diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2015-05-19 17:12:32 +0300 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2015-05-19 17:12:32 +0300 |
commit | c3b5d3cea508d2c8ff493ef18c45a9cc58fb7015 (patch) | |
tree | a80672ee82fcc3d9c8d486e53731eb19cd968eb0 /drivers/clk/clk-pwm.c | |
parent | daa67b4b70568a07fef3cffacb2055891bf42ddb (diff) | |
parent | e26081808edadfd257c6c9d81014e3b25e9a6118 (diff) | |
download | linux-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.c | 136 |
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"); |