From 824f18efc8ad59e2783570ae2df83e2cd16b9f04 Mon Sep 17 00:00:00 2001 From: Phil Elwell Date: Tue, 14 Feb 2023 14:03:54 +0000 Subject: [PATCH] pwm: Add support for RP1 PWM Add a driver for the RP1 PWM block. Signed-off-by: Phil Elwell --- .../devicetree/bindings/pwm/pwm-rp1.yaml | 38 ++++ drivers/pwm/Kconfig | 9 + drivers/pwm/Makefile | 1 + drivers/pwm/pwm-rp1.c | 203 ++++++++++++++++++ 4 files changed, 251 insertions(+) create mode 100644 Documentation/devicetree/bindings/pwm/pwm-rp1.yaml create mode 100644 drivers/pwm/pwm-rp1.c --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/pwm-rp1.yaml @@ -0,0 +1,38 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/pwm/pwm-rp1.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Raspberry Pi RP1 PWM controller + +maintainers: + - Naushir Patuck + +properties: + compatible: + enum: + - raspberrypi,rp1-pwm + + reg: + maxItems: 1 + + "#pwm-cells": + const: 3 + +required: + - compatible + - reg + - clocks + - "#pwm-cells" + +additionalProperties: false + +examples: + - | + pwm0: pwm@98000 { + compatible = "raspberrypi,rp1-pwm"; + reg = <0x0 0x98000 0x0 0x100>; + clocks = <&rp1_sys>; + #pwm-cells = <3>; + }; --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -451,6 +451,15 @@ config PWM_RASPBERRYPI_POE Enable Raspberry Pi firmware controller PWM bus used to control the official RPI PoE hat +config PWM_RP1 + tristate "RP1 PWM support" + depends on ARCH_BCM2835 || COMPILE_TEST + help + PWM framework driver for Raspberry Pi RP1 controller + + To compile this driver as a module, choose M here: the module + will be called pwm-rp1. + config PWM_RCAR tristate "Renesas R-Car PWM support" depends on ARCH_RENESAS || COMPILE_TEST --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -41,6 +41,7 @@ obj-$(CONFIG_PWM_OMAP_DMTIMER) += pwm-om obj-$(CONFIG_PWM_PCA9685) += pwm-pca9685.o obj-$(CONFIG_PWM_PXA) += pwm-pxa.o obj-$(CONFIG_PWM_RASPBERRYPI_POE) += pwm-raspberrypi-poe.o +obj-$(CONFIG_PWM_RP1) += pwm-rp1.o obj-$(CONFIG_PWM_RCAR) += pwm-rcar.o obj-$(CONFIG_PWM_RENESAS_TPU) += pwm-renesas-tpu.o obj-$(CONFIG_PWM_ROCKCHIP) += pwm-rockchip.o --- /dev/null +++ b/drivers/pwm/pwm-rp1.c @@ -0,0 +1,203 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * pwm-rp1.c + * + * Raspberry Pi RP1 PWM. + * + * Copyright © 2023 Raspberry Pi Ltd. + * + * Author: Naushir Patuck (naush@raspberrypi.com) + * + * Based on the pwm-bcm2835 driver by: + * Bart Tanghe + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define PWM_GLOBAL_CTRL 0x000 +#define PWM_CHANNEL_CTRL(x) (0x014 + ((x) * 16)) +#define PWM_RANGE(x) (0x018 + ((x) * 16)) +#define PWM_DUTY(x) (0x020 + ((x) * 16)) + +/* 8:FIFO_POP_MASK + 0:Trailing edge M/S modulation */ +#define PWM_CHANNEL_DEFAULT (BIT(8) + BIT(0)) +#define PWM_CHANNEL_ENABLE(x) BIT(x) +#define PWM_POLARITY BIT(3) +#define SET_UPDATE BIT(31) +#define PWM_MODE_MASK GENMASK(1, 0) + +struct rp1_pwm { + struct pwm_chip chip; + struct device *dev; + void __iomem *base; + struct clk *clk; +}; + +static inline struct rp1_pwm *to_rp1_pwm(struct pwm_chip *chip) +{ + return container_of(chip, struct rp1_pwm, chip); +} + +static void rp1_pwm_apply_config(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct rp1_pwm *pc = to_rp1_pwm(chip); + u32 value; + + value = readl(pc->base + PWM_GLOBAL_CTRL); + value |= SET_UPDATE; + writel(value, pc->base + PWM_GLOBAL_CTRL); +} + +static int