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pwm-mtk-disp.c
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pwm-mtk-disp.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* MediaTek display pulse-width-modulation controller driver.
* Copyright (c) 2015 MediaTek Inc.
* Author: YH Huang <[email protected]>
*/
#include <linux/bitfield.h>
#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;
bool enabled;
};
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_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
u32 clk_div, period, high_width, value;
u64 div, rate;
int err;
if (state->polarity != PWM_POLARITY_NORMAL)
return -EINVAL;
if (!state->enabled) {
mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
0x0);
if (mdp->enabled) {
clk_disable_unprepare(mdp->clk_mm);
clk_disable_unprepare(mdp->clk_main);
}
mdp->enabled = false;
return 0;
}
if (!mdp->enabled) {
err = clk_prepare_enable(mdp->clk_main);
if (err < 0) {
dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n",
ERR_PTR(err));
return err;
}
err = clk_prepare_enable(mdp->clk_mm);
if (err < 0) {
dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n",
ERR_PTR(err));
clk_disable_unprepare(mdp->clk_main);
return 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 = mul_u64_u64_div_u64(state->period, rate, NSEC_PER_SEC) >>
PWM_PERIOD_BIT_WIDTH;
if (clk_div > PWM_CLKDIV_MAX) {
if (!mdp->enabled) {
clk_disable_unprepare(mdp->clk_mm);
clk_disable_unprepare(mdp->clk_main);
}
return -EINVAL;
}
div = NSEC_PER_SEC * (clk_div + 1);
period = mul_u64_u64_div_u64(state->period, rate, div);
if (period > 0)
period--;
high_width = mul_u64_u64_div_u64(state->duty_cycle, rate, div);
value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
if (mdp->data->bls_debug && !mdp->data->has_commit) {
/*
* For MT2701, disable double buffer before writing register
* and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
*/
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);
}
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);
}
mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
mdp->data->enable_mask);
mdp->enabled = true;
return 0;
}
static int mtk_disp_pwm_get_state(struct pwm_chip *chip,
struct pwm_device *pwm,
struct pwm_state *state)
{
struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
u64 rate, period, high_width;
u32 clk_div, pwm_en, con0, con1;
int err;
err = clk_prepare_enable(mdp->clk_main);
if (err < 0) {
dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n", ERR_PTR(err));
return err;
}
err = clk_prepare_enable(mdp->clk_mm);
if (err < 0) {
dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n", ERR_PTR(err));
clk_disable_unprepare(mdp->clk_main);
return err;
}
/*
* Apply DISP_PWM_DEBUG settings to choose whether to enable or disable
* registers double buffer and manual commit to working register before
* performing any read/write operation
*/
if (mdp->data->bls_debug)
mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
mdp->data->bls_debug_mask,
mdp->data->bls_debug_mask);
rate = clk_get_rate(mdp->clk_main);
con0 = readl(mdp->base + mdp->data->con0);
con1 = readl(mdp->base + mdp->data->con1);
pwm_en = readl(mdp->base + DISP_PWM_EN);
state->enabled = !!(pwm_en & mdp->data->enable_mask);
clk_div = FIELD_GET(PWM_CLKDIV_MASK, con0);
period = FIELD_GET(PWM_PERIOD_MASK, con1);
/*
* period has 12 bits, clk_div 11 and NSEC_PER_SEC has 30,
* so period * (clk_div + 1) * NSEC_PER_SEC doesn't overflow.
*/
state->period = DIV64_U64_ROUND_UP(period * (clk_div + 1) * NSEC_PER_SEC, rate);
high_width = FIELD_GET(PWM_HIGH_WIDTH_MASK, con1);
state->duty_cycle = DIV64_U64_ROUND_UP(high_width * (clk_div + 1) * NSEC_PER_SEC,
rate);
state->polarity = PWM_POLARITY_NORMAL;
clk_disable_unprepare(mdp->clk_mm);
clk_disable_unprepare(mdp->clk_main);
return 0;
}
static const struct pwm_ops mtk_disp_pwm_ops = {
.apply = mtk_disp_pwm_apply,
.get_state = mtk_disp_pwm_get_state,
.owner = THIS_MODULE,
};
static int mtk_disp_pwm_probe(struct platform_device *pdev)
{
struct mtk_disp_pwm *mdp;
int ret;
mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL);
if (!mdp)
return -ENOMEM;
mdp->data = of_device_get_match_data(&pdev->dev);
mdp->base = devm_platform_ioremap_resource(pdev, 0);
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);
mdp->chip.dev = &pdev->dev;
mdp->chip.ops = &mtk_disp_pwm_ops;
mdp->chip.npwm = 1;
ret = pwmchip_add(&mdp->chip);
if (ret < 0) {
dev_err(&pdev->dev, "pwmchip_add() failed: %pe\n", ERR_PTR(ret));
return ret;
}
platform_set_drvdata(pdev, mdp);
return 0;
}
static void mtk_disp_pwm_remove(struct platform_device *pdev)
{
struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
pwmchip_remove(&mdp->chip);
}
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 mtk_pwm_data mt8183_pwm_data = {
.enable_mask = BIT(0),
.con0 = 0x18,
.con0_sel = 0x0,
.con1 = 0x1c,
.has_commit = false,
.bls_debug = 0x80,
.bls_debug_mask = 0x3,
};
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},
{ .compatible = "mediatek,mt8183-disp-pwm", .data = &mt8183_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_new = mtk_disp_pwm_remove,
};
module_platform_driver(mtk_disp_pwm_driver);
MODULE_AUTHOR("YH Huang <[email protected]>");
MODULE_DESCRIPTION("MediaTek SoC display PWM driver");
MODULE_LICENSE("GPL v2");