Date:	Tue, 9 Dec 2014 13:33:03 +0100
From:	Mike Looijmans <mike.looijmans@...ic.nl>
To:	<mturquette@...aro.org>
CC:	<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] Add TI CDCE925 I2C controlled clock synthesizer driver

Just a ping to ask for attention. Anyone care to review, comment or otherwise 
provide some feedback?


On 12/04/2014 08:26 AM, Mike Looijmans wrote:
> This driver supports the TI CDCE925 programmable clock synthesizer.
> The chip contains two PLLs with spread-spectrum clocking support and
> five output dividers. The driver only supports the following setup,
> and uses a fixed setting for the output muxes:
>    Y1 is derived from the input clock
>    Y2 and Y3 derive from PLL1
>    Y4 and Y5 derive from PLL2
> Given a target output frequency, the driver will set the PLL and
> divider to best approximate the desired output.
>
> Signed-off-by: Mike Looijmans <mike.looijmans@...ic.nl>
> ---
>
> v2: Coding style check
>      Add devicetree binding documentation
>
>   .../devicetree/bindings/clock/cdce925.txt          |   61 ++
>   drivers/clk/Kconfig                                |   17 +
>   drivers/clk/Makefile                               |    1 +
>   drivers/clk/clk-cdce925.c                          |  792 ++++++++++++++++++++
>   4 files changed, 871 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/clock/cdce925.txt
>   create mode 100644 drivers/clk/clk-cdce925.c
>
> diff --git a/Documentation/devicetree/bindings/clock/cdce925.txt b/Documentation/devicetree/bindings/clock/cdce925.txt
> new file mode 100644
> index 0000000..0eac770
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/cdce925.txt
> @@ -0,0 +1,61 @@
> +Binding for TO CDCE925 programmable I2C clock synthesizers.
> +
> +Reference
> +This binding uses the common clock binding[1].
> +
> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
> +[2] http://www.ti.com/product/cdce925
> +
> +Required properties:
> + - compatible: Shall be one of "cdce925", "cdce925pw",
> + - reg: I2C device address.
> + - clocks: Points to a fixed parent clock that provides the input frequency.
> + - #clock-cells: From common clock bindings: Shall be 1.
> +
> +Optional properties:
> + - xtal-load-pf: Crystal load-capacitor value to fine-tune performance on a
> +                 board, or to compensate for external influences.
> +
> +
> +For each connected output Y1 through Y5, a child node should be provided. Each
> +child node must have the following properties:
> + - #clock-cells: From common clock bindings: Shall be 0.
> +Optional properties for the output nodes:
> + - clock-frequency: Output frequency to generate. This defines the output
> +		    frequency set during boot. It can be reprogrammed during
> +		    runtime through the common clock framework.
> +
> +For both PLL1 and PLL2 an optional child node can be used to specify spread
> +spectrum clocking parameters.
> +  - spread-spectrum: SSC mode as defined in the data sheet.
> +  - spread-spectrum-center: Use "centered" mode instead of "max" mode. When this
> +    is present, the clock runs at the requested frequency on average.
> +
> +
> +Example:
> +
> +	clockgen: cdce925pw@64 {
> +		compatible = "cdce925";
> +		reg = <0x64>;
> +		clocks = <&xtal_27Mhz>;
> +		xtal-load-pf = <5>;
> +		#clock-cells = <1>;
> +		/* PLL options to get SSC 1% centered */
> +		PLL2 {
> +			spread-spectrum = <4>;
> +			spread-spectrum-center;
> +		};
> +		/* Outputs calculate mux and divider settings */
> +		Y1 {
> +			#clock-cells = <0>;
> +			clock-frequency = <27000>;
> +		};
> +		audio_clock: Y2 {
> +			#clock-cells = <0>;
> +			clock-frequency = <12288000>; /* SPDIF audio */
> +		};
> +		hdmi_pixel_clock: Y4 {
> +			#clock-cells = <0>;
> +			clock-frequency = <148500000>; /* HD-video */
> +		};
> +	};
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index 455fd17..4e474b3 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -77,6 +77,23 @@ config COMMON_CLK_SI570
>   	  This driver supports Silicon Labs 570/571/598/599 programmable
>   	  clock generators.
>
> +config COMMON_CLK_CDCE925
> +	tristate "Clock driver for TI CDCE925 devices"
> +	depends on I2C
> +	depends on OF
> +	select REGMAP_I2C
> +	help
> +	---help---
> +	  This driver supports the TI CDCE925 programmable clock synthesizer.
> +	  The chip contains two PLLs with spread-spectrum clocking support and
> +	  five output dividers. The driver only supports the following setup,
> +	  and uses a fixed setting for the output muxes.
> +	  Y1 is derived from the input clock
> +	  Y2 and Y3 derive from PLL1
> +	  Y4 and Y5 derive from PLL2
> +	  Given a target output frequency, the driver will set the PLL and
> +	  divider to best approximate the desired output.
