// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2014 Linaro Ltd * * Author: Ulf Hansson <ulf.hansson@linaro.org> * * Simple MMC power sequence management */ #include <linux/clk.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/platform_device.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/device.h> #include <linux/err.h> #include <linux/gpio/consumer.h> #include <linux/delay.h> #include <linux/property.h> #include <linux/mmc/host.h> #include "pwrseq.h" struct mmc_pwrseq_simple { struct mmc_pwrseq pwrseq; bool clk_enabled; u32 post_power_on_delay_ms; u32 power_off_delay_us; struct clk *ext_clk; struct gpio_descs *reset_gpios; }; #define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq) static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq, int value) { struct gpio_descs *reset_gpios = pwrseq->reset_gpios; if (!IS_ERR(reset_gpios)) { unsigned long *values; int nvalues = reset_gpios->ndescs; values = bitmap_alloc(nvalues, GFP_KERNEL); if (!values) return; if (value) bitmap_fill(values, nvalues); else bitmap_zero(values, nvalues); gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc, reset_gpios->info, values); bitmap_free(values); } } static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host) { struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) { clk_prepare_enable(pwrseq->ext_clk); pwrseq->clk_enabled = true; } mmc_pwrseq_simple_set_gpios_value(pwrseq, 1); } static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host) { struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); mmc_pwrseq_simple_set_gpios_value(pwrseq, 0); if (pwrseq->post_power_on_delay_ms) msleep(pwrseq->post_power_on_delay_ms); } static void mmc_pwrseq_simple_power_off(struct mmc_host *host) { struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); mmc_pwrseq_simple_set_gpios_value(pwrseq, 1); if (pwrseq->power_off_delay_us) usleep_range(pwrseq->power_off_delay_us, 2 * pwrseq->power_off_delay_us); if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) { clk_disable_unprepare(pwrseq->ext_clk); pwrseq->clk_enabled = false; } } static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = { .pre_power_on = mmc_pwrseq_simple_pre_power_on, .post_power_on = mmc_pwrseq_simple_post_power_on, .power_off = mmc_pwrseq_simple_power_off, }; static const struct of_device_id mmc_pwrseq_simple_of_match[] = { { .compatible = "mmc-pwrseq-simple",}, {/* sentinel */}, }; MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match); static int mmc_pwrseq_simple_probe(struct platform_device *pdev) { struct mmc_pwrseq_simple *pwrseq; struct device *dev = &pdev->dev; pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL); if (!pwrseq) return -ENOMEM; pwrseq->ext_clk = devm_clk_get(dev, "ext_clock"); if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT) return dev_err_probe(dev, PTR_ERR(pwrseq->ext_clk), "external clock not ready\n"); pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH); if (IS_ERR(pwrseq->reset_gpios) && PTR_ERR(pwrseq->reset_gpios) != -ENOENT && PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) { return dev_err_probe(dev, PTR_ERR(pwrseq->reset_gpios), "reset GPIOs not ready\n"); } device_property_read_u32(dev, "post-power-on-delay-ms", &pwrseq->post_power_on_delay_ms); device_property_read_u32(dev, "power-off-delay-us", &pwrseq->power_off_delay_us); pwrseq->pwrseq.dev = dev; pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops; pwrseq->pwrseq.owner = THIS_MODULE; platform_set_drvdata(pdev, pwrseq); return mmc_pwrseq_register(&pwrseq->pwrseq); } static void mmc_pwrseq_simple_remove(struct platform_device *pdev) { struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev); mmc_pwrseq_unregister(&pwrseq->pwrseq); } static struct platform_driver mmc_pwrseq_simple_driver = { .probe = mmc_pwrseq_simple_probe, .remove_new = mmc_pwrseq_simple_remove, .driver = { .name = "pwrseq_simple", .of_match_table = mmc_pwrseq_simple_of_match, }, }; module_platform_driver(mmc_pwrseq_simple_driver); MODULE_DESCRIPTION("Simple power sequence management for MMC"); MODULE_LICENSE("GPL v2");