Re: [PATCH v7 1/5] clk: Add clock driver for ASPEED BMC SoCs

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Fri, 2017-12-22 at 13:15 +1030, Joel Stanley wrote:
> This adds the stub of a driver for the ASPEED SoCs. The clocks are
> defined and the static registration is set up.
> 
> Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
> Signed-off-by: Joel Stanley <joel@jms.id.au>

Reviewed-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> ---
> v7:
>  - Rebase on dt-bindings patch
>  - Add ASPEED_NUM_CLKS as it no longer lives in the header
> v6:
>  - Add SPDX copyright notices
> v5:
>  - Add Andrew's reviewed-by
>  - Make aspeed_gates not initconst to avoid section mismatch warning
> v3:
>  - use named initlisers for aspeed_gates table
>  - fix clocks typo
>  - Move ASPEED_NUM_CLKS to the bottom of the list
>  - Put gates at the start of the list, so we can use them to initalise
>    the aspeed_gates table
>  - Add ASPEED_CLK_SELECTION_2
>  - Set parent of network MAC gates
> ---
>  drivers/clk/Kconfig      |  12 ++++
>  drivers/clk/Makefile     |   1 +
>  drivers/clk/clk-aspeed.c | 141 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 154 insertions(+)
>  create mode 100644 drivers/clk/clk-aspeed.c
> 
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index 1c4e1aa6767e..9abe063ef8d2 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -142,6 +142,18 @@ config COMMON_CLK_GEMINI
>  	  This driver supports the SoC clocks on the Cortina Systems Gemini
>  	  platform, also known as SL3516 or CS3516.
>  
> +config COMMON_CLK_ASPEED
> +	bool "Clock driver for Aspeed BMC SoCs"
> +	depends on ARCH_ASPEED || COMPILE_TEST
> +	default ARCH_ASPEED
> +	select MFD_SYSCON
> +	select RESET_CONTROLLER
> +	---help---
> +	  This driver supports the SoC clocks on the Aspeed BMC platforms.
> +
> +	  The G4 and G5 series, including the ast2400 and ast2500, are supported
> +	  by this driver.
> +
>  config COMMON_CLK_S2MPS11
>  	tristate "Clock driver for S2MPS1X/S5M8767 MFD"
>  	depends on MFD_SEC_CORE || COMPILE_TEST
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index f7f761b02bed..d260da4809f8 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -27,6 +27,7 @@ obj-$(CONFIG_ARCH_CLPS711X)		+= clk-clps711x.o
>  obj-$(CONFIG_COMMON_CLK_CS2000_CP)	+= clk-cs2000-cp.o
>  obj-$(CONFIG_ARCH_EFM32)		+= clk-efm32gg.o
>  obj-$(CONFIG_COMMON_CLK_GEMINI)		+= clk-gemini.o
> +obj-$(CONFIG_COMMON_CLK_ASPEED)		+= clk-aspeed.o
>  obj-$(CONFIG_ARCH_HIGHBANK)		+= clk-highbank.o
>  obj-$(CONFIG_CLK_HSDK)			+= clk-hsdk-pll.o
>  obj-$(CONFIG_COMMON_CLK_MAX77686)	+= clk-max77686.o
> diff --git a/drivers/clk/clk-aspeed.c b/drivers/clk/clk-aspeed.c
> new file mode 100644
> index 000000000000..7a86ee08ea4f
> --- /dev/null
> +++ b/drivers/clk/clk-aspeed.c
> @@ -0,0 +1,141 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +#define pr_fmt(fmt) "clk-aspeed: " fmt
> +
> +#include <linux/clk-provider.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/of_address.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +
> +#include <dt-bindings/clock/aspeed-clock.h>
> +
> +#define ASPEED_NUM_CLKS		35
> +
> +#define ASPEED_STRAP		0x70
> +
> +/* Keeps track of all clocks */
> +static struct clk_hw_onecell_data *aspeed_clk_data;
> +
> +static void __iomem *scu_base;
> +
> +/**
> + * struct aspeed_gate_data - Aspeed gated clocks
> + * @clock_idx: bit used to gate this clock in the clock register
> + * @reset_idx: bit used to reset this IP in the reset register. -1 if no
> + *             reset is required when enabling the clock
> + * @name: the clock name
> + * @parent_name: the name of the parent clock
> + * @flags: standard clock framework flags
> + */
> +struct aspeed_gate_data {
> +	u8		clock_idx;
> +	s8		reset_idx;
> +	const char	*name;
> +	const char	*parent_name;
> +	unsigned long	flags;
> +};
> +
> +/**
> + * struct aspeed_clk_gate - Aspeed specific clk_gate structure
> + * @hw:		handle between common and hardware-specific interfaces
> + * @reg:	register controlling gate
> + * @clock_idx:	bit used to gate this clock in the clock register
> + * @reset_idx:	bit used to reset this IP in the reset register. -1 if no
> + *		reset is required when enabling the clock
> + * @flags:	hardware-specific flags
> + * @lock:	register lock
> + *
> + * Some of the clocks in the Aspeed SoC must be put in reset before enabling.
> + * This modified version of clk_gate allows an optional reset bit to be
> + * specified.