> +
>   config COMMON_CLK_S2MPS11
>   	tristate "Clock driver for S2MPS1X/S5M8767 MFD"
>   	depends on MFD_SEC_CORE
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index d5fba5b..c476066 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -35,6 +35,7 @@ obj-$(CONFIG_COMMON_CLK_RK808)		+= clk-rk808.o
>   obj-$(CONFIG_COMMON_CLK_S2MPS11)	+= clk-s2mps11.o
>   obj-$(CONFIG_COMMON_CLK_SI5351)		+= clk-si5351.o
>   obj-$(CONFIG_COMMON_CLK_SI570)		+= clk-si570.o
> +obj-$(CONFIG_COMMON_CLK_CDCE925)	+= clk-cdce925.o
>   obj-$(CONFIG_CLK_TWL6040)		+= clk-twl6040.o
>   obj-$(CONFIG_ARCH_U300)			+= clk-u300.o
>   obj-$(CONFIG_ARCH_VT8500)		+= clk-vt8500.o
> diff --git a/drivers/clk/clk-cdce925.c b/drivers/clk/clk-cdce925.c
> new file mode 100644
> index 0000000..faa867f
> --- /dev/null
> +++ b/drivers/clk/clk-cdce925.c
> @@ -0,0 +1,792 @@
> +/*
> + * Driver for TI Dual PLL CDCE925 clock synthesizer
> + *
> + * This driver always connects the Y1 to the input clock, Y2/Y3 to PLL1
> + * and Y4/Y5 to PLL2. PLL frequency is set on a first-come-first-serve
> + * basis. Clients can directly request any frequency that the chip can
> + * deliver using the standard clk framework. In addition, the device can
> + * be configured and activated via the devicetree.
> + *
> + * Copyright (C) 2014, Topic Embedded Products
> + * Licenced under GPL
> + */
> +#include <linux/clk-provider.h>
> +#include <linux/clk-private.h>
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/gcd.h>
> +
> +/* The chip has 2 PLLs which can be routed through dividers to 5 outputs.
> + * Model this as 2 PLL clocks which are parents to the outputs.
> + */
> +#define NUMBER_OF_PLLS	2
> +#define NUMBER_OF_OUTPUTS	5
> +
> +#define CDCE925_REG_GLOBAL1	0x01
> +#define CDCE925_REG_Y1SPIPDIVH	0x02
> +#define CDCE925_REG_PDIVL	0x03
> +#define CDCE925_REG_XCSEL	0x05
> +/* PLL parameters start at 0x10, steps of 0x10 */
> +#define CDCE925_OFFSET_PLL	0x10
> +/* Add CDCE925_OFFSET_PLL * (pll) to these registers before sending */
> +#define CDCE925_PLL_MUX_OUTPUTS	0x14
> +#define CDCE925_PLL_MULDIV	0x18
> +
> +#define CDCE925_PLL_FREQUENCY_MIN	 80000000
> +#define CDCE925_PLL_FREQUENCY_MAX	230000000
> +struct clk_cdce925_chip;
> +
> +struct clk_cdce925_output {
> +	struct clk_hw hw;
> +	struct clk_cdce925_chip *chip;
> +	u8 index;
> +	u16 pdiv; /* 1..127 for Y2-Y5; 1..1023 for Y1 */
> +};
> +#define to_clk_cdce925_output(_hw) \
> +	container_of(_hw, struct clk_cdce925_output, hw)
> +
> +struct clk_cdce925_pll {
> +	struct clk_hw hw;
> +	struct clk_cdce925_chip *chip;
> +	u8 index;
> +	u16 m;   /* 1..511 */
> +	u16 n;   /* 1..4095 */
> +};
> +#define to_clk_cdce925_pll(_hw)	container_of(_hw, struct clk_cdce925_pll, hw)
> +
> +struct clk_cdce925_chip {
> +	struct regmap *regmap;
> +	struct i2c_client *i2c_client;
> +	struct clk_cdce925_pll pll[NUMBER_OF_PLLS];
> +	struct clk_cdce925_output clk[NUMBER_OF_OUTPUTS];
> +};
> +
> +/* ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** */
> +
> +static unsigned long cdce925_pll_calculate_rate(unsigned long parent_rate,
> +	u16 n, u16 m)
> +{
> +	if ((!m || !n) || (m == n))
> +		return parent_rate; /* In bypass mode runs at same frequency */
> +	return mult_frac(parent_rate, (unsigned long)n, (unsigned long)m);
> +}
> +
> +static unsigned long cdce925_pll_recalc_rate(struct clk_hw *hw,
> +		unsigned long parent_rate)
> +{
> +	/* Output frequency of PLL is Fout = (Fin/Pdiv)*(N/M) */
> +	struct clk_cdce925_pll *data = to_clk_cdce925_pll(hw);
> +
