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Date: Sat, 6 Feb 2016 21:18:43 +0200
From: Jyri Sarha <jsarha@...com>
To: Stephen Boyd <sboyd@...eaurora.org>,
Mike Turquette <mturquette@...libre.com>
CC: <linux-kernel@...r.kernel.org>,
<"linux-arm-kernel@...ts.infradead.orglinux-clk"@vger.kernel.org>,
Sergej Sawazki <ce3a@....de>,
Russell King <rmk+kernel@....linux.org.uk>,
Fabio Estevam <fabio.estevam@...escale.com>,
Jon Nettleton <jon@...id-run.com>,
Shawn Guo <shawn.guo@...aro.org>
Subject: Re: [PATCH v2] clk: gpio: Make into a platform driver
On 02/03/16 23:10, Stephen Boyd wrote:
> clk_get() for DT based clks already returns EPROBE_DEFER when the
> OF clk provider is not present. So having all this code in the
> clk provider to return EPROBE_DEFER when the gpio isn't ready yet
> can be replaced with a platform driver that doesn't add the clk
> provider until the gpio can be requested. Get rid of the
> OF_CLK_DECLARE and convert this to a platform driver instead.
>
> Cc: Jyri Sarha <jsarha@...com>
> Cc: Sergej Sawazki <ce3a@....de>
> Cc: Russell King <rmk+kernel@....linux.org.uk>
> Cc: Fabio Estevam <fabio.estevam@...escale.com>
> Cc: Jon Nettleton <jon@...id-run.com>
> Cc: Shawn Guo <shawn.guo@...aro.org>
> Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
The gate clock works for Beaglebone-black HDMI audio.
Tested-by: Jyri Sarha <jsarha@...com>
> ---
>
> Changes from v1:
> * Fix build error by removing unused module device table
>
> drivers/clk/clk-gpio.c | 165 ++++++++++++++++---------------------------------
> 1 file changed, 52 insertions(+), 113 deletions(-)
>
> diff --git a/drivers/clk/clk-gpio.c b/drivers/clk/clk-gpio.c
> index cbbea2985cc9..fb32a7366ef6 100644
> --- a/drivers/clk/clk-gpio.c
> +++ b/drivers/clk/clk-gpio.c
> @@ -20,6 +20,8 @@
> #include <linux/of_gpio.h>
> #include <linux/err.h>
> #include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/of_device.h>
>
> /**
> * DOC: basic gpio gated clock which can be enabled and disabled
> @@ -199,134 +201,71 @@ struct clk *clk_register_gpio_mux(struct device *dev, const char *name,
> }
> EXPORT_SYMBOL_GPL(clk_register_gpio_mux);
>
> -#ifdef CONFIG_OF
> -/**
> - * clk_register_get() has to be delayed, because -EPROBE_DEFER
> - * can not be handled properly at of_clk_init() call time.
> - */
> -
> -struct clk_gpio_delayed_register_data {
> - const char *gpio_name;
> - int num_parents;
> - const char **parent_names;
> - struct device_node *node;
> - struct mutex lock;
> - struct clk *clk;
> - struct clk *(*clk_register_get)(const char *name,
> - const char * const *parent_names, u8 num_parents,
> - unsigned gpio, bool active_low);
> -};
> -
> -static struct clk *of_clk_gpio_delayed_register_get(
> - struct of_phandle_args *clkspec, void *_data)
> +static int gpio_clk_driver_probe(struct platform_device *pdev)
> {
> - struct clk_gpio_delayed_register_data *data = _data;
> - struct clk *clk;
> - int gpio;
> + struct device_node *node = pdev->dev.of_node;
> + const char **parent_names, *gpio_name;
> + int num_parents, gpio;
> enum of_gpio_flags of_flags;
> + struct clk *clk;
> + bool active_low, is_mux;
> +
> + num_parents = of_clk_get_parent_count(node);
> + if (num_parents < 0)
> + return -EINVAL;
>
> - mutex_lock(&data->lock);
> + if (num_parents) {
> + parent_names = devm_kcalloc(&pdev->dev, num_parents,
> + sizeof(char *), GFP_KERNEL);
> + if (!parent_names)
> + return -ENOMEM;
>
> - if (data->clk) {
> - mutex_unlock(&data->lock);
> - return data->clk;
> + of_clk_parent_fill(node, parent_names, num_parents);
> + } else {
> + parent_names = NULL;
> }
>
> - gpio = of_get_named_gpio_flags(data->node, data->gpio_name, 0,
> - &of_flags);
> + is_mux = of_device_is_compatible(node, "gpio-mux-clock");
> +
> + gpio_name = is_mux ? "select-gpios" : "enable-gpios";
> + gpio = of_get_named_gpio_flags(node, gpio_name, 0, &of_flags);
> if (gpio < 0) {
> - mutex_unlock(&data->lock);
> if (gpio == -EPROBE_DEFER)
> pr_debug("%s: %s: GPIOs not yet available, retry later\n",
> - data->node->name, __func__);
> + node->name, __func__);
> else
> pr_err("%s: %s: Can't get '%s' DT property\n",
> - data->node->name, __func__,
> - data->gpio_name);
> - return ERR_PTR(gpio);
> + node->name, __func__,
> + gpio_name);
> + return gpio;
> }
>
> - clk = data->clk_register_get(data->node->name, data->parent_names,
> - data->num_parents, gpio, of_flags & OF_GPIO_ACTIVE_LOW);
> - if (IS_ERR(clk))
> - goto out;
> -
> - data->clk = clk;
> -out:
> - mutex_unlock(&data->lock);
> -
> - return clk;
> -}
> -
> -static struct clk *of_clk_gpio_gate_delayed_register_get(const char *name,
> - const char * const *parent_names, u8 num_parents,
> - unsigned gpio, bool active_low)
> -{
> - return clk_register_gpio_gate(NULL, name, parent_names ?
