[PATCH v2] mmc: sdhci_am654: Add sdhci_am654_start_signal_voltage_switch

Judith Mendez
2024-09-13T18:54:12Z

The sdhci_start_signal_voltage_switch function sets
V1P8_SIGNAL_ENA by default after switching to 1v8 signaling.
V1P8_SIGNAL_ENA determines whether to launch cmd/data on neg
edge or pos edge of clock.

Due to some eMMC and SD failures seen across am62x platform,
do not set V1P8_SIGNAL_ENA by default, only enable the bit
for devices that require this bit in order to switch to 1v8
voltage for uhs modes.

Signed-off-by: Judith Mendez <jm@ti.com>
---
Changes since v1:
- Invert quirk logic
- Simplify sdhci_am654_start_signal_voltage_switch() and call
sdhci_start_signal_voltage_switch() when the quirk does not apply
- Simply logic when detecting when quirk should be applied
---
drivers/mmc/host/sdhci_am654.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)

diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c
index 0aa3c40ea6ed8..9ff07aadb2d91 100644
--- a/drivers/mmc/host/sdhci_am654.c
+++ b/drivers/mmc/host/sdhci_am654.c
@@ -155,6 +155,7 @@ struct sdhci_am654_data {
u32 tuning_loop;

#define SDHCI_AM654_QUIRK_FORCE_CDTEST BIT(0)
+#define SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA BIT(1)
};

struct window {
@@ -356,6 +357,29 @@ static void sdhci_j721e_4bit_set_clock(struct sdhci_host *host,
sdhci_set_clock(host, clock);
}

+static int sdhci_am654_start_signal_voltage_switch(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+ struct sdhci_host *host = mmc_priv(mmc);
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct sdhci_am654_data *sdhci_am654 = sdhci_pltfm_priv(pltfm_host);
+ int ret;
+
+ if ((sdhci_am654->quirks & SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA) &&
+ ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
+ if (!IS_ERR(mmc->supply.vqmmc)) {
+ ret = mmc_regulator_set_vqmmc(mmc, ios);
+ if (ret < 0) {
+ pr_err("%s: Switching to 1.8V signalling voltage failed,\n",
+ mmc_hostname(mmc));
+ return -EIO;
+ }
+ }
+ return 0;
+ }
+
+ return sdhci_start_signal_voltage_switch(mmc, ios);
+}
+
static u8 sdhci_am654_write_power_on(struct sdhci_host *host, u8 val, int reg)
{
writeb(val, host->ioaddr + reg);
@@ -844,6 +868,11 @@ static int sdhci_am654_get_of_property(struct platform_device *pdev,
if (device_property_read_bool(dev, "ti,fails-without-test-cd"))
sdhci_am654->quirks |= SDHCI_AM654_QUIRK_FORCE_CDTEST;

+ /* Suppress v1p8 ena for eMMC and SD with vqmmc supply */
+ if (!!of_parse_phandle(dev->of_node, "vmmc-supply", 0) ==
+ !!of_parse_phandle(dev->of_node, "vqmmc-supply", 0))
+ sdhci_am654->quirks |= SDHCI_AM654_QUIRK_SUPPRESS_V1P8_ENA;
+
sdhci_get_of_property(pdev);

return 0;
@@ -940,6 +969,7 @@ static int sdhci_am654_probe(struct platform_device *pdev)
goto err_pltfm_free;
}

+ host->mmc_host_ops.start_signal_voltage_switch = sdhci_am654_start_signal_voltage_switch;
host->mmc_host_ops.execute_tuning = sdhci_am654_execute_tuning;

pm_runtime_get_noresume(dev);

base-commit: cf6444ba528f043398b112ac36e041a4d8685cb1
--
2.46.0