Re: [PATCH 1/2 v6] clk/axs10x: Add I2S PLL clock driver

From: Jose Abreu <Jose.Abreu@synopsys.com>
To: Jose Abreu <Jose.Abreu@synopsys.com>,
	<linux-kernel@vger.kernel.org>, <linux-clk@vger.kernel.org>,
	<linux-snps-arc@lists.infradead.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	<sboyd@codeaurora.org>, "robh+dt@kernel.org" <robh+dt@kernel.org>
Cc: <CARLOS.PALMINHA@synopsys.com>, <Alexey.Brodkin@synopsys.com>,
	<Vineet.Gupta1@synopsys.com>, <mturquette@baylibre.com>
Subject: Re: [PATCH 1/2 v6] clk/axs10x: Add I2S PLL clock driver
Date: Tue, 26 Apr 2016 10:24:13 +0100	[thread overview]
Message-ID: <571F33BD.1020606@synopsys.com> (raw)
In-Reply-To: <57191417.6040909@synopsys.com>

Hi,

@Stephen: Is this version ok? The DT bindings were already acked by Vineet and
Alexey.

@Rob: Is this version ok? You already acked the previous version[1], see the
version log for differences. Please see also if [2] is ok.

[1] https://marc.info/?l=devicetree&m=146056894500509&w=2

[2] https://marc.info/?l=devicetree&m=146126139521541&w=2

On 21-04-2016 18:55, Jose Abreu wrote:
> Adding device tree mailing list and Rob Herring.
>
> On 21-04-2016 18:19, Jose Abreu wrote:
>> The ARC SDP I2S clock can be programmed using a
>> specific PLL.
>>
>> This patch has the goal of adding a clock driver
>> that programs this PLL.
>>
>> At this moment the rate values are hardcoded in
>> a table but in the future it would be ideal to
>> use a function which determines the PLL values
>> given the desired rate.
>>
>> Signed-off-by: Jose Abreu <joabreu@synopsys.com>
>> ---
>>
>> Changes v5 -> v6:
>> * Use parent clock to determine PLL input rate instead of using hardcoded values
>> * Documentation update (added 'clocks' field)
>>
>> Changes v4 -> v5:
>> * Documentation update (as suggested by Alexey Brodkin)
>> * Changed compatible string to "snps,axs10x-i2s-pll-clock" (as suggested by Alexey Brodkin)
>>
>> Changes v3 -> v4:
>> * Added binding document (as suggested by Stephen Boyd)
>> * Minor code style fixes (as suggested by Stephen Boyd)
>> * Use ioremap (as suggested by Stephen Boyd)
>> * Implement round_rate (as suggested by Stephen Boyd)
>> * Change to platform driver (as suggested by Stephen Boyd)
>> * Use {readl/writel}_relaxed (as suggested by Vineet Gupta)
>>
>> Changes v2 -> v3:
>> * Implemented recalc_rate
>>
>> Changes v1 -> v2:
>> * Renamed folder to axs10x (as suggested by Alexey Brodkin)
>> * Added more supported rates
>>
>>  .../bindings/clock/axs10x-i2s-pll-clock.txt        |  25 +++
>>  drivers/clk/Makefile                               |   1 +
>>  drivers/clk/axs10x/Makefile                        |   1 +
>>  drivers/clk/axs10x/i2s_pll_clock.c                 | 228 +++++++++++++++++++++
>>  4 files changed, 255 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/clock/axs10x-i2s-pll-clock.txt
>>  create mode 100644 drivers/clk/axs10x/Makefile
