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