> +	return cdce925_pll_calculate_rate(parent_rate, data->n, data->m);
> +}
> +
> +static int cdce925_pll_find_rate(unsigned long rate,
> +		unsigned long parent_rate, u16 *n, u16 *m)
> +{
> +	if (rate <= parent_rate) {
> +		/* Can always deliver parent_rate in bypass mode */
> +		rate = parent_rate;
> +		*n = 0;
> +		*m = 0;
> +	} else {
> +		/* In PLL mode, need to apply min/max range */
> +		unsigned long un;
> +		unsigned long um;
> +		unsigned long g;
> +
> +		if (rate < CDCE925_PLL_FREQUENCY_MIN)
> +			rate = CDCE925_PLL_FREQUENCY_MIN;
> +		else if (rate > CDCE925_PLL_FREQUENCY_MAX)
> +			rate = CDCE925_PLL_FREQUENCY_MAX;
> +
> +		g = gcd(rate, parent_rate);
> +		um = parent_rate / g;
> +		un = rate / g;
> +		/* When outside hw range, reduce to fit (rounding errors) */
> +		while ((un > 4095) || (um > 511)) {
> +			un >>= 1;
> +			um >>= 1;
> +		}
> +		if (un == 0)
> +			un = 1;
> +		if (um == 0)
> +			um = 1;
> +
> +		*n = un;
> +		*m = um;
> +	}
> +
> +	pr_debug("%s(%lu,%lu) n=%u m=%u\n",
> +			__func__, rate, parent_rate, *n, *m);
> +
> +	return 0;
> +}
> +
> +static long cdce925_pll_round_rate(struct clk_hw *hw, unsigned long rate,
> +		unsigned long *parent_rate)
> +{
> +	struct clk_cdce925_pll *data = to_clk_cdce925_pll(hw);
> +	u16 n, m;
> +	int ret;
> +
> +	pr_debug("%s (index=%d parent_rate=%lu rate=%lu)\n", __func__,
> +		data->index, *parent_rate, rate);
> +	ret = cdce925_pll_find_rate(rate, *parent_rate, &n, &m);
> +	return (long)cdce925_pll_calculate_rate(*parent_rate, n, m);
> +}
> +
> +static int cdce925_pll_set_rate(struct clk_hw *hw, unsigned long rate,
> +		unsigned long parent_rate)
> +{
> +	struct clk_cdce925_pll *data = to_clk_cdce925_pll(hw);
> +
> +	if (!rate || (rate == parent_rate)) {
> +		data->m = 0; /* Bypass mode */
> +		data->n = 0;
> +		return 0;
> +	}
> +
> +	if ((rate < CDCE925_PLL_FREQUENCY_MIN) ||
> +		(rate > CDCE925_PLL_FREQUENCY_MAX)) {
> +		pr_debug("%s: rate %lu outside PLL range.\n", __func__, rate);
> +		return -EINVAL;
> +	}
> +
> +	if (rate < parent_rate) {
> +		pr_debug("%s: rate %lu less than parent rate %lu.\n", __func__,
> +			rate, parent_rate);
> +		return -EINVAL;
> +	}
> +
> +	return cdce925_pll_find_rate(rate, parent_rate, &data->n, &data->m);
> +}
> +
> +
> +/* calculate p = max(0, 4 - int(log2 (n/m))) */
> +static u8 cdce925_pll_calc_p(u16 n, u16 m)
> +{
> +	u8 p;
> +	u16 r = n / m;
> +
> +	if (r >= 16)
> +		return 0;
> +	p = 4;
> +	while (r > 1) {
> +		r >>= 1;
> +		--p;
> +	}
> +	return p;
> +}
> +
> +/* Returns VCO range bits for VCO1_0_RANGE */
> +static u8 cdce925_pll_calc_range_bits(struct clk_hw *hw, u16 n, u16 m)
> +{
> +	struct clk *parent = clk_get_parent(hw->clk);
> +	unsigned long rate = clk_get_rate(parent);
> +
> +	rate = mult_frac(rate, (unsigned long)n, (unsigned long)m);
> +	if (rate >= 175000000)
> +		return 0x3;
> +	if (rate >= 150000000)
> +		return 0x02;
> +	if (rate >= 125000000)
> +		return 0x01;
> +	return 0x00;
> +}
> +
> +/* I2C clock, hence everything must happen in (un)prepare because this
> + * may sleep */
> +static int cdce925_pll_prepare(struct clk_hw *hw)
> +{
> +	struct clk_cdce925_pll *data = to_clk_cdce925_pll(hw);
> +	u16 n = data->n;
> +	u16 m = data->m;
> +	u16 r;
> +	u8 q;
> +	u8 p;
> +	u16 nn;
> +	u8 pll[4]; /* Bits are spread out over 4 byte registers */
> +	u8 reg_ofs = data->index * CDCE925_OFFSET_PLL;
> +	unsigned i;
> +
> +	pr_debug("%s: index=%d\n", __func__, data->index);
> +
> +	if ((!m || !n) || (m == n)) {
