Re: [RFC PATCH 3/3] mmc: pwrseq: convert to proper platform device

From: Ulf Hansson
Date: Tue Jan 19 2016 - 08:01:57 EST

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In reply to: Srinivas Kandagatla: "[RFC PATCH 3/3] mmc: pwrseq: convert to proper platform device"
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On 19 January 2016 at 11:59, Srinivas Kandagatla
<srinivas.kandagatla@xxxxxxxxxx> wrote:
> simple-pwrseq and emmc-pwrseq drivers rely on platform_device
> structure from of_find_device_by_node(), this works mostly. But, as there
> is no driver associated with this devices, cases like default/init pinctrl
> setup would never be performed by pwrseq. This becomes problem when the
> gpios used in pwrseq require pinctrl setup.
>
> Currently most of the common pinctrl setup is done in
> drivers/base/pinctrl.c by pinctrl_bind_pins().
>
> There are two ways to slove this issue on either convert pwrseq drivers
> to a proper platform drivers or copy the exact code from
> pcintrl_bind_pins(). I prefer converting pwrseq to proper drivers so that
> other cases like setting up clks/parents from dt would also be possible.

Overall I like the approach, thanks for posting this!

I have browsed through the patch, it looks okay, besides one issue...

There is a possibility that the pwrseq drivers haven't been probed
before mmc_pwrseq_alloc() gets called. This leads to that the
pwrseq_list may be empty, which means that we would silently fail to
find a corresponding pwrseq type even if the device node would say
there should be one.

Perhaps you should do a pre-validation of the device node in
mmc_pwrseq_alloc(), to see if there is a pwrseq handle. If so, but no
corresponding pwrseq method registerd (because the driver hasnât been
probed yet), you could return -EPROBE_DEFER. Or perhaps there are
other alternatives to solved this issue!?

