--- /dev/null
+/*
+ * ECAP PWM driver
+ *
+ * Copyright (C) 2012 Texas Instruments, Inc. - http://www.ti.com/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+#include <linux/of_device.h>
+
+#include "pwm-tipwmss.h"
+
+/* ECAP registers and bits definitions */
+#define CAP1 0x08
+#define CAP2 0x0C
+#define CAP3 0x10
+#define CAP4 0x14
+#define ECCTL2 0x2A
+#define ECCTL2_APWM_POL_LOW BIT(10)
+#define ECCTL2_APWM_MODE BIT(9)
+#define ECCTL2_SYNC_SEL_DISA (BIT(7) | BIT(6))
+#define ECCTL2_TSCTR_FREERUN BIT(4)
+
+struct ecap_context {
+ u32 cap3;
+ u32 cap4;
+ u16 ecctl2;
+};
+
+struct ecap_pwm_chip {
+ struct pwm_chip chip;
+ unsigned int clk_rate;
+ void __iomem *mmio_base;
+ struct ecap_context ctx;
+};
+
+static inline struct ecap_pwm_chip *to_ecap_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct ecap_pwm_chip, chip);
+}
+
+/*
+ * period_ns = 10^9 * period_cycles / PWM_CLK_RATE
+ * duty_ns = 10^9 * duty_cycles / PWM_CLK_RATE
+ */
+static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+ unsigned long long c;
+ unsigned long period_cycles, duty_cycles;
+ unsigned int reg_val;
+
+ if (period_ns > NSEC_PER_SEC)
+ return -ERANGE;
+
+ c = pc->clk_rate;
+ c = c * period_ns;
+ do_div(c, NSEC_PER_SEC);
+ period_cycles = (unsigned long)c;
+
+ if (period_cycles < 1) {
+ period_cycles = 1;
+ duty_cycles = 1;
+ } else {
+ c = pc->clk_rate;
+ c = c * duty_ns;
+ do_div(c, NSEC_PER_SEC);
+ duty_cycles = (unsigned long)c;
+ }
+
+ pm_runtime_get_sync(pc->chip.dev);
+
+ reg_val = readw(pc->mmio_base + ECCTL2);
+
+ /* Configure APWM mode & disable sync option */
+ reg_val |= ECCTL2_APWM_MODE | ECCTL2_SYNC_SEL_DISA;
+
+ writew(reg_val, pc->mmio_base + ECCTL2);
+
+ if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
+ /* Update active registers if not running */
+ writel(duty_cycles, pc->mmio_base + CAP2);
+ writel(period_cycles, pc->mmio_base + CAP1);
+ } else {
+ /*
+ * Update shadow registers to configure period and
+ * compare values. This helps current PWM period to
+ * complete on reconfiguring
+ */
+ writel(duty_cycles, pc->mmio_base + CAP4);
+ writel(period_cycles, pc->mmio_base + CAP3);
+ }
+
+ if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
+ reg_val = readw(pc->mmio_base + ECCTL2);
+ /* Disable APWM mode to put APWM output Low */
+ reg_val &= ~ECCTL2_APWM_MODE;
+ writew(reg_val, pc->mmio_base + ECCTL2);
+ }
+
+ pm_runtime_put_sync(pc->chip.dev);
+ return 0;
+}
+
+static int ecap_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+ enum pwm_polarity polarity)
+{
+ struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+ unsigned short reg_val;
+
+ pm_runtime_get_sync(pc->chip.dev);
+ reg_val = readw(pc->mmio_base + ECCTL2);
+ if (polarity == PWM_POLARITY_INVERSED)
+ /* Duty cycle defines LOW period of PWM */
+ reg_val |= ECCTL2_APWM_POL_LOW;
+ else
+ /* Duty cycle defines HIGH period of PWM */
+ reg_val &= ~ECCTL2_APWM_POL_LOW;
+
+ writew(reg_val, pc->mmio_base + ECCTL2);
+ pm_runtime_put_sync(pc->chip.dev);
+ return 0;
+}
+
+static int ecap_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+ unsigned int reg_val;
+
+ /* Leave clock enabled on enabling PWM */
+ pm_runtime_get_sync(pc->chip.dev);
+
+ /*
+ * Enable 'Free run Time stamp counter mode' to start counter
+ * and 'APWM mode' to enable APWM output
+ */
+ reg_val = readw(pc->mmio_base + ECCTL2);
+ reg_val |= ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE;
+ writew(reg_val, pc->mmio_base + ECCTL2);
+ return 0;
+}
+
+static void ecap_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+ unsigned int reg_val;
+
+ /*
+ * Disable 'Free run Time stamp counter mode' to stop counter
+ * and 'APWM mode' to put APWM output to low
+ */
+ reg_val = readw(pc->mmio_base + ECCTL2);
+ reg_val &= ~(ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE);
+ writew(reg_val, pc->mmio_base + ECCTL2);
+
+ /* Disable clock on PWM disable */
+ pm_runtime_put_sync(pc->chip.dev);
+}
+
+static void ecap_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ if (test_bit(PWMF_ENABLED, &pwm->flags)) {
+ dev_warn(chip->dev, "Removing PWM device without disabling\n");
