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SubjectRe: [PATCH] clk: at91: utmi: Support configurable multipliers
Hi Ingo,

I did a similar patch, and I was told that you sent something similar.
I missed your patch since I have not subscribed to the linux-clk mailing
list. If it's related to at91, you should send it to linux-arm mailing list
too.

On Mon, Jul 10, 2017 at 02:24:09PM +0200, Ingo van Lil wrote:
> The AT91 UTMI clock is a PLL generating the 480 MHz USB clock.
> Originally, this PLL always had a fixed x40 multiplier, thus requiring
> a 12 MHz input clock. Recent SOCs (sama5d2 and sama5d3) have a special
> function register for configuring this multiplier, allowing to use
> different main clock frequencies.
>
> Signed-off-by: Ingo van Lil <inguin@gmx.de>

Unfortunately, replacing my patch by yours, it no longer works. More
precisely, USB stuff is broken: utmi rate is weird.

> ---
> drivers/clk/at91/clk-utmi.c | 105 +++++++++++++++++++++++++++++++++++++++++--
> include/soc/at91/atmel-sfr.h | 2 +
> 2 files changed, 104 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/at91/clk-utmi.c b/drivers/clk/at91/clk-utmi.c
> index aadabd9..d41c38b 100644
> --- a/drivers/clk/at91/clk-utmi.c
> +++ b/drivers/clk/at91/clk-utmi.c
> @@ -14,14 +14,29 @@
> #include <linux/of.h>
> #include <linux/mfd/syscon.h>
> #include <linux/regmap.h>
> +#include <soc/at91/atmel-sfr.h>
>
> #include "pmc.h"
>
> +/* default multiplier for SOCs that do not allow configuration via SFR */
> #define UTMI_FIXED_MUL 40
>
> +/* supported multiplier settings for SOCs that allow configuration via SFR */
> +struct utmi_multipliers {
> + const char *sfr_compatible_name;
> + u8 multipliers[4];
> +};
> +
> +static const struct utmi_multipliers utmi_multipliers[] = {
> + { "atmel,sama5d2-sfr", { 40, 30, 20, 40 } },
> + { "atmel,sama5d3-sfr", { 40, 30, 20, 10 } },
> +};
> +

I will see if there is no mistake in the datasheet. On my side, I deal
only with '40, 30, 20, 10' case, I am not sure we have to take care of
'40, 30, 20, 40' even if it's not a mistake in the datasheet.

> struct clk_utmi {
> struct clk_hw hw;
> struct regmap *regmap;
> + struct regmap *sfr_regmap;
> + const u8 *multipliers;
> };
>
> #define to_clk_utmi(hw) container_of(hw, struct clk_utmi, hw)
> @@ -66,8 +81,67 @@ static void clk_utmi_unprepare(struct clk_hw *hw)
> static unsigned long clk_utmi_recalc_rate(struct clk_hw *hw,
> unsigned long parent_rate)
> {
> - /* UTMI clk is a fixed clk multiplier */
> - return parent_rate * UTMI_FIXED_MUL;
> + struct clk_utmi *utmi = to_clk_utmi(hw);
> + u8 mul = UTMI_FIXED_MUL;
> +
> + if (utmi->sfr_regmap && utmi->multipliers) {
> + u32 regval;
> + regmap_read(utmi->sfr_regmap, AT91_SFR_UTMICKTRIM, &regval);
> + mul = utmi->multipliers[regval & AT91_UTMICKTRIM_FREQ_MASK];
> + }
> +
> + return parent_rate * mul;
> +}
> +
> +static long clk_utmi_round_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long *parent_rate)
> +{
> + struct clk_utmi *utmi = to_clk_utmi(hw);
> + unsigned long bestrate = 0;
> + int bestdiff = -1;
> + int i;
> +
> + if (!utmi->sfr_regmap || !utmi->multipliers)
> + return *parent_rate * UTMI_FIXED_MUL;
> +
> + for (i = 0; i < ARRAY_SIZE(utmi_multipliers); i++) {
> + unsigned long tmprate = *parent_rate * utmi->multipliers[i];
> + int tmpdiff;
> +
> + if (tmprate < rate)
> + continue;
> +
> + tmpdiff = tmprate - rate;
> + if (bestdiff < 0 || bestdiff > tmpdiff) {
> + bestrate = tmprate;
> + bestdiff = tmpdiff;
> + }
> +
> + if (!bestdiff)
> + break;
> + }
> +
> + return bestrate;
> +}
> +
> +static int clk_utmi_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct clk_utmi *utmi = to_clk_utmi(hw);
> + int i;
> +
> + if (!utmi->sfr_regmap || !utmi->multipliers)
> + return rate == parent_rate * UTMI_FIXED_MUL ? 0 : -EINVAL;
> +
> + for (i = 0; i < ARRAY_SIZE(utmi_multipliers); i++) {
> + if (rate == parent_rate * utmi->multipliers[i]) {
> + regmap_update_bits(utmi->sfr_regmap, AT91_SFR_UTMICKTRIM,
> + AT91_UTMICKTRIM_FREQ_MASK, i);
> + return 0;
> + }
> + }
> +
> + return -EINVAL;
> }

