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/*
* CLPS711X SPI bus driver
*
* Copyright (C) 2012-2016 Alexander Shiyan <shc_work@mail.ru>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/mfd/syscon.h>
#include <linux/mfd/syscon/clps711x.h>
#include <linux/spi/spi.h>
#define DRIVER_NAME "clps711x-spi"
#define SYNCIO_FRMLEN(x) ((x) << 8)
#define SYNCIO_TXFRMEN (1 << 14)
struct spi_clps711x_data {
void __iomem *syncio;
struct regmap *syscon;
struct clk *spi_clk;
u8 *tx_buf;
u8 *rx_buf;
unsigned int bpw;
int len;
};
static int spi_clps711x_prepare_message(struct spi_master *master,
struct spi_message *msg)
{
struct spi_clps711x_data *hw = spi_master_get_devdata(master);
struct spi_device *spi = msg->spi;
/* Setup mode for transfer */
return regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCKNSEN,
(spi->mode & SPI_CPHA) ?
SYSCON3_ADCCKNSEN : 0);
}
static int spi_clps711x_transfer_one(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *xfer)
{
struct spi_clps711x_data *hw = spi_master_get_devdata(master);
u8 data;
clk_set_rate(hw->spi_clk, xfer->speed_hz ? : spi->max_speed_hz);
hw->len = xfer->len;
hw->bpw = xfer->bits_per_word;
hw->tx_buf = (u8 *)xfer->tx_buf;
hw->rx_buf = (u8 *)xfer->rx_buf;
/* Initiate transfer */
data = hw->tx_buf ? *hw->tx_buf++ : 0;
writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, hw->syncio);
return 1;
}
static irqreturn_t spi_clps711x_isr(int irq, void *dev_id)
{
struct spi_master *master = dev_id;
struct spi_clps711x_data *hw = spi_master_get_devdata(master);
u8 data;
/* Handle RX */
data = readb(hw->syncio);
if (hw->rx_buf)
*hw->rx_buf++ = data;
/* Handle TX */
if (--hw->len > 0) {
data = hw->tx_buf ? *hw->tx_buf++ : 0;
writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN,
hw->syncio);
} else
spi_finalize_current_transfer(master);
return IRQ_HANDLED;
}
static int spi_clps711x_probe(struct platform_device *pdev)
{
struct spi_clps711x_data *hw;
struct spi_master *master;
struct resource *res;
int irq, ret;
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
master = spi_alloc_master(&pdev->dev, sizeof(*hw));
if (!master)
return -ENOMEM;
master->use_gpio_descriptors = true;
master->bus_num = -1;
master->mode_bits = SPI_CPHA | SPI_CS_HIGH;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 8);
master->dev.of_node = pdev->dev.of_node;
master->prepare_message = spi_clps711x_prepare_message;
master->transfer_one = spi_clps711x_transfer_one;
hw = spi_master_get_devdata(master);
hw->spi_clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(hw->spi_clk)) {
ret = PTR_ERR(hw->spi_clk);
goto err_out;
}
hw->syscon =
syscon_regmap_lookup_by_compatible("cirrus,ep7209-syscon3");
if (IS_ERR(hw->syscon)) {
ret = PTR_ERR(hw->syscon);
goto err_out;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
hw->syncio = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(hw->syncio)) {
ret = PTR_ERR(hw->syncio);
goto err_out;
}
/* Disable extended mode due hardware problems */
regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, 0);
/* Clear possible pending interrupt */
readl(hw->syncio);
ret = devm_request_irq(&pdev->dev, irq, spi_clps711x_isr, 0,
dev_name(&pdev->dev), master);
if (ret)
goto err_out;
ret = devm_spi_register_master(&pdev->dev, master);
if (!ret)
return 0;
err_out:
spi_master_put(master);
return ret;
}
static const struct of_device_id clps711x_spi_dt_ids[] = {
{ .compatible = "cirrus,ep7209-spi", },
{ }
};
MODULE_DEVICE_TABLE(of, clps711x_spi_dt_ids);
static struct platform_driver clps711x_spi_driver = {
.driver = {
.name = DRIVER_NAME,
.of_match_table = clps711x_spi_dt_ids,
},
.probe = spi_clps711x_probe,
};
module_platform_driver(clps711x_spi_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
MODULE_DESCRIPTION("CLPS711X SPI bus driver");
MODULE_ALIAS("platform:" DRIVER_NAME);
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