From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: u.kleine-koenig@pengutronix.de
Cc: f.fainelli@gmail.com, linux-kernel@vger.kernel.org,
linux-pwm@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com,
linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
wahrenst@gmx.net, linux-input@vger.kernel.org,
dmitry.torokhov@gmail.com, gregkh@linuxfoundation.org,
devel@driverdev.osuosl.org, p.zabel@pengutronix.de,
linux-gpio@vger.kernel.org, linus.walleij@linaro.org,
linux-clk@vger.kernel.org, sboyd@kernel.org,
linux-rpi-kernel@lists.infradead.org, bgolaszewski@baylibre.com,
andy.shevchenko@gmail.com
Subject: Re: [PATCH v7 11/11] pwm: Add Raspberry Pi Firmware based PWM bus
Date: Tue, 09 Mar 2021 10:59:00 +0100 [thread overview]
Message-ID: <957566acbdbe1155eeb561c324d2404bbbf7e7af.camel@suse.de> (raw)
In-Reply-To: <20210118123244.13669-12-nsaenzjulienne@suse.de>
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On Mon, 2021-01-18 at 13:32 +0100, Nicolas Saenz Julienne wrote:
> Adds support to control the PWM bus available in official Raspberry Pi
> PoE HAT. Only RPi's co-processor has access to it, so commands have to
> be sent through RPi's firmware mailbox interface.
>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
>
> ---
ping :)
> Changes since v6:
> - Use %pe
> - Round divisions properly
> - Use dev_err_probe()
> - Pass check_patch
>
> Changes since v3:
> - Rename compatible string to be more explicit WRT to bus's limitations
>
> Changes since v2:
> - Use devm_rpi_firmware_get()
> - Rename driver
> - Small cleanups
>
> Changes since v1:
> - Use default pwm bindings and get rid of xlate() function
> - Correct spelling errors
> - Correct apply() function
> - Round values
> - Fix divisions in arm32 mode
> - Small cleanups
>
> drivers/pwm/Kconfig | 9 ++
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-raspberrypi-poe.c | 220 ++++++++++++++++++++++++++++++
> 3 files changed, 230 insertions(+)
> create mode 100644 drivers/pwm/pwm-raspberrypi-poe.c
>
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 0937e1c047ac..75e2344703b3 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -423,6 +423,15 @@ config PWM_PXA
> To compile this driver as a module, choose M here: the module
> will be called pwm-pxa.
>
>
> +config PWM_RASPBERRYPI_POE
> + tristate "Raspberry Pi Firwmware PoE Hat PWM support"
> + # Make sure not 'y' when RASPBERRYPI_FIRMWARE is 'm'. This can only
> + # happen when COMPILE_TEST=y, hence the added !RASPBERRYPI_FIRMWARE.
> + depends on RASPBERRYPI_FIRMWARE || (COMPILE_TEST && !RASPBERRYPI_FIRMWARE)
> + help
> + Enable Raspberry Pi firmware controller PWM bus used to control the
> + official RPI PoE hat
> +
> config PWM_RCAR
> tristate "Renesas R-Car PWM support"
> depends on ARCH_RENESAS || COMPILE_TEST
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index 18b89d7fd092..ed28d7bd4c64 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -38,6 +38,7 @@ obj-$(CONFIG_PWM_MXS) += pwm-mxs.o
> obj-$(CONFIG_PWM_OMAP_DMTIMER) += pwm-omap-dmtimer.o
> 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_RCAR) += pwm-rcar.o
> obj-$(CONFIG_PWM_RENESAS_TPU) += pwm-renesas-tpu.o
> obj-$(CONFIG_PWM_ROCKCHIP) += pwm-rockchip.o
> diff --git a/drivers/pwm/pwm-raspberrypi-poe.c b/drivers/pwm/pwm-raspberrypi-poe.c
> new file mode 100644
> index 000000000000..ca845e8fabe6
> --- /dev/null
> +++ b/drivers/pwm/pwm-raspberrypi-poe.c
