--- /dev/null
+/*
+ * drivers/pwm/pwm-pxa.c
+ *
+ * simple driver for PWM (Pulse Width Modulator) controller
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 2008-02-13 initial version
+ * eric miao <eric.miao@marvell.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+#include <linux/of_device.h>
+
+#include <asm/div64.h>
+
+#define HAS_SECONDARY_PWM 0x10
+
+static const struct platform_device_id pwm_id_table[] = {
+ /* PWM has_secondary_pwm? */
+ { "pxa25x-pwm", 0 },
+ { "pxa27x-pwm", HAS_SECONDARY_PWM },
+ { "pxa168-pwm", 0 },
+ { "pxa910-pwm", 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(platform, pwm_id_table);
+
+/* PWM registers and bits definitions */
+#define PWMCR (0x00)
+#define PWMDCR (0x04)
+#define PWMPCR (0x08)
+
+#define PWMCR_SD (1 << 6)
+#define PWMDCR_FD (1 << 10)
+
+struct pxa_pwm_chip {
+ struct pwm_chip chip;
+ struct device *dev;
+
+ struct clk *clk;
+ void __iomem *mmio_base;
+};
+
+static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct pxa_pwm_chip, chip);
+}
+
+/*
+ * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
+ * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
+ */
+static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
+ unsigned long long c;
+ unsigned long period_cycles, prescale, pv, dc;
+ unsigned long offset;
+ int rc;
+
+ offset = pwm->hwpwm ? 0x10 : 0;
+
+ c = clk_get_rate(pc->clk);
+ c = c * period_ns;
+ do_div(c, 1000000000);
+ period_cycles = c;
+
+ if (period_cycles < 1)
+ period_cycles = 1;
+ prescale = (period_cycles - 1) / 1024;
+ pv = period_cycles / (prescale + 1) - 1;
+
+ if (prescale > 63)
+ return -EINVAL;
+
+ if (duty_ns == period_ns)
+ dc = PWMDCR_FD;
+ else
+ dc = (pv + 1) * duty_ns / period_ns;
+
+ /* NOTE: the clock to PWM has to be enabled first
+ * before writing to the registers
+ */
+ rc = clk_prepare_enable(pc->clk);
+ if (rc < 0)
+ return rc;
+
+ writel(prescale, pc->mmio_base + offset + PWMCR);
+ writel(dc, pc->mmio_base + offset + PWMDCR);
+ writel(pv, pc->mmio_base + offset + PWMPCR);
+
+ clk_disable_unprepare(pc->clk);
+ return 0;
+}
+
+static int pxa_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
+
+ return clk_prepare_enable(pc->clk);
+}
+
+static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip);
+
+ clk_disable_unprepare(pc->clk);
+}
+
+static struct pwm_ops pxa_pwm_ops = {
+ .config = pxa_pwm_config,
+ .enable = pxa_pwm_enable,
+ .disable = pxa_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+#ifdef CONFIG_OF
+/*
+ * Device tree users must create one device instance for each PWM channel.
+ * Hence we dispense with the HAS_SECONDARY_PWM and "tell" the original driver
+ * code that this is a single channel pxa25x-pwm. Currently all devices are
+ * supported identically.
+ */
+static const struct of_device_id pwm_of_match[] = {
+ { .compatible = "marvell,pxa250-pwm", .data = &pwm_id_table[0]},
+ { .compatible = "marvell,pxa270-pwm", .data = &pwm_id_table[0]},
+ { .compatible = "marvell,pxa168-pwm", .data = &pwm_id_table[0]},
+ { .compatible = "marvell,pxa910-pwm", .data = &pwm_id_table[0]},
+ { }
+};
+MODULE_DEVICE_TABLE(of, pwm_of_match);
+#else
+#define pwm_of_match NULL
+#endif
+
+static const struct platform_device_id *pxa_pwm_get_id_dt(struct device *dev)
+{
+ const struct of_device_id *id = of_match_device(pwm_of_match, dev);
+
+ return id ? id->data : NULL;
+}
+
+static struct pwm_device *
+pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
+{
+ struct pwm_device *pwm;
+
+ pwm = pwm_request_from_chip(pc, 0, NULL);
+ if (IS_ERR(pwm))
+ return pwm;
+
+ pwm_set_period(pwm, args->args[0]);
+
+ return pwm;
+}
+
+static int pwm_probe(struct platform_device *pdev)
+{
+ const struct platform_device_id *id = platform_get_device_id(pdev);
+ struct pxa_pwm_chip *pwm;
+ struct resource *r;
+ int ret = 0;
+
+ if (IS_ENABLED(CONFIG_OF) && id == NULL)
+ id = pxa_pwm_get_id_dt(&pdev->dev);
+
+ if (id == NULL)
+ return -EINVAL;
+
+ pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+ if (pwm == NULL)
+ return -ENOMEM;
+
+ pwm->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(pwm->clk))
+ return PTR_ERR(pwm->clk);
+
+ pwm->chip.dev = &pdev->dev;
+ pwm->chip.ops = &pxa_pwm_ops;
+ pwm->chip.base = -1;
+ pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1;
+
+ if (IS_ENABLED(CONFIG_OF)) {
+ pwm->chip.of_xlate = pxa_pwm_of_xlate;
+ pwm->chip.of_pwm_n_cells = 1;
+ }
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r);
+ if (IS_ERR(pwm->mmio_base))
+ return PTR_ERR(pwm->mmio_base);
+
+ ret = pwmchip_add(&pwm->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, pwm);
+ return 0;
+}
+
+static int pwm_remove(struct platform_device *pdev)
+{
+ struct pxa_pwm_chip *chip;
+
+ chip = platform_get_drvdata(pdev);
+ if (chip == NULL)
+ return -ENODEV;
+
+ return pwmchip_remove(&chip->chip);
+}
+
+static struct platform_driver pwm_driver = {
+ .driver = {
+ .name = "pxa25x-pwm",
+ .of_match_table = pwm_of_match,
+ },
+ .probe = pwm_probe,
+ .remove = pwm_remove,
+ .id_table = pwm_id_table,
+};
+
+module_platform_driver(pwm_driver);
+
+MODULE_LICENSE("GPL v2");
Code Review / kvmfornfv.git / blobdiff