What's the purpose of this addition? Who should set the rate of the utmi
clock? I mean you have no choice, the rate is 480 MHz.

>
> static const struct clk_ops utmi_ops = {
> @@ -75,10 +149,13 @@ static const struct clk_ops utmi_ops = {
> .unprepare = clk_utmi_unprepare,
> .is_prepared = clk_utmi_is_prepared,
> .recalc_rate = clk_utmi_recalc_rate,
> + .round_rate = clk_utmi_round_rate,
> + .set_rate = clk_utmi_set_rate,
> };
>
> static struct clk_hw * __init
> at91_clk_register_utmi(struct regmap *regmap,
> + struct regmap *sfr_regmap, const u8 *multipliers,
> const char *name, const char *parent_name)
> {
> struct clk_utmi *utmi;
> @@ -98,6 +175,8 @@ at91_clk_register_utmi(struct regmap *regmap,
>
> utmi->hw.init = &init;
> utmi->regmap = regmap;
> + utmi->sfr_regmap = sfr_regmap;
> + utmi->multipliers = multipliers;
>
> hw = &utmi->hw;
> ret = clk_hw_register(NULL, &utmi->hw);
> @@ -115,6 +194,9 @@ static void __init of_at91sam9x5_clk_utmi_setup(struct device_node *np)
> const char *parent_name;
> const char *name = np->name;
> struct regmap *regmap;
> + struct regmap *sfr_regmap;
> + const u8 *multipliers = NULL;
> + size_t i;
>
> parent_name = of_clk_get_parent_name(np, 0);
>
> @@ -124,7 +206,24 @@ static void __init of_at91sam9x5_clk_utmi_setup(struct device_node *np)
> if (IS_ERR(regmap))
> return;
>
> - hw = at91_clk_register_utmi(regmap, name, parent_name);
> + for (i = 0; i < ARRAY_SIZE(utmi_multipliers); i++) {
> + sfr_regmap = syscon_regmap_lookup_by_compatible(
> + utmi_multipliers[i].sfr_compatible_name);
> + if (!IS_ERR(sfr_regmap)) {
> + pr_debug("clk-utmi: found sfr node: %s\n",
> + utmi_multipliers[i].sfr_compatible_name);
> + multipliers = utmi_multipliers[i].multipliers;
> + break;
> + }
> + }
> +
> + if (IS_ERR(sfr_regmap)) {
> + pr_debug("clk-utmi: failed to find sfr node\n");
> + sfr_regmap = NULL;
> + }
> +
> + hw = at91_clk_register_utmi(regmap, sfr_regmap, multipliers,
> + name, parent_name);
> if (IS_ERR(hw))
> return;
>
> diff --git a/include/soc/at91/atmel-sfr.h b/include/soc/at91/atmel-sfr.h
> index 506ea8f..763948e 100644
> --- a/include/soc/at91/atmel-sfr.h
> +++ b/include/soc/at91/atmel-sfr.h
> @@ -17,6 +17,7 @@
> /* 0x08 ~ 0x0c: Reserved */
> #define AT91_SFR_OHCIICR 0x10 /* OHCI INT Configuration Register */
> #define AT91_SFR_OHCIISR 0x14 /* OHCI INT Status Register */
> +#define AT91_SFR_UTMICKTRIM 0x30 /* UTMI Clock Trimming Register */
> #define AT91_SFR_I2SCLKSEL 0x90 /* I2SC Register */
>
> /* Field definitions */
> @@ -28,5 +29,6 @@
> AT91_OHCIICR_SUSPEND_B | \
> AT91_OHCIICR_SUSPEND_C)
>
> +#define AT91_UTMICKTRIM_FREQ_MASK 0x03

