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path: root/drivers/pwm/pwm-lpc32xx.c
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Diffstat (limited to 'drivers/pwm/pwm-lpc32xx.c')
-rw-r--r--drivers/pwm/pwm-lpc32xx.c175
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-lpc32xx.c b/drivers/pwm/pwm-lpc32xx.c
new file mode 100644
index 0000000000..806f0bb3ad
--- /dev/null
+++ b/drivers/pwm/pwm-lpc32xx.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2012 Alexandre Pereira da Silva <aletes.xgr@gmail.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+struct lpc32xx_pwm_chip {
+ struct pwm_chip chip;
+ struct clk *clk;
+ void __iomem *base;
+};
+
+#define PWM_ENABLE BIT(31)
+#define PWM_PIN_LEVEL BIT(30)
+
+#define to_lpc32xx_pwm_chip(_chip) \
+ container_of(_chip, struct lpc32xx_pwm_chip, chip)
+
+static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
+ unsigned long long c;
+ int period_cycles, duty_cycles;
+ u32 val;
+ c = clk_get_rate(lpc32xx->clk);
+
+ /* The highest acceptable divisor is 256, which is represented by 0 */
+ period_cycles = div64_u64(c * period_ns,
+ (unsigned long long)NSEC_PER_SEC * 256);
+ if (!period_cycles || period_cycles > 256)
+ return -ERANGE;
+ if (period_cycles == 256)
+ period_cycles = 0;
+
+ /* Compute 256 x #duty/period value and care for corner cases */
+ duty_cycles = div64_u64((unsigned long long)(period_ns - duty_ns) * 256,
+ period_ns);
+ if (!duty_cycles)
+ duty_cycles = 1;
+ if (duty_cycles > 255)
+ duty_cycles = 255;
+
+ val = readl(lpc32xx->base);
+ val &= ~0xFFFF;
+ val |= (period_cycles << 8) | duty_cycles;
+ writel(val, lpc32xx->base);
+
+ return 0;
+}
+
+static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
+ u32 val;
+ int ret;
+
+ ret = clk_prepare_enable(lpc32xx->clk);
+ if (ret)
+ return ret;
+
+ val = readl(lpc32xx->base);
+ val |= PWM_ENABLE;
+ writel(val, lpc32xx->base);
+
+ return 0;
+}
+
+static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
+ u32 val;
+
+ val = readl(lpc32xx->base);
+ val &= ~PWM_ENABLE;
+ writel(val, lpc32xx->base);
+
+ clk_disable_unprepare(lpc32xx->clk);
+}
+
+static int lpc32xx_pwm_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)
+ lpc32xx_pwm_disable(chip, pwm);
+
+ return 0;
+ }
+
+ err = lpc32xx_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
+ if (err)
+ return err;
+
+ if (!pwm->state.enabled)
+ err = lpc32xx_pwm_enable(chip, pwm);
+
+ return err;
+}
+
+static const struct pwm_ops lpc32xx_pwm_ops = {
+ .apply = lpc32xx_pwm_apply,
+ .owner = THIS_MODULE,
+};
+
+static int lpc32xx_pwm_probe(struct platform_device *pdev)
+{
+ struct lpc32xx_pwm_chip *lpc32xx;
+ int ret;
+ u32 val;
+
+ lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);
+ if (!lpc32xx)
+ return -ENOMEM;
+
+ lpc32xx->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(lpc32xx->base))
+ return PTR_ERR(lpc32xx->base);
+
+ lpc32xx->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(lpc32xx->clk))
+ return PTR_ERR(lpc32xx->clk);
+
+ lpc32xx->chip.dev = &pdev->dev;
+ lpc32xx->chip.ops = &lpc32xx_pwm_ops;
+ lpc32xx->chip.npwm = 1;
+
+ /* If PWM is disabled, configure the output to the default value */
+ val = readl(lpc32xx->base);
+ val &= ~PWM_PIN_LEVEL;
+ writel(val, lpc32xx->base);
+
+ ret = devm_pwmchip_add(&pdev->dev, &lpc32xx->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id lpc32xx_pwm_dt_ids[] = {
+ { .compatible = "nxp,lpc3220-pwm", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, lpc32xx_pwm_dt_ids);
+
+static struct platform_driver lpc32xx_pwm_driver = {
+ .driver = {
+ .name = "lpc32xx-pwm",
+ .of_match_table = lpc32xx_pwm_dt_ids,
+ },
+ .probe = lpc32xx_pwm_probe,
+};
+module_platform_driver(lpc32xx_pwm_driver);
+
+MODULE_ALIAS("platform:lpc32xx-pwm");
+MODULE_AUTHOR("Alexandre Pereira da Silva <aletes.xgr@gmail.com>");
+MODULE_DESCRIPTION("LPC32XX PWM Driver");
+MODULE_LICENSE("GPL v2");