Commit d88ae293 authored by Sven Peter's avatar Sven Peter Committed by Wolfram Sang
Browse files

i2c: pasemi: Add Apple platform driver 



With all the previous preparations we can now finally add
the platform driver to support the PASemi-based controllers
in Apple SoCs. This does not work on the M1 yet but should
work on the early iPhones already.

Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarSven Peter <sven@svenpeter.dev>
Acked-by: default avatarOlof Johansson <olof@lixom.net>
Tested-by: default avatarChristian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent a2c34bfd

drivers/i2c/busses/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -859,6 +859,17 @@ config I2C_PASEMI 
	help

	  Supports the PA Semi PWRficient on-chip SMBus interfaces.



config I2C_APPLE

	tristate "Apple SMBus platform driver"

	depends on ARCH_APPLE || COMPILE_TEST

	default ARCH_APPLE

	help

	  Say Y here if you want to use the I2C controller present on Apple

	  Silicon chips such as the M1.



	  This driver can also be built as a module. If so, the module

	  will be called i2c-apple.



config I2C_PCA_PLATFORM

	tristate "PCA9564/PCA9665 as platform device"

	select I2C_ALGOPCA

drivers/i2c/busses/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -86,6 +86,8 @@ obj-$(CONFIG_I2C_OMAP) += i2c-omap.o 
obj-$(CONFIG_I2C_OWL)		+= i2c-owl.o

i2c-pasemi-objs := i2c-pasemi-core.o i2c-pasemi-pci.o

obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi.o

i2c-apple-objs := i2c-pasemi-core.o i2c-pasemi-platform.o

obj-$(CONFIG_I2C_APPLE)	+= i2c-apple.o

obj-$(CONFIG_I2C_PCA_PLATFORM)	+= i2c-pca-platform.o

obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o

obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o

drivers/i2c/busses/i2c-pasemi-platform.c

0 → 100644
+122 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (C) 2021 The Asahi Linux Contributors

 *

 * PA Semi PWRficient SMBus host driver for Apple SoCs

 */



#include <linux/clk.h>

#include <linux/i2c.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/types.h>



#include "i2c-pasemi-core.h"



struct pasemi_platform_i2c_data {

	struct pasemi_smbus smbus;

	struct clk *clk_ref;

};



static int

pasemi_platform_i2c_calc_clk_div(struct pasemi_platform_i2c_data *data,

				 u32 frequency)

{

	unsigned long clk_rate = clk_get_rate(data->clk_ref);



	if (!clk_rate)

		return -EINVAL;



	data->smbus.clk_div = DIV_ROUND_UP(clk_rate, 16 * frequency);

	if (data->smbus.clk_div < 4)

		return dev_err_probe(data->smbus.dev, -EINVAL,

				     "Bus frequency %d is too fast.\n",

				     frequency);

	if (data->smbus.clk_div > 0xff)

		return dev_err_probe(data->smbus.dev, -EINVAL,

				     "Bus frequency %d is too slow.\n",

				     frequency);



	return 0;

}



static int pasemi_platform_i2c_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct pasemi_platform_i2c_data *data;

	struct pasemi_smbus *smbus;

	u32 frequency;

	int error;



	data = devm_kzalloc(dev, sizeof(struct pasemi_platform_i2c_data),

			    GFP_KERNEL);

	if (!data)

		return -ENOMEM;



	smbus = &data->smbus;

	smbus->dev = dev;



	smbus->ioaddr = devm_platform_ioremap_resource(pdev, 0);

	if (IS_ERR(smbus->ioaddr))

		return PTR_ERR(smbus->ioaddr);



	if (of_property_read_u32(dev->of_node, "clock-frequency", &frequency))

		frequency = I2C_MAX_STANDARD_MODE_FREQ;



	data->clk_ref = devm_clk_get(dev, NULL);

	if (IS_ERR(data->clk_ref))

		return PTR_ERR(data->clk_ref);



	error = clk_prepare_enable(data->clk_ref);

	if (error)

		return error;



	error = pasemi_platform_i2c_calc_clk_div(data, frequency);

	if (error)

		goto out_clk_disable;



	smbus->adapter.dev.of_node = pdev->dev.of_node;

	error = pasemi_i2c_common_probe(smbus);

	if (error)

		goto out_clk_disable;



	platform_set_drvdata(pdev, data);



	return 0;



out_clk_disable:

	clk_disable_unprepare(data->clk_ref);



	return error;

}



static int pasemi_platform_i2c_remove(struct platform_device *pdev)

{

	struct pasemi_platform_i2c_data *data = platform_get_drvdata(pdev);



	clk_disable_unprepare(data->clk_ref);

	return 0;

}



static const struct of_device_id pasemi_platform_i2c_of_match[] = {

	{ .compatible = "apple,t8103-i2c" },

	{ .compatible = "apple,i2c" },

	{},

};

MODULE_DEVICE_TABLE(of, pasemi_platform_i2c_of_match);



static struct platform_driver pasemi_platform_i2c_driver = {

	.driver	= {

		.name			= "i2c-apple",

		.of_match_table		= pasemi_platform_i2c_of_match,

	},

	.probe	= pasemi_platform_i2c_probe,

	.remove	= pasemi_platform_i2c_remove,

};

module_platform_driver(pasemi_platform_i2c_driver);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");

MODULE_DESCRIPTION("Apple/PASemi SMBus platform driver");