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(ctlr: host);
40 struct spi_device *spi = msg->spi;
41
42 /* Setup mode for transfer */
43 return regmap_update_bits(map: hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCKNSEN,
44 val: (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(ctlr: host);
53 u8 data;
54
55 clk_set_rate(clk: hw->spi_clk, rate: 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(val: data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, addr: 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(ctlr: host);
73 u8 data;
74
75 /* Handle RX */
76 data = readb(addr: 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(val: data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN,
84 addr: hw->syncio);
85 } else
86 spi_finalize_current_transfer(ctlr: 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(dev: &pdev->dev, size: 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(ctlr: host);
115
116 hw->spi_clk = devm_clk_get(dev: &pdev->dev, NULL);
117 if (IS_ERR(ptr: hw->spi_clk)) {
118 ret = PTR_ERR(ptr: hw->spi_clk);
119 goto err_out;
120 }
121
122 hw->syscon = syscon_regmap_lookup_by_phandle(np, property: "syscon");
123 if (IS_ERR(ptr: hw->syscon)) {
124 ret = PTR_ERR(ptr: hw->syscon);
125 goto err_out;
126 }
127
128 hw->syncio = devm_platform_ioremap_resource(pdev, index: 0);
129 if (IS_ERR(ptr: hw->syncio)) {
130 ret = PTR_ERR(ptr: hw->syncio);
131 goto err_out;
132 }
133
134 /* Disable extended mode due hardware problems */
135 regmap_update_bits(map: hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, val: 0);
136
137 /* Clear possible pending interrupt */
138 readl(addr: hw->syncio);
139
140 ret = devm_request_irq(dev: &pdev->dev, irq, handler: spi_clps711x_isr, irqflags: 0,
141 devname: dev_name(dev: &pdev->dev), dev_id: host);
142 if (ret)
143 goto err_out;
144
145 ret = devm_spi_register_controller(dev: &pdev->dev, ctlr: host);
146 if (!ret)
147 return 0;
148
149err_out:
150 spi_controller_put(ctlr: 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);
174

source code of linux/drivers/spi/spi-clps711x.c