summaryrefslogtreecommitdiff
path: root/drivers/clk/clk-pwm.c
diff options
context:
space:
mode:
authorThomas Gleixner <tglx@linutronix.de>2015-05-19 17:12:32 +0300
committerThomas Gleixner <tglx@linutronix.de>2015-05-19 17:12:32 +0300
commitc3b5d3cea508d2c8ff493ef18c45a9cc58fb7015 (patch)
treea80672ee82fcc3d9c8d486e53731eb19cd968eb0 /drivers/clk/clk-pwm.c
parentdaa67b4b70568a07fef3cffacb2055891bf42ddb (diff)
parente26081808edadfd257c6c9d81014e3b25e9a6118 (diff)
downloadlinux-c3b5d3cea508d2c8ff493ef18c45a9cc58fb7015.tar.xz
Merge branch 'linus' into timers/core
Make sure the upstream fixes are applied before adding further modifications.
Diffstat (limited to 'drivers/clk/clk-pwm.c')
-rw-r--r--drivers/clk/clk-pwm.c136
1 files changed, 136 insertions, 0 deletions
diff --git a/drivers/clk/clk-pwm.c b/drivers/clk/clk-pwm.c
new file mode 100644
index 000000000000..328fcfcefd8c
--- /dev/null
+++ b/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");