[PATCH v2 3/3] clk: meson: add sub MMC clock controller driver

On Tue, 2018-07-10 at 16:36 +0000, Yixun Lan wrote:

 * Copyright (c) 2017 Baylibre SAS.
 * Author: Jerome Brunet [off-list ref]

Considering that a fair share of the code below has been copied from the clock
portion of the eMMC driver, which I wrote last year.

+ *
+ * Copyright (c) 2018 Amlogic, inc.
+ * Author: Yixun Lan [off-list ref]
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/of_device.h>
+#include <linux/mfd/syscon.h>
+#include <linux/platform_device.h>
+#include <dt-bindings/clock/amlogic,meson-mmc-clkc.h>
+
+#include "clkc.h"
+
+/* clock ID used by internal driver */
+#define CLKID_MMC_MUX				0
+#define CLKID_MMC_PHASE_CORE			2
+
+#define SD_EMMC_CLOCK		0
+#define   CLK_DIV_MASK GENMASK(5, 0)
+#define   CLK_SRC_MASK GENMASK(7, 6)
+#define   CLK_CORE_PHASE_MASK GENMASK(9, 8)
+#define   CLK_TX_PHASE_MASK GENMASK(11, 10)
+#define   CLK_RX_PHASE_MASK GENMASK(13, 12)
+#define   CLK_V2_TX_DELAY_MASK GENMASK(19, 16)
+#define   CLK_V2_RX_DELAY_MASK GENMASK(23, 20)
+#define   CLK_V2_ALWAYS_ON BIT(24)
+
+#define   CLK_V3_TX_DELAY_MASK GENMASK(21, 16)
+#define   CLK_V3_RX_DELAY_MASK GENMASK(27, 22)
+#define   CLK_V3_ALWAYS_ON BIT(28)
+
+#define   CLK_DELAY_STEP_PS 200
+#define   CLK_PHASE_STEP 30
+#define   CLK_PHASE_POINT_NUM (360 / CLK_PHASE_STEP)
+
+#define MUX_CLK_NUM_PARENTS	2
+#define MMC_MAX_CLKS		5

Some defines are aligned, some aren't. please be consistent about it.
I personally prefer when things are aligned but it is just a preference.  

+
+struct clk_regmap_phase_data {

Considering the recent addition of clk_phase in clk/meson, it is not the best
name to choose.

clk_phase_delay_data ?

+	unsigned long			phase_mask;
+	unsigned long			delay_mask;
+	unsigned int			delay_step_ps;
+};
+
+struct mmc_clkc_data {
+	struct clk_regmap_phase_data	tx;
+	struct clk_regmap_phase_data	rx;
+};

+
+struct mmc_clkc_info {
+	struct device			*dev;

I don't think you need keep dev here, considering this is the device data.

+	struct regmap			*map;
+	struct mmc_clkc_data		*data;
+};

Overall, I don't think you need this structure

+
+static inline struct clk_regmap_phase_data *
+clk_get_regmap_phase_data(struct clk_regmap *clk)

Update name as well

+{
+	return (struct clk_regmap_phase_data *)clk->data;
+}
+
+static struct clk_regmap_mux_data mmc_clkc_mux_data = {
+	.offset = SD_EMMC_CLOCK,
+	.mask = 0x3,
+	.shift = 6,
+	.flags = CLK_DIVIDER_ROUND_CLOSEST,
+};
+
+static struct clk_regmap_div_data mmc_clkc_div_data = {
+	.offset = SD_EMMC_CLOCK,
+	.shift = 0,
+	.width = 6,
+	.flags = CLK_DIVIDER_ROUND_CLOSEST | CLK_DIVIDER_ONE_BASED,
+};

Same comment on alignement. Some structure you've aligned, and some you haven't
Consistency ...

