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![Rob Herring](/assets/img/avatar_default.png)
The DT of_device.h and of_platform.h date back to the separate of_platform_bus_type before it as merged into the regular platform bus. As part of that merge prepping Arm DT support 13 years ago, they "temporarily" include each other. They also include platform_device.h and of.h. As a result, there's a pretty much random mix of those include files used throughout the tree. In order to detangle these headers and replace the implicit includes with struct declarations, users need to explicitly include the correct includes. Signed-off-by: Rob Herring <robh@kernel.org> Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
197 lines
4.7 KiB
C
197 lines
4.7 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/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, u64 duty_ns, u64 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 = mul_u64_u64_div_u64(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 int pwm_imx1_apply(struct pwm_chip *chip, struct pwm_device *pwm,
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const struct pwm_state *state)
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{
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int err;
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if (state->polarity != PWM_POLARITY_NORMAL)
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return -EINVAL;
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if (!state->enabled) {
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if (pwm->state.enabled)
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pwm_imx1_disable(chip, pwm);
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return 0;
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}
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err = pwm_imx1_config(chip, pwm, state->duty_cycle, state->period);
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if (err)
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return err;
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if (!pwm->state.enabled)
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return pwm_imx1_enable(chip, pwm);
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return 0;
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}
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static const struct pwm_ops pwm_imx1_ops = {
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.apply = pwm_imx1_apply,
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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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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 devm_pwmchip_add(&pdev->dev, &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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};
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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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