// SPDX-License-Identifier: GPL-2.0
/*
* i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
*
* Copyright (C) 2011 Weinmann Medical GmbH
* Author: Nikolaus Voss <n.voss@weinmann.de>
*
* Evolved from original work by:
* Copyright (C) 2004 Rick Bronson
* Converted to 2.6 by Andrew Victor <andrew@sanpeople.com>
*
* Borrowed heavily from original work by:
* Copyright (C) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
*/
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/platform_data/dma-atmel.h>
#include <linux/pm_runtime.h>
#include "i2c-at91.h"
void at91_init_twi_bus_master(struct at91_twi_dev *dev)
{
struct at91_twi_pdata *pdata = dev->pdata;
u32 filtr = 0;
/* FIFO should be enabled immediately after the software reset */
if (dev->fifo_size)
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_FIFOEN);
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_MSEN);
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SVDIS);
at91_twi_write(dev, AT91_TWI_CWGR, dev->twi_cwgr_reg);
/* enable digital filter */
if (pdata->has_dig_filtr && dev->enable_dig_filt)
filtr |= AT91_TWI_FILTR_FILT;
/* enable advanced digital filter */
if (pdata->has_adv_dig_filtr && dev->enable_dig_filt)
filtr |= AT91_TWI_FILTR_FILT |
(AT91_TWI_FILTR_THRES(dev->filter_width) &
AT91_TWI_FILTR_THRES_MASK);
/* enable analog filter */
if (pdata->has_ana_filtr && dev->enable_ana_filt)
filtr |= AT91_TWI_FILTR_PADFEN;
if (filtr)
at91_twi_write(dev, AT91_TWI_FILTR, filtr);
}
/*
* Calculate symmetric clock as stated in datasheet:
* twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
*/
static void at91_calc_twi_clock(struct at91_twi_dev *dev)
{
int ckdiv, cdiv, div, hold = 0, filter_width = 0;
struct at91_twi_pdata *pdata = dev->pdata;
int offset = pdata->clk_offset;
int max_ckdiv = pdata->clk_max_div;
struct i2c_timings timings, *t = &timings;
i2c_parse_fw_timings(dev->dev, t, true);
div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
2 * t->bus_freq_hz) - offset);
ckdiv = fls(div >> 8);
cdiv = div >> ckdiv;
if (ckdiv > max_ckdiv) {
dev_warn(dev->dev, "%d exceeds ckdiv max value which is %d.\n",
ckdiv, max_ckdiv);
ckdiv = max_ckdiv;
cdiv = 255;
}
if (pdata->has_hold_field) {
/*
* hold time = HOLD + 3 x T_peripheral_clock
* Use clk rate in kHz to prevent overflows when computing
* hold.
*/
hold = DIV_ROUND_UP(t->sda_hold_ns
* (clk_get_rate(dev->clk) / 1000), 1000000);
hold -= 3;
if (hold < 0)
hold = 0;
if (hold > AT91_TWI_CWGR_HOLD_MAX) {
dev_warn(dev->dev,
"HOLD field set to its maximum value (%d instead of %d)\n",
AT91_TWI_CWGR_HOLD_MAX, hold);
hold = AT91_TWI_CWGR_HOLD_MAX;
}
}
if (pdata->has_adv_dig_filtr) {
/*
* filter width = 0 to AT91_TWI_FILTR_THRES_MAX
* peripheral clocks
*/
filter_width = DIV_ROUND_UP(t->digital_filter_width_ns
* (clk_get_rate(dev->clk) / 1000), 1000000);
if (filter_width > AT91_TWI_FILTR_THRES_MAX) {
dev_warn(dev->dev,
"Filter threshold set to its maximum value (%d instead of %d)\n",
AT91_TWI_FILTR_THRES_MAX, filter_width);
filter_width = AT91_TWI_FILTR_THRES_MAX;
}
}
dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv
| AT91_TWI_CWGR_HOLD(hold);
dev->filter_width = filter_width;
dev_dbg(dev->dev, "cdiv %d ckdiv %d hold %d (%d ns), filter_width %d (%d ns)\n",
cdiv, ckdiv, hold, t->sda_hold_ns, filter_width,
t->digital_filter_width_ns);
}
static void at91_twi_dma_cleanup(struct at91_twi_dev *dev)
{
struct at91_twi_dma *dma = &dev->dma;
at91_twi_irq_save(dev);
if (dma->xfer_in_progress) {
if (dma->direction == DMA_FROM_DEVICE)
dmaengine_terminate_all(dma->chan_rx);
else
dmaengine_terminate_all(dma->chan_tx);
dma->xfer_in_progress = false;
}
if (dma->buf_mapped) {
dma_unmap_single(dev->dev, sg_dma_address(&dma->sg[0]),
dev->buf_len, dma->direction);
dma->buf_mapped = false;
}
at91_twi_irq_restore(dev);
}
static void at91_twi_write_next_byte(struct at91_twi_dev *dev)
{
if (