+ pm_runtime_put_sync(chip->dev);
+ }
+}
+
+static const struct pwm_ops ecap_pwm_ops = {
+ .free = ecap_pwm_free,
+ .config = ecap_pwm_config,
+ .set_polarity = ecap_pwm_set_polarity,
+ .enable = ecap_pwm_enable,
+ .disable = ecap_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+static const struct of_device_id ecap_of_match[] = {
+ { .compatible = "ti,am33xx-ecap" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ecap_of_match);
+
+static int ecap_pwm_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct resource *r;
+ struct clk *clk;
+ struct ecap_pwm_chip *pc;
+ u16 status;
+
+ pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
+ if (!pc)
+ return -ENOMEM;
+
+ clk = devm_clk_get(&pdev->dev, "fck");
+ if (IS_ERR(clk)) {
+ dev_err(&pdev->dev, "failed to get clock\n");
+ return PTR_ERR(clk);
+ }
+
+ pc->clk_rate = clk_get_rate(clk);
+ if (!pc->clk_rate) {
+ dev_err(&pdev->dev, "failed to get clock rate\n");
+ return -EINVAL;
+ }
+
+ pc->chip.dev = &pdev->dev;
+ pc->chip.ops = &ecap_pwm_ops;
+ pc->chip.of_xlate = of_pwm_xlate_with_flags;
+ pc->chip.of_pwm_n_cells = 3;
+ pc->chip.base = -1;
+ pc->chip.npwm = 1;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ pc->mmio_base = devm_ioremap_resource(&pdev->dev, r);
+ if (IS_ERR(pc->mmio_base))
+ return PTR_ERR(pc->mmio_base);
+
+ ret = pwmchip_add(&pc->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+ return ret;
+ }
+
+ pm_runtime_enable(&pdev->dev);
+ pm_runtime_get_sync(&pdev->dev);
+
+ status = pwmss_submodule_state_change(pdev->dev.parent,
+ PWMSS_ECAPCLK_EN);
+ if (!(status & PWMSS_ECAPCLK_EN_ACK)) {
+ dev_err(&pdev->dev, "PWMSS config space clock enable failed\n");
+ ret = -EINVAL;
+ goto pwmss_clk_failure;
+ }
+
+ pm_runtime_put_sync(&pdev->dev);
+
+ platform_set_drvdata(pdev, pc);
+ return 0;
+
+pwmss_clk_failure:
+ pm_runtime_put_sync(&pdev->dev);
+ pm_runtime_disable(&pdev->dev);
+ pwmchip_remove(&pc->chip);
+ return ret;
+}
+
+static int ecap_pwm_remove(struct platform_device *pdev)
+{
+ struct ecap_pwm_chip *pc = platform_get_drvdata(pdev);
+
+ pm_runtime_get_sync(&pdev->dev);
+ /*
+ * Due to hardware misbehaviour, acknowledge of the stop_req
+ * is missing. Hence checking of the status bit skipped.
+ */
+ pwmss_submodule_state_change(pdev->dev.parent, PWMSS_ECAPCLK_STOP_REQ);
+ pm_runtime_put_sync(&pdev->dev);
+
+ pm_runtime_disable(&pdev->dev);
+ return pwmchip_remove(&pc->chip);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static void ecap_pwm_save_context(struct ecap_pwm_chip *pc)
+{
+ pm_runtime_get_sync(pc->chip.dev);
+ pc->ctx.ecctl2 = readw(pc->mmio_base + ECCTL2);
+ pc->ctx.cap4 = readl(pc->mmio_base + CAP4);
+ pc->ctx.cap3 = readl(pc->mmio_base + CAP3);
+ pm_runtime_put_sync(pc->chip.dev);
+}
+
+static void ecap_pwm_restore_context(struct ecap_pwm_chip *pc)
+{
+ writel(pc->ctx.cap3, pc->mmio_base + CAP3);
+ writel(pc->ctx.cap4, pc->mmio_base + CAP4);
+ writew(pc->ctx.ecctl2, pc->mmio_base + ECCTL2);
+}
+
+static int ecap_pwm_suspend(struct device *dev)
+{
+ struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
+ struct pwm_device *pwm = pc->chip.pwms;
+
+ ecap_pwm_save_context(pc);
+
+ /* Disable explicitly if PWM is running */
+ if (test_bit(PWMF_ENABLED, &pwm->flags))
+ pm_runtime_put_sync(dev);
+
+ return 0;
+}
+
+static int ecap_pwm_resume(struct device *dev)
+{
+ struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
+ struct pwm_device *pwm = pc->chip.pwms;
+
+ /* Enable explicitly if PWM was running */
+ if (test_bit(PWMF_ENABLED, &pwm->flags))
+ pm_runtime_get_sync(dev);
+
+ ecap_pwm_restore_context(pc);
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(ecap_pwm_pm_ops, ecap_pwm_suspend, ecap_pwm_resume);
+
+static struct platform_driver ecap_pwm_driver = {
+ .driver = {
+ .name = "ecap",
+ .of_match_table = ecap_of_match,
+ .pm = &ecap_pwm_pm_ops,
+ },
+ .probe = ecap_pwm_probe,
+ .remove = ecap_pwm_remove,
+};
+
+module_platform_driver(ecap_pwm_driver);
+
+MODULE_DESCRIPTION("ECAP PWM driver");
+MODULE_AUTHOR("Texas Instruments");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff