1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *  CLPS711X SPI bus driver
  4 *
  5 *  Copyright (C) 2012-2016 Alexander Shiyan <shc_work@mail.ru>
  6 */
  7
  8#include <linux/io.h>
  9#include <linux/clk.h>
 10#include <linux/gpio/consumer.h>
 11#include <linux/module.h>
 12#include <linux/of.h>
 13#include <linux/interrupt.h>
 14#include <linux/platform_device.h>
 15#include <linux/regmap.h>
 16#include <linux/mfd/syscon.h>
 17#include <linux/mfd/syscon/clps711x.h>
 18#include <linux/spi/spi.h>
 19
 20#define DRIVER_NAME		"clps711x-spi"
 21
 22#define SYNCIO_FRMLEN(x)	((x) << 8)
 23#define SYNCIO_TXFRMEN		(1 << 14)
 24
 25struct spi_clps711x_data {
 26	void __iomem		*syncio;
 27	struct regmap		*syscon;
 28	struct clk		*spi_clk;
 29
 30	u8			*tx_buf;
 31	u8			*rx_buf;
 32	unsigned int		bpw;
 33	int			len;
 34};
 35
 36static int spi_clps711x_prepare_message(struct spi_controller *host,
 37					struct spi_message *msg)
 38{
 39	struct spi_clps711x_data *hw = spi_controller_get_devdata(host);
 40	struct spi_device *spi = msg->spi;
 41
 42	/* Setup mode for transfer */
 43	return regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCKNSEN,
 44				  (spi->mode & SPI_CPHA) ?
 45				  SYSCON3_ADCCKNSEN : 0);
 46}
 47
 48static int spi_clps711x_transfer_one(struct spi_controller *host,
 49				     struct spi_device *spi,
 50				     struct spi_transfer *xfer)
 51{
 52	struct spi_clps711x_data *hw = spi_controller_get_devdata(host);
 53	u8 data;
 54
 55	clk_set_rate(hw->spi_clk, xfer->speed_hz ? : spi->max_speed_hz);
 56
 57	hw->len = xfer->len;
 58	hw->bpw = xfer->bits_per_word;
 59	hw->tx_buf = (u8 *)xfer->tx_buf;
 60	hw->rx_buf = (u8 *)xfer->rx_buf;
 61
 62	/* Initiate transfer */
 63	data = hw->tx_buf ? *hw->tx_buf++ : 0;
 64	writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, hw->syncio);
 65
 66	return 1;
 67}
 68
 69static irqreturn_t spi_clps711x_isr(int irq, void *dev_id)
 70{
 71	struct spi_controller *host = dev_id;
 72	struct spi_clps711x_data *hw = spi_controller_get_devdata(host);
 73	u8 data;
 74
 75	/* Handle RX */
 76	data = readb(hw->syncio);
 77	if (hw->rx_buf)
 78		*hw->rx_buf++ = data;
 79
 80	/* Handle TX */
 81	if (--hw->len > 0) {
 82		data = hw->tx_buf ? *hw->tx_buf++ : 0;
 83		writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN,
 84		       hw->syncio);
 85	} else
 86		spi_finalize_current_transfer(host);
 87
 88	return IRQ_HANDLED;
 89}
 90
 91static int spi_clps711x_probe(struct platform_device *pdev)
 92{
 93	struct device_node *np = pdev->dev.of_node;
 94	struct spi_clps711x_data *hw;
 95	struct spi_controller *host;
 96	int irq, ret;
 97
 98	irq = platform_get_irq(pdev, 0);
 99	if (irq < 0)
100		return irq;
101
102	host = spi_alloc_host(&pdev->dev, sizeof(*hw));
103	if (!host)
104		return -ENOMEM;
105
106	host->use_gpio_descriptors = true;
107	host->bus_num = -1;
108	host->mode_bits = SPI_CPHA | SPI_CS_HIGH;
109	host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 8);
110	host->dev.of_node = pdev->dev.of_node;
111	host->prepare_message = spi_clps711x_prepare_message;
112	host->transfer_one = spi_clps711x_transfer_one;
113
114	hw = spi_controller_get_devdata(host);
115
116	hw->spi_clk = devm_clk_get(&pdev->dev, NULL);
117	if (IS_ERR(hw->spi_clk)) {
118		ret = PTR_ERR(hw->spi_clk);
119		goto err_out;
120	}
121
122	hw->syscon = syscon_regmap_lookup_by_phandle(np, "syscon");
123	if (IS_ERR(hw->syscon)) {
124		ret = PTR_ERR(hw->syscon);
125		goto err_out;
126	}
127
128	hw->syncio = devm_platform_ioremap_resource(pdev, 0);
129	if (IS_ERR(hw->syncio)) {
130		ret = PTR_ERR(hw->syncio);
131		goto err_out;
132	}
133
134	/* Disable extended mode due hardware problems */
135	regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, 0);
136
137	/* Clear possible pending interrupt */
138	readl(hw->syncio);
139
140	ret = devm_request_irq(&pdev->dev, irq, spi_clps711x_isr, 0,
141			       dev_name(&pdev->dev), host);
142	if (ret)
143		goto err_out;
144
145	ret = devm_spi_register_controller(&pdev->dev, host);
146	if (!ret)
147		return 0;
148
149err_out:
150	spi_controller_put(host);
151
152	return ret;
153}
154
155static const struct of_device_id clps711x_spi_dt_ids[] = {
156	{ .compatible = "cirrus,ep7209-spi", },
157	{ }
158};
159MODULE_DEVICE_TABLE(of, clps711x_spi_dt_ids);
160
161static struct platform_driver clps711x_spi_driver = {
162	.driver	= {
163		.name	= DRIVER_NAME,
164		.of_match_table = clps711x_spi_dt_ids,
165	},
166	.probe	= spi_clps711x_probe,
167};
168module_platform_driver(clps711x_spi_driver);
169
170MODULE_LICENSE("GPL");
171MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
172MODULE_DESCRIPTION("CLPS711X SPI bus driver");
173MODULE_ALIAS("platform:" DRIVER_NAME);