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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * CLPS711X SPI bus driver4 *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(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 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(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 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(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 } else86 spi_finalize_current_transfer(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(&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->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(host);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), host);142 if (ret)143 goto err_out;144 145 ret = devm_spi_register_controller(&pdev->dev, host);146 if (!ret)147 return 0;148 149err_out:150 spi_controller_put(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