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ASoC: wcd-spi: add SPI bus arbitration logic

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On some platforms, WCD SPI bus can be shared with other processors
(ex: sensor processor). In such cases, there is need for software
to arbitrate the bus control. Add functionality to perform SPI bus
arbitration.

Change-Id: I7df933f55ac5035a55173a04e74b74f7af1f7ece
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>
This commit is contained in:
Bhalchandra Gajare
2018-03-19 14:35:42 -07:00
committed by Gerrit - the friendly Code Review server
parent e039f16fa4
commit c5f43a1eec
1 changed files with 92 additions and 0 deletions
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92
asoc/codecs/wcd-spi.c
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@@ -14,8 +14,10 @@
#include <linux/regmap.h>
#include <linux/component.h>
#include <linux/ratelimit.h>
#include <linux/platform_device.h>
#include <sound/wcd-dsp-mgr.h>
#include <sound/wcd-spi.h>
#include <soc/wcd-spi-ac.h>
#include "wcd-spi-registers.h"
/* Byte manipulations */
@@ -157,6 +159,8 @@ struct wcd_spi_priv {
/* DMA handles for transfer buffers */
dma_addr_t tx_dma;
dma_addr_t rx_dma;
/* Handle to child (qmi client) device */
struct device *ac_dev;
};
enum xfer_request {
@@ -567,6 +571,19 @@ static int wcd_spi_clk_enable(struct spi_device *spi)
int ret;
u32 rd_status = 0;
/* Get the SPI access first */
if (wcd_spi->ac_dev) {
ret = wcd_spi_access_ctl(wcd_spi->ac_dev,
WCD_SPI_ACCESS_REQUEST,
WCD_SPI_AC_DATA_TRANSFER);
if (ret) {
dev_err(&spi->dev,
"%s: Can't get spi access, err = %d\n",
__func__, ret);
return ret;
}
}
ret = wcd_spi_cmd_nop(spi);
if (ret < 0) {
dev_err(&spi->dev, "%s: NOP1 failed, err = %d\n",
@@ -620,6 +637,17 @@ static int wcd_spi_clk_disable(struct spi_device *spi)
*/
clear_bit(WCD_SPI_CLK_STATE_ENABLED, &wcd_spi->status_mask);
/* once the clock is released, SPI access can be released as well */
if (wcd_spi->ac_dev) {
ret = wcd_spi_access_ctl(wcd_spi->ac_dev,
WCD_SPI_ACCESS_RELEASE,
WCD_SPI_AC_DATA_TRANSFER);
if (ret)
dev_err(&spi->dev,
"%s: SPI access release failed, err = %d\n",
__func__, ret);
}
return ret;
}
@@ -944,6 +972,18 @@ static int wdsp_spi_event_handler(struct device *dev, void *priv_data,
__func__, event);
switch (event) {
case WDSP_EVENT_PRE_SHUTDOWN:
if (wcd_spi->ac_dev) {
ret = wcd_spi_access_ctl(wcd_spi->ac_dev,
WCD_SPI_ACCESS_REQUEST,
WCD_SPI_AC_REMOTE_DOWN);
if (ret)
dev_err(&spi->dev,
"%s: request access failed %d\n",
__func__, ret);
}
break;
case WDSP_EVENT_POST_SHUTDOWN:
cancel_delayed_work_sync(&wcd_spi->clk_dwork);
WCD_SPI_MUTEX_LOCK(spi, wcd_spi->clk_mutex);
@@ -953,6 +993,18 @@ static int wdsp_spi_event_handler(struct device *dev, void *priv_data,
WCD_SPI_MUTEX_UNLOCK(spi, wcd_spi->clk_mutex);
break;
case WDSP_EVENT_POST_BOOTUP:
if (wcd_spi->ac_dev) {
ret = wcd_spi_access_ctl(wcd_spi->ac_dev,
WCD_SPI_ACCESS_RELEASE,
WCD_SPI_AC_REMOTE_DOWN);
if (ret)
dev_err(&spi->dev,
"%s: release access failed %d\n",
__func__, ret);
}
break;
case WDSP_EVENT_PRE_DLOAD_CODE:
case WDSP_EVENT_PRE_DLOAD_DATA:
ret = wcd_spi_clk_ctrl(spi, WCD_SPI_CLK_ENABLE,
@@ -1299,10 +1351,50 @@ static struct regmap_config wcd_spi_regmap_cfg = {
.readable_reg = wcd_spi_is_readable_reg,
};
static int wcd_spi_add_ac_dev(struct device *dev,
struct device_node *node)
{
struct spi_device *spi = to_spi_device(dev);
struct wcd_spi_priv *wcd_spi = spi_get_drvdata(spi);
struct platform_device *pdev;
int ret = 0;
pdev = platform_device_alloc("wcd-spi-ac", -1);
if (IS_ERR_OR_NULL(pdev)) {
ret = PTR_ERR(pdev);
dev_err(dev, "%s: pdev alloc failed, ret = %d\n",
__func__, ret);
return ret;
}
pdev->dev.parent = dev;
pdev->dev.of_node = node;
ret = platform_device_add(pdev);
if (ret) {
dev_err(dev, "%s: pdev add failed, ret = %d\n",
__func__, ret);
goto dealloc_pdev;
}
wcd_spi->ac_dev = &pdev->dev;
return 0;
dealloc_pdev:
platform_device_put(pdev);
return ret;
}
static int wdsp_spi_init(struct device *dev, void *priv_data)
{
struct spi_device *spi = to_spi_device(dev);
int ret;
struct device_node *node;
for_each_child_of_node(dev->of_node, node) {
if (!strcmp(node->name, "wcd_spi_ac"))
wcd_spi_add_ac_dev(dev, node);
}
ret = wcd_spi_init(spi);
if (ret < 0)