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161b96c3 AS |
1 | /* |
2 | * CLPS711X SPI bus driver | |
3 | * | |
98984796 | 4 | * Copyright (C) 2012-2014 Alexander Shiyan <shc_work@mail.ru> |
161b96c3 AS |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/io.h> | |
13 | #include <linux/clk.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/gpio.h> | |
16 | #include <linux/delay.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/interrupt.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/spi/spi.h> | |
21 | #include <linux/platform_data/spi-clps711x.h> | |
22 | ||
23 | #include <mach/hardware.h> | |
24 | ||
25 | #define DRIVER_NAME "spi-clps711x" | |
26 | ||
27 | struct spi_clps711x_data { | |
28 | struct completion done; | |
29 | ||
30 | struct clk *spi_clk; | |
31 | u32 max_speed_hz; | |
32 | ||
33 | u8 *tx_buf; | |
34 | u8 *rx_buf; | |
35 | int count; | |
36 | int len; | |
37 | ||
38 | int chipselect[0]; | |
39 | }; | |
40 | ||
41 | static int spi_clps711x_setup(struct spi_device *spi) | |
42 | { | |
43 | struct spi_clps711x_data *hw = spi_master_get_devdata(spi->master); | |
44 | ||
161b96c3 AS |
45 | /* We are expect that SPI-device is not selected */ |
46 | gpio_direction_output(hw->chipselect[spi->chip_select], | |
47 | !(spi->mode & SPI_CS_HIGH)); | |
48 | ||
49 | return 0; | |
50 | } | |
51 | ||
52 | static void spi_clps711x_setup_mode(struct spi_device *spi) | |
53 | { | |
54 | /* Setup edge for transfer */ | |
55 | if (spi->mode & SPI_CPHA) | |
56 | clps_writew(clps_readw(SYSCON3) | SYSCON3_ADCCKNSEN, SYSCON3); | |
57 | else | |
58 | clps_writew(clps_readw(SYSCON3) & ~SYSCON3_ADCCKNSEN, SYSCON3); | |
59 | } | |
60 | ||
61 | static int spi_clps711x_setup_xfer(struct spi_device *spi, | |
62 | struct spi_transfer *xfer) | |
63 | { | |
64 | u32 speed = xfer->speed_hz ? : spi->max_speed_hz; | |
766ed704 | 65 | u8 bpw = xfer->bits_per_word; |
161b96c3 AS |
66 | struct spi_clps711x_data *hw = spi_master_get_devdata(spi->master); |
67 | ||
68 | if (bpw != 8) { | |
69 | dev_err(&spi->dev, "Unsupported master bus width %i\n", bpw); | |
70 | return -EINVAL; | |
71 | } | |
72 | ||
73 | /* Setup SPI frequency divider */ | |
74 | if (!speed || (speed >= hw->max_speed_hz)) | |
75 | clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) | | |
76 | SYSCON1_ADCKSEL(3), SYSCON1); | |
77 | else if (speed >= (hw->max_speed_hz / 2)) | |
78 | clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) | | |
79 | SYSCON1_ADCKSEL(2), SYSCON1); | |
80 | else if (speed >= (hw->max_speed_hz / 8)) | |
81 | clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) | | |
82 | SYSCON1_ADCKSEL(1), SYSCON1); | |
83 | else | |
84 | clps_writel((clps_readl(SYSCON1) & ~SYSCON1_ADCKSEL_MASK) | | |
85 | SYSCON1_ADCKSEL(0), SYSCON1); | |
86 | ||
87 | return 0; | |
88 | } | |
89 | ||
90 | static int spi_clps711x_transfer_one_message(struct spi_master *master, | |
