1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * omap-ocp2scp.c - transform ocp interface protocol to scp protocol 4 * 5 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com 6 * Author: Kishon Vijay Abraham I <kishon@ti.com> 7 */ 8 9 #include <linux/io.h> 10 #include <linux/module.h> 11 #include <linux/platform_device.h> 12 #include <linux/err.h> 13 #include <linux/pm_runtime.h> 14 #include <linux/of.h> 15 #include <linux/of_platform.h> 16 17 #define OCP2SCP_TIMING 0x18 18 #define SYNC2_MASK 0xf 19 20 static int ocp2scp_remove_devices(struct device *dev, void *c) 21 { 22 struct platform_device *pdev = to_platform_device(dev); 23 24 platform_device_unregister(pdev); 25 26 return 0; 27 } 28 29 static int omap_ocp2scp_probe(struct platform_device *pdev) 30 { 31 int ret; 32 u32 reg; 33 void __iomem *regs; 34 struct resource *res; 35 struct device_node *np = pdev->dev.of_node; 36 37 if (np) { 38 ret = of_platform_populate(np, NULL, NULL, &pdev->dev); 39 if (ret) { 40 dev_err(&pdev->dev, 41 "failed to add resources for ocp2scp child\n"); 42 goto err0; 43 } 44 } 45 46 pm_runtime_enable(&pdev->dev); 47 /* 48 * As per AM572x TRM: http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf 49 * under section 26.3.2.2, table 26-26 OCP2SCP TIMING Caution; 50 * As per OMAP4430 TRM: http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf 51 * under section 23.12.6.2.2 , Table 23-1213 OCP2SCP TIMING Caution; 52 * As per OMAP4460 TRM: http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf 53 * under section 23.12.6.2.2, Table 23-1213 OCP2SCP TIMING Caution; 54 * As per OMAP543x TRM http://www.ti.com/lit/pdf/swpu249 55 * under section 27.3.2.2, Table 27-27 OCP2SCP TIMING Caution; 56 * 57 * Read path of OCP2SCP is not working properly due to low reset value 58 * of SYNC2 parameter in OCP2SCP. Suggested reset value is 0x6 or more. 59 */ 60 if (!of_device_is_compatible(np, "ti,am437x-ocp2scp")) { 61 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 62 regs = devm_ioremap_resource(&pdev->dev, res); 63 if (IS_ERR(regs)) { 64 ret = PTR_ERR(regs); 65 goto err1; 66 } 67 68 pm_runtime_get_sync(&pdev->dev); 69 reg = readl_relaxed(regs + OCP2SCP_TIMING); 70 reg &= ~(SYNC2_MASK); 71 reg |= 0x6; 72 writel_relaxed(reg, regs + OCP2SCP_TIMING); 73 pm_runtime_put_sync(&pdev->dev); 74 } 75 76 return 0; 77 78 err1: 79 pm_runtime_disable(&pdev->dev); 80 81 err0: 82 device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices); 83 84 return ret; 85 } 86 87 static int omap_ocp2scp_remove(struct platform_device *pdev) 88 { 89 pm_runtime_disable(&pdev->dev); 90 device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices); 91 92 return 0; 93 } 94 95 #ifdef CONFIG_OF 96 static const struct of_device_id omap_ocp2scp_id_table[] = { 97 { .compatible = "ti,omap-ocp2scp" }, 98 { .compatible = "ti,am437x-ocp2scp" }, 99 {} 100 }; 101 MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table); 102 #endif 103 104 static struct platform_driver omap_ocp2scp_driver = { 105 .probe = omap_ocp2scp_probe, 106 .remove = omap_ocp2scp_remove, 107 .driver = { 108 .name = "omap-ocp2scp", 109 .of_match_table = of_match_ptr(omap_ocp2scp_id_table), 110 }, 111 }; 112 113 module_platform_driver(omap_ocp2scp_driver); 114 115 MODULE_ALIAS("platform:omap-ocp2scp"); 116 MODULE_AUTHOR("Texas Instruments Inc."); 117 MODULE_DESCRIPTION("OMAP OCP2SCP driver"); 118 MODULE_LICENSE("GPL v2"); 119