> - parent_names[0] : NULL, gpio, active_low, 0);
> -}
> -
> -static struct clk *of_clk_gpio_mux_delayed_register_get(const char *name,
> - const char * const *parent_names, u8 num_parents, unsigned gpio,
> - bool active_low)
> -{
> - return clk_register_gpio_mux(NULL, name, parent_names, num_parents,
> - gpio, active_low, 0);
> -}
> -
> -static void __init of_gpio_clk_setup(struct device_node *node,
> - const char *gpio_name,
> - struct clk *(*clk_register_get)(const char *name,
> - const char * const *parent_names,
> - u8 num_parents,
> - unsigned gpio, bool active_low))
> -{
> - struct clk_gpio_delayed_register_data *data;
> - const char **parent_names;
> - int i, num_parents;
> -
> - num_parents = of_clk_get_parent_count(node);
> - if (num_parents < 0)
> - return;
> -
> - data = kzalloc(sizeof(*data), GFP_KERNEL);
> - if (!data)
> - return;
> + active_low = of_flags & OF_GPIO_ACTIVE_LOW;
>
> - if (num_parents) {
> - parent_names = kcalloc(num_parents, sizeof(char *), GFP_KERNEL);
> - if (!parent_names) {
> - kfree(data);
> - return;
> - }
> -
> - for (i = 0; i < num_parents; i++)
> - parent_names[i] = of_clk_get_parent_name(node, i);
> - } else {
> - parent_names = NULL;
> - }
> -
> - data->num_parents = num_parents;
> - data->parent_names = parent_names;
> - data->node = node;
> - data->gpio_name = gpio_name;
> - data->clk_register_get = clk_register_get;
> - mutex_init(&data->lock);
> + if (is_mux)
> + clk = clk_register_gpio_mux(&pdev->dev, node->name,
> + parent_names, num_parents, gpio, active_low, 0);
> + else
> + clk = clk_register_gpio_gate(&pdev->dev, node->name,
> + parent_names ? parent_names[0] : NULL, gpio,
> + active_low, 0);
> + if (IS_ERR(clk))
> + return PTR_ERR(clk);
>
> - of_clk_add_provider(node, of_clk_gpio_delayed_register_get, data);
> + return of_clk_add_provider(node, of_clk_src_simple_get, clk);
> }
>
> -static void __init of_gpio_gate_clk_setup(struct device_node *node)
> -{
> - of_gpio_clk_setup(node, "enable-gpios",
> - of_clk_gpio_gate_delayed_register_get);
> -}
> -CLK_OF_DECLARE(gpio_gate_clk, "gpio-gate-clock", of_gpio_gate_clk_setup);
> +static const struct of_device_id gpio_clk_match_table[] = {
> + { .compatible = "gpio-mux-clock" },
> + { .compatible = "gpio-gate-clock" },
> + { }
> +};
>
> -void __init of_gpio_mux_clk_setup(struct device_node *node)
> -{
> - of_gpio_clk_setup(node, "select-gpios",
> - of_clk_gpio_mux_delayed_register_get);
> -}
> -CLK_OF_DECLARE(gpio_mux_clk, "gpio-mux-clock", of_gpio_mux_clk_setup);
> -#endif
> +static struct platform_driver gpio_clk_driver = {
> + .probe = gpio_clk_driver_probe,
> + .driver = {
> + .name = "gpio-clk",
> + .of_match_table = gpio_clk_match_table,
> + },
> +};
> +builtin_platform_driver(gpio_clk_driver);
>
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