> @@ -0,0 +1,220 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2020 Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> + * For more information on Raspberry Pi's PoE hat see:
> + * https://www.raspberrypi.org/products/poe-hat/
> + *
> + * Limitations:
> + * - No disable bit, so a disabled PWM is simulated by duty_cycle 0
> + * - Only normal polarity
> + * - Fixed 12.5 kHz period
> + *
> + * The current period is completed when HW is reconfigured.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +
> +#include <soc/bcm2835/raspberrypi-firmware.h>
> +#include <dt-bindings/pwm/raspberrypi,firmware-poe-pwm.h>
> +
> +#define RPI_PWM_MAX_DUTY 255
> +#define RPI_PWM_PERIOD_NS 80000 /* 12.5 kHz */
> +
> +#define RPI_PWM_CUR_DUTY_REG 0x0
> +#define RPI_PWM_DEF_DUTY_REG 0x1
> +
> +struct raspberrypi_pwm {
> + struct rpi_firmware *firmware;
> + struct pwm_chip chip;
> + unsigned int duty_cycle;
> +};
> +
> +struct raspberrypi_pwm_prop {
> + __le32 reg;
> + __le32 val;
> + __le32 ret;
> +} __packed;
> +
> +static inline
> +struct raspberrypi_pwm *raspberrypi_pwm_from_chip(struct pwm_chip *chip)
> +{
> + return container_of(chip, struct raspberrypi_pwm, chip);
> +}
> +
> +static int raspberrypi_pwm_set_property(struct rpi_firmware *firmware,
> + u32 reg, u32 val)
> +{
> + struct raspberrypi_pwm_prop msg = {
> + .reg = cpu_to_le32(reg),
> + .val = cpu_to_le32(val),
> + };
> + int ret;
> +
> + ret = rpi_firmware_property(firmware, RPI_FIRMWARE_SET_POE_HAT_VAL,
> + &msg, sizeof(msg));
> + if (ret)
> + return ret;
> + if (msg.ret)
> + return -EIO;
> +
> + return 0;
> +}
> +
> +static int raspberrypi_pwm_get_property(struct rpi_firmware *firmware,
> + u32 reg, u32 *val)
> +{
> + struct raspberrypi_pwm_prop msg = {
> + .reg = reg
> + };
> + int ret;
> +
> + ret = rpi_firmware_property(firmware, RPI_FIRMWARE_GET_POE_HAT_VAL,
> + &msg, sizeof(msg));
> + if (ret)
> + return ret;
> + if (msg.ret)
> + return -EIO;
> +
> + *val = le32_to_cpu(msg.val);
> +
> + return 0;
> +}
> +
> +static void raspberrypi_pwm_get_state(struct pwm_chip *chip,
> + struct pwm_device *pwm,
> + struct pwm_state *state)
> +{
> + struct raspberrypi_pwm *rpipwm = raspberrypi_pwm_from_chip(chip);
> +
> + state->period = RPI_PWM_PERIOD_NS;
> + state->duty_cycle = DIV_ROUND_UP(rpipwm->duty_cycle * RPI_PWM_PERIOD_NS,
> + RPI_PWM_MAX_DUTY);
> + state->enabled = !!(rpipwm->duty_cycle);
> + state->polarity = PWM_POLARITY_NORMAL;
> +}
> +
> +static int raspberrypi_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> + const struct pwm_state *state)
> +{
> + struct raspberrypi_pwm *rpipwm = raspberrypi_pwm_from_chip(chip);
> + unsigned int duty_cycle;
> + int ret;
> +
> + if (state->period < RPI_PWM_PERIOD_NS ||
> + state->polarity != PWM_POLARITY_NORMAL)
> + return -EINVAL;
> +
> + if (!state->enabled)
> + duty_cycle = 0;
> + else if (state->duty_cycle < RPI_PWM_PERIOD_NS)
> + duty_cycle = DIV_ROUND_DOWN_ULL(state->duty_cycle * RPI_PWM_MAX_DUTY,
> + RPI_PWM_PERIOD_NS);
> + else
> + duty_cycle = RPI_PWM_MAX_DUTY;
> +
> + if (duty_cycle == rpipwm->duty_cycle)
> + return 0;
> +
> + ret = raspberrypi_pwm_set_property(rpipwm->firmware, RPI_PWM_CUR_DUTY_REG,
> + duty_cycle);
> + if (ret) {
> + dev_err(chip->dev, "Failed to set duty cycle: %pe\n",
> + ERR_PTR(ret));
> + return ret;
> + }
> +
> + /*
> + * This sets the default duty cycle after resetting the board, we
> + * updated it every time to mimic Raspberry Pi's downstream's driver
> + * behaviour.
