drivers/pwm: Add SiFive PWM PTC driver

drivers/pwm/Kconfig

@@ -494,6 +494,17 @@ config PWM_SIFIVE
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-sifive.
 
+config PWM_SIFIVE_PTC
+	tristate "SiFive PWM PTC support"
+	depends on SOC_SIFIVE || SOC_STARFIVE || COMPILE_TEST
+	depends on OF
+	depends on COMMON_CLK
+	help
+	  Generic PWM framework driver for SiFive SoCs.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-sifive-ptc.
+
 config PWM_SL28CPLD
 	tristate "Kontron sl28cpld PWM support"
 	depends on MFD_SL28CPLD || COMPILE_TEST

drivers/pwm/Makefile

@@ -45,6 +45,7 @@ obj-$(CONFIG_PWM_RENESAS_TPU)	+= pwm-renesas-tpu.o
 obj-$(CONFIG_PWM_ROCKCHIP)	+= pwm-rockchip.o
 obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o
 obj-$(CONFIG_PWM_SIFIVE)	+= pwm-sifive.o
+obj-$(CONFIG_PWM_SIFIVE_PTC)	+= pwm-sifive-ptc.o
 obj-$(CONFIG_PWM_SL28CPLD)	+= pwm-sl28cpld.o
 obj-$(CONFIG_PWM_SPEAR)		+= pwm-spear.o
 obj-$(CONFIG_PWM_SPRD)		+= pwm-sprd.o

