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![Uwe Kleine-König](/assets/img/avatar_default.png)
.get_state() might fail in some cases. To make it possible that a driver signals such a failure change the prototype of .get_state() to return an error code. This patch was created using coccinelle and the following semantic patch: @p1@ identifier getstatefunc; identifier driver; @@ struct pwm_ops driver = { ..., .get_state = getstatefunc ,... }; @p2@ identifier p1.getstatefunc; identifier chip, pwm, state; @@ -void +int getstatefunc(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state) { ... - return; + return 0; ... } plus the actual change of the prototype in include/linux/pwm.h (plus some manual fixing of indentions and empty lines). So for now all drivers return success unconditionally. They are adapted in the following patches to make the changes easier reviewable. Reviewed-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org> Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> Reviewed-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com> Acked-by: Douglas Anderson <dianders@chromium.org> Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> Acked-by: Pavel Machek <pavel@ucw.cz> Acked-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20221130152148.2769768-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
197 lines
4.8 KiB
C
197 lines
4.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2021 Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
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* For more information on Raspberry Pi's PoE hat see:
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* https://www.raspberrypi.org/products/poe-hat/
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*
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* Limitations:
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* - No disable bit, so a disabled PWM is simulated by duty_cycle 0
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* - Only normal polarity
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* - Fixed 12.5 kHz period
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*
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* The current period is completed when HW is reconfigured.
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*/
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/pwm.h>
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#include <soc/bcm2835/raspberrypi-firmware.h>
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#include <dt-bindings/pwm/raspberrypi,firmware-poe-pwm.h>
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#define RPI_PWM_MAX_DUTY 255
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#define RPI_PWM_PERIOD_NS 80000 /* 12.5 kHz */
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#define RPI_PWM_CUR_DUTY_REG 0x0
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struct raspberrypi_pwm {
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struct rpi_firmware *firmware;
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struct pwm_chip chip;
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unsigned int duty_cycle;
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};
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struct raspberrypi_pwm_prop {
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__le32 reg;
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__le32 val;
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__le32 ret;
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} __packed;
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static inline
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struct raspberrypi_pwm *raspberrypi_pwm_from_chip(struct pwm_chip *chip)
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{
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return container_of(chip, struct raspberrypi_pwm, chip);
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}
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static int raspberrypi_pwm_set_property(struct rpi_firmware *firmware,
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u32 reg, u32 val)
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{
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struct raspberrypi_pwm_prop msg = {
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.reg = cpu_to_le32(reg),
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.val = cpu_to_le32(val),
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};
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int ret;
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ret = rpi_firmware_property(firmware, RPI_FIRMWARE_SET_POE_HAT_VAL,
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&msg, sizeof(msg));
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if (ret)
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return ret;
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if (msg.ret)
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return -EIO;
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return 0;
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}
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static int raspberrypi_pwm_get_property(struct rpi_firmware *firmware,
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u32 reg, u32 *val)
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{
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struct raspberrypi_pwm_prop msg = {
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.reg = cpu_to_le32(reg),
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};
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int ret;
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ret = rpi_firmware_property(firmware, RPI_FIRMWARE_GET_POE_HAT_VAL,
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&msg, sizeof(msg));
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if (ret)
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return ret;
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if (msg.ret)
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return -EIO;
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*val = le32_to_cpu(msg.val);
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return 0;
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}
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static int raspberrypi_pwm_get_state(struct pwm_chip *chip,
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struct pwm_device *pwm,
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struct pwm_state *state)
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{
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struct raspberrypi_pwm *rpipwm = raspberrypi_pwm_from_chip(chip);
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state->period = RPI_PWM_PERIOD_NS;
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state->duty_cycle = DIV_ROUND_UP(rpipwm->duty_cycle * RPI_PWM_PERIOD_NS,
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RPI_PWM_MAX_DUTY);
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state->enabled = !!(rpipwm->duty_cycle);
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state->polarity = PWM_POLARITY_NORMAL;
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return 0;
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}
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static int raspberrypi_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
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const struct pwm_state *state)
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{
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struct raspberrypi_pwm *rpipwm = raspberrypi_pwm_from_chip(chip);
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unsigned int duty_cycle;
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int ret;
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if (state->period < RPI_PWM_PERIOD_NS ||
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state->polarity != PWM_POLARITY_NORMAL)
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return -EINVAL;
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if (!state->enabled)
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duty_cycle = 0;
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else if (state->duty_cycle < RPI_PWM_PERIOD_NS)
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duty_cycle = DIV_ROUND_DOWN_ULL(state->duty_cycle * RPI_PWM_MAX_DUTY,
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RPI_PWM_PERIOD_NS);
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else
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duty_cycle = RPI_PWM_MAX_DUTY;
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if (duty_cycle == rpipwm->duty_cycle)
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return 0;
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ret = raspberrypi_pwm_set_property(rpipwm->firmware, RPI_PWM_CUR_DUTY_REG,
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duty_cycle);
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if (ret) {
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dev_err(chip->dev, "Failed to set duty cycle: %pe\n",
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ERR_PTR(ret));
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return ret;
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}
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rpipwm->duty_cycle = duty_cycle;
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return 0;
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}
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static const struct pwm_ops raspberrypi_pwm_ops = {
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.get_state = raspberrypi_pwm_get_state,
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.apply = raspberrypi_pwm_apply,
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.owner = THIS_MODULE,
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};
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static int raspberrypi_pwm_probe(struct platform_device *pdev)
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{
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struct device_node *firmware_node;
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struct device *dev = &pdev->dev;
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struct rpi_firmware *firmware;
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struct raspberrypi_pwm *rpipwm;
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int ret;
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firmware_node = of_get_parent(dev->of_node);
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if (!firmware_node) {
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dev_err(dev, "Missing firmware node\n");
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return -ENOENT;
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}
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firmware = devm_rpi_firmware_get(&pdev->dev, firmware_node);
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of_node_put(firmware_node);
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if (!firmware)
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return dev_err_probe(dev, -EPROBE_DEFER,
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"Failed to get firmware handle\n");
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rpipwm = devm_kzalloc(&pdev->dev, sizeof(*rpipwm), GFP_KERNEL);
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if (!rpipwm)
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return -ENOMEM;
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rpipwm->firmware = firmware;
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rpipwm->chip.dev = dev;
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rpipwm->chip.ops = &raspberrypi_pwm_ops;
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rpipwm->chip.npwm = RASPBERRYPI_FIRMWARE_PWM_NUM;
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ret = raspberrypi_pwm_get_property(rpipwm->firmware, RPI_PWM_CUR_DUTY_REG,
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&rpipwm->duty_cycle);
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if (ret) {
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dev_err(dev, "Failed to get duty cycle: %pe\n", ERR_PTR(ret));
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return ret;
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}
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return devm_pwmchip_add(dev, &rpipwm->chip);
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}
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static const struct of_device_id raspberrypi_pwm_of_match[] = {
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{ .compatible = "raspberrypi,firmware-poe-pwm", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, raspberrypi_pwm_of_match);
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static struct platform_driver raspberrypi_pwm_driver = {
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.driver = {
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.name = "raspberrypi-poe-pwm",
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.of_match_table = raspberrypi_pwm_of_match,
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},
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.probe = raspberrypi_pwm_probe,
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};
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module_platform_driver(raspberrypi_pwm_driver);
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MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
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MODULE_DESCRIPTION("Raspberry Pi Firmware Based PWM Bus Driver");
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MODULE_LICENSE("GPL v2");
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