You can use GENMASK here.

>
> #endif /* _LINUX_MFD_SYSCON_ATMEL_SFR_H */

I have attached the patch I did.

Regards

Ludovic
diff --git a/drivers/clk/at91/clk-utmi.c b/drivers/clk/at91/clk-utmi.c
index aadabd9d1e2b..0b88147c4ec6 100644
--- a/drivers/clk/at91/clk-utmi.c
+++ b/drivers/clk/at91/clk-utmi.c
@@ -14,14 +14,15 @@
#include <linux/of.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
+#include <soc/at91/atmel-sfr.h>

#include "pmc.h"

-#define UTMI_FIXED_MUL 40
-
struct clk_utmi {
struct clk_hw hw;
- struct regmap *regmap;
+ unsigned int mul;
+ struct regmap *regmap_pmc;
+ struct regmap *regmap_sfr;
};

#define to_clk_utmi(hw) container_of(hw, struct clk_utmi, hw)
@@ -37,13 +38,54 @@ static inline bool clk_utmi_ready(struct regmap *regmap)

static int clk_utmi_prepare(struct clk_hw *hw)
{
+ struct clk_hw *hw_parent;
struct clk_utmi *utmi = to_clk_utmi(hw);
unsigned int uckr = AT91_PMC_UPLLEN | AT91_PMC_UPLLCOUNT |
AT91_PMC_BIASEN;
+ unsigned int utmi_ref_clk_freq;
+ unsigned long parent_rate;
+
+ /*
+ * If mainck rate is different from 12 MHz, we have to configure the
+ * FREQ field of the SFR_UTMICKTRIM register to generate properly
+ * the utmi clock.
+ */
+ hw_parent = clk_hw_get_parent(hw);
+ parent_rate = clk_hw_get_rate(hw_parent);
+
+ switch (parent_rate) {
+ case 12000000:
+ utmi_ref_clk_freq = 0;
+ utmi->mul = 40;
+ break;
+ case 16000000:
+ utmi_ref_clk_freq = 1;
+ utmi->mul = 30;
+ break;
+ case 24000000:
+ utmi_ref_clk_freq = 2;
+ utmi->mul = 20;
+ break;
+ case 48000000:
+ utmi_ref_clk_freq = 3;
+ utmi->mul = 10;
+ break;
+ default:
+ pr_err("Unsupported mainck rate to generate the utmi clock\n");
+ return -EINVAL;
+ }
+
+ if (utmi_ref_clk_freq & !utmi->regmap_sfr) {
+ pr_err("If mainck rate is different from 12 MHz, the sfr node is required to generate the utmi clock\n");
+ return -EINVAL;
+ }

- regmap_update_bits(utmi->regmap, AT91_CKGR_UCKR, uckr, uckr);
+ regmap_update_bits(utmi->regmap_sfr, AT91_SFR_UTMICKTRIM,
+ AT91_UTMICKTRIM_FREQ, utmi_ref_clk_freq);

