Re: [PATCHv2 2/8] clk: at91: add a driver for the h32mx clock

[Nicolas Ferre]

On 12/09/2014 17:43, Alexandre Belloni :
> Newer SoCs have two different peripheral master clocks, h32mx is able to divide

Well, it is not the h32mx that allows it, it is the clock associated
with it.

> mck for slower peripherals.

Maybe say at the beginning that h32mx stands for "AHB 32 bits Matrix
interconnect" and that we are talking about the particular clock that is
associated with it. This particular clock can be setup at the half of
the H64mx clock which is the mck.

> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
> ---
> Cc: Mike Turquette <mturquette@xxxxxxxxxx>
>  .../devicetree/bindings/clock/at91-clock.txt       |  15 +++
>  arch/arm/mach-at91/Kconfig                         |   3 +
>  drivers/clk/at91/Makefile                          |   1 +
>  drivers/clk/at91/clk-h32mx.c                       | 121 +++++++++++++++++++++
>  drivers/clk/at91/pmc.c                             |   6 +
>  drivers/clk/at91/pmc.h                             |   5 +
>  include/linux/clk/at91_pmc.h                       |   1 +
>  7 files changed, 152 insertions(+)
>  create mode 100644 drivers/clk/at91/clk-h32mx.c
> 
> diff --git a/Documentation/devicetree/bindings/clock/at91-clock.txt b/Documentation/devicetree/bindings/clock/at91-clock.txt
> index b3d544ca522a..c8dcbbd242e5 100644
> --- a/Documentation/devicetree/bindings/clock/at91-clock.txt
> +++ b/Documentation/devicetree/bindings/clock/at91-clock.txt
> @@ -74,6 +74,9 @@ Required properties:
>  	"atmel,at91sam9x5-clk-utmi":
>  		at91 utmi clock
>  
> +	"atmel,sama5d4-clk-h32mx":
> +		at91 h32mx clock
> +
>  Required properties for SCKC node:
>  - reg : defines the IO memory reserved for the SCKC.
>  - #size-cells : shall be 0 (reg is used to encode clk id).
> @@ -447,3 +450,15 @@ For example:
>  		#clock-cells = <0>;
>  		clocks = <&main>;
>  	};
> +
> +Required properties for h32mx clock:

for the 32 bits bus Matrix clock (h32mx clock):

> +- #clock-cells : from common clock binding; shall be set to 0.
> +- clocks : shall be the master clock source phandle.
> +
> +For example:
> +	h32ck: h32mxck {
> +		#clock-cells = <0>;
> +		compatible = "atmel,sama5d4-clk-h32mx";
> +		clocks = <&mck>;
> +	};
> +
> diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
> index 6eb3c658761d..a2c8ecb10730 100644
> --- a/arch/arm/mach-at91/Kconfig
> +++ b/arch/arm/mach-at91/Kconfig
> @@ -39,6 +39,9 @@ config AT91_SAM9_TIME
>  config HAVE_AT91_SMD
>  	bool
>  
> +config HAVE_AT91_H64MX

HAVE_AT91_H32MX

> +	bool
> +
>  config SOC_AT91SAM9
>  	bool
>  	select AT91_SAM9_TIME
> diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
> index 4998aee59267..b2d43ff8112b 100644
> --- a/drivers/clk/at91/Makefile
> +++ b/drivers/clk/at91/Makefile
> @@ -9,3 +9,4 @@ obj-y += clk-system.o clk-peripheral.o clk-programmable.o
>  obj-$(CONFIG_HAVE_AT91_UTMI)		+= clk-utmi.o
>  obj-$(CONFIG_HAVE_AT91_USB_CLK)		+= clk-usb.o
>  obj-$(CONFIG_HAVE_AT91_SMD)		+= clk-smd.o
> +obj-$(CONFIG_HAVE_AT91_H64MX)		+= clk-h32mx.o

Ditto.

> diff --git a/drivers/clk/at91/clk-h32mx.c b/drivers/clk/at91/clk-h32mx.c
> new file mode 100644
> index 000000000000..21a2f3630a43
> --- /dev/null
> +++ b/drivers/clk/at91/clk-h32mx.c
> @@ -0,0 +1,121 @@
> +/*
> + * drivers/clk/at91/clk-h32mx.c

Not the whole path, please.

> + *
> + *  Copyright (C) 2014 Atmel
> + *
> + * Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk/at91_pmc.h>
> +#include <linux/delay.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/io.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/sched.h>
> +#include <linux/wait.h>
> +
> +#include "pmc.h"
> +
> +struct clk_sama5d4_h32mx {
> +	struct clk_hw hw;
> +	struct at91_pmc *pmc;
> +};
> +
> +#define to_clk_sama5d4_h32mx(hw) container_of(hw, struct clk_sama5d4_h32mx, hw)
> +
> +static unsigned long clk_sama5d4_h32mx_recalc_rate(struct clk_hw *hw,
> +						 unsigned long parent_rate)
> +{
> +	struct clk_sama5d4_h32mx *h32mxclk = to_clk_sama5d4_h32mx(hw);
> +
> +	if (pmc_read(h32mxclk->pmc, AT91_PMC_MCKR) & AT91_PMC_H32MXDIV)
> +		return parent_rate / 2;
> +
> +	if (parent_rate > 90000000)

A #define here?