>>  create mode 100644 drivers/clk/axs10x/i2s_pll_clock.c
>>
>> diff --git a/Documentation/devicetree/bindings/clock/axs10x-i2s-pll-clock.txt b/Documentation/devicetree/bindings/clock/axs10x-i2s-pll-clock.txt
>> new file mode 100644
>> index 0000000..5ffc8df
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/clock/axs10x-i2s-pll-clock.txt
>> @@ -0,0 +1,25 @@
>> +Binding for the AXS10X I2S PLL clock
>> +
>> +This binding uses the common clock binding[1].
>> +
>> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
>> +
>> +Required properties:
>> +- compatible: shall be "snps,axs10x-i2s-pll-clock"
>> +- reg : address and length of the I2S PLL register set.
>> +- clocks: shall be the input parent clock phandle for the PLL.
>> +- #clock-cells: from common clock binding; Should always be set to 0.
>> +
>> +Example:
>> +	pll_clock: pll_clock {
>> +		compatible = "fixed-clock";
>> +		clock-frequency = <27000000>;
>> +		#clock-cells = <0>;
>> +	};
>> +
>> +	i2s_clock@100a0 {
>> +		compatible = "snps,axs10x-i2s-pll-clock";
>> +		reg = <0x100a0 0x10>;
>> +		clocks = <&pll_clock>;
>> +		#clock-cells = <0>;
>> +	};
>> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
>> index 46869d6..2ca62dc6 100644
>> --- a/drivers/clk/Makefile
>> +++ b/drivers/clk/Makefile
>> @@ -84,3 +84,4 @@ obj-$(CONFIG_X86)			+= x86/
>>  obj-$(CONFIG_ARCH_ZX)			+= zte/
>>  obj-$(CONFIG_ARCH_ZYNQ)			+= zynq/
>>  obj-$(CONFIG_H8300)		+= h8300/
>> +obj-$(CONFIG_ARC_PLAT_AXS10X)		+= axs10x/
>> diff --git a/drivers/clk/axs10x/Makefile b/drivers/clk/axs10x/Makefile
>> new file mode 100644
>> index 0000000..01996b8
>> --- /dev/null
>> +++ b/drivers/clk/axs10x/Makefile
>> @@ -0,0 +1 @@
>> +obj-y += i2s_pll_clock.o
>> diff --git a/drivers/clk/axs10x/i2s_pll_clock.c b/drivers/clk/axs10x/i2s_pll_clock.c
>> new file mode 100644
>> index 0000000..411310d
>> --- /dev/null
>> +++ b/drivers/clk/axs10x/i2s_pll_clock.c
>> @@ -0,0 +1,228 @@
>> +/*
>> + * Synopsys AXS10X SDP I2S PLL clock driver
>> + *
>> + * Copyright (C) 2016 Synopsys
>> + *
>> + * This file is licensed under the terms of the GNU General Public
>> + * License version 2. This program is licensed "as is" without any
>> + * warranty of any kind, whether express or implied.
>> + */
>> +
>> +#include <linux/platform_device.h>
>> +#include <linux/module.h>
>> +#include <linux/clk-provider.h>
>> +#include <linux/err.h>
>> +#include <linux/device.h>
>> +#include <linux/of_address.h>
>> +#include <linux/slab.h>
>> +#include <linux/of.h>
>> +
>> +/* PLL registers addresses */
>> +#define PLL_IDIV_REG	0x0
>> +#define PLL_FBDIV_REG	0x4
>> +#define PLL_ODIV0_REG	0x8
>> +#define PLL_ODIV1_REG	0xC
>> +
>> +struct i2s_pll_cfg {
>> +	unsigned int rate;
>> +	unsigned int idiv;
>> +	unsigned int fbdiv;
>> +	unsigned int odiv0;
>> +	unsigned int odiv1;
>> +};
>> +
>> +static const struct i2s_pll_cfg i2s_pll_cfg_27m[] = {
>> +	/* 27 Mhz */
>> +	{ 1024000, 0x104, 0x451, 0x10E38, 0x2000 },