91 | struct spi_message *msg) | |
92 | { | |
93 | struct spi_clps711x_data *hw = spi_master_get_devdata(master); | |
94 | struct spi_transfer *xfer; | |
95 | int status = 0, cs = hw->chipselect[msg->spi->chip_select]; | |
96 | u32 data; | |
97 | ||
98 | spi_clps711x_setup_mode(msg->spi); | |
99 | ||
100 | list_for_each_entry(xfer, &msg->transfers, transfer_list) { | |
101 | if (spi_clps711x_setup_xfer(msg->spi, xfer)) { | |
102 | status = -EINVAL; | |
103 | goto out_xfr; | |
104 | } | |
105 | ||
106 | gpio_set_value(cs, !!(msg->spi->mode & SPI_CS_HIGH)); | |
107 | ||
16735d02 | 108 | reinit_completion(&hw->done); |
161b96c3 AS |
109 | |
110 | hw->count = 0; | |
111 | hw->len = xfer->len; | |
112 | hw->tx_buf = (u8 *)xfer->tx_buf; | |
113 | hw->rx_buf = (u8 *)xfer->rx_buf; | |
114 | ||
115 | /* Initiate transfer */ | |
116 | data = hw->tx_buf ? hw->tx_buf[hw->count] : 0; | |
117 | clps_writel(data | SYNCIO_FRMLEN(8) | SYNCIO_TXFRMEN, SYNCIO); | |
118 | ||
119 | wait_for_completion(&hw->done); | |
120 | ||
121 | if (xfer->delay_usecs) | |
122 | udelay(xfer->delay_usecs); | |
123 | ||
124 | if (xfer->cs_change || | |
125 | list_is_last(&xfer->transfer_list, &msg->transfers)) | |
126 | gpio_set_value(cs, !(msg->spi->mode & SPI_CS_HIGH)); | |
127 | ||
128 | msg->actual_length += xfer->len; | |
129 | } | |
130 | ||
131 | out_xfr: | |
132 | msg->status = status; | |
133 | spi_finalize_current_message(master); | |
134 | ||
135 | return 0; | |
136 | } | |
137 | ||
138 | static irqreturn_t spi_clps711x_isr(int irq, void *dev_id) | |
139 | { | |
140 | struct spi_clps711x_data *hw = (struct spi_clps711x_data *)dev_id; | |
141 | u32 data; | |
142 | ||
143 | /* Handle RX */ | |
144 | data = clps_readb(SYNCIO); | |
145 | if (hw->rx_buf) | |
146 | hw->rx_buf[hw->count] = (u8)data; | |
147 | ||
148 | hw->count++; | |
149 | ||
150 | /* Handle TX */ | |
151 | if (hw->count < hw->len) { | |
152 | data = hw->tx_buf ? hw->tx_buf[hw->count] : 0; | |
153 | clps_writel(data | SYNCIO_FRMLEN(8) | SYNCIO_TXFRMEN, SYNCIO); | |
154 | } else | |
155 | complete(&hw->done); | |
156 | ||
157 | return IRQ_HANDLED; | |
158 | } | |
159 | ||
fd4a319b | 160 | static int spi_clps711x_probe(struct platform_device *pdev) |
161b96c3 AS |
161 | { |
162 | int i, ret; | |
163 | struct spi_master *master; | |
164 | struct spi_clps711x_data *hw; | |
165 | struct spi_clps711x_pdata *pdata = dev_get_platdata(&pdev->dev); | |
166 | ||
167 | if (!pdata) { | |
168 | dev_err(&pdev->dev, "No platform data supplied\n"); | |
169 | return -EINVAL; | |
170 | } | |
171 | ||
172 | if (pdata->num_chipselect < 1) { | |
173 | dev_err(&pdev->dev, "At least one CS must be defined\n"); | |
174 | return -EINVAL; | |
175 | } | |
176 | ||
177 | master = spi_alloc_master(&pdev->dev, | |
178 | sizeof(struct spi_clps711x_data) + | |
179 | sizeof(int) * pdata->num_chipselect); | |
180 | if (!master) { | |
