diff options
Diffstat (limited to 'drivers/pwm/pwm-mtk-disp.c')
| -rw-r--r-- | drivers/pwm/pwm-mtk-disp.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c new file mode 100644 index 000000000000..0ad3385298c0 --- /dev/null +++ b/drivers/pwm/pwm-mtk-disp.c @@ -0,0 +1,243 @@ +/* + * 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"); |