk(hw); + int ret = __scpi_find_dvfs_index(clk, rate); + + if (ret < 0) + return ret; + return clk->scpi_ops->dvfs_set_idx(clk->id, (u8)ret); +} + +static const struct clk_ops scpi_dvfs_ops = { + .recalc_rate = scpi_dvfs_recalc_rate, + .round_rate = scpi_dvfs_round_rate, + .set_rate = scpi_dvfs_set_rate, +}; + +static const struct of_device_id scpi_clk_match[] = { + { .compatible = "arm,scpi-dvfs-clocks", .data = &scpi_dvfs_ops, }, + { .compatible = "arm,scpi-variable-clocks", .data = &scpi_clk_ops, }, + {} +}; + +static struct clk * +scpi_clk_ops_init(struct device *dev, const struct of_device_id *match, + struct scpi_clk *sclk, const char *name) +{ + struct clk_init_data init; + struct clk *clk; + unsigned long min = 0, max = 0; + + init.name = name; + init.flags = CLK_IS_ROOT; + init.num_parents = 0; + init.ops = match->data; + sclk->hw.init = &init; + sclk->scpi_ops = get_scpi_ops(); + + if (init.ops == &scpi_dvfs_ops) { + sclk->info = sclk->scpi_ops->dvfs_get_info(sclk->id); + if (IS_ERR(sclk->info)) + return NULL; + } else if (init.ops == &scpi_clk_ops) { + if (sclk->scpi_ops->clk_get_range(sclk->id, &min, &max) || !max) + return NULL; + } else { + return NULL; + } + + clk = devm_clk_register(dev, &sclk->hw); + if (!IS_ERR(clk) && max) + clk_hw_set_rate_range(&sclk->hw, min, max); + return clk; +} + +struct scpi_clk_data { + struct scpi_clk **clk; + unsigned int clk_num; +}; + +static struct clk * +scpi_of_clk_src_get(struct of_phandle_args *clkspec, void *data) +{ + struct scpi_clk *sclk; + struct scpi_clk_data *clk_data = data; + unsigned int idx = clkspec->args[0], count; + + for (count = 0; count < clk_data->clk_num; count++) { + sclk = clk_data->clk[count]; + if (idx == sclk->id) + return sclk->hw.clk; + } + + return ERR_PTR(-EINVAL); +} + +static int scpi_clk_add(struct device *dev, struct device_node *np, + const struct of_device_id *match) +{ + struct clk **clks; + int idx, count; + struct scpi_clk_data *clk_data; + + count = of_property_count_strings(np, "clock-output-names"); + if (count < 0) { + dev_err(dev, "%s: invalid clock output count\n", np->name); + return -EINVAL; + } + + clk_data = devm_kmalloc(dev, sizeof(*clk_data), GFP_KERNEL); + if (!clk_data) + return -ENOMEM; + + clk_data->clk_num = count; + clk_data->clk = devm_kcalloc(dev, count, sizeof(*clk_data->clk), + GFP_KERNEL); + if (!clk_data->clk) + return -ENOMEM; + + clks = devm_kcalloc(dev, count, sizeof(*clks), GFP_KERNEL); + if (!clks) + return -ENOMEM; + + for (idx = 0; idx < count; idx++) { + struct scpi_clk *sclk; + const char *name; + u32 val; + + sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL); + if (!sclk) + return -ENOMEM; + + if (of_property_read_string_index(np, "clock-output-names", + idx, &name)) { + dev_err(dev, "invalid clock name @ %s\n", np->name); + return -EINVAL; + } + + if (of_property_read_u32_index(np, "clock-indices", + idx, &val)) { + dev_err(dev, "invalid clock index @ %s\n", np->name); + return -EINVAL; + } + + sclk->id = val; + + clks[idx] = scpi_clk_ops_init(dev, match, sclk, name); + if (IS_ERR_OR_NULL(clks[idx])) + dev_err(dev, "failed to register clock '%s'\n", name); + else + dev_dbg(dev, "Registered clock '%s'\n", name); + clk_data->clk[idx] = sclk; + } + + return of_clk_add_provider(np, scpi_of_clk_src_get, clk_data); +} + +static int scpi_clocks_remove(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *child, *np = dev->of_node; + + for_each_available_child_of_node(np, child) + of_clk_del_provider(np); + return 0; +} + +static int scpi_clocks_probe(struct platform_device *pdev) +{ + int ret; + struct device *dev = &pdev->dev; + struct device_node *child, *np = dev->of_node; + const struct of_device_id *match; + + if (!get_scpi_ops()) + return -ENXIO; + + for_each_available_child_of_node(np, child) { + match = of_match_node(scpi_clk_match, child); + if (!match) + continue; + ret = scpi_clk_add(dev, child, match); + if (ret) { + scpi_clocks_remove(pdev); + return ret; + } + } + return 0; +} + +static const struct of_device_id scpi_clocks_ids[] = { + { .compatible = "arm,scpi-clocks", }, + {} +}; +MODULE_DEVICE_TABLE(of, scpi_clocks_ids); + +static struct platform_driver scpi_clocks_driver = { + .driver = { + .name = "scpi_clocks", + .of_match_table = scpi_clocks_ids, + }, + .probe = scpi_clocks_probe, + .remove = scpi_clocks_remove, +}; +module_platform_driver(scpi_clocks_driver); + +MODULE_AUTHOR("Sudeep Holla "); +MODULE_DESCRIPTION("ARM SCPI clock driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.2.3