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Commit c13045b1 authored by Javier Martinez Canillas's avatar Javier Martinez Canillas Committed by Ulf Hansson
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mmc: pwrseq_simple: Add optional reference clock support 



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: default avatarJavier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 3f656a16

drivers/mmc/core/pwrseq_simple.c

+36 −2
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
 *

 *  Simple MMC power sequence management

 */

#include <linux/clk.h>

#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/device.h>
@@ -20,6 +21,8 @@ 


struct mmc_pwrseq_simple {

	struct mmc_pwrseq pwrseq;

	bool clk_enabled;

	struct clk *ext_clk;

	int nr_gpios;

	struct gpio_desc *reset_gpios[0];

};
@@ -39,6 +42,11 @@ 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);

}
@@ -50,6 +58,19 @@ static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host) 
	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,
@@ -60,6 +81,9 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host) 
		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;

}
@@ -67,7 +91,7 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host) 
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_pre_power_on,

	.power_off = mmc_pwrseq_simple_power_off,

	.free = mmc_pwrseq_simple_free,

};
@@ -85,6 +109,13 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev) 
	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);
@@ -96,7 +127,7 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev) 
			while (--i)

				gpiod_put(pwrseq->reset_gpios[i]);



			goto free;

			goto clk_put;

		}

	}
@@ -105,6 +136,9 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev) 
	host->pwrseq = &pwrseq->pwrseq;



	return 0;

clk_put:

	if (!IS_ERR(pwrseq->ext_clk))

		clk_put(pwrseq->ext_clk);

free:

	kfree(pwrseq);

	return ret;