Kind regards
Uffe

>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> ---
> drivers/mmc/core/pwrseq.c | 99 ++++++++++++++++++++--------------------
> drivers/mmc/core/pwrseq.h | 13 ++++--
> drivers/mmc/core/pwrseq_emmc.c | 65 ++++++++++++++++----------
> drivers/mmc/core/pwrseq_simple.c | 71 ++++++++++++++++++----------
> 4 files changed, 145 insertions(+), 103 deletions(-)
>
> diff --git a/drivers/mmc/core/pwrseq.c b/drivers/mmc/core/pwrseq.c
> index 4c1d175..669608e 100644
> --- a/drivers/mmc/core/pwrseq.c
> +++ b/drivers/mmc/core/pwrseq.c
> @@ -8,50 +8,30 @@
> * MMC power sequence management
> */
> #include <linux/kernel.h>
> -#include <linux/platform_device.h>
> #include <linux/err.h>
> #include <linux/of.h>
> -#include <linux/of_platform.h>
>
> #include <linux/mmc/host.h>
>
> #include "pwrseq.h"
>
> -struct mmc_pwrseq_match {
> - const char *compatible;
> - struct mmc_pwrseq *(*alloc)(struct mmc_host *host, struct device *dev);
> -};
> -
> -static struct mmc_pwrseq_match pwrseq_match[] = {
> - {
> - .compatible = "mmc-pwrseq-simple",
> - .alloc = mmc_pwrseq_simple_alloc,
> - }, {
> - .compatible = "mmc-pwrseq-emmc",
> - .alloc = mmc_pwrseq_emmc_alloc,
> - },
> -};
> -
> -static struct mmc_pwrseq_match *mmc_pwrseq_find(struct device_node *np)
> +static DEFINE_MUTEX(pwrseq_list_mutex);
> +static LIST_HEAD(pwrseq_list);
> +
> +static struct mmc_pwrseq *of_find_mmc_pwrseq(struct device_node *np)
> {
> - struct mmc_pwrseq_match *match = ERR_PTR(-ENODEV);
> - int i;
> + struct mmc_pwrseq *p;
>
> - for (i = 0; i < ARRAY_SIZE(pwrseq_match); i++) {
> - if (of_device_is_compatible(np, pwrseq_match[i].compatible)) {
> - match = &pwrseq_match[i];
> - break;
> - }
> - }
> + list_for_each_entry(p, &pwrseq_list, list)
> + if (p->dev->of_node == np)
> + return p;
>
> - return match;
> + return NULL;
> }
>
> int mmc_pwrseq_alloc(struct mmc_host *host)
> {
> - struct platform_device *pdev;
> struct device_node *np;
> - struct mmc_pwrseq_match *match;
> struct mmc_pwrseq *pwrseq;
> int ret = 0;
>
> @@ -59,25 +39,18 @@ int mmc_pwrseq_alloc(struct mmc_host *host)
> if (!np)
> return 0;
>
> - pdev = of_find_device_by_node(np);
> - if (!pdev) {
> - ret = -ENODEV;
> - goto err;
> - }
> + pwrseq = of_find_mmc_pwrseq(np);
>
> - match = mmc_pwrseq_find(np);
> - if (IS_ERR(match)) {
> - ret = PTR_ERR(match);
> - goto err;
> - }
> + if (pwrseq && pwrseq->ops && pwrseq->ops->alloc) {
> + host->pwrseq = pwrseq;
> + ret = pwrseq->ops->alloc(host);
> + if (IS_ERR_VALUE(ret)) {
> + host->pwrseq = NULL;
> + goto err;
> + }
>
> - pwrseq = match->alloc(host, &pdev->dev);
> - if (IS_ERR(pwrseq)) {
> - ret = PTR_ERR(pwrseq);
> - goto err;
> }
>
> - host->pwrseq = pwrseq;
> dev_info(host->parent, "allocated mmc-pwrseq\n");
>
> err:
> @@ -89,7 +62,7 @@ void mmc_pwrseq_pre_power_on(struct mmc_host *host)
> {
> struct mmc_pwrseq *pwrseq = host->pwrseq;
>
> - if (pwrseq && pwrseq->ops && pwrseq->ops->pre_power_on)
> + if (pwrseq && pwrseq->ops->pre_power_on)
> pwrseq->ops->pre_power_on(host);
> }
>
> @@ -97,7 +70,7 @@ void mmc_pwrseq_post_power_on(struct mmc_host *host)
> {
> struct mmc_pwrseq *pwrseq = host->pwrseq;
>
> - if (pwrseq && pwrseq->ops && pwrseq->ops->post_power_on)
> + if (pwrseq && pwrseq->ops->post_power_on)
> pwrseq->ops->post_power_on(host);
> }
>
> @@ -105,7 +78,7 @@ void mmc_pwrseq_power_off(struct mmc_host *host)
> {
> struct mmc_pwrseq *pwrseq = host->pwrseq;
>
> - if (pwrseq && pwrseq->ops && pwrseq->ops->power_off)
> + if (pwrseq && pwrseq->ops->power_off)
> pwrseq->ops->power_off(host);
> }
>
> @@ -113,8 +86,34 @@ void mmc_pwrseq_free(struct mmc_host *host)
> {
> struct mmc_pwrseq *pwrseq = host->pwrseq;
>
> - if (pwrseq && pwrseq->ops && pwrseq->ops->free)
> - pwrseq->ops->free(host);
> + if (pwrseq) {
> + if (pwrseq->ops->free)
> + pwrseq->ops->free(host);
> +
> + host->pwrseq = NULL;
> + }