> +		/* Set PLL mux to bypass mode, leave the rest as is */
> +		regmap_update_bits(data->chip->regmap,
> +			reg_ofs + CDCE925_PLL_MUX_OUTPUTS, 0x80, 0x80);
> +	} else {
> +		/* According to data sheet: */
> +		/* p = max(0, 4 - int(log2 (n/m))) */
> +		p = cdce925_pll_calc_p(n, m);
> +		/* nn = n * 2^p */
> +		nn = n * BIT(p);
> +		/* q = int(nn/m) */
> +		q = nn / m;
> +		if ((q < 16) || (1 > 64)) {
> +			pr_debug("%s invalid q=%d\n", __func__, q);
> +			return -EINVAL;
> +		}
> +		r = nn - (m*q);
> +		if (r > 511) {
> +			pr_debug("%s invalid r=%d\n", __func__, r);
> +			return -EINVAL;
> +		}
> +		pr_debug("%s n=%d m=%d p=%d q=%d r=%d\n", __func__,
> +			n, m, p, q, r);
> +		/* encode into register bits */
> +		pll[0] = n >> 4;
> +		pll[1] = ((n & 0x0F) << 4) | ((r >> 5) & 0x0F);
> +		pll[2] = ((r & 0x1F) << 3) | ((q >> 3) & 0x07);
> +		pll[3] = ((q & 0x07) << 5) | (p << 2) |
> +				cdce925_pll_calc_range_bits(hw, n, m);
> +		/* Write to registers */
> +		for (i = 0; i < ARRAY_SIZE(pll); ++i)
> +			regmap_write(data->chip->regmap,
> +				reg_ofs + CDCE925_PLL_MULDIV + i, pll[i]);
> +		/* Enable PLL */
> +		regmap_update_bits(data->chip->regmap,
> +			reg_ofs + CDCE925_PLL_MUX_OUTPUTS, 0x80, 0x00);
> +	}
> +
> +	return 0;
> +}
> +
> +static void cdce925_pll_unprepare(struct clk_hw *hw)
> +{
> +	struct clk_cdce925_pll *data = to_clk_cdce925_pll(hw);
> +	u8 reg_ofs = data->index * CDCE925_OFFSET_PLL;
> +
> +	pr_debug("%s: index=%d\n", __func__, data->index);
> +	regmap_update_bits(data->chip->regmap,
> +			reg_ofs + CDCE925_PLL_MUX_OUTPUTS, 0x80, 0x80);
> +}
> +
> +static const struct clk_ops cdce925_pll_ops = {
> +	.prepare = cdce925_pll_prepare,
> +	.unprepare = cdce925_pll_unprepare,
> +	.recalc_rate = cdce925_pll_recalc_rate,
> +	.round_rate = cdce925_pll_round_rate,
> +	.set_rate = cdce925_pll_set_rate,
> +};
> +
> +
> +static void cdce925_clk_set_pdiv(struct clk_cdce925_output *data, u16 pdiv)
> +{
> +	pr_debug("%s: index=%d pdiv=%d\n", __func__, data->index, pdiv);
> +	switch (data->index) {
> +	case 0:
> +		regmap_update_bits(data->chip->regmap,
> +			CDCE925_REG_Y1SPIPDIVH,
> +			0x03, (pdiv >> 8) & 0x03);
> +		regmap_write(data->chip->regmap, 0x03, pdiv & 0xFF);
> +		break;
> +	case 1:
> +		regmap_update_bits(data->chip->regmap, 0x16, 0x7F, pdiv);
> +		break;
> +	case 2:
> +		regmap_update_bits(data->chip->regmap, 0x17, 0x7F, pdiv);
> +		break;
> +	case 3:
> +		regmap_update_bits(data->chip->regmap, 0x26, 0x7F, pdiv);
> +		break;
> +	case 4:
> +		regmap_update_bits(data->chip->regmap, 0x27, 0x7F, pdiv);
> +		break;
> +	}
> +}
> +
> +static void cdce925_clk_activate(struct clk_cdce925_output *data)
> +{
> +	pr_debug("%s: index=%d\n", __func__, data->index);
> +	switch (data->index) {
> +	case 0:
> +		regmap_update_bits(data->chip->regmap,
> +			CDCE925_REG_Y1SPIPDIVH, 0x0c, 0x0c);
> +		break;
> +	case 1:
> +	case 2:
> +		regmap_update_bits(data->chip->regmap, 0x14, 0x03, 0x03);
> +		break;
> +	case 3:
> +	case 4:
> +		regmap_update_bits(data->chip->regmap, 0x24, 0x03, 0x03);
> +		break;
> +	}
> +}
> +
> +static int cdce925_clk_prepare(struct clk_hw *hw)
> +{
> +	struct clk_cdce925_output *data = to_clk_cdce925_output(hw);
> +
> +	pr_debug("%s: index=%d\n", __func__, data->index);
> +	cdce925_clk_set_pdiv(data, data->pdiv);
> +	cdce925_clk_activate(data);
> +	return 0;
> +}
> +
> +static void cdce925_clk_unprepare(struct clk_hw *hw)
> +{
> +	struct clk_cdce925_output *data = to_clk_cdce925_output(hw);
> +
> +	pr_debug("%s: index=%d\n", __func__, data->index);
