pwm: rockchip: Add a PWM driver for Rockchip SoCs

Add a simple driver which implements the standard PWM uclass interface.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/arm/include/asm/arch-rockchip/pwm.h

@@ -0,0 +1,41 @@
+/*
+ * (C) Copyright 2016 Google, Inc
+ * (C) Copyright 2008-2014 Rockchip Electronics
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#ifndef _ASM_ARCH_PWM_H
+#define _ASM_ARCH_PWM_H
+
+struct rk3288_pwm {
+	u32 cnt;
+	u32 period_hpr;
+	u32 duty_lpr;
+	u32 ctrl;
+};
+check_member(rk3288_pwm, ctrl, 0xc);
+
+#define RK_PWM_DISABLE                  (0 << 0)
+#define RK_PWM_ENABLE                   (1 << 0)
+
+#define PWM_ONE_SHOT                    (0 << 1)
+#define PWM_CONTINUOUS                  (1 << 1)
+#define RK_PWM_CAPTURE                  (1 << 2)
+
+#define PWM_DUTY_POSTIVE                (1 << 3)
+#define PWM_DUTY_NEGATIVE               (0 << 3)
+
+#define PWM_INACTIVE_POSTIVE            (1 << 4)
+#define PWM_INACTIVE_NEGATIVE           (0 << 4)
+
+#define PWM_OUTPUT_LEFT                 (0 << 5)
+#define PWM_OUTPUT_CENTER               (1 << 5)
+
+#define PWM_LP_ENABLE                   (1 << 8)
+#define PWM_LP_DISABLE                  (0 << 8)
+
+#define PWM_SEL_SCALE_CLK		(1 << 9)
+#define PWM_SEL_SRC_CLK			(0 << 9)
+
+#endif

drivers/pwm/Kconfig

@@ -8,3 +8,12 @@ config DM_PWM
 	  spends in the 'high' state, the higher the voltage. The PWM's
 	  frequency/period can be controlled along with the proportion of that
 	  time that the signal is high.
+
+config PWM_ROCKCHIP
+	bool "Enable support for the Rockchip PWM"
+	depends on DM_PWM
+	help
+	  This PWM is found on RK3288 and other Rockchip SoCs. It supports a
+	  programmable period and duty cycle. A 32-bit counter is used.
+	  Various options provided in the hardware (such as capture mode and
+	  continuous/single-shot) are not supported by the driver.

drivers/pwm/Makefile

@@ -11,4 +11,5 @@
 #ccflags-y += -DDEBUG
 
 obj-$(CONFIG_DM_PWM) += pwm-uclass.o
+obj-$(CONFIG_PWM_ROCKCHIP) += rk_pwm.o
 obj-$(CONFIG_PWM_IMX) += pwm-imx.o pwm-imx-util.o

drivers/pwm/rk_pwm.c

@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2016 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <div64.h>
+#include <dm.h>
+#include <pwm.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/cru_rk3288.h>
+#include <asm/arch/grf_rk3288.h>
+#include <asm/arch/pwm.h>
+#include <power/regulator.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct rk_pwm_priv {
+	struct rk3288_pwm *regs;
+	struct rk3288_grf *grf;
+};
+
+static int rk_pwm_set_config(struct udevice *dev, uint channel, uint period_ns,
+			     uint duty_ns)
+{
+	struct rk_pwm_priv *priv = dev_get_priv(dev);
+	struct rk3288_pwm *regs = priv->regs;
+	unsigned long period, duty;
+
+	debug("%s: period_ns=%u, duty_ns=%u\n", __func__, period_ns, duty_ns);
+	writel(PWM_SEL_SRC_CLK | PWM_OUTPUT_LEFT | PWM_LP_DISABLE |
+		PWM_CONTINUOUS | PWM_DUTY_POSTIVE | PWM_INACTIVE_POSTIVE |
+		RK_PWM_DISABLE,
+		&regs->ctrl);
+
+	period = lldiv((uint64_t)(PD_BUS_PCLK_HZ / 1000) * period_ns, 1000000);
+	duty = lldiv((uint64_t)(PD_BUS_PCLK_HZ / 1000) * duty_ns, 1000000);
+
+	writel(period, &regs->period_hpr);
+	writel(duty, &regs->duty_lpr);
+	debug("%s: period=%lu, duty=%lu\n", __func__, period, duty);
+
+	return 0;
+}
+
+static int rk_pwm_set_enable(struct udevice *dev, uint channel, bool enable)
+{
+	struct rk_pwm_priv *priv = dev_get_priv(dev);
+	struct rk3288_pwm *regs = priv->regs;
+
+	debug("%s: Enable '%s'\n", __func__, dev->name);
+	clrsetbits_le32(&regs->ctrl, RK_PWM_ENABLE, enable ? RK_PWM_ENABLE : 0);
+
+	return 0;
+}
+
+static int rk_pwm_ofdata_to_platdata(struct udevice *dev)
+{
+	struct rk_pwm_priv *priv = dev_get_priv(dev);
+	struct regmap *map;
+
+	priv->regs = (struct rk3288_pwm *)dev_get_addr(dev);
+	map = syscon_get_regmap_by_driver_data(ROCKCHIP_SYSCON_GRF);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+	priv->grf = regmap_get_range(map, 0);
+
+	return 0;
+}
+
+static int rk_pwm_probe(struct udevice *dev)
+{
+	struct rk_pwm_priv *priv = dev_get_priv(dev);
+
+	rk_setreg(&priv->grf->soc_con2, 1 << 0);
+
+	return 0;
+}
+
+static const struct pwm_ops rk_pwm_ops = {
+	.set_config	= rk_pwm_set_config,
+	.set_enable	= rk_pwm_set_enable,
+};
+
+static const struct udevice_id rk_pwm_ids[] = {
+	{ .compatible = "rockchip,rk3288-pwm" },
+	{ }
+};
+
+U_BOOT_DRIVER(rk_pwm) = {
+	.name	= "rk_pwm",
+	.id	= UCLASS_PWM,
+	.of_match = rk_pwm_ids,
+	.ops	= &rk_pwm_ops,
+	.ofdata_to_platdata	= rk_pwm_ofdata_to_platdata,
+	.probe		= rk_pwm_probe,
+	.priv_auto_alloc_size	= sizeof(struct rk_pwm_priv),
+};