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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/pwm/pwm-imx1.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/pwm/pwm-imx1.c')
-rw-r--r--drivers/pwm/pwm-imx1.c198
1 files changed, 198 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-imx1.c b/drivers/pwm/pwm-imx1.c
new file mode 100644
index 000000000..1f2eb1c8f
--- /dev/null
+++ b/drivers/pwm/pwm-imx1.c
@@ -0,0 +1,198 @@
+// 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>");