> +	/* Disable clock by setting divider to "0" */
> +	cdce925_clk_set_pdiv(data, 0);
> +}
> +
> +static unsigned long cdce925_clk_recalc_rate(struct clk_hw *hw,
> +		unsigned long parent_rate)
> +{
> +	struct clk_cdce925_output *data = to_clk_cdce925_output(hw);
> +
> +	pr_debug("%s: index=%d parent_rate=%lu pdiv=%d\n", __func__,
> +		data->index, parent_rate, data->pdiv);
> +	if (data->pdiv)
> +		return parent_rate / data->pdiv;
> +	return 0;
> +}
> +
> +static u16 cdce925_calc_divider(unsigned long rate,
> +		unsigned long parent_rate)
> +{
> +	if (rate >= parent_rate) {
> +		return 1;
> +	} else if (rate) {
> +		unsigned long divider = DIV_ROUND_CLOSEST(parent_rate, rate);
> +
> +		if (divider > 0x7F) /* TODO: Y1 has 10-bit divider */
> +			divider = 0x7F;
> +		return (u16)divider;
> +	} else {
> +		return 0;
> +	}
> +}
> +
> +static unsigned long cdce925_clk_best_parent_rate(
> +	struct clk_hw *hw, unsigned long rate)
> +{
> +	struct clk *pll = clk_get_parent(hw->clk);
> +	struct clk *root = clk_get_parent(pll);
> +	unsigned long root_rate = clk_get_rate(root);
> +	unsigned long best_rate_error = rate;
> +	u16 pdiv_min;
> +	u16 pdiv_max;
> +	u16 pdiv_best;
> +	u16 pdiv_now;
> +
> +	if (root_rate % rate == 0)
> +		return root_rate; /* Don't need the PLL, use bypass */
> +
> +	pdiv_min = (u16)max(1u, DIV_ROUND_UP(CDCE925_PLL_FREQUENCY_MIN, rate));
> +	pdiv_max = (u16)min(127u, CDCE925_PLL_FREQUENCY_MAX / rate);
> +
> +	if (pdiv_min > pdiv_max)
> +		return 0; /* No can do? */
> +
> +	pdiv_best = pdiv_min;
> +	for (pdiv_now = pdiv_min; pdiv_now < pdiv_max; ++pdiv_now) {
> +		unsigned long target_rate = rate * pdiv_now;
> +		long pll_rate = clk_round_rate(pll, target_rate);
> +		unsigned long actual_rate;
> +		unsigned long rate_error;
> +
> +		if (pll_rate <= 0)
> +			continue;
> +		actual_rate = pll_rate / pdiv_now;
> +		rate_error = abs((long)actual_rate - (long)rate);
> +		if (rate_error < best_rate_error) {
> +			pdiv_best = pdiv_now;
> +			best_rate_error = rate_error;
> +		}
> +		/* TODO: Consider PLL frequency based on smaller n/m values
> +		 * and pick the better one if the error is equal */
> +	}
> +
> +	return rate * pdiv_best;
> +}
> +
> +static long cdce925_clk_round_rate(struct clk_hw *hw, unsigned long rate,
> +		unsigned long *parent_rate)
> +{
> +	struct clk_cdce925_output *data = to_clk_cdce925_output(hw);
> +	unsigned long l_parent_rate = *parent_rate;
> +	u16 divider = cdce925_calc_divider(rate, l_parent_rate);
> +
> +	pr_debug("%s (index=%d parent_rate=%lu rate=%lu)\n", __func__,
> +		data->index, l_parent_rate, rate);
> +	if (l_parent_rate / divider != rate) {
> +		l_parent_rate = cdce925_clk_best_parent_rate(hw, rate);
> +		divider = cdce925_calc_divider(rate, l_parent_rate);
> +		*parent_rate = l_parent_rate;
> +	}
> +	pr_debug("%s parent_rate=%lu pdiv=%u\n", __func__,
> +		l_parent_rate, divider);
> +	if (divider)
> +		return (long)(l_parent_rate / divider);
> +	return 0;
> +}
> +
> +static int cdce925_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> +		unsigned long parent_rate)
> +{
> +	struct clk_cdce925_output *data = to_clk_cdce925_output(hw);
> +
> +	data->pdiv = cdce925_calc_divider(rate, parent_rate);
> +	pr_debug("%s (index=%d parent_rate=%lu rate=%lu div=%d)\n", __func__,
> +		data->index, parent_rate, rate, data->pdiv);
> +	return 0;
> +}
> +
> +static const struct clk_ops cdce925_clk_ops = {
> +	.prepare = cdce925_clk_prepare,
> +	.unprepare = cdce925_clk_unprepare,
> +	.recalc_rate = cdce925_clk_recalc_rate,
