/*
* MediaTek display pulse-width-modulation controller driver.
* Copyright (c) 2015 MediaTek Inc.
* Author: YH Huang <yh.huang@mediatek.com>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>
#define DISP_PWM_EN 0x00
#define PWM_ENABLE_MASK BIT(0)
#define DISP_PWM_COMMIT 0x08
#define PWM_COMMIT_MASK BIT(0)
#define DISP_PWM_CON_0 0x10
#define PWM_CLKDIV_SHIFT 16
#define PWM_CLKDIV_MAX 0x3ff
#define PWM_CLKDIV_MASK (PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT)
#define DISP_PWM_CON_1 0x14
#define PWM_PERIOD_BIT_WIDTH 12
#define PWM_PERIOD_MASK ((1 << PWM_PERIOD_BIT_WIDTH) - 1)
#define PWM_HIGH_WIDTH_SHIFT 16
#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT)
struct mtk_disp_pwm {
struct pwm_chip chip;
struct clk *clk_main;
struct clk *clk_mm;
void __iomem *base;
};
static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
{
return container_of(chip, struct mtk_disp_pwm, chip);
}
static void mtk_disp_pwm_update_bits(struct mtk_disp_pwm *mdp, u32 offset,
u32 mask, u32 data)
{
void __iomem *address = mdp->base + offset;
u32 value;
value = readl(address);
value &= ~mask;
value |= data;
writel(value, address);
}
static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
u32 clk_div, period, high_width, value;
u64 div, rate;
int err;
/*
* Find period, high_width and clk_div to suit duty_ns and period_ns.
* Calculate proper div value to keep period value in the bound.
*
* period_ns = 10^9 * (clk_div + 1) * (period + 1) / PWM_CLK_RATE
* duty_ns = 10^9 * (clk_div + 1) * high_width / PWM_CLK_RATE
*
* period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1
* high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
*/
rate = clk_get_rate(mdp->clk_main);
clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >>
PWM_PERIOD_BIT_WIDTH;
if (clk_div > PWM_CLKDIV_MAX)
return -EINVAL;
div = NSEC_PER_SEC * (clk_div + 1);
period = div64_u64(rate * period_ns, div);
if (period > 0)
period--;
high_width = div64_u64(rate * duty_ns, div);
value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
err = clk_enable(mdp->clk_main);
if (err < 0)
return err;
err = clk_enable(mdp->clk_mm);
if (err < 0) {
clk_disable(mdp->clk_main);
return err;
}
mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_0, PWM_CLKDIV_MASK,
clk_div << PWM_CLKDIV_SHIFT);
mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_1,
PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, value);
mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 1);
mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 0);
clk_disable(mdp->clk_mm);
clk_disable(mdp->clk_main);
return 0;
}
static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
int err;
err = clk_enable(mdp->clk_main);
if (err < 0)
return err;
err = clk_enable(mdp->clk_mm);
if (err < 0) {
clk_disable(mdp->clk_main);
return err;
}
mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 1);
return 0;
}
static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 0);
clk_disable(mdp->clk_mm);
clk_disable(mdp->clk_main);
}
static const struct pwm_ops mtk_disp_pwm_ops = {
.config = mtk_disp_pwm_config,
.enable = mtk_disp_pwm_enable,
.disable = mtk_disp_pwm_disable,
.owner = THIS_MODULE,
};
static int mtk_disp_pwm_probe(struct platform_device *pdev)
{
struct mtk_disp_pwm *mdp;
struct resource *r;
int ret;
mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL);
if (!mdp)
return -ENOMEM;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
mdp->base = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(mdp->base))
return PTR_ERR(mdp->base);
mdp->clk_main = devm_clk_get(&pdev->dev, "main");
if (IS_ERR(mdp->clk_main))
return PTR_ERR(mdp->clk_main);
mdp->clk_mm = devm_clk_get(&pdev->dev, "mm");
if (IS_ERR(mdp->clk_mm))
return PTR_ERR(mdp->clk_mm);
ret = clk_prepare(mdp->clk_main);
if (ret < 0)
return ret;
ret = clk_prepare(mdp->clk_mm);
if (ret < 0)
goto disable_clk_main;
mdp->chip.dev = &pdev->dev;
mdp->chip.ops = &mtk_disp_pwm_ops;
mdp->chip.base = -1;
mdp->chip.npwm = 1;
ret = pwmchip_add(&mdp->chip);
if (ret < 0) {
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
goto disable_clk_mm;
}
platform_set_drvdata(pdev, mdp);
return 0;
disable_clk_mm:
clk_unprepare(mdp->clk_mm);
disable_clk_main:
clk_unprepare(mdp->clk_main);
return ret;
}
static int mtk_disp_pwm_remove(struct platform_device *pdev)
{
struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
int ret;
ret = pwmchip_remove(&mdp->chip);
clk_unprepare(mdp->clk_mm);
clk_unprepare(mdp->clk_main);
return ret;
}
static const struct of_device_id mtk_disp_pwm_of_match[] = {
{ .compatible = "mediatek,mt8173-disp-pwm" },
{ .compatible = "mediatek,mt6595-disp-pwm" },
{ }
};
MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match);
static struct platform_driver mtk_disp_pwm_driver = {
.driver = {
.name = "mediatek-disp-pwm",
.of_match_table = mtk_disp_pwm_of_match,
},
.probe = mtk_disp_pwm_probe,
.remove = mtk_disp_pwm_remove,
};
module_platform_driver(mtk_disp_pwm_driver);
MODULE_AUTHOR("YH Huang <yh.huang@mediatek.com>");
MODULE_DESCRIPTION("MediaTek SoC display PWM driver");
MODULE_LICENSE("GPL v2");