>> +	{ 1411200, 0x104, 0x596, 0x10D35, 0x2000 },
>> +	{ 1536000, 0x208, 0xA28, 0x10B2C, 0x2000 },
>> +	{ 2048000, 0x82, 0x451, 0x10E38, 0x2000 },
>> +	{ 2822400, 0x82, 0x596, 0x10D35, 0x2000 },
>> +	{ 3072000, 0x104, 0xA28, 0x10B2C, 0x2000 },
>> +	{ 2116800, 0x82, 0x3CF, 0x10C30, 0x2000 },
>> +	{ 2304000, 0x104, 0x79E, 0x10B2C, 0x2000 },
>> +	{ 0, 0, 0, 0, 0 },
>> +};
>> +
>> +static const struct i2s_pll_cfg i2s_pll_cfg_28m[] = {
>> +	/* 28.224 Mhz */
>> +	{ 1024000, 0x82, 0x105, 0x107DF, 0x2000 },
>> +	{ 1411200, 0x28A, 0x1, 0x10001, 0x2000 },
>> +	{ 1536000, 0xA28, 0x187, 0x10042, 0x2000 },
>> +	{ 2048000, 0x41, 0x105, 0x107DF, 0x2000 },
>> +	{ 2822400, 0x145, 0x1, 0x10001, 0x2000 },
>> +	{ 3072000, 0x514, 0x187, 0x10042, 0x2000 },
>> +	{ 2116800, 0x514, 0x42, 0x10001, 0x2000 },
>> +	{ 2304000, 0x619, 0x82, 0x10001, 0x2000 },
>> +	{ 0, 0, 0, 0, 0 },
>> +};
>> +
>> +struct i2s_pll_clk {
>> +	void __iomem *base;
>> +	struct clk_hw hw;
>> +	struct device *dev;
>> +};
>> +
>> +static inline void i2s_pll_write(struct i2s_pll_clk *clk, unsigned int reg,
>> +		unsigned int val)
>> +{
>> +	writel_relaxed(val, clk->base + reg);
>> +}
>> +
>> +static inline unsigned int i2s_pll_read(struct i2s_pll_clk *clk,
>> +		unsigned int reg)
>> +{
>> +	return readl_relaxed(clk->base + reg);
>> +}
>> +
>> +static inline struct i2s_pll_clk *to_i2s_pll_clk(struct clk_hw *hw)
>> +{
>> +	return container_of(hw, struct i2s_pll_clk, hw);
>> +}
>> +
>> +static inline unsigned int i2s_pll_get_value(unsigned int val)
>> +{
>> +	return (val & 0x3F) + ((val >> 6) & 0x3F);
>> +}
>> +
>> +static const struct i2s_pll_cfg *i2s_pll_get_cfg(unsigned long prate)
>> +{
>> +	switch (prate) {
>> +	case 27000000:
>> +		return i2s_pll_cfg_27m;
>> +	case 28224000:
>> +		return i2s_pll_cfg_28m;
>> +	default:
>> +		return NULL;
>> +	}
>> +}
>> +
>> +static unsigned long i2s_pll_recalc_rate(struct clk_hw *hw,
>> +			unsigned long parent_rate)
>> +{
>> +	struct i2s_pll_clk *clk = to_i2s_pll_clk(hw);
>> +	unsigned int idiv, fbdiv, odiv;
>> +
>> +	idiv = i2s_pll_get_value(i2s_pll_read(clk, PLL_IDIV_REG));
>> +	fbdiv = i2s_pll_get_value(i2s_pll_read(clk, PLL_FBDIV_REG));
>> +	odiv = i2s_pll_get_value(i2s_pll_read(clk, PLL_ODIV0_REG));
>> +
>> +	return ((parent_rate / idiv) * fbdiv) / odiv;
>> +}
>> +
>> +static long i2s_pll_round_rate(struct clk_hw *hw, unsigned long rate,
>> +			unsigned long *prate)
>> +{
>> +	struct i2s_pll_clk *clk = to_i2s_pll_clk(hw);
>> +	const struct i2s_pll_cfg *pll_cfg = i2s_pll_get_cfg(*prate);
>> +	int i;
>> +
>> +	if (!pll_cfg) {
>> +		dev_err(clk->dev, "invalid parent rate=%ld\n", *prate);
>> +		return -EINVAL;
>> +	}
>> +
>> +	for (i = 0; pll_cfg[i].rate != 0; i++)
>> +		if (pll_cfg[i].rate == rate)
>> +			return rate;
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static int i2s_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>> +			unsigned long parent_rate)