> +	.round_rate = cdce925_clk_round_rate,
> +	.set_rate = cdce925_clk_set_rate,
> +};
> +
> +
> +static u16 cdce925_y1_calc_divider(unsigned long rate,
> +		unsigned long parent_rate)
> +{
> +	if (rate >= parent_rate)
> +		return 1;
> +	else if (rate) {
> +		unsigned long divider = DIV_ROUND_CLOSEST(parent_rate, rate);
> +
> +		if (divider > 0x3FF) /* Y1 has 10-bit divider */
> +			divider = 0x3FF;
> +		return (u16)divider;
> +	} else
> +		return 0;
> +}
> +
> +static long cdce925_clk_y1_round_rate(struct clk_hw *hw, unsigned long rate,
> +		unsigned long *parent_rate)
> +{
> +	struct clk_cdce925_output *data = to_clk_cdce925_output(hw);
> +	unsigned long l_parent_rate = *parent_rate;
> +	u16 divider = cdce925_y1_calc_divider(rate, l_parent_rate);
> +
> +	pr_debug("%s (index=%d parent_rate=%lu rate=%lu pdiv=%u)\n", __func__,
> +		data->index, l_parent_rate, rate, divider);
> +	if (divider)
> +		return (long)(l_parent_rate / divider);
> +	return 0;
> +}
> +
> +static int cdce925_clk_y1_set_rate(struct clk_hw *hw, unsigned long rate,
> +		unsigned long parent_rate)
> +{
> +	struct clk_cdce925_output *data = to_clk_cdce925_output(hw);
> +
> +	data->pdiv = cdce925_y1_calc_divider(rate, parent_rate);
> +	pr_debug("%s (index=%d parent_rate=%lu rate=%lu div=%d)\n", __func__,
> +		data->index, parent_rate, rate, data->pdiv);
> +	return 0;
> +}
> +
> +static const struct clk_ops cdce925_clk_y1_ops = {
> +	.prepare = cdce925_clk_prepare,
> +	.unprepare = cdce925_clk_unprepare,
> +	.recalc_rate = cdce925_clk_recalc_rate,
> +	.round_rate = cdce925_clk_y1_round_rate,
> +	.set_rate = cdce925_clk_y1_set_rate,
> +};
> +
> +
> +static struct regmap_config cdce925_regmap_config = {
> +	.name = "configuration0",
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.cache_type = REGCACHE_RBTREE,
> +	.max_register = 0x2F,
> +};
> +
> +#define CDCE925_I2C_COMMAND_BLOCK_TRANSFER	0x00
> +#define CDCE925_I2C_COMMAND_BYTE_TRANSFER	0x80
> +
> +static int cdce925_regmap_i2c_write(
> +	void *context, const void *data, size_t count)
> +{
> +	struct device *dev = context;
> +	struct i2c_client *i2c = to_i2c_client(dev);
> +	int ret;
> +	u8 reg_data[2];
> +
> +	if (count != 2)
> +		return -ENOTSUPP;
> +
> +	/* First byte is command code */
> +	reg_data[0] = CDCE925_I2C_COMMAND_BYTE_TRANSFER | ((u8 *)data)[0];
> +	reg_data[1] = ((u8 *)data)[1];
> +
> +	dev_dbg(&i2c->dev, "%s(%u) %#x %#x\n", __func__, count,
> +			reg_data[0], reg_data[1]);
> +
> +	ret = i2c_master_send(i2c, reg_data, count);
> +	if (likely(ret == count))
> +		return 0;
> +	else if (ret < 0)
> +		return ret;
> +	else
> +		return -EIO;
> +}
> +
> +static int cdce925_regmap_i2c_read(void *context,
> +	   const void *reg, size_t reg_size, void *val, size_t val_size)
> +{
> +	struct device *dev = context;
> +	struct i2c_client *i2c = to_i2c_client(dev);
> +	struct i2c_msg xfer[2];
> +	int ret;
> +	u8 reg_data[2];
> +
> +	if (reg_size != 1)
> +		return -ENOTSUPP;
> +
> +	xfer[0].addr = i2c->addr;
> +	xfer[0].flags = 0;
> +	xfer[0].buf = reg_data;
> +	if (val_size == 1) {
> +		reg_data[0] =
> +			CDCE925_I2C_COMMAND_BYTE_TRANSFER | ((u8 *)reg)[0];
> +		xfer[0].len = 1;
> +	} else {
> +		reg_data[0] =
> +			CDCE925_I2C_COMMAND_BLOCK_TRANSFER | ((u8 *)reg)[0];
> +		reg_data[1] = val_size;
> +		xfer[0].len = 2;
> +	}
> +
> +	xfer[1].addr = i2c->addr;
> +	xfer[1].flags = I2C_M_RD;
> +	xfer[1].len = val_size;
> +	xfer[1].buf = val;
> +
> +	ret = i2c_transfer(i2c->adapter, xfer, 2);
> +	if (likely(ret == 2)) {
