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Subject: Re: [PATCH 2/7] soc: davinci: new genpd driver
To:     Bartosz Golaszewski <brgl@bgdev.pl>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Sekhar Nori <nsekhar@ti.com>,
        Kevin Hilman <khilman@kernel.org>,
        Russell King <linux@armlinux.org.uk>
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>
References: <20180207134553.13510-1-brgl@bgdev.pl>
 <20180207134553.13510-3-brgl@bgdev.pl>
From:   David Lechner <david@lechnology.com>
Message-ID: <42938acb-7ad3-f19a-29d5-79151a7b7f4b@lechnology.com>
Date:   Wed, 7 Feb 2018 15:49:40 -0600
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On 02/07/2018 07:45 AM, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> 
> Add a simple clock_pm-based driver for DaVinci SoCs. This is required
> to complete the transision to using the common clock framework for this
> architecture.
> 
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>   drivers/soc/Kconfig                      |   1 +
>   drivers/soc/Makefile                     |   1 +
>   drivers/soc/davinci/Kconfig              |  16 ++++
>   drivers/soc/davinci/Makefile             |   1 +
>   drivers/soc/davinci/davinci_pm_domains.c | 125 +++++++++++++++++++++++++++++++
>   5 files changed, 144 insertions(+)
>   create mode 100644 drivers/soc/davinci/Kconfig
>   create mode 100644 drivers/soc/davinci/Makefile
>   create mode 100644 drivers/soc/davinci/davinci_pm_domains.c
> 
> diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
> index fc9e98047421..f318899a6cf6 100644
> --- a/drivers/soc/Kconfig
> +++ b/drivers/soc/Kconfig
> @@ -4,6 +4,7 @@ source "drivers/soc/actions/Kconfig"
>   source "drivers/soc/amlogic/Kconfig"
>   source "drivers/soc/atmel/Kconfig"
>   source "drivers/soc/bcm/Kconfig"
> +source "drivers/soc/davinci/Kconfig"
>   source "drivers/soc/fsl/Kconfig"
>   source "drivers/soc/imx/Kconfig"
>   source "drivers/soc/mediatek/Kconfig"
> diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
> index deecb16e7256..8e5fe23d6678 100644
> --- a/drivers/soc/Makefile
> +++ b/drivers/soc/Makefile
> @@ -8,6 +8,7 @@ obj-$(CONFIG_ARCH_AT91)		+= atmel/
>   obj-y				+= bcm/
>   obj-$(CONFIG_ARCH_DOVE)		+= dove/
>   obj-$(CONFIG_MACH_DOVE)		+= dove/
> +obj-$(CONFIG_ARCH_DAVINCI)	+= davinci/
>   obj-y				+= fsl/
>   obj-$(CONFIG_ARCH_MXC)		+= imx/
>   obj-$(CONFIG_SOC_XWAY)		+= lantiq/
> diff --git a/drivers/soc/davinci/Kconfig b/drivers/soc/davinci/Kconfig
> new file mode 100644
> index 000000000000..7ee44f4ff41e
> --- /dev/null
> +++ b/drivers/soc/davinci/Kconfig
> @@ -0,0 +1,16 @@
> +#
> +# TI DaVinci SOC drivers
> +#
> +menuconfig SOC_DAVINCI
> +	bool "TI DaVinci SOC drivers support"
> +
> +if SOC_DAVINCI
> +
> +config DAVINCI_PM_DOMAINS
> +	tristate "TI DaVinci PM Domains Driver"
> +	depends on ARCH_DAVINCI
> +	depends on PM_GENERIC_DOMAINS
> +	help
> +	  Generic power domains driver for TI DaVinci family of SoCs.
