Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Uwe Kleine-König | 783 | 98.12% | 3 | 60.00% |
Anson Huang | 13 | 1.63% | 1 | 20.00% |
Yangtao Li | 2 | 0.25% | 1 | 20.00% |
Total | 798 | 5 |
// SPDX-License-Identifier: GPL-2.0 /* * simple driver for PWM (Pulse Width Modulator) controller * * Derived from pxa PWM driver by eric miao <eric.miao@marvell.com> */ #include <linux/bitfield.h> #include <linux/bitops.h> #include <linux/clk.h> #include <linux/delay.h> #include <linux/err.h> #include <linux/io.h> #include <linux/kernel.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 MX1_PWMC 0x00 /* PWM Control Register */ #define MX1_PWMS 0x04 /* PWM Sample Register */ #define MX1_PWMP 0x08 /* PWM Period Register */ #define MX1_PWMC_EN BIT(4) struct pwm_imx1_chip { struct clk *clk_ipg; struct clk *clk_per; void __iomem *mmio_base; struct pwm_chip chip; }; #define to_pwm_imx1_chip(chip) container_of(chip, struct pwm_imx1_chip, chip) static int pwm_imx1_clk_prepare_enable(struct pwm_chip *chip) { struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip); int ret; ret = clk_prepare_enable(imx->clk_ipg); if (ret) return ret; ret = clk_prepare_enable(imx->clk_per); if (ret) { clk_disable_unprepare(imx->clk_ipg); return ret; } return 0; } static void pwm_imx1_clk_disable_unprepare(struct pwm_chip *chip) { struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip); clk_disable_unprepare(imx->clk_per); clk_disable_unprepare(imx->clk_ipg); } static int pwm_imx1_config(struct pwm_chip *chip, struct pwm_device *pwm, u64 duty_ns, u64 period_ns) { struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip); u32 max, p; /* * The PWM subsystem allows for exact frequencies. However, * I cannot connect a scope on my device to the PWM line and * thus cannot provide the program the PWM controller * exactly. Instead, I'm relying on the fact that the * Bootloader (u-boot or WinCE+haret) has programmed the PWM * function group already. So I'll just modify the PWM sample * register to follow the ratio of duty_ns vs. period_ns * accordingly. * * This is good enough for programming the brightness of * the LCD backlight. * * The real implementation would divide PERCLK[0] first by * both the prescaler (/1 .. /128) and then by CLKSEL * (/2 .. /16). */ max = readl(imx->mmio_base + MX1_PWMP); p = mul_u64_u64_div_u64(max, duty_ns, period_ns); writel(max - p, imx->mmio_base + MX1_PWMS); return 0; } static int pwm_imx1_enable(struct pwm_chip *chip, struct pwm_device *pwm) { struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip); u32 value; int ret; ret = pwm_imx1_clk_prepare_enable(chip); if (ret < 0) return ret; value = readl(imx->mmio_base + MX1_PWMC); value |= MX1_PWMC_EN; writel(value, imx->mmio_base + MX1_PWMC); return 0; } static void pwm_imx1_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip); u32 value; value = readl(imx->mmio_base + MX1_PWMC); value &= ~MX1_PWMC_EN; writel(value, imx->mmio_base + MX1_PWMC); pwm_imx1_clk_disable_unprepare(chip); } static int pwm_imx1_apply(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_state *state) { int err; if (state->polarity != PWM_POLARITY_NORMAL) return -EINVAL; if (!state->enabled) { if (pwm->state.enabled) pwm_imx1_disable(chip, pwm); return 0; } err = pwm_imx1_config(chip, pwm, state->duty_cycle, state->period); if (err) return err; if (!pwm->state.enabled) return pwm_imx1_enable(chip, pwm); return 0; } static const struct pwm_ops pwm_imx1_ops = { .apply = pwm_imx1_apply, .owner = THIS_MODULE, }; static const struct of_device_id pwm_imx1_dt_ids[] = { { .compatible = "fsl,imx1-pwm", }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, pwm_imx1_dt_ids); static int pwm_imx1_probe(struct platform_device *pdev) { struct pwm_imx1_chip *imx; imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL); if (!imx) return -ENOMEM; imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg"); if (IS_ERR(imx->clk_ipg)) return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_ipg), "getting ipg clock failed\n"); imx->clk_per = devm_clk_get(&pdev->dev, "per"); if (IS_ERR(imx->clk_per)) return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_per), "failed to get peripheral clock\n"); imx->chip.ops = &pwm_imx1_ops; imx->chip.dev = &pdev->dev; imx->chip.npwm = 1; imx->mmio_base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(imx->mmio_base)) return PTR_ERR(imx->mmio_base); return devm_pwmchip_add(&pdev->dev, &imx->chip); } static struct platform_driver pwm_imx1_driver = { .driver = { .name = "pwm-imx1", .of_match_table = pwm_imx1_dt_ids, }, .probe = pwm_imx1_probe, }; module_platform_driver(pwm_imx1_driver); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
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