1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * Copyright 2005-2008 Freescale Semiconductor, Inc. All Rights Reserved.
22 # define MXC_W1_CONTROL_WR(x)	BIT(5 - (x))
37  * reset the device on the One Wire interface
45 	writeb(MXC_W1_CONTROL_RPP, dev->regs + MXC_W1_CONTROL);  in mxc_w1_ds2_reset_bus()
53 		u8 ctrl = readb(dev->regs + MXC_W1_CONTROL);  in mxc_w1_ds2_reset_bus()
55 		/* PST bit is valid after the RPP bit is self-cleared */  in mxc_w1_ds2_reset_bus()
64  * this is the low level routine to read/write a bit on the One Wire
73 	writeb(MXC_W1_CONTROL_WR(bit), dev->regs + MXC_W1_CONTROL);  in mxc_w1_ds2_touch_bit()
81 		u8 ctrl = readb(dev->regs + MXC_W1_CONTROL);  in mxc_w1_ds2_touch_bit()
83 		/* RDST bit is valid after the WR1/RD bit is self-cleared */  in mxc_w1_ds2_touch_bit()
98 	mdev = devm_kzalloc(&pdev->dev, sizeof(struct mxc_w1_device),  in mxc_w1_probe()
101 		return -ENOMEM;  in mxc_w1_probe()
103 	mdev->clk = devm_clk_get(&pdev->dev, NULL);  in mxc_w1_probe()
104 	if (IS_ERR(mdev->clk))  in mxc_w1_probe()
105 		return PTR_ERR(mdev->clk);  in mxc_w1_probe()
107 	err = clk_prepare_enable(mdev->clk);  in mxc_w1_probe()
111 	clkrate = clk_get_rate(mdev->clk);  in mxc_w1_probe()
113 		dev_warn(&pdev->dev,  in mxc_w1_probe()
119 		dev_warn(&pdev->dev,  in mxc_w1_probe()
122 	mdev->regs = devm_platform_ioremap_resource(pdev, 0);  in mxc_w1_probe()
123 	if (IS_ERR(mdev->regs)) {  in mxc_w1_probe()
124 		err = PTR_ERR(mdev->regs);  in mxc_w1_probe()
128 	/* Software reset 1-Wire module */  in mxc_w1_probe()
129 	writeb(MXC_W1_RESET_RST, mdev->regs + MXC_W1_RESET);  in mxc_w1_probe()
130 	writeb(0, mdev->regs + MXC_W1_RESET);  in mxc_w1_probe()
132 	writeb(clkdiv - 1, mdev->regs + MXC_W1_TIME_DIVIDER);  in mxc_w1_probe()
134 	mdev->bus_master.data = mdev;  in mxc_w1_probe()
135 	mdev->bus_master.reset_bus = mxc_w1_ds2_reset_bus;  in mxc_w1_probe()
136 	mdev->bus_master.touch_bit = mxc_w1_ds2_touch_bit;  in mxc_w1_probe()
140 	err = w1_add_master_device(&mdev->bus_master);  in mxc_w1_probe()
147 	clk_disable_unprepare(mdev->clk);  in mxc_w1_probe()
158 	w1_remove_master_device(&mdev->bus_master);  in mxc_w1_remove()
160 	clk_disable_unprepare(mdev->clk);  in mxc_w1_remove()
164 	{ .compatible = "fsl,imx21-owire" },
181 MODULE_DESCRIPTION("Driver for One-Wire on MXC");