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 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 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 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 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->prepare_message = spi_clps711x_prepare_message; 111 host->transfer_one = spi_clps711x_transfer_one; 112 113 hw = spi_controller_get_devdata(host); 114 115 hw->spi_clk = devm_clk_get(&pdev->dev, NULL); 116 if (IS_ERR(hw->spi_clk)) { 117 ret = PTR_ERR(hw->spi_clk); 118 goto err_out; 119 } 120 121 hw->syscon = syscon_regmap_lookup_by_phandle(np, "syscon"); 122 if (IS_ERR(hw->syscon)) { 123 ret = PTR_ERR(hw->syscon); 124 goto err_out; 125 } 126 127 hw->syncio = devm_platform_ioremap_resource(pdev, 0); 128 if (IS_ERR(hw->syncio)) { 129 ret = PTR_ERR(hw->syncio); 130 goto err_out; 131 } 132 133 /* Disable extended mode due hardware problems */ 134 regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, 0); 135 136 /* Clear possible pending interrupt */ 137 readl(hw->syncio); 138 139 ret = devm_request_irq(&pdev->dev, irq, spi_clps711x_isr, 0, 140 dev_name(&pdev->dev), host); 141 if (ret) 142 goto err_out; 143 144 ret = devm_spi_register_controller(&pdev->dev, host); 145 if (!ret) 146 return 0; 147 148 err_out: 149 spi_controller_put(host); 150 151 return ret; 152 } 153 154 static const struct of_device_id clps711x_spi_dt_ids[] = { 155 { .compatible = "cirrus,ep7209-spi", }, 156 { } 157 }; 158 MODULE_DEVICE_TABLE(of, clps711x_spi_dt_ids); 159 160 static struct platform_driver clps711x_spi_driver = { 161 .driver = { 162 .name = DRIVER_NAME, 163 .of_match_table = clps711x_spi_dt_ids, 164 }, 165 .probe = spi_clps711x_probe, 166 }; 167 module_platform_driver(clps711x_spi_driver); 168 169 MODULE_LICENSE("GPL"); 170 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); 171 MODULE_DESCRIPTION("CLPS711X SPI bus driver"); 172 MODULE_ALIAS("platform:" DRIVER_NAME); 173