[PATCH v1 28/43] i2c: designware_i2c: Support ACPI table generation

[Wolfgang Wallner <wolfgang.wallner@br-automation.com>]

Hi Simon,

-----"Simon Glass" <sjg@chromium.org> schrieb: -----
> Betreff: [PATCH v1 28/43] i2c: designware_i2c: Support ACPI table generation
> 
> Update the PCI driver to generate ACPI information so that Linux has the
> full information about each I2C bus.
> 
> Signed-off-by: Simon Glass <sjg@chromium.org>
> 
> ---
> 
> Changes in v1:
> - Capitalise ACPI_OPS_PTR
> 
>  drivers/i2c/designware_i2c.c     |  25 ++++++++
>  drivers/i2c/designware_i2c.h     |  15 +++++
>  drivers/i2c/designware_i2c_pci.c | 104 ++++++++++++++++++++++++++++++-
>  3 files changed, 143 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c
> index 44a1f33398..630938743f 100644
> --- a/drivers/i2c/designware_i2c.c
> +++ b/drivers/i2c/designware_i2c.c
> @@ -333,6 +333,31 @@ static int _dw_i2c_set_bus_speed(struct dw_i2c *priv, struct i2c_regs *i2c_base,
>  	/* Restore back i2c now speed set */
>  	if (ena == IC_ENABLE_0B)
>  		dw_i2c_enable(i2c_base, true);
> +	if (priv)
> +		priv->config = config;
> +	return 0;
> +}
> +
> +int dw_i2c_gen_speed_config(const struct udevice *dev, int speed_hz,
> +			    struct dw_i2c_speed_config *config)
> +{
> +	struct dw_i2c *priv = dev_get_priv(dev);
> +	ulong rate;
> +	int ret;
> +
> +#if CONFIG_IS_ENABLED(CLK)
> +	rate = clk_get_rate(&priv->clk);
> +	if (IS_ERR_VALUE(rate))
> +		return log_msg_ret("clk", -EINVAL);
> +#else
> +	rate = IC_CLK;
> +#endif
> +
> +	ret = calc_bus_speed(priv, priv->regs, speed_hz, rate, config);
> +	if (ret)
> +		printf("%s: ret=%d\n", __func__, ret);
> +	if (ret)
> +		return log_msg_ret("calc_bus_speed", ret);
>  
>  	return 0;
>  }
> diff --git a/drivers/i2c/designware_i2c.h b/drivers/i2c/designware_i2c.h
> index dc9a6ccb63..d87a3bff93 100644
> --- a/drivers/i2c/designware_i2c.h
> +++ b/drivers/i2c/designware_i2c.h
> @@ -205,6 +205,7 @@ struct dw_i2c {
>  #if CONFIG_IS_ENABLED(CLK)
>  	struct clk clk;
>  #endif
> +	struct dw_i2c_speed_config config;
>  };
>  
>  extern const struct dm_i2c_ops designware_i2c_ops;
> @@ -213,4 +214,18 @@ int designware_i2c_probe(struct udevice *bus);
>  int designware_i2c_remove(struct udevice *dev);
>  int designware_i2c_ofdata_to_platdata(struct udevice *bus);
>  
> +/**
> + * dw_i2c_gen_speed_config() - Calculate config info from requested speed1
> + *
> + * Calculate the speed config from the given @speed_hz and return it so that
> + * it can be incorporated in ACPI tables
> + *
> + * @dev: I2C bus to check
> + * @speed_hz: Requested speed in Hz
> + * @config: Returns config to use for that speed
> + * @return 0 if OK, -ve on error
> + */
> +int dw_i2c_gen_speed_config(const struct udevice *dev, int speed_hz,
> +			    struct dw_i2c_speed_config *config);
> +
>  #endif /* __DW_I2C_H_ */
> diff --git a/drivers/i2c/designware_i2c_pci.c b/drivers/i2c/designware_i2c_pci.c
> index bd34ec0b47..d5108e9064 100644
> --- a/drivers/i2c/designware_i2c_pci.c
> +++ b/drivers/i2c/designware_i2c_pci.c
> @@ -9,7 +9,12 @@
>  #include <dm.h>
>  #include <log.h>
>  #include <spl.h>
> +#include <acpi/acpigen.h>
> +#include <acpi/acpi_device.h>
>  #include <asm/lpss.h>
> +#include <dm/acpi.h>
> +#include <dm/device-internal.h>
> +#include <dm/uclass-internal.h>
>  #include "designware_i2c.h"
>  
>  enum {
> @@ -87,6 +92,8 @@ static int designware_i2c_pci_bind(struct udevice *dev)
>  {
>  	char name[20];
>  
> +	if (dev_of_valid(dev))
> +		return 0;
>  	/*
>  	 * Create a unique device name for PCI type devices
>  	 * ToDo:
> @@ -100,13 +107,107 @@ static int designware_i2c_pci_bind(struct udevice *dev)
>  	 * be possible. We cannot use static data in drivers since they may be
>  	 * used in SPL or before relocation.
>  	 */
> -	dev->req_seq = gd->arch.dw_i2c_num_cards++;
> +	dev->req_seq = uclass_find_next_free_req_seq(UCLASS_I2C);
>  	sprintf(name, "i2c_designware#%u", dev->req_seq);
>  	device_set_name(dev, name);
>  
>  	return 0;
>  }
>  
> +/*
> + * Write ACPI object to describe speed configuration.
> + *
> + * ACPI Object: Name ("xxxx", Package () { scl_lcnt, scl_hcnt, sda_hold }
> + *
> + * SSCN: I2C_SPEED_STANDARD
> + * FMCN: I2C_SPEED_FAST
> + * FPCN: I2C_SPEED_FAST_PLUS
> + * HSCN: I2C_SPEED_HIGH
> + */
> +static void dw_i2c_acpi_write_speed_config(struct acpi_ctx *ctx,
> +					   struct dw_i2c_speed_config *config)
> +{
> +	switch (config->speed_mode) {
> +	case IC_SPEED_MODE_HIGH:
> +		acpigen_write_name(ctx, "HSCN");
> +		break;
> +	case IC_SPEED_MODE_FAST_PLUS:
> +		acpigen_write_name(ctx, "FPCN");
> +		break;
> +	case IC_SPEED_MODE_FAST:
> +		acpigen_write_name(ctx, "FMCN");
> +		break;
> +	case IC_SPEED_MODE_STANDARD:
> +	default:
> +		acpigen_write_name(ctx, "SSCN");
> +	}
> +
> +	/* Package () { scl_lcnt, scl_hcnt, sda_hold } */
> +	acpigen_write_package(ctx, 3);
> +	acpigen_write_word(ctx, config->scl_hcnt);
> +	acpigen_write_word(ctx, config->scl_lcnt);
> +	acpigen_write_dword(ctx, config->sda_hold);
> +	acpigen_pop_len(ctx);
> +}