> +		dev_dbg(&i2c->dev, "%s(%u, %u) %#x %#x\n", __func__,
> +				reg_size, val_size, reg_data[0], *((u8 *)val));
> +		return 0;
> +	} else if (ret < 0)
> +		return ret;
> +	else
> +		return -EIO;
> +}
> +
> +/* The CDCE925 uses a funky way to read/write registers. Bulk mode is
> + * just weird, so just use the single byte mode exclusively. */
> +static struct regmap_bus regmap_cdce925_bus = {
> +	.write = cdce925_regmap_i2c_write,
> +	.read = cdce925_regmap_i2c_read,
> +};
> +
> +static int cdce925_probe(struct i2c_client *client,
> +		const struct i2c_device_id *id)
> +{
> +	struct clk_cdce925_chip *data;
> +	struct device_node *node = client->dev.of_node;
> +	const char *parent_name;
> +	struct clk_init_data init;
> +	struct clk *clk;
> +	u32 value;
> +	int i;
> +	int err;
> +	struct device_node *np_output;
> +	char child_name[6];
> +
> +	dev_dbg(&client->dev, "%s\n", __func__);
> +	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->i2c_client = client;
> +	data->regmap = devm_regmap_init(&client->dev, &regmap_cdce925_bus,
> +			&client->dev, &cdce925_regmap_config);
> +	if (IS_ERR(data->regmap)) {
> +		dev_err(&client->dev, "failed to allocate register map\n");
> +		return PTR_ERR(data->regmap);
> +	}
> +	i2c_set_clientdata(client, data);
> +
> +	parent_name = of_clk_get_parent_name(node, 0);
> +	if (!parent_name) {
> +		dev_err(&client->dev, "missing parent clock\n");
> +		return -ENODEV;
> +	}
> +	dev_dbg(&client->dev, "parent is: %s\n", parent_name);
> +
> +	if (of_property_read_u32(node, "xtal-load-pf", &value) == 0)
> +		regmap_write(data->regmap,
> +			CDCE925_REG_XCSEL, (value << 3) & 0xF8);
> +	/* PWDN bit */
> +	regmap_update_bits(data->regmap, CDCE925_REG_GLOBAL1, BIT(4), 0);
> +
> +	/* Set input source for Y1 to be the XTAL */
> +	regmap_update_bits(data->regmap, 0x02, BIT(7), 0);
> +
> +	init.ops = &cdce925_pll_ops;
> +	init.flags = 0;
> +	init.parent_names = &parent_name;
> +	init.num_parents = parent_name ? 1 : 0;
> +
> +	/* Register PLL clocks */
> +	for (i = 0; i < NUMBER_OF_PLLS; ++i) {
> +		init.name = kasprintf(GFP_KERNEL, "%s.pll%d",
> +			client->dev.of_node->name, i);
> +		data->pll[i].chip = data;
> +		data->pll[i].hw.init = &init;
> +		data->pll[i].index = i;
> +		clk = devm_clk_register(&client->dev, &data->pll[i].hw);
> +		kfree(init.name); /* clock framework made a copy of the name */
> +		if (IS_ERR(clk)) {
> +			dev_err(&client->dev, "Failed register PLL %d\n", i);
> +			err = PTR_ERR(clk);
> +			goto error;
> +		}
> +		sprintf(child_name, "PLL%d", i+1);
> +		np_output = of_get_child_by_name(node, child_name);
> +		if (!np_output)
> +			continue;
> +		if (!of_property_read_u32(np_output,
> +			"clock-frequency", &value)) {
> +			err = clk_set_rate(clk, value);
> +			if (err)
> +				dev_err(&client->dev,
> +					"unable to set PLL frequency %ud\n",
> +					value);
> +		}
> +		if (!of_property_read_u32(np_output,
> +			"spread-spectrum", &value)) {
> +			u8 flag = of_property_read_bool(np_output,
> +				"spread-spectrum-center") ? 0x80 : 0x00;
> +			regmap_update_bits(data->regmap,
> +				0x16 + (i*CDCE925_OFFSET_PLL),
> +				0x80, flag);
> +			regmap_update_bits(data->regmap,
> +				0x12 + (i*CDCE925_OFFSET_PLL),
> +				0x07, value & 0x07);
> +		}
> +	}
> +
> +	/* Register output clock Y1 */
> +	init.ops = &cdce925_clk_y1_ops;
> +	init.flags = 0;
> +	init.num_parents = 1;
> +	init.parent_names = &parent_name; /* Mux Y1 to input */
> +	init.name = kasprintf(GFP_KERNEL, "%s.Y1", client->dev.of_node->name);