+
+static struct clk_regmap_phase_data mmc_clkc_core_phase = {
+	.phase_mask	= CLK_CORE_PHASE_MASK,
+};
+
+static const struct mmc_clkc_data mmc_clkc_gx_data = {
+	{
+		.phase_mask	= CLK_TX_PHASE_MASK,
+		.delay_mask	= CLK_V2_TX_DELAY_MASK,
+		.delay_step_ps	= CLK_DELAY_STEP_PS,
+	},
+	{
+		.phase_mask	= CLK_RX_PHASE_MASK,
+		.delay_mask	= CLK_V2_RX_DELAY_MASK,
+		.delay_step_ps	= CLK_DELAY_STEP_PS,
+	},
+};
+
+static const struct mmc_clkc_data mmc_clkc_axg_data = {
+	{
+		.phase_mask	= CLK_TX_PHASE_MASK,
+		.delay_mask	= CLK_V3_TX_DELAY_MASK,
+		.delay_step_ps	= CLK_DELAY_STEP_PS,
+	},
+	{
+		.phase_mask	= CLK_RX_PHASE_MASK,
+		.delay_mask	= CLK_V3_RX_DELAY_MASK,
+		.delay_step_ps	= CLK_DELAY_STEP_PS,
+	},
+};
+
+static const struct of_device_id mmc_clkc_match_table[] = {
+	{
+		.compatible = "amlogic,meson-gx-mmc-clkc",
+		.data = &mmc_clkc_gx_data
+	},
+	{
+		.compatible = "amlogic,meson-axg-mmc-clkc",
+		.data = &mmc_clkc_axg_data
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, mmc_clkc_match_table);
+
+static struct clk_regmap *mmc_clkc_register_mux(struct mmc_clkc_info *clkc)
+{
+	const char *parent_names[MUX_CLK_NUM_PARENTS];
+	struct device *dev = clkc->dev;
+	struct clk_init_data init;
+	struct clk_regmap *mux;
+	struct clk *clk;
+	char *mux_name;
+	int i, ret;
+
+	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
+	if (!mux)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < MUX_CLK_NUM_PARENTS; i++) {
+		char name[8];
+
+		snprintf(name, sizeof(name), "clkin%d", i);
+		clk = devm_clk_get(dev, name);
+		if (IS_ERR(clk)) {
+			if (clk != ERR_PTR(-EPROBE_DEFER))
+				dev_err(dev, "Missing clock %s\n", name);
+			return ERR_PTR((long)clk);
+		}
+
+		parent_names[i] = __clk_get_name(clk);
+	}
+
+	mux_name = kasprintf(GFP_KERNEL, "%s#mux", dev_name(dev));
+	if (!mux_name)
+		return ERR_PTR(-ENOMEM);
+
+	mux->map = clkc->map;
+	mux->data = &mmc_clkc_mux_data;
+
+	init.name = mux_name;
+	init.ops = &clk_regmap_mux_ops;
+	init.flags = CLK_SET_RATE_PARENT;
+	init.parent_names = parent_names;
+	init.num_parents = MUX_CLK_NUM_PARENTS;
+
+	mux->hw.init = &init;
+	ret = devm_clk_hw_register(dev, &mux->hw);
+	if (ret) {
+		dev_err(dev, "Mux clock registration failed\n");
+		mux = ERR_PTR(ret);
+	}
+
+	kfree(mux_name);
+	return mux;
+}
+
+static struct clk_regmap *mmc_clkc_register_div(struct mmc_clkc_info *clkc)
+{
+	const char *parent_names[MUX_CLK_NUM_PARENTS];
+	struct device *dev = clkc->dev;
+	struct clk_init_data init;
+	struct clk_regmap *div;
+	char *mux_name, *div_name;
+	int ret;
+
+	div = devm_kzalloc(dev, sizeof(*div), GFP_KERNEL);
+	if (!div)
+		return ERR_PTR(-ENOMEM);
+
+	mux_name = kasprintf(GFP_KERNEL, "%s#mux", dev_name(dev));
+	div_name = kasprintf(GFP_KERNEL, "%s#div", dev_name(dev));
+	if (!mux_name || !div_name) {
+		div = ERR_PTR(-ENOMEM);
+		goto err;
+	}
+
+	parent_names[0] = mux_name;
+	div->map = clkc->map;
