1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * SPI master driver for ICP DAS LP-8841 RTC
11  * Copyright (C) 2003 - 2007 Paul Mundt
19 #include <linux/spi/spi.h>
30  * REVISIT If there is support for SPI_3WIRE and SPI_LSB_FIRST in SPI
31  * GPIO driver, this SPI driver can be replaced by a simple GPIO driver
44 		data->state |= SPI_LP8841_RTC_CLK;  in setsck()
46 		data->state &= ~SPI_LP8841_RTC_CLK;  in setsck()
47 	writeb(data->state, data->iomem);  in setsck()
54 		data->state |= SPI_LP8841_RTC_MOSI;  in setmosi()
56 		data->state &= ~SPI_LP8841_RTC_MOSI;  in setmosi()
57 	writeb(data->state, data->iomem);  in setmosi()
63 	return ioread8(data->iomem) & SPI_LP8841_RTC_MISO;  in getmiso()
68 		unsigned usecs, unsigned cpol, unsigned flags,  in bitbang_txrx_be_cpha0_lsb()  argument
71 	/* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */  in bitbang_txrx_be_cpha0_lsb()
73 	u32 shift = 32 - bits;  in bitbang_txrx_be_cpha0_lsb()
75 	for (; likely(bits); bits--) {  in bitbang_txrx_be_cpha0_lsb()
88 		setsck(data, !cpol);  in bitbang_txrx_be_cpha0_lsb()
91 		setsck(data, cpol);  in bitbang_txrx_be_cpha0_lsb()
100 			    struct spi_device *spi,  in spi_lp8841_rtc_transfer_one()  argument
104 	unsigned		count = t->len;  in spi_lp8841_rtc_transfer_one()
105 	const u8		*tx = t->tx_buf;  in spi_lp8841_rtc_transfer_one()
106 	u8			*rx = t->rx_buf;  in spi_lp8841_rtc_transfer_one()
111 		data->state &= ~SPI_LP8841_RTC_nWE;  in spi_lp8841_rtc_transfer_one()
112 		writeb(data->state, data->iomem);  in spi_lp8841_rtc_transfer_one()
117 			count--;  in spi_lp8841_rtc_transfer_one()
120 		data->state |= SPI_LP8841_RTC_nWE;  in spi_lp8841_rtc_transfer_one()
121 		writeb(data->state, data->iomem);  in spi_lp8841_rtc_transfer_one()
126 			count--;  in spi_lp8841_rtc_transfer_one()
129 		ret = -EINVAL;  in spi_lp8841_rtc_transfer_one()
138 spi_lp8841_rtc_set_cs(struct spi_device *spi, bool enable)  in spi_lp8841_rtc_set_cs()  argument
140 	struct spi_lp8841_rtc *data = spi_master_get_devdata(spi->master);  in spi_lp8841_rtc_set_cs()
142 	data->state = 0;  in spi_lp8841_rtc_set_cs()
143 	writeb(data->state, data->iomem);  in spi_lp8841_rtc_set_cs()
146 		data->state |= SPI_LP8841_RTC_CE;  in spi_lp8841_rtc_set_cs()
147 		writeb(data->state, data->iomem);  in spi_lp8841_rtc_set_cs()
153 spi_lp8841_rtc_setup(struct spi_device *spi)  in spi_lp8841_rtc_setup()  argument
155 	if ((spi->mode & SPI_CS_HIGH) == 0) {  in spi_lp8841_rtc_setup()
156 		dev_err(&spi->dev, "unsupported active low chip select\n");  in spi_lp8841_rtc_setup()
157 		return -EINVAL;  in spi_lp8841_rtc_setup()
160 	if ((spi->mode & SPI_LSB_FIRST) == 0) {  in spi_lp8841_rtc_setup()
161 		dev_err(&spi->dev, "unsupported MSB first mode\n");  in spi_lp8841_rtc_setup()
162 		return -EINVAL;  in spi_lp8841_rtc_setup()
165 	if ((spi->mode & SPI_3WIRE) == 0) {  in spi_lp8841_rtc_setup()
166 		dev_err(&spi->dev, "unsupported wiring. 3 wires required\n");  in spi_lp8841_rtc_setup()
167 		return -EINVAL;  in spi_lp8841_rtc_setup()
175 	{ .compatible = "icpdas,lp8841-spi-rtc" },
189 	master = spi_alloc_master(&pdev->dev, sizeof(*data));  in spi_lp8841_rtc_probe()
191 		return -ENOMEM;  in spi_lp8841_rtc_probe()
194 	master->flags = SPI_MASTER_HALF_DUPLEX;  in spi_lp8841_rtc_probe()
195 	master->mode_bits = SPI_CS_HIGH | SPI_3WIRE | SPI_LSB_FIRST;  in spi_lp8841_rtc_probe()
197 	master->bus_num = pdev->id;  in spi_lp8841_rtc_probe()
198 	master->num_chipselect = 1;  in spi_lp8841_rtc_probe()
199 	master->setup = spi_lp8841_rtc_setup;  in spi_lp8841_rtc_probe()
200 	master->set_cs = spi_lp8841_rtc_set_cs;  in spi_lp8841_rtc_probe()
201 	master->transfer_one = spi_lp8841_rtc_transfer_one;  in spi_lp8841_rtc_probe()
202 	master->bits_per_word_mask = SPI_BPW_MASK(8);  in spi_lp8841_rtc_probe()
204 	master->dev.of_node = pdev->dev.of_node;  in spi_lp8841_rtc_probe()
209 	data->iomem = devm_platform_ioremap_resource(pdev, 0);  in spi_lp8841_rtc_probe()
210 	ret = PTR_ERR_OR_ZERO(data->iomem);  in spi_lp8841_rtc_probe()
212 		dev_err(&pdev->dev, "failed to get IO address\n");  in spi_lp8841_rtc_probe()
216 	/* register with the SPI framework */  in spi_lp8841_rtc_probe()
217 	ret = devm_spi_register_master(&pdev->dev, master);  in spi_lp8841_rtc_probe()
219 		dev_err(&pdev->dev, "cannot register spi master\n");  in spi_lp8841_rtc_probe()
243 MODULE_DESCRIPTION("SPI master driver for ICP DAS LP-8841 RTC");