drivers/pwm/pwm-sifive-ptc.c

@@ -0,0 +1,291 @@
+/*
+ * Copyright (C) 2018 SiFive, Inc
+ *
+ * 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.
+ */
+
+#include <dt-bindings/pwm/pwm.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#define PTC_DEBUG			0
+
+/* max channel of pwm */
+#define MAX_PWM				8
+
+/* PTC Register offsets */
+#define REG_RPTC_CNTR			0x0
+#define REG_RPTC_HRC			0x4
+#define REG_RPTC_LRC			0x8
+#define REG_RPTC_CTRL			0xC
+
+/* Bit for PWM clock */
+#define BIT_PWM_CLOCK_EN		31
+
+/* Bit for clock gen soft reset */
+#define BIT_CLK_GEN_SOFT_RESET		13
+
+#define NS_1				1000000000
+
+/* Access PTC register (cntr hrc lrc and ctrl) ,need to replace PWM_BASE_ADDR */
+#define REG_PTC_BASE_ADDR_SUB(base, N)	((base) + ((N>3)?((N-4)*0x10+(1<<15)):(N*0x10)))
+#define REG_PTC_RPTC_CNTR(base,N)	(REG_PTC_BASE_ADDR_SUB(base,N))
+#define REG_PTC_RPTC_HRC(base,N)	(REG_PTC_BASE_ADDR_SUB(base,N) + 0x4)
+#define REG_PTC_RPTC_LRC(base,N)	(REG_PTC_BASE_ADDR_SUB(base,N) + 0x8)
+#define REG_PTC_RPTC_CTRL(base,N)	(REG_PTC_BASE_ADDR_SUB(base,N) + 0xC)
+
+/* pwm ptc device */
+struct sifive_pwm_ptc_device {
+	struct pwm_chip	chip;
+	struct clk	*clk;
+	void __iomem	*regs;
+	int		irq;
+	/* apb clock frequency , from dts */
+	unsigned int	approx_period;
+};
+
+static inline struct sifive_pwm_ptc_device *chip_to_sifive_ptc(struct pwm_chip *c)
+{
+	return container_of(c, struct sifive_pwm_ptc_device, chip);
+}
+
+
+static void sifive_pwm_ptc_get_state(struct pwm_chip *chip, struct pwm_device *dev, struct pwm_state *state)
+{
+	struct sifive_pwm_ptc_device *pwm = chip_to_sifive_ptc(chip);
+	uint32_t data_lrc;
+	uint32_t data_hrc;
+	uint32_t pwm_clk_ns = 0;
+
+	/* get lrc and hrc data from registe*/
+	data_lrc = ioread32(REG_PTC_RPTC_LRC(pwm->regs, dev->hwpwm));
+	data_hrc = ioread32(REG_PTC_RPTC_HRC(pwm->regs, dev->hwpwm));
+
+	/* how many ns does apb clock elapse */
+	pwm_clk_ns = NS_1 / pwm->approx_period;
+
+	/* pwm period(ns) */
+	state->period     = data_lrc*pwm_clk_ns;
+
+	/* duty cycle(ns) ,means high level eclapse ns if it is normal polarity */
+	state->duty_cycle = data_hrc*pwm_clk_ns;
+
+	/* polarity,we don't use it now because it is not in dts */
+	state->polarity   = PWM_POLARITY_NORMAL;
+
+	/* enabled or not */
+	state->enabled    = 1;
+#ifdef PTC_DEBUG
+	printk("sifive_pwm_ptc_get_state in,no:%d....\r\n",dev->hwpwm);
+	printk("data_hrc:0x%x 0x%x \n", data_hrc, data_lrc);
+	printk("period:%llu\r\n",state->period);
+	printk("duty_cycle:%llu\r\n",state->duty_cycle);
+	printk("polarity:%d\r\n",state->polarity);
+	printk("enabled:%d\r\n",state->enabled);
+#endif
+}
+
+
+static int sifive_pwm_ptc_apply(struct pwm_chip *chip, struct pwm_device *dev, struct pwm_state *state)
+{
+	struct sifive_pwm_ptc_device *pwm = chip_to_sifive_ptc(chip);
+	uint32_t pwm_clk_ns = 0;
+	uint32_t data_hrc = 0;
+	uint32_t data_lrc = 0;
+	uint32_t period_data = 0;
+	uint32_t duty_data = 0;
+	void __iomem* reg_addr;
+
+#if PTC_DEBUG
+	printk("sifive_pwm_ptc_apply in,no:%d....\r\n",dev->hwpwm);
+	printk("set parameter......\r\n");
+	printk("period:%d\r\n",state->period);
+	printk("duty_cycle:%d\r\n",state->duty_cycle);
+	printk("polarity:%d\r\n",state->polarity);
+	printk("enabled:%d\r\n",state->enabled);
+#endif
+	/* duty_cycle should be less or equal than period */
+	if(state->duty_cycle > state->period)
+		state->duty_cycle = state->period;
+
+	/* calculate pwm real period (ns) */
+	pwm_clk_ns = NS_1 / pwm->approx_period;
+
+#if PTC_DEBUG
+	printk("approx_period,:%d,pwm_clk_ns:%d\r\n",pwm->approx_period,pwm_clk_ns);
+#endif
+
+	/* calculate period count */
+	period_data = state->period / pwm_clk_ns;
+
+	if (!state->enabled)
+		/* if is unenable,just set duty_dat to 0 , means low level always */
+		duty_data = 0;
+	else
+		/* calculate duty count*/
+		duty_data = state->duty_cycle / pwm_clk_ns;
+
+#if PTC_DEBUG