>
> - host->pwrseq = NULL;
> }
> +
> +int mmc_pwrseq_register(struct mmc_pwrseq *pwrseq)
> +{
> + if (!pwrseq || !pwrseq->ops || !pwrseq->dev)
> + return -EINVAL;
> +
> + mutex_lock(&pwrseq_list_mutex);
> + list_add(&pwrseq->list, &pwrseq_list);
> + mutex_unlock(&pwrseq_list_mutex);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(mmc_pwrseq_register);
> +
> +void mmc_pwrseq_unregister(struct mmc_pwrseq *pwrseq)
> +{
> + if (pwrseq) {
> + mutex_lock(&pwrseq_list_mutex);
> + list_del(&pwrseq->list);
> + mutex_unlock(&pwrseq_list_mutex);
> + }
> +}
> +EXPORT_SYMBOL_GPL(mmc_pwrseq_unregister);
> diff --git a/drivers/mmc/core/pwrseq.h b/drivers/mmc/core/pwrseq.h
> index 096da48..08a7d2d 100644
> --- a/drivers/mmc/core/pwrseq.h
> +++ b/drivers/mmc/core/pwrseq.h
> @@ -8,7 +8,10 @@
> #ifndef _MMC_CORE_PWRSEQ_H
> #define _MMC_CORE_PWRSEQ_H
>
> +#include <linux/mmc/host.h>
> +
> struct mmc_pwrseq_ops {
> + int (*alloc)(struct mmc_host *host);
> void (*pre_power_on)(struct mmc_host *host);
> void (*post_power_on)(struct mmc_host *host);
> void (*power_off)(struct mmc_host *host);
> @@ -17,21 +20,21 @@ struct mmc_pwrseq_ops {
>
> struct mmc_pwrseq {
> struct mmc_pwrseq_ops *ops;
> + struct device *dev;
> + struct list_head list;
> };
>
> #ifdef CONFIG_OF
>
> +int mmc_pwrseq_register(struct mmc_pwrseq *pwrseq);
> +void mmc_pwrseq_unregister(struct mmc_pwrseq *pwrseq);
> +
> int mmc_pwrseq_alloc(struct mmc_host *host);
> void mmc_pwrseq_pre_power_on(struct mmc_host *host);
> void mmc_pwrseq_post_power_on(struct mmc_host *host);
> void mmc_pwrseq_power_off(struct mmc_host *host);
> void mmc_pwrseq_free(struct mmc_host *host);
>
> -struct mmc_pwrseq *mmc_pwrseq_simple_alloc(struct mmc_host *host,
> - struct device *dev);
> -struct mmc_pwrseq *mmc_pwrseq_emmc_alloc(struct mmc_host *host,
> - struct device *dev);
> -
> #else
>
> static inline int mmc_pwrseq_alloc(struct mmc_host *host) { return 0; }
> diff --git a/drivers/mmc/core/pwrseq_emmc.c b/drivers/mmc/core/pwrseq_emmc.c
> index 7978fb7..75f7423 100644
> --- a/drivers/mmc/core/pwrseq_emmc.c
> +++ b/drivers/mmc/core/pwrseq_emmc.c
> @@ -9,6 +9,7 @@
> */
> #include <linux/delay.h>
> #include <linux/kernel.h>
> +#include <linux/platform_device.h>
> #include <linux/slab.h>
> #include <linux/device.h>
> #include <linux/err.h>
> @@ -48,14 +49,8 @@ static void mmc_pwrseq_emmc_free(struct mmc_host *host)
>
> unregister_restart_handler(&pwrseq->reset_nb);
> gpiod_put(pwrseq->reset_gpio);
> - kfree(pwrseq);
> }
>
> -static struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = {
> - .post_power_on = mmc_pwrseq_emmc_reset,
> - .free = mmc_pwrseq_emmc_free,
> -};
> -
> static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this,
> unsigned long mode, void *cmd)
> {
> @@ -66,21 +61,14 @@ static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this,
> return NOTIFY_DONE;
> }
>
> -struct mmc_pwrseq *mmc_pwrseq_emmc_alloc(struct mmc_host *host,
> - struct device *dev)
> +static int mmc_pwrseq_emmc_alloc(struct mmc_host *host)
> {
> - struct mmc_pwrseq_emmc *pwrseq;
> - int ret = 0;
> -
> - pwrseq = kzalloc(sizeof(struct mmc_pwrseq_emmc), GFP_KERNEL);
> - if (!pwrseq)
> - return ERR_PTR(-ENOMEM);
> + struct mmc_pwrseq_emmc *pwrseq = to_pwrseq_emmc(host->pwrseq);
>
> - pwrseq->reset_gpio = gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> - if (IS_ERR(pwrseq->reset_gpio)) {
> - ret = PTR_ERR(pwrseq->reset_gpio);
> - goto free;
> - }
> + pwrseq->reset_gpio = gpiod_get(host->pwrseq->dev,
> + "reset", GPIOD_OUT_LOW);
> + if (IS_ERR(pwrseq->reset_gpio))
> + return PTR_ERR(pwrseq->reset_gpio);
>
> /*
> * register reset handler to ensure emmc reset also from
> @@ -91,10 +79,41 @@ struct mmc_pwrseq *mmc_pwrseq_emmc_alloc(struct mmc_host *host,
> pwrseq->reset_nb.priority = 255;
> register_restart_handler(&pwrseq->reset_nb);
>
> + return 0;
> +}
> +