>> +{
>> +	struct i2s_pll_clk *clk = to_i2s_pll_clk(hw);
>> +	const struct i2s_pll_cfg *pll_cfg = i2s_pll_get_cfg(parent_rate);
>> +	int i;
>> +
>> +	if (!pll_cfg) {
>> +		dev_err(clk->dev, "invalid parent rate=%ld\n", parent_rate);
>> +		return -EINVAL;
>> +	}
>> +
>> +	for (i = 0; pll_cfg[i].rate != 0; i++) {
>> +		if (pll_cfg[i].rate == rate) {
>> +			i2s_pll_write(clk, PLL_IDIV_REG, pll_cfg[i].idiv);
>> +			i2s_pll_write(clk, PLL_FBDIV_REG, pll_cfg[i].fbdiv);
>> +			i2s_pll_write(clk, PLL_ODIV0_REG, pll_cfg[i].odiv0);
>> +			i2s_pll_write(clk, PLL_ODIV1_REG, pll_cfg[i].odiv1);
>> +			return 0;
>> +		}
>> +	}
>> +
>> +	dev_err(clk->dev, "invalid rate=%ld, parent_rate=%ld\n", rate,
>> +			parent_rate);
>> +	return -EINVAL;
>> +}
>> +
>> +static const struct clk_ops i2s_pll_ops = {
>> +	.recalc_rate = i2s_pll_recalc_rate,
>> +	.round_rate = i2s_pll_round_rate,
>> +	.set_rate = i2s_pll_set_rate,
>> +};
>> +
>> +static int i2s_pll_clk_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct device_node *node = dev->of_node;
>> +	const char *clk_name;
>> +	const char *parent_name;
>> +	struct clk *clk;
>> +	struct i2s_pll_clk *pll_clk;
>> +	struct clk_init_data init;
>> +	struct resource *mem;
>> +
>> +	pll_clk = devm_kzalloc(dev, sizeof(*pll_clk), GFP_KERNEL);
>> +	if (!pll_clk)
>> +		return -ENOMEM;
>> +
>> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	pll_clk->base = devm_ioremap_resource(dev, mem);
>> +	if (IS_ERR(pll_clk->base))
>> +		return PTR_ERR(pll_clk->base);
>> +
>> +	clk_name = node->name;
>> +	init.name = clk_name;
>> +	init.ops = &i2s_pll_ops;
>> +	parent_name = of_clk_get_parent_name(node, 0);
>> +	init.parent_names = &parent_name;
>> +	init.num_parents = 1;
>> +	pll_clk->hw.init = &init;
>> +	pll_clk->dev = dev;
>> +
>> +	clk = devm_clk_register(dev, &pll_clk->hw);
>> +	if (IS_ERR(clk)) {
>> +		dev_err(dev, "failed to register %s clock (%ld)\n",
>> +				clk_name, PTR_ERR(clk));
>> +		return PTR_ERR(clk);
>> +	}
>> +
>> +	return of_clk_add_provider(node, of_clk_src_simple_get, clk);
>> +}
>> +
>> +static int i2s_pll_clk_remove(struct platform_device *pdev)
>> +{
>> +	of_clk_del_provider(pdev->dev.of_node);
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id i2s_pll_clk_id[] = {
>> +	{ .compatible = "snps,axs10x-i2s-pll-clock", },
>> +	{ },
>> +};
>> +MODULE_DEVICE_TABLE(of, i2s_pll_clk_id);
>> +
>> +static struct platform_driver i2s_pll_clk_driver = {
>> +	.driver = {
>> +		.name = "axs10x-i2s-pll-clock",
>> +		.of_match_table = i2s_pll_clk_id,
>> +	},
>> +	.probe = i2s_pll_clk_probe,
>> +	.remove = i2s_pll_clk_remove,
>> +};
>> +module_platform_driver(i2s_pll_clk_driver);
>> +
>> +MODULE_AUTHOR("Jose Abreu <joabreu@synopsys.com>");
>> +MODULE_DESCRIPTION("Synopsys AXS10X SDP I2S PLL Clock Driver");
>> +MODULE_LICENSE("GPL v2");
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Best regards,
Jose Miguel Abreu