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_master * master,struct spi_message * msg)36 static int spi_clps711x_prepare_message(struct spi_master *master,
37 struct spi_message *msg)
38 {
39 struct spi_clps711x_data *hw = spi_master_get_devdata(master);
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_master * master,struct spi_device * spi,struct spi_transfer * xfer)48 static int spi_clps711x_transfer_one(struct spi_master *master,
49 struct spi_device *spi,
50 struct spi_transfer *xfer)
51 {
52 struct spi_clps711x_data *hw = spi_master_get_devdata(master);
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_master *master = dev_id;
72 struct spi_clps711x_data *hw = spi_master_get_devdata(master);
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(master);
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_master *master;
96 int irq, ret;
97
98 irq = platform_get_irq(pdev, 0);
99 if (irq < 0)
100 return irq;
101
102 master = spi_alloc_master(&pdev->dev, sizeof(*hw));
103 if (!master)
104 return -ENOMEM;
105
106 master->use_gpio_descriptors = true;
107 master->bus_num = -1;
108 master->mode_bits = SPI_CPHA | SPI_CS_HIGH;
109 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 8);
110 master->dev.of_node = pdev->dev.of_node;
111 master->prepare_message = spi_clps711x_prepare_message;
112 master->transfer_one = spi_clps711x_transfer_one;
113
114 hw = spi_master_get_devdata(master);
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), master);
142 if (ret)
143 goto err_out;
144
145 ret = devm_spi_register_master(&pdev->dev, master);
146 if (!ret)
147 return 0;
148
149 err_out:
150 spi_master_put(master);
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