1 /* 2 * CLPS711X SPI bus driver 3 * 4 * Copyright (C) 2012-2016 Alexander Shiyan <shc_work@mail.ru> 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/gpio/consumer.h> 15 #include <linux/module.h> 16 #include <linux/interrupt.h> 17 #include <linux/platform_device.h> 18 #include <linux/regmap.h> 19 #include <linux/mfd/syscon.h> 20 #include <linux/mfd/syscon/clps711x.h> 21 #include <linux/spi/spi.h> 22 23 #define DRIVER_NAME "clps711x-spi" 24 25 #define SYNCIO_FRMLEN(x) ((x) << 8) 26 #define SYNCIO_TXFRMEN (1 << 14) 27 28 struct spi_clps711x_data { 29 void __iomem *syncio; 30 struct regmap *syscon; 31 struct clk *spi_clk; 32 33 u8 *tx_buf; 34 u8 *rx_buf; 35 unsigned int bpw; 36 int len; 37 }; 38 39 static int spi_clps711x_prepare_message(struct spi_master *master, 40 struct spi_message *msg) 41 { 42 struct spi_clps711x_data *hw = spi_master_get_devdata(master); 43 struct spi_device *spi = msg->spi; 44 45 /* Setup mode for transfer */ 46 return regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCKNSEN, 47 (spi->mode & SPI_CPHA) ? 48 SYSCON3_ADCCKNSEN : 0); 49 } 50 51 static int spi_clps711x_transfer_one(struct spi_master *master, 52 struct spi_device *spi, 53 struct spi_transfer *xfer) 54 { 55 struct spi_clps711x_data *hw = spi_master_get_devdata(master); 56 u8 data; 57 58 clk_set_rate(hw->spi_clk, xfer->speed_hz ? : spi->max_speed_hz); 59 60 hw->len = xfer->len; 61 hw->bpw = xfer->bits_per_word; 62 hw->tx_buf = (u8 *)xfer->tx_buf; 63 hw->rx_buf = (u8 *)xfer->rx_buf; 64 65 /* Initiate transfer */ 66 data = hw->tx_buf ? *hw->tx_buf++ : 0; 67 writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, hw->syncio); 68 69 return 1; 70 } 71 72 static irqreturn_t spi_clps711x_isr(int irq, void *dev_id) 73 { 74 struct spi_master *master = dev_id; 75 struct spi_clps711x_data *hw = spi_master_get_devdata(master); 76 u8 data; 77 78 /* Handle RX */ 79 data = readb(hw->syncio); 80 if (hw->rx_buf) 81 *hw->rx_buf++ = data; 82 83 /* Handle TX */ 84 if (--hw->len > 0) { 85 data = hw->tx_buf ? *hw->tx_buf++ : 0; 86 writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, 87 hw->syncio); 88 } else 89 spi_finalize_current_transfer(master); 90 91 return IRQ_HANDLED; 92 } 93 94 static int spi_clps711x_probe(struct platform_device *pdev) 95 { 96 struct spi_clps711x_data *hw; 97 struct spi_master *master; 98 struct resource *res; 99 int irq, ret; 100 101 irq = platform_get_irq(pdev, 0); 102 if (irq < 0) 103 return irq; 104 105 master = spi_alloc_master(&pdev->dev, sizeof(*hw)); 106 if (!master) 107 return -ENOMEM; 108 109 master->use_gpio_descriptors = true; 110 master->bus_num = -1; 111 master->mode_bits = SPI_CPHA | SPI_CS_HIGH; 112 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 8); 113 master->dev.of_node = pdev->dev.of_node; 114 master->prepare_message = spi_clps711x_prepare_message; 115 master->transfer_one = spi_clps711x_transfer_one; 116 117 hw = spi_master_get_devdata(master); 118 119 hw->spi_clk = devm_clk_get(&pdev->dev, NULL); 120 if (IS_ERR(hw->spi_clk)) { 121 ret = PTR_ERR(hw->spi_clk); 122 goto err_out; 123 } 124 125 hw->syscon = 126 syscon_regmap_lookup_by_compatible("cirrus,ep7209-syscon3"); 127 if (IS_ERR(hw->syscon)) { 128 ret = PTR_ERR(hw->syscon); 129 goto err_out; 130 } 131 132 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 133 hw->syncio = devm_ioremap_resource(&pdev->dev, res); 134 if (IS_ERR(hw->syncio)) { 135 ret = PTR_ERR(hw->syncio); 136 goto err_out; 137 } 138 139 /* Disable extended mode due hardware problems */ 140 regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, 0); 141 142 /* Clear possible pending interrupt */ 143 readl(hw->syncio); 144 145 ret = devm_request_irq(&pdev->dev, irq, spi_clps711x_isr, 0, 146 dev_name(&pdev->dev), master); 147 if (ret) 148 goto err_out; 149 150 ret = devm_spi_register_master(&pdev->dev, master); 151 if (!ret) 152 return 0; 153 154 err_out: 155 spi_master_put(master); 156 157 return ret; 158 } 159 160 static const struct of_device_id clps711x_spi_dt_ids[] = { 161 { .compatible = "cirrus,ep7209-spi", }, 162 { } 163 }; 164 MODULE_DEVICE_TABLE(of, clps711x_spi_dt_ids); 165 166 static struct platform_driver clps711x_spi_driver = { 167 .driver = { 168 .name = DRIVER_NAME, 169 .of_match_table = clps711x_spi_dt_ids, 170 }, 171 .probe = spi_clps711x_probe, 172 }; 173 module_platform_driver(clps711x_spi_driver); 174 175 MODULE_LICENSE("GPL"); 176 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); 177 MODULE_DESCRIPTION("CLPS711X SPI bus driver"); 178 MODULE_ALIAS("platform:" DRIVER_NAME); 179