linux/drivers/spi/spi-meson-spifc.c
Uwe Kleine-König a4f5ad1196
spi: meson-spifc: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20230303172041.2103336-36-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-03-06 12:31:33 +00:00

456 lines
11 KiB
C

// SPDX-License-Identifier: GPL-2.0+
//
// Driver for Amlogic Meson SPI flash controller (SPIFC)
//
// Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
//
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/spi/spi.h>
#include <linux/types.h>
/* register map */
#define REG_CMD 0x00
#define REG_ADDR 0x04
#define REG_CTRL 0x08
#define REG_CTRL1 0x0c
#define REG_STATUS 0x10
#define REG_CTRL2 0x14
#define REG_CLOCK 0x18
#define REG_USER 0x1c
#define REG_USER1 0x20
#define REG_USER2 0x24
#define REG_USER3 0x28
#define REG_USER4 0x2c
#define REG_SLAVE 0x30
#define REG_SLAVE1 0x34
#define REG_SLAVE2 0x38
#define REG_SLAVE3 0x3c
#define REG_C0 0x40
#define REG_B8 0x60
#define REG_MAX 0x7c
/* register fields */
#define CMD_USER BIT(18)
#define CTRL_ENABLE_AHB BIT(17)
#define CLOCK_SOURCE BIT(31)
#define CLOCK_DIV_SHIFT 12
#define CLOCK_DIV_MASK (0x3f << CLOCK_DIV_SHIFT)
#define CLOCK_CNT_HIGH_SHIFT 6
#define CLOCK_CNT_HIGH_MASK (0x3f << CLOCK_CNT_HIGH_SHIFT)
#define CLOCK_CNT_LOW_SHIFT 0
#define CLOCK_CNT_LOW_MASK (0x3f << CLOCK_CNT_LOW_SHIFT)
#define USER_DIN_EN_MS BIT(0)
#define USER_CMP_MODE BIT(2)
#define USER_UC_DOUT_SEL BIT(27)
#define USER_UC_DIN_SEL BIT(28)
#define USER_UC_MASK ((BIT(5) - 1) << 27)
#define USER1_BN_UC_DOUT_SHIFT 17
#define USER1_BN_UC_DOUT_MASK (0xff << 16)
#define USER1_BN_UC_DIN_SHIFT 8
#define USER1_BN_UC_DIN_MASK (0xff << 8)
#define USER4_CS_ACT BIT(30)
#define SLAVE_TRST_DONE BIT(4)
#define SLAVE_OP_MODE BIT(30)
#define SLAVE_SW_RST BIT(31)
#define SPIFC_BUFFER_SIZE 64
/**
* struct meson_spifc
* @master: the SPI master
* @regmap: regmap for device registers
* @clk: input clock of the built-in baud rate generator
* @dev: the device structure
*/
struct meson_spifc {
struct spi_master *master;
struct regmap *regmap;
struct clk *clk;
struct device *dev;
};
static const struct regmap_config spifc_regmap_config = {
.reg_bits = 32,
.val_bits = 32,
.reg_stride = 4,
.max_register = REG_MAX,
};
/**
* meson_spifc_wait_ready() - wait for the current operation to terminate
* @spifc: the Meson SPI device
* Return: 0 on success, a negative value on error
*/
static int meson_spifc_wait_ready(struct meson_spifc *spifc)
{
unsigned long deadline = jiffies + msecs_to_jiffies(5);
u32 data;
do {
regmap_read(spifc->regmap, REG_SLAVE, &data);
if (data & SLAVE_TRST_DONE)
return 0;
cond_resched();
} while (!time_after(jiffies, deadline));
return -ETIMEDOUT;
}
/**
* meson_spifc_drain_buffer() - copy data from device buffer to memory
* @spifc: the Meson SPI device
* @buf: the destination buffer
* @len: number of bytes to copy
*/
static void meson_spifc_drain_buffer(struct meson_spifc *spifc, u8 *buf,
int len)
{
u32 data;
int i = 0;
while (i < len) {
regmap_read(spifc->regmap, REG_C0 + i, &data);
if (len - i >= 4) {
*((u32 *)buf) = data;
buf += 4;
} else {
memcpy(buf, &data, len - i);
break;
}
i += 4;
}
}
/**
* meson_spifc_fill_buffer() - copy data from memory to device buffer
* @spifc: the Meson SPI device
* @buf: the source buffer
* @len: number of bytes to copy
*/
static void meson_spifc_fill_buffer(struct meson_spifc *spifc, const u8 *buf,
int len)
{
u32 data;
int i = 0;
while (i < len) {
if (len - i >= 4)
data = *(u32 *)buf;
else
memcpy(&data, buf, len - i);
regmap_write(spifc->regmap, REG_C0 + i, data);