- while (!clk_utmi_ready(utmi->regmap))
+ regmap_update_bits(utmi->regmap_pmc, AT91_CKGR_UCKR, uckr, uckr);
+
+ while (!clk_utmi_ready(utmi->regmap_pmc))
cpu_relax();

return 0;
@@ -53,21 +95,22 @@ static int clk_utmi_is_prepared(struct clk_hw *hw)
{
struct clk_utmi *utmi = to_clk_utmi(hw);

- return clk_utmi_ready(utmi->regmap);
+ return clk_utmi_ready(utmi->regmap_pmc);
}

static void clk_utmi_unprepare(struct clk_hw *hw)
{
struct clk_utmi *utmi = to_clk_utmi(hw);

- regmap_update_bits(utmi->regmap, AT91_CKGR_UCKR, AT91_PMC_UPLLEN, 0);
+ regmap_update_bits(utmi->regmap_pmc, AT91_CKGR_UCKR, AT91_PMC_UPLLEN, 0);
}

static unsigned long clk_utmi_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
- /* UTMI clk is a fixed clk multiplier */
- return parent_rate * UTMI_FIXED_MUL;
+ struct clk_utmi *utmi = to_clk_utmi(hw);
+
+ return parent_rate * utmi->mul;
}

static const struct clk_ops utmi_ops = {
@@ -78,7 +121,7 @@ static const struct clk_ops utmi_ops = {
};

static struct clk_hw * __init
-at91_clk_register_utmi(struct regmap *regmap,
+at91_clk_register_utmi(struct regmap *regmap_pmc, struct regmap *regmap_sfr,
const char *name, const char *parent_name)
{
struct clk_utmi *utmi;
@@ -97,7 +140,8 @@ at91_clk_register_utmi(struct regmap *regmap,
init.flags = CLK_SET_RATE_GATE;

utmi->hw.init = &init;
- utmi->regmap = regmap;
+ utmi->regmap_pmc = regmap_pmc;
+ utmi->regmap_sfr = regmap_sfr;

hw = &utmi->hw;
ret = clk_hw_register(NULL, &utmi->hw);
@@ -114,17 +158,20 @@ static void __init of_at91sam9x5_clk_utmi_setup(struct device_node *np)
struct clk_hw *hw;
const char *parent_name;
const char *name = np->name;
- struct regmap *regmap;
+ struct regmap *regmap_pmc, *regmap_sfr;

parent_name = of_clk_get_parent_name(np, 0);

of_property_read_string(np, "clock-output-names", &name);

- regmap = syscon_node_to_regmap(of_get_parent(np));
- if (IS_ERR(regmap))
+ regmap_pmc = syscon_node_to_regmap(of_get_parent(np));
+ if (IS_ERR(regmap_pmc))
return;

- hw = at91_clk_register_utmi(regmap, name, parent_name);
+ /* SFR node missing is not necessarily an issue, we'll check it later. */
+ regmap_sfr = syscon_regmap_lookup_by_compatible("atmel,sama5d2-sfr");
+
+ hw = at91_clk_register_utmi(regmap_pmc, regmap_sfr, name, parent_name);
if (IS_ERR(hw))
return;

diff --git a/include/soc/at91/atmel-sfr.h b/include/soc/at91/atmel-sfr.h
index 506ea8ffda19..ad97856f8964 100644
--- a/include/soc/at91/atmel-sfr.h
+++ b/include/soc/at91/atmel-sfr.h
@@ -17,6 +17,7 @@
/* 0x08 ~ 0x0c: Reserved */
#define AT91_SFR_OHCIICR 0x10 /* OHCI INT Configuration Register */
#define AT91_SFR_OHCIISR 0x14 /* OHCI INT Status Register */
+#define AT91_SFR_UTMICKTRIM 0x30
#define AT91_SFR_I2SCLKSEL 0x90 /* I2SC Register */

/* Field definitions */
@@ -28,5 +29,6 @@
AT91_OHCIICR_SUSPEND_B | \
AT91_OHCIICR_SUSPEND_C)

+#define AT91_UTMICKTRIM_FREQ GENMASK(1,0)

#endif /* _LINUX_MFD_SYSCON_ATMEL_SFR_H */
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