summaryrefslogtreecommitdiff
path: root/drivers/clk/clk-pwm.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2015-04-21 09:24:09 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-21 09:24:09 -0700
commite98bf5cedf25eb32f8f224e8dff9845f0856d18f (patch)
treef8a33eb26cb9d47bfbb36e50de7ad85081cc349e /drivers/clk/clk-pwm.c
parent8f443e2372ba23d51ee365974f54507acd6f69d1 (diff)
parent03bc10ab5b0f9b8f81bffbe6e40c944f9d3dbcc5 (diff)
Merge tag 'clk-for-linus-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
Pull clock framework updates from Michael Turquette: "The changes to the common clock framework for 4.0 are mostly new clock drivers and updates to existing ones for feature enhancements and bug fixes. There is more churn than usual in the framework core due to the change to introduce per-user unique struct clk pointers in 4.0. This caused several regressions to surface, some of which were sent as fixes to 4.0. New generic clock drivers were added for GPIO- and PWM-based clock controllers. Additionally the common clk-divider code recieved several fixes to the way it rounds rates" * tag 'clk-for-linus-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: (91 commits) clk: check ->determine/round_rate() return value in clk_calc_new_rates clk: at91: usb: propagate rate modification to the parent clk clk: samsung: exynos4: Disable ARMCLK down feature on Exynos4210 SoC clk: don't use __initconst for non-const arrays clk: at91: change to using endian agnositc IO clk: clk-gpio-gate: Fix active low clk: Add PWM clock driver clk: Add clock driver for mb86s7x clk: pxa: pxa3xx: add missing os timer clock clk: tegra: Use the proper parent for plld_dsi clk: tegra: Use generic tegra_osc_clk_init() on Tegra114 clk: tegra: Model oscillator as clock clk: tegra: Add peripheral registers for bank Y clk: tegra: Register the proper number of resets clk: tegra: Remove needless initializations clk: tegra: Use consistent indentation clk: tegra: Various whitespace cleanups clk: tegra: Enable HDA to HDMI clocks on Tegra124 clk: tegra: Fix a bunch of sparse warnings clk: tegra: Fix typo tabel -> table ...
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");