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Date: Tue, 10 Mar 2015 09:58:12 +0100
From: Mike Looijmans <mike.looijmans@...ic.nl>
To: Mike Turquette <mturquette@...aro.org>
CC: devicetree <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] Add TI CDCE925 I2C controlled clock synthesizer driver
On 12-01-15 04:04, Mike Turquette wrote:
> On Thu, Jan 8, 2015 at 11:01 PM, Mike Looijmans <mike.looijmans@...ic.nl> wrote:
>> Just a ping to inform if you've had had time to look at this?
>
> Its in the queue for review this week. A lot to catch up on after the
> holidays. Thanks for the ping.
Just another ping, you haven't forgotten me I hope?
We're using this chip on several boards now, and we'd really like to get all
the drivers "mainlined".
M.
>> 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, ®map_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
Telefoon: (+31) (0) 499 33 69 79
Telefax: (+31) (0) 499 33 69 70
E-mail: mike.looijmans@...ic.nl
Website: www.topic.nl
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