> +		pr_warn("H32 clock is too fast\n");

H32MX

> +	return parent_rate;
> +}
> +
> +static long clk_sama5d4_h32mx_round_rate(struct clk_hw *hw, unsigned long rate,
> +				       unsigned long *parent_rate)
> +{
> +	unsigned long div;
> +
> +	if (rate > *parent_rate)
> +		return *parent_rate;
> +	div = *parent_rate / 2;
> +	if (rate < div)
> +		return div;
> +
> +	if (rate - div < *parent_rate - rate)
> +		return div;
> +
> +	return *parent_rate;
> +}
> +
> +static int clk_sama5d4_h32mx_set_rate(struct clk_hw *hw, unsigned long rate,
> +				    unsigned long parent_rate)
> +{
> +	struct clk_sama5d4_h32mx *h32mxclk = to_clk_sama5d4_h32mx(hw);
> +	struct at91_pmc *pmc = h32mxclk->pmc;
> +	u32 tmp;
> +
> +	if (parent_rate != rate && (parent_rate / 2) != rate)
> +		return -EINVAL;
> +
> +	pmc_lock(pmc);
> +	tmp = pmc_read(pmc, AT91_PMC_MCKR) & ~AT91_PMC_H32MXDIV;
> +	if ((parent_rate / 2) == rate)
> +		tmp |= AT91_PMC_H32MXDIV;
> +	pmc_write(pmc, AT91_PMC_MCKR, tmp);
> +	pmc_unlock(pmc);
> +
> +	return 0;
> +}
> +
> +static const struct clk_ops h32mx_ops = {
> +	.recalc_rate = clk_sama5d4_h32mx_recalc_rate,
> +	.round_rate = clk_sama5d4_h32mx_round_rate,
> +	.set_rate = clk_sama5d4_h32mx_set_rate,
> +};
> +
> +void __init of_sama5d4_clk_h32mx_setup(struct device_node *np,
> +				     struct at91_pmc *pmc)
> +{
> +	struct clk_sama5d4_h32mx *h32mxclk;
> +	struct clk_init_data init;
> +	const char *parent_name;
> +	struct clk *clk;
> +
> +	h32mxclk = kzalloc(sizeof(*h32mxclk), GFP_KERNEL);
> +	if (!h32mxclk)
> +		return;
> +
> +	parent_name = of_clk_get_parent_name(np, 0);
> +
> +	init.name = np->name;
> +	init.ops = &h32mx_ops;
> +	init.parent_names = parent_name ? &parent_name : NULL;
> +	init.num_parents = parent_name ? 1 : 0;
> +	init.flags = CLK_SET_RATE_GATE;
> +
> +	h32mxclk->hw.init = &init;
> +	h32mxclk->pmc = pmc;
> +
> +	clk = clk_register(NULL, &h32mxclk->hw);
> +	if (!clk)
> +		return;
> +
> +	of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +}
> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> index 524196bb35a5..0d98b3f2b780 100644
> --- a/drivers/clk/at91/pmc.c
> +++ b/drivers/clk/at91/pmc.c
> @@ -337,6 +337,12 @@ static const struct of_device_id pmc_clk_ids[] __initconst = {
>  		.data = of_at91sam9x5_clk_smd_setup,
>  	},
>  #endif
> +#if defined(CONFIG_HAVE_AT91_H64MX)
> +	{
> +		.compatible = "atmel,sama5d4-clk-h32mx",
> +		.data = of_sama5d4_clk_h32mx_setup,
> +	},
> +#endif
>  	{ /*sentinel*/ }
>  };
>  
> diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
> index 6c7625976113..52d2041fa3f6 100644
> --- a/drivers/clk/at91/pmc.h
> +++ b/drivers/clk/at91/pmc.h
> @@ -120,4 +120,9 @@ extern void __init of_at91sam9x5_clk_smd_setup(struct device_node *np,
>  					       struct at91_pmc *pmc);
>  #endif
>  
> +#if defined(CONFIG_HAVE_AT91_SMD)
> +extern void __init of_sama5d4_clk_h32mx_setup(struct device_node *np,
> +					      struct at91_pmc *pmc);
> +#endif
> +
>  #endif /* __PMC_H_ */
> diff --git a/include/linux/clk/at91_pmc.h b/include/linux/clk/at91_pmc.h
> index de4268d4987a..c8e3b3d1eded 100644
> --- a/include/linux/clk/at91_pmc.h
> +++ b/include/linux/clk/at91_pmc.h
> @@ -125,6 +125,7 @@ extern void __iomem *at91_pmc_base;
>  #define		AT91_PMC_PLLADIV2	(1 << 12)		/* PLLA divisor by 2 [some SAM9 only] */
>  #define			AT91_PMC_PLLADIV2_OFF		(0 << 12)
>  #define			AT91_PMC_PLLADIV2_ON		(1 << 12)
> +#define		AT91_PMC_H32MXDIV	BIT(24)
>  
>  #define	AT91_PMC_USB		0x38			/* USB Clock Register [some SAM9 only] */
>  #define		AT91_PMC_USBS		(0x1 <<  0)		/* USB OHCI Input clock selection */
> 

Best regards,
-- 
Nicolas Ferre
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