> +	data->clk[0].chip = data;
> +	data->clk[0].hw.init = &init;
> +	data->clk[0].index = 0;
> +	data->clk[0].pdiv = 1;
> +	clk = devm_clk_register(&client->dev, &data->clk[0].hw);
> +	kfree(init.name); /* clock framework made a copy of the name */
> +	if (IS_ERR(clk)) {
> +		dev_err(&client->dev, "clock registration Y1 failed\n");
> +		err = PTR_ERR(clk);
> +		goto error;
> +	}
> +
> +	/* Register output clocks Y2 .. Y5*/
> +	init.ops = &cdce925_clk_ops;
> +	init.flags = CLK_SET_RATE_PARENT;
> +	init.num_parents = 1;
> +	for (i = 1; i < NUMBER_OF_OUTPUTS; ++i) {
> +		init.name = kasprintf(GFP_KERNEL, "%s.Y%d",
> +			client->dev.of_node->name, i+1);
> +		data->clk[i].chip = data;
> +		data->clk[i].hw.init = &init;
> +		data->clk[i].index = i;
> +		data->clk[i].pdiv = 1;
> +		switch (i) {
> +		case 1:
> +		case 2:
> +			/* Mux Y2/3 to PLL1 */
> +			init.parent_names = &data->pll[0].hw.clk->name;
> +			break;
> +		case 3:
> +		case 4:
> +			/* Mux Y4/5 to PLL2 */
> +			init.parent_names = &data->pll[1].hw.clk->name;
> +			break;
> +		}
> +		clk = devm_clk_register(&client->dev, &data->clk[i].hw);
> +		kfree(init.name); /* clock framework made a copy of the name */
> +		if (IS_ERR(clk)) {
> +			dev_err(&client->dev, "clock registration failed\n");
> +			err = PTR_ERR(clk);
> +			goto error;
> +		}
> +	}
> +
> +	/* Fetch settings from devicetree, if any */
> +	for (i = 0; i < NUMBER_OF_OUTPUTS; ++i) {
> +		sprintf(child_name, "Y%d", i+1);
> +		np_output = of_get_child_by_name(node, child_name);
> +		if (!np_output) {
> +			/* Disable unlisted/unused clock outputs explicitly */
> +			cdce925_clk_unprepare(&data->clk[i].hw);
> +			continue;
> +		}
> +		clk = data->clk[i].hw.clk;
> +		if (!of_property_read_u32(np_output,
> +			"clock-frequency", &value)) {
> +			err = clk_set_rate(clk, value);
> +			if (err)
> +				dev_err(&client->dev,
> +					"unable to set frequency %ud\n",
> +					value);
> +		}
> +		if (of_property_read_bool(np_output, "clock-enabled")) {
> +			err = clk_prepare_enable(clk);
> +			if (err)
> +				dev_err(&client->dev,
> +					"Failed to enable clock %s\n",
> +					init.name);
> +		} else {
> +			cdce925_clk_unprepare(&data->clk[i].hw);
> +		}
> +		err = of_clk_add_provider(np_output,
> +			of_clk_src_simple_get, clk);
> +		if (err)
> +			dev_err(&client->dev,
> +				"unable to add clock provider '%s'\n",
> +				init.name);
> +	}
> +
> +	return 0;
> +
> +error:
> +	return err;
> +}
> +
> +static const struct i2c_device_id cdce925_id[] = {
> +	{ "cdce925", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, cdce925_id);
> +
> +static const struct of_device_id clk_cdce925_of_match[] = {
> +	{ .compatible = "cdce925pw" },
> +	{ .compatible = "cdce925" },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, clk_cdce925_of_match);
> +
> +static struct i2c_driver cdce925_driver = {
> +	.driver = {
> +		.name = "cdce925",
> +		.of_match_table = of_match_ptr(clk_cdce925_of_match),
> +	},
> +	.probe		= cdce925_probe,
> +	.id_table	= cdce925_id,
> +};
> +module_i2c_driver(cdce925_driver);
> +
> +MODULE_AUTHOR("Mike Looijmans <mike.looijmans@...ic.nl>");
> +MODULE_DESCRIPTION("cdce925 driver");
> +MODULE_LICENSE("GPL");
>



Met vriendelijke groet / kind regards,

Mike Looijmans
System Expert


TOPIC Embedded Systems
Eindhovenseweg 32-C, NL-5683 KH Best
Postbus 440, NL-5680 AK Best
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E-mail: mike.looijmans@...ic.nl
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