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![Uwe Kleine-König](/assets/img/avatar_default.png)
Since commit 5e5da1e9fb
("pwm: ab8500: Explicitly allocate pwm chip
base dynamically") all drivers use dynamic ID allocation explicitly. New
drivers are supposed to do the same, so remove support for driver
specified base IDs and drop all assignments in the low-level drivers.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
187 lines
4.6 KiB
C
187 lines
4.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* simple driver for PWM (Pulse Width Modulator) controller
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*
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* Derived from pxa PWM driver by eric miao <eric.miao@marvell.com>
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*/
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#include <linux/bitfield.h>
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#include <linux/bitops.h>
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/pwm.h>
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#include <linux/slab.h>
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#define MX1_PWMC 0x00 /* PWM Control Register */
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#define MX1_PWMS 0x04 /* PWM Sample Register */
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#define MX1_PWMP 0x08 /* PWM Period Register */
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#define MX1_PWMC_EN BIT(4)
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struct pwm_imx1_chip {
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struct clk *clk_ipg;
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struct clk *clk_per;
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void __iomem *mmio_base;
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struct pwm_chip chip;
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};
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#define to_pwm_imx1_chip(chip) container_of(chip, struct pwm_imx1_chip, chip)
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static int pwm_imx1_clk_prepare_enable(struct pwm_chip *chip)
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{
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struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
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int ret;
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ret = clk_prepare_enable(imx->clk_ipg);
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if (ret)
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return ret;
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ret = clk_prepare_enable(imx->clk_per);
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if (ret) {
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clk_disable_unprepare(imx->clk_ipg);
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return ret;
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}
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return 0;
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}
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static void pwm_imx1_clk_disable_unprepare(struct pwm_chip *chip)
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{
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struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
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clk_disable_unprepare(imx->clk_per);
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clk_disable_unprepare(imx->clk_ipg);
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}
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static int pwm_imx1_config(struct pwm_chip *chip,
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struct pwm_device *pwm, int duty_ns, int period_ns)
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{
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struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
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u32 max, p;
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/*
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* The PWM subsystem allows for exact frequencies. However,
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* I cannot connect a scope on my device to the PWM line and
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* thus cannot provide the program the PWM controller
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* exactly. Instead, I'm relying on the fact that the
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* Bootloader (u-boot or WinCE+haret) has programmed the PWM
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* function group already. So I'll just modify the PWM sample
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* register to follow the ratio of duty_ns vs. period_ns
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* accordingly.
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*
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* This is good enough for programming the brightness of
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* the LCD backlight.
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*
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* The real implementation would divide PERCLK[0] first by
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* both the prescaler (/1 .. /128) and then by CLKSEL
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* (/2 .. /16).
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*/
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max = readl(imx->mmio_base + MX1_PWMP);
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p = max * duty_ns / period_ns;
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writel(max - p, imx->mmio_base + MX1_PWMS);
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return 0;
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}
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static int pwm_imx1_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
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u32 value;
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int ret;
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ret = pwm_imx1_clk_prepare_enable(chip);
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if (ret < 0)
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return ret;
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value = readl(imx->mmio_base + MX1_PWMC);
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value |= MX1_PWMC_EN;
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writel(value, imx->mmio_base + MX1_PWMC);
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return 0;
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}
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static void pwm_imx1_disable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct pwm_imx1_chip *imx = to_pwm_imx1_chip(chip);
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u32 value;
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value = readl(imx->mmio_base + MX1_PWMC);
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value &= ~MX1_PWMC_EN;
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writel(value, imx->mmio_base + MX1_PWMC);
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pwm_imx1_clk_disable_unprepare(chip);
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}
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static const struct pwm_ops pwm_imx1_ops = {
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.enable = pwm_imx1_enable,
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.disable = pwm_imx1_disable,
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.config = pwm_imx1_config,
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.owner = THIS_MODULE,
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};
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static const struct of_device_id pwm_imx1_dt_ids[] = {
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{ .compatible = "fsl,imx1-pwm", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, pwm_imx1_dt_ids);
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static int pwm_imx1_probe(struct platform_device *pdev)
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{
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struct pwm_imx1_chip *imx;
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imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL);
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if (!imx)
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return -ENOMEM;
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platform_set_drvdata(pdev, imx);
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imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
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if (IS_ERR(imx->clk_ipg))
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return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_ipg),
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"getting ipg clock failed\n");
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imx->clk_per = devm_clk_get(&pdev->dev, "per");
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if (IS_ERR(imx->clk_per))
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return dev_err_probe(&pdev->dev, PTR_ERR(imx->clk_per),
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"failed to get peripheral clock\n");
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imx->chip.ops = &pwm_imx1_ops;
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imx->chip.dev = &pdev->dev;
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imx->chip.npwm = 1;
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imx->mmio_base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(imx->mmio_base))
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return PTR_ERR(imx->mmio_base);
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return pwmchip_add(&imx->chip);
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}
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static int pwm_imx1_remove(struct platform_device *pdev)
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{
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struct pwm_imx1_chip *imx = platform_get_drvdata(pdev);
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pwm_imx1_clk_disable_unprepare(&imx->chip);
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return pwmchip_remove(&imx->chip);
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}
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static struct platform_driver pwm_imx1_driver = {
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.driver = {
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.name = "pwm-imx1",
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.of_match_table = pwm_imx1_dt_ids,
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},
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.probe = pwm_imx1_probe,
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.remove = pwm_imx1_remove,
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};
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module_platform_driver(pwm_imx1_driver);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
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