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: Javier Martinez Canillas <javier.martinez@collabora.co.uk> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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3f656a168c
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c13045b1e9
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@ -7,6 +7,7 @@
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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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@ -20,6 +21,8 @@
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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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@ -39,6 +42,11 @@ static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
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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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@ -50,6 +58,19 @@ static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
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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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@ -60,6 +81,9 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host)
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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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@ -67,7 +91,7 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host)
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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_pre_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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@ -85,6 +109,13 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
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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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@ -96,7 +127,7 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
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while (--i)
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gpiod_put(pwrseq->reset_gpios[i]);
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goto free;
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goto clk_put;
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}
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}
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@ -105,6 +136,9 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
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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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