181 | dev_err(&pdev->dev, "SPI allocating memory error\n"); | |
182 | return -ENOMEM; | |
183 | } | |
184 | ||
185 | master->bus_num = pdev->id; | |
186 | master->mode_bits = SPI_CPHA | SPI_CS_HIGH; | |
24778be2 | 187 | master->bits_per_word_mask = SPI_BPW_MASK(8); |
161b96c3 AS |
188 | master->num_chipselect = pdata->num_chipselect; |
189 | master->setup = spi_clps711x_setup; | |
190 | master->transfer_one_message = spi_clps711x_transfer_one_message; | |
191 | ||
192 | hw = spi_master_get_devdata(master); | |
193 | ||
194 | for (i = 0; i < master->num_chipselect; i++) { | |
195 | hw->chipselect[i] = pdata->chipselect[i]; | |
196 | if (!gpio_is_valid(hw->chipselect[i])) { | |
197 | dev_err(&pdev->dev, "Invalid CS GPIO %i\n", i); | |
198 | ret = -EINVAL; | |
199 | goto err_out; | |
200 | } | |
98984796 | 201 | if (devm_gpio_request(&pdev->dev, hw->chipselect[i], NULL)) { |
161b96c3 AS |
202 | dev_err(&pdev->dev, "Can't get CS GPIO %i\n", i); |
203 | ret = -EINVAL; | |
204 | goto err_out; | |
205 | } | |
206 | } | |
207 | ||
208 | hw->spi_clk = devm_clk_get(&pdev->dev, "spi"); | |
209 | if (IS_ERR(hw->spi_clk)) { | |
210 | dev_err(&pdev->dev, "Can't get clocks\n"); | |
211 | ret = PTR_ERR(hw->spi_clk); | |
212 | goto err_out; | |
213 | } | |
214 | hw->max_speed_hz = clk_get_rate(hw->spi_clk); | |
215 | ||
216 | init_completion(&hw->done); | |
217 | platform_set_drvdata(pdev, master); | |
218 | ||
219 | /* Disable extended mode due hardware problems */ | |
220 | clps_writew(clps_readw(SYSCON3) & ~SYSCON3_ADCCON, SYSCON3); | |
221 | ||
222 | /* Clear possible pending interrupt */ | |
223 | clps_readl(SYNCIO); | |
224 | ||
225 | ret = devm_request_irq(&pdev->dev, IRQ_SSEOTI, spi_clps711x_isr, 0, | |
226 | dev_name(&pdev->dev), hw); | |
227 | if (ret) { | |
228 | dev_err(&pdev->dev, "Can't request IRQ\n"); | |
c7083790 | 229 | goto err_out; |
161b96c3 AS |
230 | } |
231 | ||
c493fc4b | 232 | ret = devm_spi_register_master(&pdev->dev, master); |
161b96c3 AS |
233 | if (!ret) { |
234 | dev_info(&pdev->dev, | |
235 | "SPI bus driver initialized. Master clock %u Hz\n", | |
236 | hw->max_speed_hz); | |
237 | return 0; | |
238 | } | |
239 | ||
240 | dev_err(&pdev->dev, "Failed to register master\n"); | |
161b96c3 | 241 | |
161b96c3 | 242 | err_out: |
161b96c3 | 243 | spi_master_put(master); |
161b96c3 AS |
244 | |
245 | return ret; | |
246 | } | |
247 | ||
161b96c3 AS |
248 | static struct platform_driver clps711x_spi_driver = { |
249 | .driver = { | |
250 | .name = DRIVER_NAME, | |
251 | .owner = THIS_MODULE, | |
252 | }, | |
253 | .probe = spi_clps711x_probe, | |
161b96c3 AS |
254 | }; |
255 | module_platform_driver(clps711x_spi_driver); | |
256 | ||
257 | MODULE_LICENSE("GPL"); | |
258 | MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); | |
259 | MODULE_DESCRIPTION("CLPS711X SPI bus driver"); | |
350a9b33 | 260 | MODULE_ALIAS("platform:" DRIVER_NAME); |