Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / clk / clk-pwm.c

diff --git a/kernel/drivers/clk/clk-pwm.c b/kernel/drivers/clk/clk-pwm.c
new file mode 100644 (file)
index 0000000..328fcfc
--- /dev/null
+++ b/kernel/drivers/clk/clk-pwm.c
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2014 Philipp Zabel, Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * PWM (mis)used as clock output
+ */
+#include <linux/clk-provider.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+struct clk_pwm {
+       struct clk_hw hw;
+       struct pwm_device *pwm;
+       u32 fixed_rate;
+};
+
+static inline struct clk_pwm *to_clk_pwm(struct clk_hw *hw)
+{
+       return container_of(hw, struct clk_pwm, hw);
+}
+
+static int clk_pwm_prepare(struct clk_hw *hw)
+{
+       struct clk_pwm *clk_pwm = to_clk_pwm(hw);
+
+       return pwm_enable(clk_pwm->pwm);
+}
+
+static void clk_pwm_unprepare(struct clk_hw *hw)
+{
+       struct clk_pwm *clk_pwm = to_clk_pwm(hw);
+
+       pwm_disable(clk_pwm->pwm);
+}
+
+static unsigned long clk_pwm_recalc_rate(struct clk_hw *hw,
+                                        unsigned long parent_rate)
+{
+       struct clk_pwm *clk_pwm = to_clk_pwm(hw);
+
+       return clk_pwm->fixed_rate;
+}
+
+static const struct clk_ops clk_pwm_ops = {
+       .prepare = clk_pwm_prepare,
+       .unprepare = clk_pwm_unprepare,
+       .recalc_rate = clk_pwm_recalc_rate,
+};
+
+static int clk_pwm_probe(struct platform_device *pdev)
+{
+       struct device_node *node = pdev->dev.of_node;
+       struct clk_init_data init;
+       struct clk_pwm *clk_pwm;
+       struct pwm_device *pwm;
+       const char *clk_name;
+       struct clk *clk;
+       int ret;
+
+       clk_pwm = devm_kzalloc(&pdev->dev, sizeof(*clk_pwm), GFP_KERNEL);
+       if (!clk_pwm)
+               return -ENOMEM;
+
+       pwm = devm_pwm_get(&pdev->dev, NULL);
+       if (IS_ERR(pwm))
+               return PTR_ERR(pwm);
+
+       if (!pwm->period) {
+               dev_err(&pdev->dev, "invalid PWM period\n");
+               return -EINVAL;
+       }
+
+       if (of_property_read_u32(node, "clock-frequency", &clk_pwm->fixed_rate))
+               clk_pwm->fixed_rate = NSEC_PER_SEC / pwm->period;
+
+       if (pwm->period != NSEC_PER_SEC / clk_pwm->fixed_rate &&
+           pwm->period != DIV_ROUND_UP(NSEC_PER_SEC, clk_pwm->fixed_rate)) {
+               dev_err(&pdev->dev,
+                       "clock-frequency does not match PWM period\n");
+               return -EINVAL;
+       }
+
+       ret = pwm_config(pwm, (pwm->period + 1) >> 1, pwm->period);
+       if (ret < 0)
+               return ret;
+
+       clk_name = node->name;
+       of_property_read_string(node, "clock-output-names", &clk_name);
+
+       init.name = clk_name;
+       init.ops = &clk_pwm_ops;
+       init.flags = CLK_IS_BASIC | CLK_IS_ROOT;
+       init.num_parents = 0;
+
+       clk_pwm->pwm = pwm;
+       clk_pwm->hw.init = &init;
+       clk = devm_clk_register(&pdev->dev, &clk_pwm->hw);
+       if (IS_ERR(clk))
+               return PTR_ERR(clk);
+
+       return of_clk_add_provider(node, of_clk_src_simple_get, clk);
+}
+
+static int clk_pwm_remove(struct platform_device *pdev)
+{
+       of_clk_del_provider(pdev->dev.of_node);
+
+       return 0;
+}
+
+static const struct of_device_id clk_pwm_dt_ids[] = {
+       { .compatible = "pwm-clock" },
+       { }
+};
+MODULE_DEVICE_TABLE(of, clk_pwm_dt_ids);
+
+static struct platform_driver clk_pwm_driver = {
+       .probe = clk_pwm_probe,
+       .remove = clk_pwm_remove,
+       .driver = {
+               .name = "pwm-clock",
+               .of_match_table = of_match_ptr(clk_pwm_dt_ids),
+       },
+};
+
+module_platform_driver(clk_pwm_driver);
+
+MODULE_AUTHOR("Philipp Zabel <p.zabel@pengutronix.de>");
+MODULE_DESCRIPTION("PWM clock driver");
+MODULE_LICENSE("GPL");