[PATCH v6 3/3] mfd: atmel-flexcom: Add support for lan966x flexcom chip-select configuration

From: Kavyasree Kotagiri
Date: Tue Jul 05 2022 - 02:58:33 EST


LAN966x SoC have 5 flexcoms. Each flexcom has 2 chip-selects
which are optional I/O lines. For each chip select of each
flexcom there is a configuration register FLEXCOM_SHARED[0-4]:SS_MASK[0-1].
The width of configuration register is 21 because there are
21 shared pins on each of which the chip select can be mapped.
Each bit of the register represents a different FLEXCOM_SHARED pin.

Signed-off-by: Kavyasree Kotagiri <kavyasree.kotagiri@xxxxxxxxxxxxx>
Reviewed-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
---
v5 -> v6:
- No changes.

v4 -> v5:
- No changes.

v3 -> v4:
- Add condition for a flexcom whether to configure chip-select lines
or not, based on "microchip,flx-shrd-pins" property existence because
chip-select lines are optional.

v2 -> v3:
- used goto label for clk_disable in error cases.

v1 -> v2:
- use GENMASK for mask, macros for maximum allowed values.
- use u32 values for flexcom chipselects instead of strings.
- disable clock in case of errors.

drivers/mfd/atmel-flexcom.c | 94 ++++++++++++++++++++++++++++++++++++-
1 file changed, 93 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
index 33caa4fba6af..430b6783b5a7 100644
--- a/drivers/mfd/atmel-flexcom.c
+++ b/drivers/mfd/atmel-flexcom.c
@@ -28,15 +28,68 @@
#define FLEX_MR_OPMODE(opmode) (((opmode) << FLEX_MR_OPMODE_OFFSET) & \
FLEX_MR_OPMODE_MASK)

+/* LAN966x flexcom shared register offsets */
+#define FLEX_SHRD_SS_MASK_0 0x0
+#define FLEX_SHRD_SS_MASK_1 0x4
+#define FLEX_SHRD_PIN_MAX 20
+#define FLEX_CS_MAX 1
+#define FLEX_SHRD_MASK GENMASK(20, 0)
+
+struct atmel_flex_caps {
+ bool has_flx_cs;
+};
+
struct atmel_flexcom {
void __iomem *base;
+ void __iomem *flexcom_shared_base;
u32 opmode;
struct clk *clk;
};

+static int atmel_flexcom_lan966x_cs_config(struct platform_device *pdev)
+{
+ struct atmel_flexcom *ddata = dev_get_drvdata(&pdev->dev);
+ struct device_node *np = pdev->dev.of_node;
+ u32 flx_shrd_pins[2], flx_cs[2], val;
+ int err, i, count;
+
+ count = of_property_count_u32_elems(np, "microchip,flx-shrd-pins");
+ if (count <= 0 || count > 2) {
+ dev_err(&pdev->dev, "Invalid %s property (%d)\n", "flx-shrd-pins",
+ count);
+ return -EINVAL;
+ }
+
+ err = of_property_read_u32_array(np, "microchip,flx-shrd-pins", flx_shrd_pins, count);
+ if (err)
+ return err;
+
+ err = of_property_read_u32_array(np, "microchip,flx-cs", flx_cs, count);
+ if (err)
+ return err;
+
+ for (i = 0; i < count; i++) {
+ if (flx_shrd_pins[i] > FLEX_SHRD_PIN_MAX)
+ return -EINVAL;
+
+ if (flx_cs[i] > FLEX_CS_MAX)
+ return -EINVAL;
+
+ val = ~(1 << flx_shrd_pins[i]) & FLEX_SHRD_MASK;
+
+ if (flx_cs[i] == 0)
+ writel(val, ddata->flexcom_shared_base + FLEX_SHRD_SS_MASK_0);
+ else
+ writel(val, ddata->flexcom_shared_base + FLEX_SHRD_SS_MASK_1);
+ }
+
+ return 0;
+}
+
static int atmel_flexcom_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
+ const struct atmel_flex_caps *caps;
struct resource *res;
struct atmel_flexcom *ddata;
int err;
@@ -76,13 +129,52 @@ static int atmel_flexcom_probe(struct platform_device *pdev)
*/
writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR);

+ caps = of_device_get_match_data(&pdev->dev);
+ if (!caps) {
+ dev_err(&pdev->dev, "Could not retrieve flexcom caps\n");
+ err = -EINVAL;
+ goto clk_disable;
+ }
+
+ if (caps->has_flx_cs && of_property_read_bool(np, "microchip,flx-shrd-pins")) {
+ ddata->flexcom_shared_base = devm_platform_get_and_ioremap_resource(pdev, 1, NULL);
+ if (IS_ERR(ddata->flexcom_shared_base)) {
+ err = dev_err_probe(&pdev->dev,
+ PTR_ERR(ddata->flexcom_shared_base),
+ "failed to get flexcom shared base address\n");
+ goto clk_disable;
+ }
+
+ err = atmel_flexcom_lan966x_cs_config(pdev);
+ if (err)
+ goto clk_disable;
+ }
+
+clk_disable:
clk_disable_unprepare(ddata->clk);
+ if (err)
+ return err;

return devm_of_platform_populate(&pdev->dev);
}

+static const struct atmel_flex_caps atmel_flexcom_caps = {};
+
+static const struct atmel_flex_caps lan966x_flexcom_caps = {
+ .has_flx_cs = true,
+};
+
static const struct of_device_id atmel_flexcom_of_match[] = {
- { .compatible = "atmel,sama5d2-flexcom" },
+ {
+ .compatible = "atmel,sama5d2-flexcom",
+ .data = &atmel_flexcom_caps,
+ },
+
+ {
+ .compatible = "microchip,lan966x-flexcom",
+ .data = &lan966x_flexcom_caps,
+ },
+
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);
--
2.25.1