buf += 4;
i += 4;
}
}
/**
* meson_spifc_setup_speed() - program the clock divider
* @spifc: the Meson SPI device
* @speed: desired speed in Hz
*/
static void meson_spifc_setup_speed(struct meson_spifc *spifc, u32 speed)
{
unsigned long parent, value;
int n;
parent = clk_get_rate(spifc->clk);
n = max_t(int, parent / speed - 1, 1);
dev_dbg(spifc->dev, "parent %lu, speed %u, n %d\n", parent,
speed, n);
value = (n << CLOCK_DIV_SHIFT) & CLOCK_DIV_MASK;
value |= (n << CLOCK_CNT_LOW_SHIFT) & CLOCK_CNT_LOW_MASK;
value |= (((n + 1) / 2 - 1) << CLOCK_CNT_HIGH_SHIFT) &
CLOCK_CNT_HIGH_MASK;
regmap_write(spifc->regmap, REG_CLOCK, value);
}
/**
* meson_spifc_txrx() - transfer a chunk of data
* @spifc: the Meson SPI device
* @xfer: the current SPI transfer
* @offset: offset of the data to transfer
* @len: length of the data to transfer
* @last_xfer: whether this is the last transfer of the message
* @last_chunk: whether this is the last chunk of the transfer
* Return: 0 on success, a negative value on error
*/
static int meson_spifc_txrx(struct meson_spifc *spifc,
struct spi_transfer *xfer,
int offset, int len, bool last_xfer,
bool last_chunk)
{
bool keep_cs = true;
int ret;
if (xfer->tx_buf)
meson_spifc_fill_buffer(spifc, xfer->tx_buf + offset, len);
/* enable DOUT stage */
regmap_update_bits(spifc->regmap, REG_USER, USER_UC_MASK,
USER_UC_DOUT_SEL);
regmap_write(spifc->regmap, REG_USER1,
(8 * len - 1) << USER1_BN_UC_DOUT_SHIFT);
/* enable data input during DOUT */
regmap_update_bits(spifc->regmap, REG_USER, USER_DIN_EN_MS,
USER_DIN_EN_MS);
if (last_chunk) {
if (last_xfer)
keep_cs = xfer->cs_change;
else
keep_cs = !xfer->cs_change;
}
regmap_update_bits(spifc->regmap, REG_USER4, USER4_CS_ACT,
keep_cs ? USER4_CS_ACT : 0);
/* clear transition done bit */
regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_TRST_DONE, 0);
/* start transfer */
regmap_update_bits(spifc->regmap, REG_CMD, CMD_USER, CMD_USER);
ret = meson_spifc_wait_ready(spifc);
if (!ret && xfer->rx_buf)
meson_spifc_drain_buffer(spifc, xfer->rx_buf + offset, len);
return ret;
}
/**
* meson_spifc_transfer_one() - perform a single transfer
* @master: the SPI master
* @spi: the SPI device
* @xfer: the current SPI transfer
* Return: 0 on success, a negative value on error
*/
static int meson_spifc_transfer_one(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *xfer)
{
struct meson_spifc *spifc = spi_master_get_devdata(master);
int len, done = 0, ret = 0;
meson_spifc_setup_speed(spifc, xfer->speed_hz);
regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB, 0);
while (done < xfer->len && !ret) {
len = min_t(int, xfer->len - done, SPIFC_BUFFER_SIZE);
ret = meson_spifc_txrx(spifc, xfer, done, len,
spi_transfer_is_last(master, xfer),
done + len >= xfer->len);
done += len;
}
regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB,
CTRL_ENABLE_AHB);
return ret;
}
/**
* meson_spifc_hw_init() - reset and initialize the SPI controller
* @spifc: the Meson SPI device
*/
static void meson_spifc_hw_init(struct meson_spifc *spifc)
{
/* reset device */
regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_SW_RST,
SLAVE_SW_RST);
/* disable compatible mode */
regmap_update_bits(spifc->regmap, REG_USER, USER_CMP_MODE, 0);
/* set master mode */
regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_OP_MODE, 0);
}
static int meson_spifc_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct meson_spifc *spifc;
void __iomem *base;
unsigned int rate;
int ret = 0;
master = spi_alloc_master(&pdev->dev, sizeof(struct meson_spifc));
