linux-kernel - Re: [PATCH 08/17] clk: Add PLX Technology OXNAS Standard Clocks

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Date:	Thu, 3 Mar 2016 18:25:32 -0800
From:	Stephen Boyd <sboyd@...eaurora.org>
To:	Neil Armstrong <narmstrong@...libre.com>
Cc:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-clk@...r.kernel.org
Subject: Re: [PATCH 08/17] clk: Add PLX Technology OXNAS Standard Clocks

On 03/03, Neil Armstrong wrote:
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index eca8e01..b75ef5c 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -192,6 +192,12 @@ config COMMON_CLK_PXA
>  	---help---
>  	  Sypport for the Marvell PXA SoC.
>  
> +config COMMON_CLK_OXNAS
> +	def_bool COMMON_CLK
> +	select MFD_SYSCON

So this is always built if I have the common clk framework
enabled? Not good.

> +	---help---
> +	  Sypport for the OXNAS SoC Family clocks.
> +
>  config COMMON_CLK_CDCE706
>  	tristate "Clock driver for TI CDCE706 clock synthesizer"
>  	depends on I2C
> diff --git a/drivers/clk/clk-oxnas.c b/drivers/clk/clk-oxnas.c
> new file mode 100644
> index 0000000..c4b903f
> --- /dev/null
> +++ b/drivers/clk/clk-oxnas.c
> @@ -0,0 +1,159 @@
> +/*
> + * Copyright (C) 2010 Broadcom
> + * Copyright (C) 2012 Stephen Warren
> + * Copyright (C) 2016 Neil Armstrong <narmstrong@...libre.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clkdev.h>

Are either of these includes used?

> +#include <linux/clk-provider.h>
> +#include <linux/of.h>
> +#include <linux/delay.h>

Is this include used?

> +#include <linux/stringify.h>
> +#include <linux/reset.h>

Is this include used?

> +#include <linux/io.h>

Is this include used?

> +#include <linux/regmap.h>
> +#include <linux/mfd/syscon.h>

#include <linux/kernel.h> for container_of?

> +
> +/* Standard regmap gate clocks */
> +struct clk_std {
> +	struct clk_hw hw;
> +	signed char bit;
> +	struct regmap *regmap;
> +};
> +
> +/* Regmap offsets */
> +#define CLK_STAT_REGOFFSET	0x24
> +#define CLK_SET_REGOFFSET	0x2c
> +#define CLK_CLR_REGOFFSET	0x30
> +
> +#define NUM_STD_CLKS 10
> +#define to_stdclk(_hw) container_of(_hw, struct clk_std, hw)
> +
> +static int std_clk_is_enabled(struct clk_hw *hw)
> +{
> +	struct clk_std *std = to_stdclk(hw);
> +	int ret;
> +	unsigned int val;
> +
> +	ret = regmap_read(std->regmap, CLK_STAT_REGOFFSET, &val);
> +	if (ret < 0)
> +		return ret;
> +
> +	return val & BIT(std->bit);
> +}
> +
> +static int std_clk_enable(struct clk_hw *hw)
> +{
> +	struct clk_std *std = to_stdclk(hw);
> +
> +	regmap_write(std->regmap, CLK_SET_REGOFFSET, BIT(std->bit));

I hope the regmap is fast_io? Otherwise this is scheduling while
atomic.

> +
> +	return 0;
> +}
> +
> +static void std_clk_disable(struct clk_hw *hw)
> +{
> +	struct clk_std *std = to_stdclk(hw);
> +
> +	regmap_write(std->regmap, CLK_CLR_REGOFFSET, BIT(std->bit));
> +}
> +
> +static struct clk_ops std_clk_ops = {

const?

> +	.enable = std_clk_enable,
> +	.disable = std_clk_disable,
> +	.is_enabled = std_clk_is_enabled,
> +};
> +
[..]
> +
> +static struct clk_hw *std_clk_hw_tbl[] = {

const?

> +	&clk_leon.hw,
> +	&clk_dma_sgdma.hw,
> +	&clk_cipher.hw,
> +	&clk_sata.hw,
> +	&clk_audio.hw,
> +	&clk_usbmph.hw,
> +	&clk_etha.hw,
> +	&clk_pciea.hw,
> +	&clk_nand.hw,
> +};
> +
> +static struct clk *std_clk_tbl[ARRAY_SIZE(std_clk_hw_tbl)];
> +
> +static struct clk_onecell_data std_clk_data;

These are pretty generic. Perhaps oxnas_clk_data and
oxnas_clk_hw_tbl?

> +
> +static void __init oxnas_init_stdclk(struct device_node *np)
> +{
> +	int i;
> +	struct regmap *regmap = syscon_node_to_regmap(of_get_parent(np));
> +
> +	if (!regmap)
> +		panic("failed to have parent regmap\n");
> +
> +	for (i = 0; i < ARRAY_SIZE(std_clk_hw_tbl); i++) {
> +		struct clk_std *std = container_of(std_clk_hw_tbl[i],
> +						   struct clk_std, hw);
> +
> +		if (WARN_ON(!std))
> +			return;
> +		std->regmap = regmap;
> +
> +		std_clk_tbl[i] = clk_register(NULL, std_clk_hw_tbl[i]);
> +		if (WARN_ON(IS_ERR(std_clk_tbl[i])))
> +			return;
> +	}
> +
> +	std_clk_data.clks = std_clk_tbl;
> +	std_clk_data.clk_num = ARRAY_SIZE(std_clk_tbl);
> +
> +	of_clk_add_provider(np, of_clk_src_onecell_get, &std_clk_data);
> +}
> +CLK_OF_DECLARE(oxnas_pllstd, "plxtech,ox810se-stdclk", oxnas_init_stdclk);

Can this be a platform driver instead?

Is there a binding for this compatible?

-- 
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