diff options
Diffstat (limited to 'drivers/bus/omap-ocp2scp.c')
| -rw-r--r-- | drivers/bus/omap-ocp2scp.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/drivers/bus/omap-ocp2scp.c b/drivers/bus/omap-ocp2scp.c new file mode 100644 index 000000000..9f1856948 --- /dev/null +++ b/drivers/bus/omap-ocp2scp.c @@ -0,0 +1,123 @@ +/* + * omap-ocp2scp.c - transform ocp interface protocol to scp protocol + * + * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * Author: Kishon Vijay Abraham I <kishon@ti.com> + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/io.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/err.h> +#include <linux/pm_runtime.h> +#include <linux/of.h> +#include <linux/of_platform.h> + +#define OCP2SCP_TIMING 0x18 +#define SYNC2_MASK 0xf + +static int ocp2scp_remove_devices(struct device *dev, void *c) +{ + struct platform_device *pdev = to_platform_device(dev); + + platform_device_unregister(pdev); + + return 0; +} + +static int omap_ocp2scp_probe(struct platform_device *pdev) +{ + int ret; + u32 reg; + void __iomem *regs; + struct resource *res; + struct device_node *np = pdev->dev.of_node; + + if (np) { + ret = of_platform_populate(np, NULL, NULL, &pdev->dev); + if (ret) { + dev_err(&pdev->dev, + "failed to add resources for ocp2scp child\n"); + goto err0; + } + } + + pm_runtime_enable(&pdev->dev); + /* + * As per AM572x TRM: http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf + * under section 26.3.2.2, table 26-26 OCP2SCP TIMING Caution; + * As per OMAP4430 TRM: http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf + * under section 23.12.6.2.2 , Table 23-1213 OCP2SCP TIMING Caution; + * As per OMAP4460 TRM: http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf + * under section 23.12.6.2.2, Table 23-1213 OCP2SCP TIMING Caution; + * As per OMAP543x TRM http://www.ti.com/lit/pdf/swpu249 + * under section 27.3.2.2, Table 27-27 OCP2SCP TIMING Caution; + * + * Read path of OCP2SCP is not working properly due to low reset value + * of SYNC2 parameter in OCP2SCP. Suggested reset value is 0x6 or more. + */ + if (!of_device_is_compatible(np, "ti,am437x-ocp2scp")) { + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + regs = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(regs)) + goto err0; + + pm_runtime_get_sync(&pdev->dev); + reg = readl_relaxed(regs + OCP2SCP_TIMING); + reg &= ~(SYNC2_MASK); + reg |= 0x6; + writel_relaxed(reg, regs + OCP2SCP_TIMING); + pm_runtime_put_sync(&pdev->dev); + } + + return 0; + +err0: + device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices); + + return ret; +} + +static int omap_ocp2scp_remove(struct platform_device *pdev) +{ + pm_runtime_disable(&pdev->dev); + device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices); + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id omap_ocp2scp_id_table[] = { + { .compatible = "ti,omap-ocp2scp" }, + { .compatible = "ti,am437x-ocp2scp" }, + {} +}; +MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table); +#endif + +static struct platform_driver omap_ocp2scp_driver = { + .probe = omap_ocp2scp_probe, + .remove = omap_ocp2scp_remove, + .driver = { + .name = "omap-ocp2scp", + .of_match_table = of_match_ptr(omap_ocp2scp_id_table), + }, +}; + +module_platform_driver(omap_ocp2scp_driver); + +MODULE_ALIAS("platform: omap-ocp2scp"); +MODULE_AUTHOR("Texas Instruments Inc."); +MODULE_DESCRIPTION("OMAP OCP2SCP driver"); +MODULE_LICENSE("GPL v2"); |