if (!master)
return -ENOMEM;
platform_set_drvdata(pdev, master);
spifc = spi_master_get_devdata(master);
spifc->dev = &pdev->dev;
base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(base)) {
ret = PTR_ERR(base);
goto out_err;
}
spifc->regmap = devm_regmap_init_mmio(spifc->dev, base,
&spifc_regmap_config);
if (IS_ERR(spifc->regmap)) {
ret = PTR_ERR(spifc->regmap);
goto out_err;
}
spifc->clk = devm_clk_get(spifc->dev, NULL);
if (IS_ERR(spifc->clk)) {
dev_err(spifc->dev, "missing clock\n");
ret = PTR_ERR(spifc->clk);
goto out_err;
}
ret = clk_prepare_enable(spifc->clk);
if (ret) {
dev_err(spifc->dev, "can't prepare clock\n");
goto out_err;
}
rate = clk_get_rate(spifc->clk);
master->num_chipselect = 1;
master->dev.of_node = pdev->dev.of_node;
master->bits_per_word_mask = SPI_BPW_MASK(8);
master->auto_runtime_pm = true;
master->transfer_one = meson_spifc_transfer_one;
master->min_speed_hz = rate >> 6;
master->max_speed_hz = rate >> 1;
meson_spifc_hw_init(spifc);
pm_runtime_set_active(spifc->dev);
pm_runtime_enable(spifc->dev);
ret = devm_spi_register_master(spifc->dev, master);
if (ret) {
dev_err(spifc->dev, "failed to register spi master\n");
goto out_clk;
}
return 0;
out_clk:
clk_disable_unprepare(spifc->clk);
pm_runtime_disable(spifc->dev);
out_err:
spi_master_put(master);
return ret;
}
static void meson_spifc_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct meson_spifc *spifc = spi_master_get_devdata(master);
pm_runtime_get_sync(&pdev->dev);
clk_disable_unprepare(spifc->clk);
pm_runtime_disable(&pdev->dev);
}
#ifdef CONFIG_PM_SLEEP
static int meson_spifc_suspend(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct meson_spifc *spifc = spi_master_get_devdata(master);
int ret;
ret = spi_master_suspend(master);
if (ret)
return ret;
if (!pm_runtime_suspended(dev))
clk_disable_unprepare(spifc->clk);
return 0;
}
static int meson_spifc_resume(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct meson_spifc *spifc = spi_master_get_devdata(master);
int ret;
if (!pm_runtime_suspended(dev)) {
ret = clk_prepare_enable(spifc->clk);
if (ret)
return ret;
}
meson_spifc_hw_init(spifc);
ret = spi_master_resume(master);
if (ret)
clk_disable_unprepare(spifc->clk);
return ret;
}
#endif /* CONFIG_PM_SLEEP */
#ifdef CONFIG_PM
static int meson_spifc_runtime_suspend(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct meson_spifc *spifc = spi_master_get_devdata(master);
clk_disable_unprepare(spifc->clk);
return 0;
}
static int meson_spifc_runtime_resume(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct meson_spifc *spifc = spi_master_get_devdata(master);
return clk_prepare_enable(spifc->clk);
}
#endif /* CONFIG_PM */
static const struct dev_pm_ops meson_spifc_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(meson_spifc_suspend, meson_spifc_resume)
SET_RUNTIME_PM_OPS(meson_spifc_runtime_suspend,
meson_spifc_runtime_resume,
NULL)
};
static const struct of_device_id meson_spifc_dt_match[] = {
{ .compatible = "amlogic,meson6-spifc", },
{ .compatible = "amlogic,meson-gxbb-spifc", },
{ },
};
MODULE_DEVICE_TABLE(of, meson_spifc_dt_match);
static struct platform_driver meson_spifc_driver = {
.probe = meson_spifc_probe,
.remove_new = meson_spifc_remove,
.driver = {
.name = "meson-spifc",
.of_match_table = of_match_ptr(meson_spifc_dt_match),
.pm = &meson_spifc_pm_ops,
},
};
module_platform_driver(meson_spifc_driver);
MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
MODULE_DESCRIPTION("Amlogic Meson SPIFC driver");
MODULE_LICENSE("GPL v2");