diff options
Diffstat (limited to 'drivers/mmc/core/pwrseq_simple.c')
| -rw-r--r-- | drivers/mmc/core/pwrseq_simple.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c new file mode 100644 index 000000000..988467fbb --- /dev/null +++ b/drivers/mmc/core/pwrseq_simple.c @@ -0,0 +1,164 @@ +// 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 PTR_ERR(pwrseq->ext_clk); + + 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 PTR_ERR(pwrseq->reset_gpios); + } + + 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 int mmc_pwrseq_simple_remove(struct platform_device *pdev) +{ + struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev); + + mmc_pwrseq_unregister(&pwrseq->pwrseq); + + return 0; +} + +static struct platform_driver mmc_pwrseq_simple_driver = { + .probe = mmc_pwrseq_simple_probe, + .remove = mmc_pwrseq_simple_remove, + .driver = { + .name = "pwrseq_simple", + .of_match_table = mmc_pwrseq_simple_of_match, + }, +}; + +module_platform_driver(mmc_pwrseq_simple_driver); +MODULE_LICENSE("GPL v2"); |