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 static int gsbi_probe(struct platform_device *pdev) 26 { 27 struct device_node *node = pdev->dev.of_node; 28 struct resource *res; 29 void __iomem *base; 30 struct clk *hclk; 31 u32 mode, crci = 0; 32 33 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 34 base = devm_ioremap_resource(&pdev->dev, res); 35 if (IS_ERR(base)) 36 return PTR_ERR(base); 37 38 if (of_property_read_u32(node, "qcom,mode", &mode)) { 39 dev_err(&pdev->dev, "missing mode configuration\n"); 40 return -EINVAL; 41 } 42 43 /* not required, so default to 0 if not present */ 44 of_property_read_u32(node, "qcom,crci", &crci); 45 46 dev_info(&pdev->dev, "GSBI port protocol: %d crci: %d\n", mode, crci); 47 48 hclk = devm_clk_get(&pdev->dev, "iface"); 49 if (IS_ERR(hclk)) 50 return PTR_ERR(hclk); 51 52 clk_prepare_enable(hclk); 53 54 writel_relaxed((mode << GSBI_PROTOCOL_SHIFT) | crci, 55 base + GSBI_CTRL_REG); 56 57 /* make sure the gsbi control write is not reordered */ 58 wmb(); 59 60 clk_disable_unprepare(hclk); 61 62 return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev); 63 } 64 65 static const struct of_device_id gsbi_dt_match[] = { 66 { .compatible = "qcom,gsbi-v1.0.0", }, 67 { }, 68 }; 69 70 MODULE_DEVICE_TABLE(of, gsbi_dt_match); 71 72 static struct platform_driver gsbi_driver = { 73 .driver = { 74 .name = "gsbi", 75 .owner = THIS_MODULE, 76 .of_match_table = gsbi_dt_match, 77 }, 78 .probe = gsbi_probe, 79 }; 80 81 module_platform_driver(gsbi_driver); 82 83 MODULE_AUTHOR("Andy Gross <agross@codeaurora.org>"); 84 MODULE_DESCRIPTION("QCOM GSBI driver"); 85 MODULE_LICENSE("GPL v2"); 86