> +static struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = {
> + .alloc = mmc_pwrseq_emmc_alloc,
> + .post_power_on = mmc_pwrseq_emmc_reset,
> + .free = mmc_pwrseq_emmc_free,
> +};
> +
> +static int mmc_pwrseq_emmc_probe(struct platform_device *pdev)
> +{
> + struct mmc_pwrseq_emmc *pwrseq;
> + struct device *dev = &pdev->dev;
> +
> + pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
> + if (!pwrseq)
> + return -ENOMEM;
> +
> pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops;
> + pwrseq->pwrseq.dev = dev;
>
> - return &pwrseq->pwrseq;
> -free:
> - kfree(pwrseq);
> - return ERR_PTR(ret);
> + return mmc_pwrseq_register(&pwrseq->pwrseq);
> }
> +
> +static const struct of_device_id mmc_pwrseq_emmc_of_match[] = {
> + { .compatible = "mmc-pwrseq-emmc",},
> + {/* sentinel */},
> +};
> +
> +static struct platform_driver mmc_pwrseq_emmc_driver = {
> + .probe = mmc_pwrseq_emmc_probe,
> + .driver = {
> + .name = "pwrseq_emmc",
> + .of_match_table = mmc_pwrseq_emmc_of_match,
> + },
> +};
> +
> +builtin_platform_driver(mmc_pwrseq_emmc_driver);
> diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c
> index c091f98..b04cc2d 100644
> --- a/drivers/mmc/core/pwrseq_simple.c
> +++ b/drivers/mmc/core/pwrseq_simple.c
> @@ -9,6 +9,7 @@
> */
> #include <linux/clk.h>
> #include <linux/kernel.h>
> +#include <linux/platform_device.h>
> #include <linux/slab.h>
> #include <linux/device.h>
> #include <linux/err.h>
> @@ -82,46 +83,66 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host)
> if (!IS_ERR(pwrseq->ext_clk))
> clk_put(pwrseq->ext_clk);
>
> - kfree(pwrseq);
> }
>
> -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,
> -};
> -
> -struct mmc_pwrseq *mmc_pwrseq_simple_alloc(struct mmc_host *host,
> - struct device *dev)
> +int mmc_pwrseq_simple_alloc(struct mmc_host *host)
> {
> - struct mmc_pwrseq_simple *pwrseq;
> + struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
> + struct device *dev = host->pwrseq->dev;
> int ret = 0;
>
> - pwrseq = kzalloc(sizeof(*pwrseq), GFP_KERNEL);
> - if (!pwrseq)
> - return ERR_PTR(-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;
> + return PTR_ERR(pwrseq->ext_clk);
> +
> }
>
> pwrseq->reset_gpios = gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH);
> if (IS_ERR(pwrseq->reset_gpios)) {
> ret = PTR_ERR(pwrseq->reset_gpios);
> - goto clk_put;
> + clk_put(pwrseq->ext_clk);
> + return ret;
> }
>
> + return 0;
> +}
> +
> +static struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
> + .alloc = mmc_pwrseq_simple_alloc,
> + .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,
> +};
> +
> +static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
> + { .compatible = "mmc-pwrseq-simple",},
> + {/* sentinel */},
> +};
> +
> +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 ERR_PTR(-ENOMEM);
> +
> + pwrseq->pwrseq.dev = dev;
> pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
>
> - return &pwrseq->pwrseq;
> -clk_put:
> - if (!IS_ERR(pwrseq->ext_clk))
> - clk_put(pwrseq->ext_clk);
> -free:
> - kfree(pwrseq);
> - return ERR_PTR(ret);
> + return mmc_pwrseq_register(&pwrseq->pwrseq);
> }
> +
> +
> +static struct platform_driver mmc_pwrseq_simple_driver = {
> + .probe = mmc_pwrseq_simple_probe,
> + .driver = {
> + .name = "pwrseq_simple",
> + .of_match_table = mmc_pwrseq_simple_of_match,
> + },
> +};
> +
> +builtin_platform_driver(mmc_pwrseq_simple_driver);
> --
> 1.9.1
>

Next message: Kalle Valo: "Re: [PATCH, RESEND^2] ssb: mark ssb_bus_register as __maybe_unused"
Previous message: Namhyung Kim: "Re: [RFC 00/26] perf tools: Introduce hists specific format entries"
In reply to: Srinivas Kandagatla: "[RFC PATCH 3/3] mmc: pwrseq: convert to proper platform device"
Next in thread: Srinivas Kandagatla: "Re: [RFC PATCH 3/3] mmc: pwrseq: convert to proper platform device"
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