1 /* 2 * omap-ocp2scp.c - transform ocp interface protocol to scp protocol 3 * 4 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * Author: Kishon Vijay Abraham I <kishon@ti.com> 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 */ 18 19 #include <linux/io.h> 20 #include <linux/module.h> 21 #include <linux/platform_device.h> 22 #include <linux/err.h> 23 #include <linux/pm_runtime.h> 24 #include <linux/of.h> 25 #include <linux/of_platform.h> 26 27 #define OCP2SCP_TIMING 0x18 28 #define SYNC2_MASK 0xf 29 30 static int ocp2scp_remove_devices(struct device *dev, void *c) 31 { 32 struct platform_device *pdev = to_platform_device(dev); 33 34 platform_device_unregister(pdev); 35 36 return 0; 37 } 38 39 static int omap_ocp2scp_probe(struct platform_device *pdev) 40 { 41 int ret; 42 u32 reg; 43 void __iomem *regs; 44 struct resource *res; 45 struct device_node *np = pdev->dev.of_node; 46 47 if (np) { 48 ret = of_platform_populate(np, NULL, NULL, &pdev->dev); 49 if (ret) { 50 dev_err(&pdev->dev, 51 "failed to add resources for ocp2scp child\n"); 52 goto err0; 53 } 54 } 55 56 pm_runtime_enable(&pdev->dev); 57 /* 58 * As per AM572x TRM: http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf 59 * under section 26.3.2.2, table 26-26 OCP2SCP TIMING Caution; 60 * As per OMAP4430 TRM: http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf 61 * under section 23.12.6.2.2 , Table 23-1213 OCP2SCP TIMING Caution; 62 * As per OMAP4460 TRM: http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf 63 * under section 23.12.6.2.2, Table 23-1213 OCP2SCP TIMING Caution; 64 * As per OMAP543x TRM http://www.ti.com/lit/pdf/swpu249 65 * under section 27.3.2.2, Table 27-27 OCP2SCP TIMING Caution; 66 * 67 * Read path of OCP2SCP is not working properly due to low reset value 68 * of SYNC2 parameter in OCP2SCP. Suggested reset value is 0x6 or more. 69 */ 70 if (!of_device_is_compatible(np, "ti,am437x-ocp2scp")) { 71 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 72 regs = devm_ioremap_resource(&pdev->dev, res); 73 if (IS_ERR(regs)) 74 goto err0; 75 76 pm_runtime_get_sync(&pdev->dev); 77 reg = readl_relaxed(regs + OCP2SCP_TIMING); 78 reg &= ~(SYNC2_MASK); 79 reg |= 0x6; 80 writel_relaxed(reg, regs + OCP2SCP_TIMING); 81 pm_runtime_put_sync(&pdev->dev); 82 } 83 84 return 0; 85 86 err0: 87 device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices); 88 89 return ret; 90 } 91 92 static int omap_ocp2scp_remove(struct platform_device *pdev) 93 { 94 pm_runtime_disable(&pdev->dev); 95 device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices); 96 97 return 0; 98 } 99 100 #ifdef CONFIG_OF 101 static const struct of_device_id omap_ocp2scp_id_table[] = { 102 { .compatible = "ti,omap-ocp2scp" }, 103 { .compatible = "ti,am437x-ocp2scp" }, 104 {} 105 }; 106 MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table); 107 #endif 108 109 static struct platform_driver omap_ocp2scp_driver = { 110 .probe = omap_ocp2scp_probe, 111 .remove = omap_ocp2scp_remove, 112 .driver = { 113 .name = "omap-ocp2scp", 114 .of_match_table = of_match_ptr(omap_ocp2scp_id_table), 115 }, 116 }; 117 118 module_platform_driver(omap_ocp2scp_driver); 119 120 MODULE_ALIAS("platform:omap-ocp2scp"); 121 MODULE_AUTHOR("Texas Instruments Inc."); 122 MODULE_DESCRIPTION("OMAP OCP2SCP driver"); 123 MODULE_LICENSE("GPL v2"); 124