> +
> +endif # SOC_DAVINCI
> diff --git a/drivers/soc/davinci/Makefile b/drivers/soc/davinci/Makefile
> new file mode 100644
> index 000000000000..822b03c18260
> --- /dev/null
> +++ b/drivers/soc/davinci/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_DAVINCI_PM_DOMAINS)        += davinci_pm_domains.o
> diff --git a/drivers/soc/davinci/davinci_pm_domains.c b/drivers/soc/davinci/davinci_pm_domains.c
> new file mode 100644
> index 000000000000..c27d4c404d52
> --- /dev/null
> +++ b/drivers/soc/davinci/davinci_pm_domains.c
> @@ -0,0 +1,125 @@
> +/*
> + * TI DaVinci Generic Power Domain Driver
> + *
> + * Copyright (C) 2018 BayLibre SAS
> + *         Bartosz Golaszewski <bgolaszewski@baylibre.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/clk.h>
> +#include <linux/pm_domain.h>
> +#include <linux/pm_clock.h>
> +
> +struct davinci_genpd_ctx {
> +	struct device *dev;
> +	struct generic_pm_domain pd;
> +	struct clk *pm_clk;
> +};
> +
> +static int davinci_genpd_attach_dev(struct generic_pm_domain *domain,
> +				    struct device *dev)
> +{
> +	struct davinci_genpd_ctx *ctx;
> +	struct clk *clk;
> +	int rv;
> +
> +	ctx = container_of(domain, struct davinci_genpd_ctx, pd);
> +
> +	if (dev->pm_domain)
> +		return -EEXIST;
> +
> +	/*
> +	 * DaVinci always uses a single clock for power-management. We assume
> +	 * it's the first one in the clocks property.
> +	 */
> +	clk = of_clk_get(dev->of_node, 0);
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	rv = pm_clk_create(dev);
> +	if (rv) {
> +		clk_put(clk);
> +		return rv;
> +	}
> +
> +	rv = pm_clk_add_clk(dev, clk);
> +	if (rv) {
> +		pm_clk_destroy(dev);
> +		return rv;
> +	}
> +
> +	dev_pm_domain_set(dev, &domain->domain);
> +	ctx->pm_clk = clk;
> +
> +	return 0;
> +}
> +
> +static void davinci_genpd_detach_dev(struct generic_pm_domain *domain,
> +				     struct device *dev)
> +{
> +	struct davinci_genpd_ctx *ctx;
> +
> +	ctx = container_of(domain, struct davinci_genpd_ctx, pd);
> +
> +	pm_clk_remove_clk(dev, ctx->pm_clk);
> +	pm_clk_destroy(dev);
> +}
> +
> +static const struct of_device_id davinci_genpd_matches[] = {
> +	{ .compatible = "ti,davinci-pm-domains", },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, davinci_genpd_matches);
> +
> +static int davinci_genpd_probe(struct platform_device *pdev)
> +{
> +	struct davinci_genpd_ctx *pd;
> +	struct device_node *np;
> +	struct device *dev;
> +
> +	dev = &pdev->dev;
> +	np = dev->of_node;
> +
> +	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
> +	if (!pd)
> +		return -ENOMEM;
> +
> +	pd->pd.name = devm_kasprintf(dev, GFP_KERNEL,
> +				     "davinci_pwc_pd%d",
> +				     of_alias_get_id(np, "pwc"));
> +	if (!pd->pd.name)
> +		return -ENOMEM;
> +
> +	pd->dev = dev;
> +	pd->pd.attach_dev = davinci_genpd_attach_dev;
> +	pd->pd.detach_dev = davinci_genpd_detach_dev;
> +	pd->pd.flags |= GENPD_FLAG_PM_CLK;
> +
> +	pm_genpd_init(&pd->pd, NULL, true);
> +
> +	return of_genpd_add_provider_simple(np, &pd->pd);
> +}
> +
> +static struct platform_driver davinci_genpd_driver = {
> +	.probe = davinci_genpd_probe,
> +	.driver = {
> +		.name = "davinci_genpd",
> +		.of_match_table = davinci_genpd_matches,
> +	},
> +};
> +module_platform_driver(davinci_genpd_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("TI DaVinci Generic Power Domains driver");
> +MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski@baylibre.com>");
> 

Likewise, I don't think we need a separate driver for this. Just
register a genpd provider from the PSC clock driver.