1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2021 The Asahi Linux Contributors 4 * 5 * PA Semi PWRficient SMBus host driver for Apple SoCs 6 */ 7 8 #include <linux/clk.h> 9 #include <linux/i2c.h> 10 #include <linux/io.h> 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/platform_device.h> 14 #include <linux/types.h> 15 16 #include "i2c-pasemi-core.h" 17 18 struct pasemi_platform_i2c_data { 19 struct pasemi_smbus smbus; 20 struct clk *clk_ref; 21 }; 22 23 static int 24 pasemi_platform_i2c_calc_clk_div(struct pasemi_platform_i2c_data *data, 25 u32 frequency) 26 { 27 unsigned long clk_rate = clk_get_rate(data->clk_ref); 28 29 if (!clk_rate) 30 return -EINVAL; 31 32 data->smbus.clk_div = DIV_ROUND_UP(clk_rate, 16 * frequency); 33 if (data->smbus.clk_div < 4) 34 return dev_err_probe(data->smbus.dev, -EINVAL, 35 "Bus frequency %d is too fast.\n", 36 frequency); 37 if (data->smbus.clk_div > 0xff) 38 return dev_err_probe(data->smbus.dev, -EINVAL, 39 "Bus frequency %d is too slow.\n", 40 frequency); 41 42 return 0; 43 } 44 45 static int pasemi_platform_i2c_probe(struct platform_device *pdev) 46 { 47 struct device *dev = &pdev->dev; 48 struct pasemi_platform_i2c_data *data; 49 struct pasemi_smbus *smbus; 50 u32 frequency; 51 int error; 52 int irq_num; 53 54 data = devm_kzalloc(dev, sizeof(struct pasemi_platform_i2c_data), 55 GFP_KERNEL); 56 if (!data) 57 return -ENOMEM; 58 59 smbus = &data->smbus; 60 smbus->dev = dev; 61 62 smbus->ioaddr = devm_platform_ioremap_resource(pdev, 0); 63 if (IS_ERR(smbus->ioaddr)) 64 return PTR_ERR(smbus->ioaddr); 65 66 if (of_property_read_u32(dev->of_node, "clock-frequency", &frequency)) 67 frequency = I2C_MAX_STANDARD_MODE_FREQ; 68 69 data->clk_ref = devm_clk_get_enabled(dev, NULL); 70 if (IS_ERR(data->clk_ref)) 71 return PTR_ERR(data->clk_ref); 72 73 error = pasemi_platform_i2c_calc_clk_div(data, frequency); 74 if (error) 75 return error; 76 77 smbus->adapter.dev.of_node = pdev->dev.of_node; 78 error = pasemi_i2c_common_probe(smbus); 79 if (error) 80 return error; 81 82 irq_num = platform_get_irq(pdev, 0); 83 error = devm_request_irq(smbus->dev, irq_num, pasemi_irq_handler, 0, "pasemi_apple_i2c", (void *)smbus); 84 85 if (!error) 86 smbus->use_irq = 1; 87 platform_set_drvdata(pdev, data); 88 89 return 0; 90 } 91 92 static void pasemi_platform_i2c_remove(struct platform_device *pdev) { } 93 94 static const struct of_device_id pasemi_platform_i2c_of_match[] = { 95 { .compatible = "apple,t8103-i2c" }, 96 { .compatible = "apple,i2c" }, 97 {}, 98 }; 99 MODULE_DEVICE_TABLE(of, pasemi_platform_i2c_of_match); 100 101 static struct platform_driver pasemi_platform_i2c_driver = { 102 .driver = { 103 .name = "i2c-apple", 104 .of_match_table = pasemi_platform_i2c_of_match, 105 }, 106 .probe = pasemi_platform_i2c_probe, 107 .remove_new = pasemi_platform_i2c_remove, 108 }; 109 module_platform_driver(pasemi_platform_i2c_driver); 110 111 MODULE_LICENSE("GPL"); 112 MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>"); 113 MODULE_DESCRIPTION("Apple/PASemi SMBus platform driver"); 114