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c13045b1e9
Some WLAN chips attached to a SDIO interface, need a reference clock. Since this is very common, extend the prseq_simple driver to support an optional clock that is enabled prior the card power up procedure. Note: the external clock is optional. Thus an error is not returned if the clock is not found. Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
146 lines
3.5 KiB
C
146 lines
3.5 KiB
C
/*
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* Copyright (C) 2014 Linaro Ltd
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*
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* Author: Ulf Hansson <ulf.hansson@linaro.org>
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*
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* License terms: GNU General Public License (GPL) version 2
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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/kernel.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/of_gpio.h>
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#include <linux/gpio/consumer.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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struct clk *ext_clk;
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int nr_gpios;
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struct gpio_desc *reset_gpios[0];
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};
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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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int i;
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for (i = 0; i < pwrseq->nr_gpios; i++)
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if (!IS_ERR(pwrseq->reset_gpios[i]))
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gpiod_set_value_cansleep(pwrseq->reset_gpios[i], value);
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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 = container_of(host->pwrseq,
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struct mmc_pwrseq_simple, 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 = container_of(host->pwrseq,
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struct mmc_pwrseq_simple, pwrseq);
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mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
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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 = container_of(host->pwrseq,
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struct mmc_pwrseq_simple, pwrseq);
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mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
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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 void mmc_pwrseq_simple_free(struct mmc_host *host)
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{
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struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
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struct mmc_pwrseq_simple, pwrseq);
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int i;
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for (i = 0; i < pwrseq->nr_gpios; i++)
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if (!IS_ERR(pwrseq->reset_gpios[i]))
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gpiod_put(pwrseq->reset_gpios[i]);
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if (!IS_ERR(pwrseq->ext_clk))
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clk_put(pwrseq->ext_clk);
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kfree(pwrseq);
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host->pwrseq = NULL;
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}
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static 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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.free = mmc_pwrseq_simple_free,
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};
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int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
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{
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struct mmc_pwrseq_simple *pwrseq;
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int i, nr_gpios, ret = 0;
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nr_gpios = of_gpio_named_count(dev->of_node, "reset-gpios");
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if (nr_gpios < 0)
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nr_gpios = 0;
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pwrseq = kzalloc(sizeof(struct mmc_pwrseq_simple) + nr_gpios *
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sizeof(struct gpio_desc *), GFP_KERNEL);
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if (!pwrseq)
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return -ENOMEM;
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pwrseq->ext_clk = clk_get(dev, "ext_clock");
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if (IS_ERR(pwrseq->ext_clk) &&
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PTR_ERR(pwrseq->ext_clk) != -ENOENT) {
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ret = PTR_ERR(pwrseq->ext_clk);
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goto free;
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}
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for (i = 0; i < nr_gpios; i++) {
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pwrseq->reset_gpios[i] = gpiod_get_index(dev, "reset", i,
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GPIOD_OUT_HIGH);
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if (IS_ERR(pwrseq->reset_gpios[i]) &&
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PTR_ERR(pwrseq->reset_gpios[i]) != -ENOENT &&
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PTR_ERR(pwrseq->reset_gpios[i]) != -ENOSYS) {
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ret = PTR_ERR(pwrseq->reset_gpios[i]);
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while (--i)
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gpiod_put(pwrseq->reset_gpios[i]);
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goto clk_put;
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}
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}
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pwrseq->nr_gpios = nr_gpios;
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pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
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host->pwrseq = &pwrseq->pwrseq;
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return 0;
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clk_put:
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if (!IS_ERR(pwrseq->ext_clk))
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clk_put(pwrseq->ext_clk);
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free:
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kfree(pwrseq);
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return ret;
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}
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