linux/drivers/pwm/pwm-mtk-disp.c
Weiqing Kong cd4b45ac44 pwm: Add MediaTek MT2701 display PWM driver support
Use the mtk_pwm_data struction to define different registers
and add MT2701 specific register operations, such as MT2701
doesn't have commit register, needs to disable double buffer
before writing register, and needs to select manual mode
and use PWM_PERIOD/PWM_HIGH_WIDTH.

Signed-off-by: Weiqing Kong <weiqing.kong@mediatek.com>
[thierry.reding@gmail.com: use of_device_get_match_data()]
[thierry.reding@gmail.com: parameterize more consistently]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-09-06 10:48:53 +02:00

301 lines
7.2 KiB
C

/*
* 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/of_device.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>
#define DISP_PWM_EN 0x00
#define PWM_CLKDIV_SHIFT 16
#define PWM_CLKDIV_MAX 0x3ff
#define PWM_CLKDIV_MASK (PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT)
#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_pwm_data {
u32 enable_mask;
unsigned int con0;
u32 con0_sel;
unsigned int con1;
bool has_commit;
unsigned int commit;
unsigned int commit_mask;
unsigned int bls_debug;
u32 bls_debug_mask;
};
struct mtk_disp_pwm {
struct pwm_chip chip;
const struct mtk_pwm_data *data;
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, mdp->data->con0,
PWM_CLKDIV_MASK,
clk_div << PWM_CLKDIV_SHIFT);
mtk_disp_pwm_update_bits(mdp, mdp->data->con1,
PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK,
value);
if (mdp->data->has_commit) {
mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
mdp->data->commit_mask,
mdp->data->commit_mask);
mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
mdp->data->commit_mask,
0x0);
}
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, mdp->data->enable_mask,
mdp->data->enable_mask);
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, mdp->data->enable_mask,
0x0);
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;
mdp->data = of_device_get_match_data(&pdev->dev);
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);
/*
* For MT2701, disable double buffer before writing register
* and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
*/
if (!mdp->data->has_commit) {
mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
mdp->data->bls_debug_mask,
mdp->data->bls_debug_mask);
mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
mdp->data->con0_sel,
mdp->data->con0_sel);
}
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 mtk_pwm_data mt2701_pwm_data = {
.enable_mask = BIT(16),
.con0 = 0xa8,
.con0_sel = 0x2,
.con1 = 0xac,
.has_commit = false,
.bls_debug = 0xb0,
.bls_debug_mask = 0x3,
};
static const struct mtk_pwm_data mt8173_pwm_data = {
.enable_mask = BIT(0),
.con0 = 0x10,
.con0_sel = 0x0,
.con1 = 0x14,
.has_commit = true,
.commit = 0x8,
.commit_mask = 0x1,
};
static const struct of_device_id mtk_disp_pwm_of_match[] = {
{ .compatible = "mediatek,mt2701-disp-pwm", .data = &mt2701_pwm_data},
{ .compatible = "mediatek,mt6595-disp-pwm", .data = &mt8173_pwm_data},
{ .compatible = "mediatek,mt8173-disp-pwm", .data = &mt8173_pwm_data},
{ }
};
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");