xref: /openbmc/linux/drivers/spi/spi-clps711x.c (revision 1baba77b)
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 
25 struct 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 
spi_clps711x_prepare_message(struct spi_controller * host,struct spi_message * msg)36 static 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 
spi_clps711x_transfer_one(struct spi_controller * host,struct spi_device * spi,struct spi_transfer * xfer)48 static 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 
spi_clps711x_isr(int irq,void * dev_id)69 static 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 
spi_clps711x_probe(struct platform_device * pdev)91 static 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 
149 err_out:
150 	spi_controller_put(host);
151 
152 	return ret;
153 }
154 
155 static const struct of_device_id clps711x_spi_dt_ids[] = {
156 	{ .compatible = "cirrus,ep7209-spi", },
157 	{ }
158 };
159 MODULE_DEVICE_TABLE(of, clps711x_spi_dt_ids);
160 
161 static 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 };
168 module_platform_driver(clps711x_spi_driver);
169 
170 MODULE_LICENSE("GPL");
171 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
172 MODULE_DESCRIPTION("CLPS711X SPI bus driver");
173 MODULE_ALIAS("platform:" DRIVER_NAME);
174