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Message-ID: <1965445.mLnp8rmPxd@avalon>
Date: Tue, 01 Apr 2014 15:15:41 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Sylwester Nawrocki <s.nawrocki@...sung.com>
Cc: devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, gregkh@...uxfoundation.org,
mturquette@...aro.org, linux@....linux.org.uk, robh+dt@...nel.org,
grant.likely@...aro.org, mark.rutland@....com,
galak@...eaurora.org, kyungmin.park@...sung.com,
sw0312.kim@...sung.com, m.szyprowski@...sung.com,
t.figa@...sung.com, s.hauer@...gutronix.de
Subject: Re: [PATCH RFC v4 2/2] clk: Add handling of clk parent and rate assigned from DT
Hi Sylwester,
Thank you for the patch.
On Monday 31 March 2014 18:41:56 Sylwester Nawrocki wrote:
> This function adds a helper function to configure clock parents and rates
> as specified in clock-parents, clock-rates DT properties for a consumer
> device and a call to it before driver is bound to a device.
>
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@...sung.com>
> ---
> Changes since v3:
> - added detailed description of the assigned-clocks subnode,
> - clk-conf.c is now excluded when CONFIG_OF is not set,
> - s/of_clk_device_setup/of_clk_device_init,
> - added missing 'static inline' to the function stub definition.
>
> Changes since v2:
> - edited in clock-bindings.txt, added note about 'assigned-clocks'
> subnode which may be used to specify "global" clocks configuration
> at a clock provider node,
> - moved of_clk_device_setup() function declaration from clk-provider.h
> to clk-conf.h so required function stubs are available when
> CONFIG_COMMON_CLK is not enabled,
>
> Changes since v1:
> - the helper function to parse and set assigned clock parents and
> rates made public so it is available to clock providers to call
> directly;
> - dropped the platform bus notification and call of_clk_device_setup()
> is is now called from the driver core, rather than from the
> notification callback;
> - s/of_clk_get_list_entry/of_clk_get_by_property.
> ---
> .../devicetree/bindings/clock/clock-bindings.txt | 42 ++++++++++
> drivers/base/dd.c | 7 ++
> drivers/clk/Makefile | 3 +
> drivers/clk/clk-conf.c | 87 +++++++++++++++++
> drivers/clk/clk.c | 10 ++-
> include/linux/clk/clk-conf.h | 19 +++++
> 6 files changed, 167 insertions(+), 1 deletion(-)
> create mode 100644 drivers/clk/clk-conf.c
> create mode 100644 include/linux/clk/clk-conf.h
[snip]
> diff --git a/drivers/clk/clk-conf.c b/drivers/clk/clk-conf.c
> new file mode 100644
> index 0000000..a2e992e
> --- /dev/null
> +++ b/drivers/clk/clk-conf.c
> @@ -0,0 +1,87 @@
> +/*
> + * Copyright (C) 2014 Samsung Electronics Co., Ltd.
> + * Sylwester Nawrocki <s.nawrocki@...sung.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.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/device.h>
> +#include <linux/of.h>
> +#include <linux/printk.h>
> +
> +/**
> + * of_clk_device_init() - parse and set clk configuration assigned to a
> device
> + * @node: device node to apply the configuration for
> + *
> + * This function parses 'clock-parents' and 'clock-rates' properties and
> sets
> + * any specified clock parents and rates.
> + */
> +int of_clk_device_init(struct device_node *node)
> +{
> + struct property *prop;
> + const __be32 *cur;
> + int rc, index, num_parents;
> + struct clk *clk, *pclk;
> + u32 rate;
> +
> + num_parents = of_count_phandle_with_args(node, "clock-parents",
> + "#clock-cells");
> + if (num_parents == -EINVAL)
> + pr_err("clk: Invalid value of clock-parents property at %s\n",
> + node->full_name);
This is an implementation detail, but wouldn't it simplify the code if you
merged the two loops by iterating of the clocks property instead of over the
clock-parents and clock-rates properties separately ?
> + for (index = 0; index < num_parents; index++) {
> + pclk = of_clk_get_by_property(node, "clock-parents", index);
> + if (IS_ERR(pclk)) {
> + /* skip empty (null) phandles */
> + if (PTR_ERR(pclk) == -ENOENT)
> + continue;
> +
> + pr_warn("clk: couldn't get parent clock %d for %s\n",
> + index, node->full_name);
> + return PTR_ERR(pclk);
> + }
> +
> + clk = of_clk_get(node, index);
> + if (IS_ERR(clk)) {
> + pr_warn("clk: couldn't get clock %d for %s\n",
> + index, node->full_name);
> + return PTR_ERR(clk);
> + }
> +
> + rc = clk_set_parent(clk, pclk);
> + if (rc < 0)
> + pr_err("clk: failed to reparent %s to %s: %d\n",
> + __clk_get_name(clk), __clk_get_name(pclk), rc);
> + else
> + pr_debug("clk: set %s as parent of %s\n",
> + __clk_get_name(pclk), __clk_get_name(clk));
> + }
> +
> + index = 0;
> + of_property_for_each_u32(node, "clock-rates", prop, cur, rate) {
> + if (rate) {
> + clk = of_clk_get(node, index);
> + if (IS_ERR(clk)) {
> + pr_warn("clk: couldn't get clock %d for %s\n",
> + index, node->full_name);
> + return PTR_ERR(clk);
> + }
> +
> + rc = clk_set_rate(clk, rate);
> + if (rc < 0)
> + pr_err("clk: couldn't set %s clock rate: %d\n",
> + __clk_get_name(clk), rc);
> + else
> + pr_debug("clk: set rate of clock %s to %lu\n",
> + __clk_get_name(clk), clk_get_rate(clk));
> + }
> + index++;
> + }
> +
> + return 0;
> +}
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index dff0373..ea6d8bd 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
[snip]
> @@ -2620,7 +2621,15 @@ void __init of_clk_init(const struct of_device_id
> *matches) list_for_each_entry_safe(clk_provider, next,
> &clk_provider_list, node) {
> if (force || parent_ready(clk_provider->np)) {
> +
> clk_provider->clk_init_cb(clk_provider->np);
> +
> + /* Set any assigned clock parents and rates */
> + np = of_get_child_by_name(clk_provider->np,
> + "assigned-clocks");
> + if (np)
> + of_clk_device_init(np);
Aren't you missing an of_node_put() here ?
> +
> list_del(&clk_provider->node);
> kfree(clk_provider);
> is_init_done = true;
--
Regards,
Laurent Pinchart
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