linux/drivers/pwm/pwm-rockchip.c
Boris Brezillon 2bf1c98aa5 pwm: rockchip: Add support for atomic update
Implement the ->apply() function to add support for atomic update.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-07-11 12:49:28 +02:00

390 lines
9.6 KiB
C

/*
* PWM driver for Rockchip SoCs
*
* Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
* Copyright (C) 2014 ROCKCHIP, Inc.
*
* 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.
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/time.h>
#define PWM_CTRL_TIMER_EN (1 << 0)
#define PWM_CTRL_OUTPUT_EN (1 << 3)
#define PWM_ENABLE (1 << 0)
#define PWM_CONTINUOUS (1 << 1)
#define PWM_DUTY_POSITIVE (1 << 3)
#define PWM_DUTY_NEGATIVE (0 << 3)
#define PWM_INACTIVE_NEGATIVE (0 << 4)
#define PWM_INACTIVE_POSITIVE (1 << 4)
#define PWM_OUTPUT_LEFT (0 << 5)
#define PWM_LP_DISABLE (0 << 8)
struct rockchip_pwm_chip {
struct pwm_chip chip;
struct clk *clk;
const struct rockchip_pwm_data *data;
void __iomem *base;
};
struct rockchip_pwm_regs {
unsigned long duty;
unsigned long period;
unsigned long cntr;
unsigned long ctrl;
};
struct rockchip_pwm_data {
struct rockchip_pwm_regs regs;
unsigned int prescaler;
bool supports_polarity;
const struct pwm_ops *ops;
void (*set_enable)(struct pwm_chip *chip,
struct pwm_device *pwm, bool enable,
enum pwm_polarity polarity);
void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state);
};
static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *c)
{
return container_of(c, struct rockchip_pwm_chip, chip);
}
static void rockchip_pwm_set_enable_v1(struct pwm_chip *chip,
struct pwm_device *pwm, bool enable,
enum pwm_polarity polarity)
{
struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
u32 enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN;
u32 val;
val = readl_relaxed(pc->base + pc->data->regs.ctrl);
if (enable)
val |= enable_conf;
else
val &= ~enable_conf;
writel_relaxed(val, pc->base + pc->data->regs.ctrl);
}
static void rockchip_pwm_get_state_v1(struct pwm_chip *chip,
struct pwm_device *pwm,
struct pwm_state *state)
{
struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
u32 enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN;
u32 val;
val = readl_relaxed(pc->base + pc->data->regs.ctrl);
if ((val & enable_conf) == enable_conf)
state->enabled = true;
}
static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip,
struct pwm_device *pwm, bool enable,
enum pwm_polarity polarity)
{
struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
PWM_CONTINUOUS;
u32 val;
if (polarity == PWM_POLARITY_INVERSED)
enable_conf |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
else
enable_conf |= PWM_DUTY_POSITIVE | PWM_INACTIVE_NEGATIVE;
val = readl_relaxed(pc->base + pc->data->regs.ctrl);
if (enable)
val |= enable_conf;
else
val &= ~enable_conf;
writel_relaxed(val, pc->base + pc->data->regs.ctrl);
}
static void rockchip_pwm_get_state_v2(struct pwm_chip *chip,
struct pwm_device *pwm,
struct pwm_state *state)
{
struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
PWM_CONTINUOUS;
u32 val;
val = readl_relaxed(pc->base + pc->data->regs.ctrl);
if ((val & enable_conf) != enable_conf)
return;
state->enabled = true;
if (!(val & PWM_DUTY_POSITIVE))
state->polarity = PWM_POLARITY_INVERSED;
}
static void rockchip_pwm_get_state(struct pwm_chip *chip,
struct pwm_device *pwm,
struct pwm_state *state)
{
struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
unsigned long clk_rate;
u64 tmp;
int ret;
ret = clk_enable(pc->clk);
if (ret)
return;
clk_rate = clk_get_rate(pc->clk);
tmp = readl_relaxed(pc->base + pc->data->regs.period);
tmp *= pc->data->prescaler * NSEC_PER_SEC;
state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
tmp = readl_relaxed(pc->base + pc->data->regs.duty);
tmp *= pc->data->prescaler * NSEC_PER_SEC;
state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
pc->data->get_state(chip, pwm, state);
clk_disable(pc->clk);
}
static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
unsigned long period, duty;
u64 clk_rate, div;
clk_rate = clk_get_rate(pc->clk);
/*
* Since period and duty cycle registers have a width of 32
* bits, every possible input period can be obtained using the
* default prescaler value for all practical clock rate values.