This function is rather generic, and probably the same for any I2C controller.
Is the intention to implement it for Designware as a first step and move it to
a generic place if the need arises, or should it stay here?

> +
> +/*
> + * Generate I2C timing information into the SSDT for the OS driver to consume,
> + * optionally applying override values provided by the caller.
> + */
> +static int dw_i2c_acpi_fill_ssdt(const struct udevice *dev,
> +				 struct acpi_ctx *ctx)
> +{
> +	struct dw_i2c_speed_config config;
> +	char path[ACPI_PATH_MAX];
> +	u32 speeds[4];
> +	int size, i;
> +	int ret;
> +
> +	/* If no device-tree node, ignore this since we assume it isn't used */
> +	if (!dev_of_valid(dev))
> +		return 0;
> +	ret = acpi_device_path(dev, path, sizeof(path));
> +	if (ret)
> +		return log_msg_ret("path", ret);
> +
> +	size = dev_read_size(dev, "i2c,speeds");
> +	if (size < 0)
> +		return log_msg_ret("i2c,speeds", -EINVAL);
> +	size /= sizeof(u32);
> +	if (size > ARRAY_SIZE(speeds))
> +		return log_msg_ret("array", -E2BIG);
> +
> +	ret = dev_read_u32_array(dev, "i2c,speeds", speeds, size);
> +	if (ret)
> +		return log_msg_ret("read", -E2BIG);
> +
> +	if (0) {

This seems like some left-over debugging code ... ?

> +		acpigen_write_scope(ctx, path);
> +		for (i = 0; i < size; i++) {
> +			ret = dw_i2c_gen_speed_config(dev, speeds[i], &config);
> +			if (ret)
> +				return log_msg_ret("config", ret);
> +			dw_i2c_acpi_write_speed_config(ctx, &config);
> +		}
> +	} else {
> +		uint speed;
> +
> +		speed = dev_read_u32_default(dev, "clock-frequency", 100000);
> +		acpigen_write_scope(ctx, path);
> +		ret = dw_i2c_gen_speed_config(dev, speed, &config);
> +		if (ret)
> +			return log_msg_ret("config", ret);
> +		dw_i2c_acpi_write_speed_config(ctx, &config);
> +	}
> +	acpigen_pop_len(ctx);
> +
> +	return 0;
> +}
> +
> +struct acpi_ops dw_i2c_acpi_ops = {
> +	.fill_ssdt	= dw_i2c_acpi_fill_ssdt,
> +};
> +
>  static const struct udevice_id designware_i2c_pci_ids[] = {
>  	{ .compatible = "snps,designware-i2c-pci" },
>  	{ .compatible = "intel,apl-i2c", .data = INTEL_APL },
> @@ -124,6 +225,7 @@ U_BOOT_DRIVER(i2c_designware_pci) = {
>  	.remove = designware_i2c_remove,
>  	.flags = DM_FLAG_OS_PREPARE,
>  	.ops	= &designware_i2c_ops,
> +	ACPI_OPS_PTR(&dw_i2c_acpi_ops)
>  };
>  
>  static struct pci_device_id designware_pci_supported[] = {
> -- 
> 2.27.0.290.gba653c62da-goog

regards, Wolfgang