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>
145 lines
3.5 KiB
C
145 lines
3.5 KiB
C
/*
|
|
* Copyright (C) 2014 Linaro Ltd
|
|
*
|
|
* Author: Ulf Hansson <ulf.hansson@linaro.org>
|
|
*
|
|
* License terms: GNU General Public License (GPL) version 2
|
|
*
|
|
* Simple MMC power sequence management
|
|
*/
|
|
#include <linux/clk.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/device.h>
|
|
#include <linux/err.h>
|
|
#include <linux/of_gpio.h>
|
|
#include <linux/gpio/consumer.h>
|
|
|
|
#include <linux/mmc/host.h>
|
|
|
|
#include "pwrseq.h"
|
|
|
|
struct mmc_pwrseq_simple {
|
|
struct mmc_pwrseq pwrseq;
|
|
bool clk_enabled;
|
|
struct clk *ext_clk;
|
|
int nr_gpios;
|
|
struct gpio_desc *reset_gpios[0];
|
|
};
|
|
|
|
static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
|
|
int value)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < pwrseq->nr_gpios; i++)
|
|
if (!IS_ERR(pwrseq->reset_gpios[i]))
|
|
gpiod_set_value_cansleep(pwrseq->reset_gpios[i], value);
|
|
}
|
|
|
|
static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
|
|
{
|
|
struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
|
|
struct mmc_pwrseq_simple, 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 = container_of(host->pwrseq,
|
|
struct mmc_pwrseq_simple, pwrseq);
|
|
|
|
mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
|
|
}
|
|
|
|
static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
|
|
{
|
|
struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
|
|
struct mmc_pwrseq_simple, pwrseq);
|
|
|
|
mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
|
|
|
|
if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
|
|
clk_disable_unprepare(pwrseq->ext_clk);
|
|
pwrseq->clk_enabled = false;
|
|
}
|
|
}
|
|
|
|
static void mmc_pwrseq_simple_free(struct mmc_host *host)
|
|
{
|
|
struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
|
|
struct mmc_pwrseq_simple, pwrseq);
|
|
int i;
|
|
|
|
for (i = 0; i < pwrseq->nr_gpios; i++)
|
|
if (!IS_ERR(pwrseq->reset_gpios[i]))
|
|
gpiod_put(pwrseq->reset_gpios[i]);
|
|
|
|
if (!IS_ERR(pwrseq->ext_clk))
|
|
clk_put(pwrseq->ext_clk);
|
|
|
|
kfree(pwrseq);
|
|
host->pwrseq = NULL;
|
|
}
|
|
|
|
static 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,
|
|
.free = mmc_pwrseq_simple_free,
|
|
};
|
|
|
|
int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
|
|
{
|
|
struct mmc_pwrseq_simple *pwrseq;
|
|
int i, nr_gpios, ret = 0;
|
|
|
|
nr_gpios = of_gpio_named_count(dev->of_node, "reset-gpios");
|
|
if (nr_gpios < 0)
|
|
nr_gpios = 0;
|
|
|
|
pwrseq = kzalloc(sizeof(struct mmc_pwrseq_simple) + nr_gpios *
|
|
sizeof(struct gpio_desc *), GFP_KERNEL);
|
|
if (!pwrseq)
|
|
return -ENOMEM;
|
|
|
|
pwrseq->ext_clk = clk_get(dev, "ext_clock");
|
|
if (IS_ERR(pwrseq->ext_clk) &&
|
|
PTR_ERR(pwrseq->ext_clk) != -ENOENT) {
|
|
ret = PTR_ERR(pwrseq->ext_clk);
|
|
goto free;
|
|
}
|
|
|
|
for (i = 0; i < nr_gpios; i++) {
|
|
pwrseq->reset_gpios[i] = gpiod_get_index(dev, "reset", i,
|
|
GPIOD_OUT_HIGH);
|
|
if (IS_ERR(pwrseq->reset_gpios[i]) &&
|
|
PTR_ERR(pwrseq->reset_gpios[i]) != -ENOENT &&
|
|
PTR_ERR(pwrseq->reset_gpios[i]) != -ENOSYS) {
|
|
ret = PTR_ERR(pwrseq->reset_gpios[i]);
|
|
|
|
while (--i)
|
|
gpiod_put(pwrseq->reset_gpios[i]);
|
|
|
|
goto clk_put;
|
|
}
|
|
}
|
|
|
|
pwrseq->nr_gpios = nr_gpios;
|
|
pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
|
|
host->pwrseq = &pwrseq->pwrseq;
|
|
|
|
return 0;
|
|
clk_put:
|
|
if (!IS_ERR(pwrseq->ext_clk))
|
|
clk_put(pwrseq->ext_clk);
|
|
free:
|
|
kfree(pwrseq);
|
|
return ret;
|
|
}
|