+	div->data = &mmc_clkc_div_data;
+
+	init.name = div_name;
+	init.ops = &clk_regmap_divider_ops;
+	init.flags = CLK_SET_RATE_PARENT;
+	init.parent_names = parent_names;
+	init.num_parents = 1;
+
+	div->hw.init = &init;
+	ret = devm_clk_hw_register(dev, &div->hw);
+	if (ret) {
+		dev_err(dev, "Divider clock registration failed\n");
+		div = ERR_PTR(ret);
+	}
+
+err:
+	kfree(mux_name);
+	kfree(div_name);
+	return div;
+}
+
+static int clk_regmap_get_phase(struct clk_hw *hw)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_phase_data *ph = clk_get_regmap_phase_data(clk);
+	unsigned int phase_num = 1 <<  hweight_long(ph->phase_mask);
+	unsigned long period_ps, p, d;
+	int degrees;
+	u32 val;
+
+	regmap_read(clk->map, SD_EMMC_CLOCK, &val);
+	p = (val & ph->phase_mask) >> __ffs(ph->phase_mask);
+	degrees = p * 360 / phase_num;
+
+	if (ph->delay_mask) {
+		period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
+					 clk_get_rate(hw->clk));
+		d = (val & ph->delay_mask) >> __ffs(ph->delay_mask);
+		degrees += d * ph->delay_step_ps * 360 / period_ps;
+		degrees %= 360;
+	}
+
+	return degrees;
+}
+
+static void clk_regmap_apply_phase_delay(struct clk_regmap *clk,
+					 unsigned int phase,
+					 unsigned int delay)
+{
+	struct clk_regmap_phase_data *ph = clk->data;
+	u32 val;
+
+	regmap_read(clk->map, SD_EMMC_CLOCK, &val);
+
+	val &= ~ph->phase_mask;
+	val |= phase << __ffs(ph->phase_mask);
+
+	if (ph->delay_mask) {
+		val &= ~ph->delay_mask;
+		val |= delay << __ffs(ph->delay_mask);
+	}
+
+	regmap_write(clk->map, SD_EMMC_CLOCK, val);
+}
+
+static int clk_regmap_set_phase(struct clk_hw *hw, int degrees)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct clk_regmap_phase_data *ph = clk_get_regmap_phase_data(clk);
+	unsigned int phase_num = 1 <<  hweight_long(ph->phase_mask);
+	unsigned long period_ps, d = 0, r;
+	u64 p;
+
+	p = degrees % 360;
+
+	if (!ph->delay_mask) {
+		p = DIV_ROUND_CLOSEST_ULL(p, 360 / phase_num);
+	} else {
+		period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
+					 clk_get_rate(hw->clk));
+
+		/* First compute the phase index (p), the remainder (r) is the
+		 * part we'll try to acheive using the delays (d).
+		 */
+		r = do_div(p, 360 / phase_num);
+		d = DIV_ROUND_CLOSEST(r * period_ps,
+				      360 * ph->delay_step_ps);
+		d = min(d, ph->delay_mask >> __ffs(ph->delay_mask));
+	}
+
+	clk_regmap_apply_phase_delay(clk, p, d);
+	return 0;
+}
+
+static const struct clk_ops clk_regmap_phase_ops = {
+	.get_phase = clk_regmap_get_phase,
+	.set_phase = clk_regmap_set_phase,
+};
+
+static struct clk_regmap *
+mmc_clkc_register_phase_clk(struct mmc_clkc_info *clkc,
+			    char *name, char *parent_name, unsigned long flags,
+			    struct clk_regmap_phase_data *phase_data)
+
+{
+	const char *parent_names[MUX_CLK_NUM_PARENTS];
+	struct device *dev = clkc->dev;
+	struct clk_init_data init;
+	struct clk_regmap *x;

