--- /dev/null
+/*
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/scpi_protocol.h>
+
+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 <sudeep.holla@arm.com>");
+MODULE_DESCRIPTION("ARM SCPI clock driver");
+MODULE_LICENSE("GPL v2");
projects / karo-tx-linux.git / commitdiff