linux-kernel - Re: [PATCH 06/11] clk: rp1: Add support for clocks provided by RP1

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Message-ID: <ZscNMk3hBWs5yKTH@apocalypse>
Date: Thu, 22 Aug 2024 12:04:34 +0200
From: Andrea della Porta <andrea.porta@...e.com>
To: Simon Horman <horms@...nel.org>
Cc: Andrea della Porta <andrea.porta@...e.com>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Derek Kiernan <derek.kiernan@....com>,
	Dragan Cvetic <dragan.cvetic@....com>,
	Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Nicolas Ferre <nicolas.ferre@...rochip.com>,
	Claudiu Beznea <claudiu.beznea@...on.dev>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Saravana Kannan <saravanak@...gle.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>, linux-clk@...r.kernel.org,
	devicetree@...r.kernel.org, linux-rpi-kernel@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-gpio@...r.kernel.org, netdev@...r.kernel.org,
	linux-pci@...r.kernel.org, linux-arch@...r.kernel.org,
	Lee Jones <lee@...nel.org>, Andrew Lunn <andrew@...n.ch>,
	Stefan Wahren <wahrenst@....net>
Subject: Re: [PATCH 06/11] clk: rp1: Add support for clocks provided by RP1

Hi Simon,

On 14:17 Wed 21 Aug     , Simon Horman wrote:
> On Tue, Aug 20, 2024 at 04:36:08PM +0200, Andrea della Porta wrote:
> > RaspberryPi RP1 is an MFD providing, among other peripherals, several
> > clock generators and PLLs that drives the sub-peripherals.
> > Add the driver to support the clock providers.
> > 
> > Signed-off-by: Andrea della Porta <andrea.porta@...e.com>
> 
> ...
> 
> > diff --git a/drivers/clk/clk-rp1.c b/drivers/clk/clk-rp1.c
> > new file mode 100644
> > index 000000000000..d18e711c0623
> > --- /dev/null
> > +++ b/drivers/clk/clk-rp1.c
> > @@ -0,0 +1,1655 @@
> > +// SPDX-License-Identifier: GPL
> 
> checkpatch says:
> 
> WARNING: 'SPDX-License-Identifier: GPL' is not supported in LICENSES/...
>

Alas, the system on which I executed checkpatch was missing git python module,
so spdxcheck.py wasn't working properly, sorry about that. Fixed in the next
release.

> ...
> 
> > +static int rp1_clock_set_parent(struct clk_hw *hw, u8 index)
> > +{
> > +	struct rp1_clock *clock = container_of(hw, struct rp1_clock, hw);
> > +	struct rp1_clockman *clockman = clock->clockman;
> > +	const struct rp1_clock_data *data = clock->data;
> > +	u32 ctrl, sel;
> > +
> > +	spin_lock(&clockman->regs_lock);
> > +	ctrl = clockman_read(clockman, data->ctrl_reg);
> > +
> > +	if (index >= data->num_std_parents) {
> > +		/* This is an aux source request */
> > +		if (index >= data->num_std_parents + data->num_aux_parents)
> 
> It looks like &clockman->regs_lock needs to be unlocked here.
> 
> Flagged by Smatch, Sparse. and Coccinelle.

Ack.

Many thanks,
Andrea

> 
> > +			return -EINVAL;
> > +
> > +		/* Select parent from aux list */
> > +		ctrl = set_register_field(ctrl, index - data->num_std_parents,
> > +					  CLK_CTRL_AUXSRC_MASK,
> > +					  CLK_CTRL_AUXSRC_SHIFT);
> > +		/* Set src to aux list */
> > +		ctrl = set_register_field(ctrl, AUX_SEL, data->clk_src_mask,
> > +					  CLK_CTRL_SRC_SHIFT);
> > +	} else {
> > +		ctrl = set_register_field(ctrl, index, data->clk_src_mask,
> > +					  CLK_CTRL_SRC_SHIFT);
> > +	}
> > +
> > +	clockman_write(clockman, data->ctrl_reg, ctrl);
> > +	spin_unlock(&clockman->regs_lock);
> > +
> > +	sel = rp1_clock_get_parent(hw);
> > +	WARN(sel != index, "(%s): Parent index req %u returned back %u\n",
> > +	     data->name, index, sel);
> > +
> > +	return 0;
> > +}
> 
> ...