x is not a very good name, 'clk' is just 2 more letters ...

+	char *clk_name, *core_name;
+	int ret;
+
+	/* create the mmc rx clock */
+	x = devm_kzalloc(dev, sizeof(*x), GFP_KERNEL);
+	if (!x)
+		return ERR_PTR(-ENOMEM);
+
+	clk_name = kasprintf(GFP_KERNEL, "%s#%s", dev_name(dev), name);
+	core_name = kasprintf(GFP_KERNEL, "%s#%s", dev_name(dev), parent_name);
+
+	if (!clk_name || !core_name) {
+		x = ERR_PTR(-ENOMEM);
+		goto err;
+	}
+	parent_names[0] = core_name;
+
+	init.name = clk_name;
+	init.ops = &clk_regmap_phase_ops;
+	init.flags = flags;
+	init.parent_names = parent_names;
+	init.num_parents = 1;
+
+	x->map = clkc->map;
+	x->data = phase_data;
+	x->hw.init = &init;
+
+	ret = devm_clk_hw_register(dev, &x->hw);
+	if (ret) {
+		dev_err(dev, "Core %s clock registration failed\n", name);
+		x = ERR_PTR(ret);
+	}
+err:
+	kfree(clk_name);
+	kfree(core_name);
+	return x;
+}

In all your mmc_clkc_register_xxx_() you should a pattern repeating itself. It
is something I pointed out in the previous version of your patchset

1. allocate a clk_regmap
2. allocate a clock name using dev name and a suffix.
3. register clk_hw
4. free clock name
5. return clk_regmap

You should be able to make an helper function out of this
Prototype will probably look like this:

static struct clk_regmap *
mmc_clkc_register_clk(struct device *dev, struct regmap *map,
		      struct clk_init_data *init, const char* suffix)

+
+static int mmc_clkc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mmc_clkc_info *clkc;
+	struct clk_regmap *mux, *div, *core, *rx, *tx;
+	struct clk_hw_onecell_data *onecell_data;
+
+	clkc = devm_kzalloc(dev, sizeof(*clkc), GFP_KERNEL);
+	if (!clkc)
+		return -ENOMEM;
+
+	clkc->data = (struct mmc_clkc_data *)of_device_get_match_data(dev);
+	if (!clkc->data)
+		return -EINVAL;

Prefer ENODEV for this

+
+	clkc->dev = dev;
+	clkc->map = syscon_node_to_regmap(dev->of_node);
+
+	if (IS_ERR(clkc->map)) {
+		dev_err(dev, "could not find mmc clock controller\n");
+		return PTR_ERR(clkc->map);
+	}
+
+	onecell_data = devm_kzalloc(dev, sizeof(*onecell_data) +
+				    sizeof(*onecell_data->hws) * MMC_MAX_CLKS,
+				    GFP_KERNEL);
+	if (!onecell_data)
+		return -ENOMEM;
+
+	mux = mmc_clkc_register_mux(clkc);
+	if (IS_ERR(mux))
+		return PTR_ERR(mux);
+
+	div = mmc_clkc_register_div(clkc);
+	if (IS_ERR(div))
+		return PTR_ERR(div);
+
+	core = mmc_clkc_register_phase_clk(clkc, "core", "div",
+					   CLK_SET_RATE_PARENT,
+					   &mmc_clkc_core_phase);
+	if (IS_ERR(core))
+		return PTR_ERR(core);
+
+	rx = mmc_clkc_register_phase_clk(clkc, "rx", "core", 0,
+					 &clkc->data->rx);
+	if (IS_ERR(rx))
+		return PTR_ERR(rx);
+
+	tx = mmc_clkc_register_phase_clk(clkc, "tx", "core", 0,
+					 &clkc->data->tx);
+	if (IS_ERR(tx))
+		return PTR_ERR(tx);
+
+	onecell_data->hws[CLKID_MMC_MUX]		= &mux->hw,
+	onecell_data->hws[CLKID_MMC_DIV]		= &div->hw,
+	onecell_data->hws[CLKID_MMC_PHASE_CORE]		= &core->hw,
+	onecell_data->hws[CLKID_MMC_PHASE_RX]		= &rx->hw,
+	onecell_data->hws[CLKID_MMC_PHASE_TX]		= &tx->hw,
+	onecell_data->num				= MMC_MAX_CLKS;
+
+	return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
+					   onecell_data);
+}
+
+static struct platform_driver mmc_clkc_driver = {
+	.probe		= mmc_clkc_probe,
+	.driver		= {
+		.name	= "meson-mmc-clkc",
+		.of_match_table = of_match_ptr(mmc_clkc_match_table),
+	},
+};
+
+module_platform_driver(mmc_clkc_driver);