rp1_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct rp1_pwm *pc = to_rp1_pwm(chip); + + writel(PWM_CHANNEL_DEFAULT, pc->base + PWM_CHANNEL_CTRL(pwm->hwpwm)); + return 0; +} + +static void rp1_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct rp1_pwm *pc = to_rp1_pwm(chip); + u32 value; + + value = readl(pc->base + PWM_CHANNEL_CTRL(pwm->hwpwm)); + value &= ~PWM_MODE_MASK; + writel(value, pc->base + PWM_CHANNEL_CTRL(pwm->hwpwm)); + rp1_pwm_apply_config(chip, pwm); +} + +static int rp1_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + struct rp1_pwm *pc = to_rp1_pwm(chip); + unsigned long clk_rate = clk_get_rate(pc->clk); + unsigned long clk_period; + u32 value; + + if (!clk_rate) { + dev_err(pc->dev, "failed to get clock rate\n"); + return -EINVAL; + } + + /* set period */ + clk_period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, clk_rate); + + writel(DIV_ROUND_CLOSEST(state->duty_cycle, clk_period), + pc->base + PWM_DUTY(pwm->hwpwm)); + + /* set duty cycle */ + writel(DIV_ROUND_CLOSEST(state->period, clk_period), + pc->base + PWM_RANGE(pwm->hwpwm)); + + /* set polarity */ + value = readl(pc->base + PWM_CHANNEL_CTRL(pwm->hwpwm)); + if (state->polarity == PWM_POLARITY_NORMAL) + value &= ~PWM_POLARITY; + else + value |= PWM_POLARITY; + writel(value, pc->base + PWM_CHANNEL_CTRL(pwm->hwpwm)); + + /* enable/disable */ + value = readl(pc->base + PWM_GLOBAL_CTRL); + if (state->enabled) + value |= PWM_CHANNEL_ENABLE(pwm->hwpwm); + else + value &= ~PWM_CHANNEL_ENABLE(pwm->hwpwm); + writel(value, pc->base + PWM_GLOBAL_CTRL); + + rp1_pwm_apply_config(chip, pwm); + + return 0; +} + +static const struct pwm_ops rp1_pwm_ops = { + .request = rp1_pwm_request, + .free = rp1_pwm_free, + .apply = rp1_pwm_apply, + .owner = THIS_MODULE, +}; + +static int rp1_pwm_probe(struct platform_device *pdev) +{ + struct rp1_pwm *pc; + struct resource *res; + int ret; + + pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL); + if (!pc) + return -ENOMEM; + + pc->dev = &pdev->dev; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + pc->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(pc->base)) + return PTR_ERR(pc->base); + + pc->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(pc->clk)) + return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk), + "clock not found\n"); + + ret = clk_prepare_enable(pc->clk); + if (ret) + return ret; + + pc->chip.dev = &pdev->dev; + pc->chip.ops = &rp1_pwm_ops; + pc->chip.base = -1; + pc->chip.npwm = 4; + pc->chip.of_xlate = of_pwm_xlate_with_flags; + pc->chip.of_pwm_n_cells = 3; + + platform_set_drvdata(pdev, pc); + + ret = pwmchip_add(&pc->chip); + if (ret < 0) + goto add_fail; + + return 0; + +add_fail: + clk_disable_unprepare(pc->clk); + return ret; +} + +static int rp1_pwm_remove(struct platform_device *pdev) +{ + struct rp1_pwm *pc = platform_get_drvdata(pdev); + + clk_disable_unprepare(pc->clk); + + pwmchip_remove(&pc->chip); + + return 0; +} + +static const struct of_device_id rp1_pwm_of_match[] = { + { .compatible = "raspberrypi,rp1-pwm" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, rp1_pwm_of_match); + +static struct platform_driver rp1_pwm_driver = { + .driver = { + .name = "rpi-pwm", + .of_match_table = rp1_pwm_of_match, + }, + .probe = rp1_pwm_probe, + .remove = rp1_pwm_remove, +}; +module_platform_driver(rp1_pwm_driver); + +MODULE_AUTHOR("Naushir Patuck