Quoting Andrew Bresticker (2013-09-25 14:12:47)
> The Exynos AudioSS clock controller will later be modified to allow
> input clocks to be specified via device-tree in order to support
> multiple Exynos SoCs. This will introduce a dependency on the core
> SoC clock controller being initialized first so that the AudioSS driver
> can look up its input clocks, but the order in which clock providers
> are probed in of_clk_init() is not guaranteed. Since deferred probing
> is not supported in of_clk_init() and the AudioSS block is not the core
> controller, we can initialize it later as a platform device.
>
> Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
> Acked-by: Tomasz Figa <t.figa@xxxxxxxxxxx>
> Reviewed-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
Acked-by: Mike Turquette <mturquette@xxxxxxxxxx>
> ---
> Changes since v3:
> - __init -> __exit for module exit function
> - fixed nits from Sylwester
> Changes since v2:
> - add error handling to probe callback
> - fixed ordering of of_clk_{add,del}_provider
> - fixed nits from Tomasz and Sylwester
> Changes since v1:
> - add clk_unregister() calls to remove callback
> - fixed minor nits from Tomasz
> ---
> drivers/clk/samsung/clk-exynos-audss.c | 104 ++++++++++++++++++++++++++++-----
> 1 file changed, 88 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/clk/samsung/clk-exynos-audss.c b/drivers/clk/samsung/clk-exynos-audss.c
> index 39b40aa..742dabc 100644
> --- a/drivers/clk/samsung/clk-exynos-audss.c
> +++ b/drivers/clk/samsung/clk-exynos-audss.c
> @@ -14,6 +14,8 @@
> #include <linux/clk-provider.h>
> #include <linux/of_address.h>
> #include <linux/syscore_ops.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
>
> #include <dt-bindings/clk/exynos-audss-clk.h>
>
> @@ -62,24 +64,26 @@ static struct syscore_ops exynos_audss_clk_syscore_ops = {
> #endif /* CONFIG_PM_SLEEP */
>
> /* register exynos_audss clocks */
> -static void __init exynos_audss_clk_init(struct device_node *np)
> +static int exynos_audss_clk_probe(struct platform_device *pdev)
> {
> - reg_base = of_iomap(np, 0);
> - if (!reg_base) {
> - pr_err("%s: failed to map audss registers\n", __func__);
> - return;
> + int i, ret = 0;
> + struct resource *res;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + reg_base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(reg_base)) {
> + dev_err(&pdev->dev, "failed to map audss registers\n");
> + return PTR_ERR(reg_base);
> }
>
> - clk_table = kzalloc(sizeof(struct clk *) * EXYNOS_AUDSS_MAX_CLKS,
> + clk_table = devm_kzalloc(&pdev->dev,
> + sizeof(struct clk *) * EXYNOS_AUDSS_MAX_CLKS,
> GFP_KERNEL);
> - if (!clk_table) {
> - pr_err("%s: could not allocate clk lookup table\n", __func__);
> - return;
> - }
> + if (!clk_table)
> + return -ENOMEM;
>
> clk_data.clks = clk_table;
> clk_data.clk_num = EXYNOS_AUDSS_MAX_CLKS;
> - of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
>
> clk_table[EXYNOS_MOUT_AUDSS] = clk_register_mux(NULL, "mout_audss",
> mout_audss_p, ARRAY_SIZE(mout_audss_p),
> @@ -123,13 +127,81 @@ static void __init exynos_audss_clk_init(struct device_node *np)
> "div_pcm0", CLK_SET_RATE_PARENT,
> reg_base + ASS_CLK_GATE, 5, 0, &lock);
>
> + for (i = 0; i < clk_data.clk_num; i++) {
> + if (IS_ERR(clk_table[i])) {
> + dev_err(&pdev->dev, "failed to register clock %d\n", i);
> + ret = PTR_ERR(clk_table[i]);
> + goto unregister;
> + }
> + }
> +
> + ret = of_clk_add_provider(pdev->dev.of_node, of_clk_src_onecell_get,
> + &clk_data);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to add clock provider\n");
> + goto unregister;
> + }
> +
> #ifdef CONFIG_PM_SLEEP
> register_syscore_ops(&exynos_audss_clk_syscore_ops);
> #endif
>
> - pr_info("Exynos: Audss: clock setup completed\n");
> + dev_info(&pdev->dev, "setup completed\n");
> +
> + return 0;
> +
> +unregister:
> + for (i = 0; i < clk_data.clk_num; i++) {
> + if (!IS_ERR(clk_table[i]))
> + clk_unregister(clk_table[i]);
> + }
> +
> + return ret;
> +}
> +
> +static int exynos_audss_clk_remove(struct platform_device *pdev)
> +{
> + int i;
> +
> + of_clk_del_provider(pdev->dev.of_node);
> +
> + for (i = 0; i < clk_data.clk_num; i++) {
> + if (!IS_ERR(clk_table[i]))
> + clk_unregister(clk_table[i]);
> + }
> +
> + return 0;
> }
> -CLK_OF_DECLARE(exynos4210_audss_clk, "samsung,exynos4210-audss-clock",
> - exynos_audss_clk_init);
> -CLK_OF_DECLARE(exynos5250_audss_clk, "samsung,exynos5250-audss-clock",
> - exynos_audss_clk_init);
> +
> +static const struct of_device_id exynos_audss_clk_of_match[] = {
> + { .compatible = "samsung,exynos4210-audss-clock", },
> + { .compatible = "samsung,exynos5250-audss-clock", },
> + {},
> +};
> +
> +static struct platform_driver exynos_audss_clk_driver = {
> + .driver = {
> + .name = "exynos-audss-clk",
> + .owner = THIS_MODULE,
> + .of_match_table = exynos_audss_clk_of_match,
> + },
> + .probe = exynos_audss_clk_probe,
> + .remove = exynos_audss_clk_remove,
> +};
> +
> +static int __init exynos_audss_clk_init(void)
> +{
> + return platform_driver_register(&exynos_audss_clk_driver);
> +}
> +core_initcall(exynos_audss_clk_init);
> +
> +static void __exit exynos_audss_clk_exit(void)
> +{
> + platform_driver_unregister(&exynos_audss_clk_driver);
> +}
> +module_exit(exynos_audss_clk_exit);
> +
> +MODULE_AUTHOR("Padmavathi Venna <padma.v@xxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Exynos Audio Subsystem Clock Controller");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:exynos-audss-clk");
> --
> 1.8.4
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