![Stephen Boyd](/assets/img/avatar_default.png)
This flag was historically used to indicate that a clk is a "basic" type of clk like a mux, divider, gate, etc. This never turned out to be very useful though because it was hard to cleanly split "basic" clks from other clks in a system. This one flag was a way for type introspection and it just didn't scale. If anything, it was used by the TI clk driver to indicate that a clk_hw wasn't contained in the SoC specific clk structure. We can get rid of this define now that TI is finding those clks a different way. Cc: Tero Kristo <t-kristo@ti.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> Cc: James Hogan <jhogan@kernel.org> Cc: <linux-mips@vger.kernel.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: <linux-pwm@vger.kernel.org> Cc: <linux-amlogic@lists.infradead.org> Acked-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Stephen Boyd <sboyd@kernel.org>
143 lines
3.2 KiB
C
143 lines
3.2 KiB
C
/*
|
|
* 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;
|
|
struct pwm_args pargs;
|
|
const char *clk_name;
|
|
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);
|
|
|
|
pwm_get_args(pwm, &pargs);
|
|
if (!pargs.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 / pargs.period;
|
|
|
|
if (pargs.period != NSEC_PER_SEC / clk_pwm->fixed_rate &&
|
|
pargs.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;
|
|
}
|
|
|
|
/*
|
|
* FIXME: pwm_apply_args() should be removed when switching to the
|
|
* atomic PWM API.
|
|
*/
|
|
pwm_apply_args(pwm);
|
|
ret = pwm_config(pwm, (pargs.period + 1) >> 1, pargs.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 = 0;
|
|
init.num_parents = 0;
|
|
|
|
clk_pwm->pwm = pwm;
|
|
clk_pwm->hw.init = &init;
|
|
ret = devm_clk_hw_register(&pdev->dev, &clk_pwm->hw);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return of_clk_add_hw_provider(node, of_clk_hw_simple_get, &clk_pwm->hw);
|
|
}
|
|
|
|
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");
|