> + */
> +struct aspeed_clk_gate {
> +	struct clk_hw	hw;
> +	struct regmap	*map;
> +	u8		clock_idx;
> +	s8		reset_idx;
> +	u8		flags;
> +	spinlock_t	*lock;
> +};
> +
> +#define to_aspeed_clk_gate(_hw) container_of(_hw, struct aspeed_clk_gate, hw)
> +
> +/* TODO: ask Aspeed about the actual parent data */
> +static const struct aspeed_gate_data aspeed_gates[] = {
> +	/*				 clk rst   name			parent	flags */
> +	[ASPEED_CLK_GATE_ECLK] =	{  0, -1, "eclk-gate",		"eclk",	0 }, /* Video Engine */
> +	[ASPEED_CLK_GATE_GCLK] =	{  1,  7, "gclk-gate",		NULL,	0 }, /* 2D engine */
> +	[ASPEED_CLK_GATE_MCLK] =	{  2, -1, "mclk-gate",		"mpll",	CLK_IS_CRITICAL }, /* SDRAM */
> +	[ASPEED_CLK_GATE_VCLK] =	{  3,  6, "vclk-gate",		NULL,	0 }, /* Video Capture */
> +	[ASPEED_CLK_GATE_BCLK] =	{  4, 10, "bclk-gate",		"bclk",	0 }, /* PCIe/PCI */
> +	[ASPEED_CLK_GATE_DCLK] =	{  5, -1, "dclk-gate",		NULL,	0 }, /* DAC */
> +	[ASPEED_CLK_GATE_REFCLK] =	{  6, -1, "refclk-gate",	"clkin", CLK_IS_CRITICAL },
> +	[ASPEED_CLK_GATE_USBPORT2CLK] =	{  7,  3, "usb-port2-gate",	NULL,	0 }, /* USB2.0 Host port 2 */
> +	[ASPEED_CLK_GATE_LCLK] =	{  8,  5, "lclk-gate",		NULL,	0 }, /* LPC */
> +	[ASPEED_CLK_GATE_USBUHCICLK] =	{  9, 15, "usb-uhci-gate",	NULL,	0 }, /* USB1.1 (requires port 2 enabled) */
> +	[ASPEED_CLK_GATE_D1CLK] =	{ 10, 13, "d1clk-gate",		NULL,	0 }, /* GFX CRT */
> +	[ASPEED_CLK_GATE_YCLK] =	{ 13,  4, "yclk-gate",		NULL,	0 }, /* HAC */
> +	[ASPEED_CLK_GATE_USBPORT1CLK] = { 14, 14, "usb-port1-gate",	NULL,	0 }, /* USB2 hub/USB2 host port 1/USB1.1 dev */
> +	[ASPEED_CLK_GATE_UART1CLK] =	{ 15, -1, "uart1clk-gate",	"uart",	0 }, /* UART1 */
> +	[ASPEED_CLK_GATE_UART2CLK] =	{ 16, -1, "uart2clk-gate",	"uart",	0 }, /* UART2 */
> +	[ASPEED_CLK_GATE_UART5CLK] =	{ 17, -1, "uart5clk-gate",	"uart",	0 }, /* UART5 */
> +	[ASPEED_CLK_GATE_ESPICLK] =	{ 19, -1, "espiclk-gate",	NULL,	0 }, /* eSPI */
> +	[ASPEED_CLK_GATE_MAC1CLK] =	{ 20, 11, "mac1clk-gate",	"mac",	0 }, /* MAC1 */
> +	[ASPEED_CLK_GATE_MAC2CLK] =	{ 21, 12, "mac2clk-gate",	"mac",	0 }, /* MAC2 */
> +	[ASPEED_CLK_GATE_RSACLK] =	{ 24, -1, "rsaclk-gate",	NULL,	0 }, /* RSA */
> +	[ASPEED_CLK_GATE_UART3CLK] =	{ 25, -1, "uart3clk-gate",	"uart",	0 }, /* UART3 */
> +	[ASPEED_CLK_GATE_UART4CLK] =	{ 26, -1, "uart4clk-gate",	"uart",	0 }, /* UART4 */
> +	[ASPEED_CLK_GATE_SDCLKCLK] =	{ 27, 16, "sdclk-gate",		NULL,	0 }, /* SDIO/SD */
> +	[ASPEED_CLK_GATE_LHCCLK] =	{ 28, -1, "lhclk-gate",		"lhclk", 0 }, /* LPC master/LPC+ */
> +};
> +
> +static void __init aspeed_cc_init(struct device_node *np)
> +{
> +	struct regmap *map;
> +	u32 val;
> +	int ret;
> +	int i;
> +
> +	scu_base = of_iomap(np, 0);
> +	if (IS_ERR(scu_base))
> +		return;
> +
> +	aspeed_clk_data = kzalloc(sizeof(*aspeed_clk_data) +
> +			sizeof(*aspeed_clk_data->hws) * ASPEED_NUM_CLKS,
> +			GFP_KERNEL);
> +	if (!aspeed_clk_data)
> +		return;
> +
> +	/*
> +	 * This way all clocks fetched before the platform device probes,
> +	 * except those we assign here for early use, will be deferred.
> +	 */
> +	for (i = 0; i < ASPEED_NUM_CLKS; i++)
> +		aspeed_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);
> +
> +	map = syscon_node_to_regmap(np);
> +	if (IS_ERR(map)) {
> +		pr_err("no syscon regmap\n");
> +		return;
> +	}
> +	/*
> +	 * We check that the regmap works on this very first access,
> +	 * but as this is an MMIO-backed regmap, subsequent regmap
> +	 * access is not going to fail and we skip error checks from
> +	 * this point.
> +	 */
> +	ret = regmap_read(map, ASPEED_STRAP, &val);
> +	if (ret) {
> +		pr_err("failed to read strapping register\n");
> +		return;
> +	}
> +
> +	aspeed_clk_data->num = ASPEED_NUM_CLKS;
> +	ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, aspeed_clk_data);
> +	if (ret)
> +		pr_err("failed to add DT provider: %d\n", ret);
> +};
> +CLK_OF_DECLARE_DRIVER(aspeed_cc_g5, "aspeed,ast2500-scu", aspeed_cc_init);
> +CLK_OF_DECLARE_DRIVER(aspeed_cc_g4, "aspeed,ast2400-scu", aspeed_cc_init);