pwm: imx: Split into two drivers

The two PWM implementations called v1 (for i.MX1 and i.MX21) and v2 (for
i.MX27 and later) have nothing in common apart from needing two clocks
named "per" and "ipg" and being integrated in a SoC named i.MX.

So split the file containing the two disjunct drivers into two files and
two complete separate drivers.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[thierry.reding@gmail.com: fix a modular build issue]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

1 files changed, 199 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-imx1.c b/drivers/pwm/pwm-imx1.c
new file mode 100644
index 000000000000..f8b2c2e001a7
--- /dev/null
+++ b/drivers/pwm/pwm-imx1.c
@@ -0,0 +1,199 @@
+// 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, int duty_ns, int 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 = 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 const struct pwm_ops pwm_imx1_ops = {
+        .enable = pwm_imx1_enable,
+        .disable = pwm_imx1_disable,
+        .config = pwm_imx1_config,
+        .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;
+        struct resource *r;
+
+        imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL);
+        if (!imx)
+                return -ENOMEM;
+
+        platform_set_drvdata(pdev, imx);
+
+        imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
+        if (IS_ERR(imx->clk_ipg)) {
+                dev_err(&pdev->dev, "getting ipg clock failed with %ld\n",
+                                PTR_ERR(imx->clk_ipg));
+                return PTR_ERR(imx->clk_ipg);
+        }
+
+        imx->clk_per = devm_clk_get(&pdev->dev, "per");
+        if (IS_ERR(imx->clk_per)) {
+                int ret = PTR_ERR(imx->clk_per);
+
+                if (ret != -EPROBE_DEFER)
+                        dev_err(&pdev->dev,
+                                "failed to get peripheral clock: %d\n",
+                                ret);
+
+                return ret;
+        }
+
+        imx->chip.ops = &pwm_imx1_ops;
+        imx->chip.dev = &pdev->dev;
+        imx->chip.base = -1;
+        imx->chip.npwm = 1;
+
+        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        imx->mmio_base = devm_ioremap_resource(&pdev->dev, r);
+        if (IS_ERR(imx->mmio_base))
+                return PTR_ERR(imx->mmio_base);
+
+        return pwmchip_add(&imx->chip);
+}
+
+static int pwm_imx1_remove(struct platform_device *pdev)
+{
+        struct pwm_imx1_chip *imx = platform_get_drvdata(pdev);
+
+        pwm_imx1_clk_disable_unprepare(&imx->chip);
+
+        return pwmchip_remove(&imx->chip);
+}
+
+static struct platform_driver pwm_imx1_driver = {
+        .driver = {
+                .name = "pwm-imx1",
+                .of_match_table = pwm_imx1_dt_ids,
+        },
+        .probe = pwm_imx1_probe,
+        .remove = pwm_imx1_remove,
+};
+module_platform_driver(pwm_imx1_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");