1 /* 2 * Copyright (c) 2014, The Linux foundation. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License rev 2 and 6 * only rev 2 as published by the free Software foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or fITNESS fOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 */ 13 14 #include <linux/clk.h> 15 #include <linux/err.h> 16 #include <linux/io.h> 17 #include <linux/module.h> 18 #include <linux/of.h> 19 #include <linux/of_platform.h> 20 #include <linux/platform_device.h> 21 22 #define GSBI_CTRL_REG 0x0000 23 #define GSBI_PROTOCOL_SHIFT 4 24 25 struct gsbi_info { 26 struct clk *hclk; 27 u32 mode; 28 u32 crci; 29 }; 30 31 static int gsbi_probe(struct platform_device *pdev) 32 { 33 struct device_node *node = pdev->dev.of_node; 34 struct resource *res; 35 void __iomem *base; 36 struct gsbi_info *gsbi; 37 38 gsbi = devm_kzalloc(&pdev->dev, sizeof(*gsbi), GFP_KERNEL); 39 40 if (!gsbi) 41 return -ENOMEM; 42 43 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 44 base = devm_ioremap_resource(&pdev->dev, res); 45 if (IS_ERR(base)) 46 return PTR_ERR(base); 47 48 if (of_property_read_u32(node, "qcom,mode", &gsbi->mode)) { 49 dev_err(&pdev->dev, "missing mode configuration\n"); 50 return -EINVAL; 51 } 52 53 /* not required, so default to 0 if not present */ 54 of_property_read_u32(node, "qcom,crci", &gsbi->crci); 55 56 dev_info(&pdev->dev, "GSBI port protocol: %d crci: %d\n", 57 gsbi->mode, gsbi->crci); 58 gsbi->hclk = devm_clk_get(&pdev->dev, "iface"); 59 if (IS_ERR(gsbi->hclk)) 60 return PTR_ERR(gsbi->hclk); 61 62 clk_prepare_enable(gsbi->hclk); 63 64 writel_relaxed((gsbi->mode << GSBI_PROTOCOL_SHIFT) | gsbi->crci, 65 base + GSBI_CTRL_REG); 66 67 /* make sure the gsbi control write is not reordered */ 68 wmb(); 69 70 platform_set_drvdata(pdev, gsbi); 71 72 return of_platform_populate(node, NULL, NULL, &pdev->dev); 73 } 74 75 static int gsbi_remove(struct platform_device *pdev) 76 { 77 struct gsbi_info *gsbi = platform_get_drvdata(pdev); 78 79 clk_disable_unprepare(gsbi->hclk); 80 81 return 0; 82 } 83 84 static const struct of_device_id gsbi_dt_match[] = { 85 { .compatible = "qcom,gsbi-v1.0.0", }, 86 { }, 87 }; 88 89 MODULE_DEVICE_TABLE(of, gsbi_dt_match); 90 91 static struct platform_driver gsbi_driver = { 92 .driver = { 93 .name = "gsbi", 94 .of_match_table = gsbi_dt_match, 95 }, 96 .probe = gsbi_probe, 97 .remove = gsbi_remove, 98 }; 99 100 module_platform_driver(gsbi_driver); 101 102 MODULE_AUTHOR("Andy Gross <agross@codeaurora.org>"); 103 MODULE_DESCRIPTION("QCOM GSBI driver"); 104 MODULE_LICENSE("GPL v2"); 105