> + */
> + ret = raspberrypi_pwm_set_property(rpipwm->firmware, RPI_PWM_DEF_DUTY_REG,
> + duty_cycle);
> + if (ret) {
> + dev_err(chip->dev, "Failed to set default duty cycle: %pe\n",
> + ERR_PTR(ret));
> + return ret;
> + }
> +
> + rpipwm->duty_cycle = duty_cycle;
> +
> + return 0;
> +}
> +
> +static const struct pwm_ops raspberrypi_pwm_ops = {
> + .get_state = raspberrypi_pwm_get_state,
> + .apply = raspberrypi_pwm_apply,
> + .owner = THIS_MODULE,
> +};
> +
> +static int raspberrypi_pwm_probe(struct platform_device *pdev)
> +{
> + struct device_node *firmware_node;
> + struct device *dev = &pdev->dev;
> + struct rpi_firmware *firmware;
> + struct raspberrypi_pwm *rpipwm;
> + int ret;
> +
> + firmware_node = of_get_parent(dev->of_node);
> + if (!firmware_node) {
> + dev_err(dev, "Missing firmware node\n");
> + return -ENOENT;
> + }
> +
> + firmware = devm_rpi_firmware_get(&pdev->dev, firmware_node);
> + of_node_put(firmware_node);
> + if (!firmware)
> + return dev_err_probe(dev, -EPROBE_DEFER,
> + "Failed to get firmware handle\n");
> +
> + rpipwm = devm_kzalloc(&pdev->dev, sizeof(*rpipwm), GFP_KERNEL);
> + if (!rpipwm)
> + return -ENOMEM;
> +
> + rpipwm->firmware = firmware;
> + rpipwm->chip.dev = dev;
> + rpipwm->chip.ops = &raspberrypi_pwm_ops;
> + rpipwm->chip.base = -1;
> + rpipwm->chip.npwm = RASPBERRYPI_FIRMWARE_PWM_NUM;
> +
> + platform_set_drvdata(pdev, rpipwm);
> +
> + ret = raspberrypi_pwm_get_property(rpipwm->firmware, RPI_PWM_CUR_DUTY_REG,
> + &rpipwm->duty_cycle);
> + if (ret) {
> + dev_err(dev, "Failed to get duty cycle: %pe\n", ERR_PTR(ret));
> + return ret;
> + }
> +
> + return pwmchip_add(&rpipwm->chip);
> +}
> +
> +static int raspberrypi_pwm_remove(struct platform_device *pdev)
> +{
> + struct raspberrypi_pwm *rpipwm = platform_get_drvdata(pdev);
> +
> + return pwmchip_remove(&rpipwm->chip);
> +}
> +
> +static const struct of_device_id raspberrypi_pwm_of_match[] = {
> + { .compatible = "raspberrypi,firmware-poe-pwm", },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, raspberrypi_pwm_of_match);
> +
> +static struct platform_driver raspberrypi_pwm_driver = {
> + .driver = {
> + .name = "raspberrypi-poe-pwm",
> + .of_match_table = raspberrypi_pwm_of_match,
> + },
> + .probe = raspberrypi_pwm_probe,
> + .remove = raspberrypi_pwm_remove,
> +};
> +module_platform_driver(raspberrypi_pwm_driver);
> +
> +MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
> +MODULE_DESCRIPTION("Raspberry Pi Firmware Based PWM Bus Driver");
> +MODULE_LICENSE("GPL v2");
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next prev parent reply other threads:[~2021-03-09 9:59 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-18 12:32 [PATCH v7 00/11] Raspberry Pi PoE HAT fan support Nicolas Saenz Julienne
2021-01-18 12:32 ` [PATCH v7 01/11] firmware: raspberrypi: Keep count of all consumers Nicolas Saenz Julienne
2021-01-18 12:32 ` [PATCH v7 02/11] firmware: raspberrypi: Introduce devm_rpi_firmware_get() Nicolas Saenz Julienne
2021-01-18 12:32 ` [PATCH v7 03/11] clk: bcm: rpi: Release firmware handle on unbind Nicolas Saenz Julienne
2021-01-18 12:32 ` [PATCH v7 04/11] gpio: raspberrypi-exp: " Nicolas Saenz Julienne
2021-01-18 12:32 ` [PATCH v7 05/11] reset: raspberrypi: " Nicolas Saenz Julienne
2021-01-18 12:32 ` [PATCH v7 06/11] soc: bcm: raspberrypi-power: " Nicolas Saenz Julienne
2021-01-18 12:32 ` [PATCH v7 07/11] staging: vchiq: " Nicolas Saenz Julienne
2021-01-26 17:47 ` Greg KH
2021-01-18 12:32 ` [PATCH v7 08/11] input: raspberrypi-ts: Release firmware handle when not needed Nicolas Saenz Julienne
2021-01-18 12:32 ` [PATCH v7 09/11] dt-bindings: pwm: Add binding for RPi firmware PWM bus Nicolas Saenz Julienne
2021-01-18 12:32 ` [PATCH v7 10/11] DO NOT MERGE: ARM: dts: Add RPi's official PoE hat support Nicolas Saenz Julienne
2021-01-18 12:32 ` [PATCH v7 11/11] pwm: Add Raspberry Pi Firmware based PWM bus Nicolas Saenz Julienne
2021-02-08 20:53 ` Nicolas Saenz Julienne
2021-03-09 9:59 ` Nicolas Saenz Julienne [this message]
2021-03-10 11:50 ` Uwe Kleine-König
2021-03-11 13:01 ` Nicolas Saenz Julienne
2021-03-11 13:18 ` Uwe Kleine-König
2021-03-11 13:41 ` Nicolas Saenz Julienne
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