*/
div = clk_rate * period_ns;
period = DIV_ROUND_CLOSEST_ULL(div,
pc->data->prescaler * NSEC_PER_SEC);
div = clk_rate * duty_ns;
duty = DIV_ROUND_CLOSEST_ULL(div, pc->data->prescaler * NSEC_PER_SEC);
writel(period, pc->base + pc->data->regs.period);
writel(duty, pc->base + pc->data->regs.duty);
return 0;
}
static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
struct pwm_state curstate;
bool enabled;
int ret;
pwm_get_state(pwm, &curstate);
enabled = curstate.enabled;
ret = clk_enable(pc->clk);
if (ret)
return ret;
if (state->polarity != curstate.polarity && enabled) {
pc->data->set_enable(chip, pwm, false, state->polarity);
enabled = false;
}
ret = rockchip_pwm_config(chip, pwm, state->duty_cycle, state->period);
if (ret) {
if (enabled != curstate.enabled)
pc->data->set_enable(chip, pwm, !enabled,
state->polarity);
goto out;
}
if (state->enabled != enabled)
pc->data->set_enable(chip, pwm, state->enabled,
state->polarity);
/*
* Update the state with the real hardware, which can differ a bit
* because of period/duty_cycle approximation.
*/
rockchip_pwm_get_state(chip, pwm, state);
out:
clk_disable(pc->clk);
return ret;
}
static const struct pwm_ops rockchip_pwm_ops_v1 = {
.get_state = rockchip_pwm_get_state,
.apply = rockchip_pwm_apply,
.owner = THIS_MODULE,
};
static const struct pwm_ops rockchip_pwm_ops_v2 = {
.get_state = rockchip_pwm_get_state,
.apply = rockchip_pwm_apply,
.owner = THIS_MODULE,
};
static const struct rockchip_pwm_data pwm_data_v1 = {
.regs = {
.duty = 0x04,
.period = 0x08,
.cntr = 0x00,
.ctrl = 0x0c,
},
.prescaler = 2,
.ops = &rockchip_pwm_ops_v1,
.set_enable = rockchip_pwm_set_enable_v1,
.get_state = rockchip_pwm_get_state_v1,
};
static const struct rockchip_pwm_data pwm_data_v2 = {
.regs = {
.duty = 0x08,
.period = 0x04,
.cntr = 0x00,
.ctrl = 0x0c,
},
.prescaler = 1,
.supports_polarity = true,
.ops = &rockchip_pwm_ops_v2,
.set_enable = rockchip_pwm_set_enable_v2,
.get_state = rockchip_pwm_get_state_v2,
};
static const struct rockchip_pwm_data pwm_data_vop = {
.regs = {
.duty = 0x08,
.period = 0x04,
.cntr = 0x0c,
.ctrl = 0x00,
},
.prescaler = 1,
.supports_polarity = true,
.ops = &rockchip_pwm_ops_v2,
.set_enable = rockchip_pwm_set_enable_v2,
.get_state = rockchip_pwm_get_state_v2,
};
static const struct of_device_id rockchip_pwm_dt_ids[] = {
{ .compatible = "rockchip,rk2928-pwm", .data = &pwm_data_v1},
{ .compatible = "rockchip,rk3288-pwm", .data = &pwm_data_v2},
{ .compatible = "rockchip,vop-pwm", .data = &pwm_data_vop},
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, rockchip_pwm_dt_ids);
static int rockchip_pwm_probe(struct platform_device *pdev)
{
const struct of_device_id *id;
struct rockchip_pwm_chip *pc;
struct resource *r;
int ret;
id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev);
if (!id)
return -EINVAL;
pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
if (!pc)
return -ENOMEM;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
pc->base = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(pc->base))
return PTR_ERR(pc->base);
pc->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(pc->clk))
return PTR_ERR(pc->clk);
ret = clk_prepare_enable(pc->clk);
if (ret)
return ret;
platform_set_drvdata(pdev, pc);
pc->data = id->data;
pc->chip.dev = &pdev->dev;
pc->chip.ops = pc->data->ops;
pc->chip.base = -1;
pc->chip.npwm = 1;
if (pc->data->supports_polarity) {
pc->chip.of_xlate = of_pwm_xlate_with_flags;
pc->chip.of_pwm_n_cells = 3;
}
ret = pwmchip_add(&pc->chip);
if (ret < 0) {
clk_unprepare(pc->clk);
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
}
/* Keep the PWM clk enabled if the PWM appears to be up and running. */
if (!pwm_is_enabled(pc->chip.pwms))
clk_disable(pc->clk);
return ret;
}
static int rockchip_pwm_remove(struct platform_device *pdev)
{
struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev);
/*
* Disable the PWM clk before unpreparing it if the PWM device is still
* running. This should only happen when the last PWM user left it
* enabled, or when nobody requested a PWM that was previously enabled
* by the bootloader.
*
* FIXME: Maybe the core should disable all PWM devices in
* pwmchip_remove(). In this case we'd only have to call
* clk_unprepare() after pwmchip_remove().
*
*/
if (pwm_is_enabled(pc->chip.pwms))
clk_disable(pc->clk);
clk_unprepare(pc->clk);
return pwmchip_remove(&pc->chip);
}
static struct platform_driver rockchip_pwm_driver = {
.driver = {
.name = "rockchip-pwm",
.of_match_table = rockchip_pwm_dt_ids,
},
.probe = rockchip_pwm_probe,
.remove = rockchip_pwm_remove,
};
module_platform_driver(rockchip_pwm_driver);
MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
MODULE_DESCRIPTION("Rockchip SoC PWM driver");
MODULE_LICENSE("GPL v2");