+	printk("period_data:%d,duty_data:%d\r\n",period_data,duty_data);
+#endif
+
+	if(state->polarity == PWM_POLARITY_NORMAL)
+		/* calculate data_hrc */
+		data_hrc = period_data - duty_data;
+	else
+		/* calculate data_hrc */
+		data_hrc = duty_data;
+
+	data_lrc = period_data;
+
+	/* set hrc */
+	reg_addr = REG_PTC_RPTC_HRC(pwm->regs, dev->hwpwm);
+#if PTC_DEBUG
+	printk("[sifive_pwm_ptc_config]reg_addr:0x%lx,data:%d....\n",reg_addr,data_hrc);
+#endif
+	iowrite32(data_hrc, reg_addr);
+
+#if PTC_DEBUG
+	printk("[sifive_pwm_ptc_config]hrc ok....\n");
+#endif
+
+	/* set lrc */
+	reg_addr = REG_PTC_RPTC_LRC(pwm->regs, dev->hwpwm);
+#if PTC_DEBUG
+	printk("[sifive_pwm_ptc_config]reg_addr:0x%lx,data:%d....\n",reg_addr,data_lrc);
+#endif
+
+	iowrite32(data_lrc, reg_addr);
+
+#if PTC_DEBUG
+	printk("[sifive_pwm_ptc_config]lrc ok....\n");
+#endif
+
+	return 0;
+}
+
+
+
+static const struct pwm_ops sifive_pwm_ptc_ops = {
+	.get_state	= sifive_pwm_ptc_get_state,
+	.apply		= (void *)sifive_pwm_ptc_apply,
+	.owner		= THIS_MODULE,
+};
+
+
+
+
+static int sifive_pwm_ptc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = pdev->dev.of_node;
+	struct sifive_pwm_ptc_device *pwm;
+	struct pwm_chip *chip;
+	struct resource *res;
+	int ret;
+
+#if PTC_DEBUG
+	printk("sifive_pwm_ptc_probe in....\r\n");
+#endif
+	pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL);
+	if (!pwm) {
+		dev_err(dev, "Out of memory\n");
+		return -ENOMEM;
+	}
+
+	chip = &pwm->chip;
+	chip->dev = dev;
+	chip->ops = &sifive_pwm_ptc_ops;
+
+	/* how many parameters can be transfered to ptc,need to fix */
+	chip->of_pwm_n_cells = 3;
+	chip->base = -1;
+
+	/* get pwm channels count, max value is 8 */
+	ret = of_property_read_u32(node, "starfive,npwm", &chip->npwm);
+	if (ret < 0 || chip->npwm > MAX_PWM)
+		chip->npwm = MAX_PWM;
+
+#if PTC_DEBUG
+	printk("[sifive_pwm_ptc_probe] npwm:0x%lx....\r\n",chip->npwm);
+#endif
+	/* get apb clock frequency */
+	ret = of_property_read_u32(node, "sifive,approx-period", &pwm->approx_period);
+
+#if PTC_DEBUG
+	printk("[sifive_pwm_ptc_probe] approx_period:%d....\r\n",pwm->approx_period);
+#endif
+	/* get IO base address*/
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+#if PTC_DEBUG
+	printk("[sifive_pwm_ptc_probe] res start:0x%lx,end:0x%lx....\r\n",res->start,res->end);
+#endif
+	pwm->regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(pwm->regs))
+	{
+		dev_err(dev, "Unable to map IO resources\n");
+		return PTR_ERR(pwm->regs);
+	}
+
+#if PTC_DEBUG
+	printk("[sifive_pwm_ptc_probe] regs:0x%lx....\r\n",pwm->regs);
+#endif
+
+	pwm->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(pwm->clk)) {
+		dev_err(dev, "Unable to find controller clock\n");
+		return PTR_ERR(pwm->clk);
+	}
+
+	/* after add,it will display as /sys/class/pwm/pwmchip0,0 is chip->base
+	 * after execute echo 0 > export in  , pwm0 can be seen */
+	ret = pwmchip_add(chip);
+	if (ret < 0) {
+		dev_err(dev, "cannot register PTC: %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, pwm);
+
+#if PTC_DEBUG
+	printk("SiFive PWM PTC chip registered %d PWMs\n", chip->npwm);
+#endif
+
+	return 0;
+}
+
+static int sifive_pwm_ptc_remove(struct platform_device *dev)
+{
+	struct sifive_pwm_ptc_device *pwm = platform_get_drvdata(dev);
+	struct pwm_chip *chip = &pwm->chip;
+
+	pwmchip_remove(chip);
+	return 0;
+}
+
+static const struct of_device_id sifive_pwm_ptc_of_match[] = {
+	{ .compatible = "sifive,pwm0" },
+	{ .compatible = "starfive,pwm0" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, sifive_pwm_ptc_of_match);
+
+static struct platform_driver sifive_pwm_ptc_driver = {
+	.probe = sifive_pwm_ptc_probe,
+	.remove = sifive_pwm_ptc_remove,
+	.driver = {
+		.name = "pwm-sifive-ptc",
+		.of_match_table = of_match_ptr(sifive_pwm_ptc_of_match),
+	},
+};
+module_platform_driver(sifive_pwm_ptc_driver);
+
+MODULE_DESCRIPTION("SiFive PWM PTC driver");
+MODULE_LICENSE("GPL v2");